hba.c

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/*-------------------------------------------------------------------------
 *
 * hba.c
 *    Routines to handle host based authentication (that's the scheme
 *    wherein you authenticate a user by seeing what IP address the system
 *    says he comes from and choosing authentication method based on it).
 *
 * Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *    src/backend/libpq/hba.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include <ctype.h>
#include <pwd.h>
#include <fcntl.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>

#include "access/htup_details.h"
#include "catalog/pg_collation.h"
#include "catalog/pg_type.h"
#include "common/ip.h"
#include "funcapi.h"
#include "libpq/ifaddr.h"
#include "libpq/libpq.h"
#include "miscadmin.h"
#include "postmaster/postmaster.h"
#include "regex/regex.h"
#include "replication/walsender.h"
#include "storage/fd.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/varlena.h"
#include "utils/guc.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"

#ifdef USE_LDAP
#ifdef WIN32
#include <winldap.h>
#else
#include <ldap.h>
#endif
#endif


#define MAX_TOKEN   256
#define MAX_LINE    8192

/* callback data for check_network_callback */
typedef struct check_network_data
{
    IPCompareMethod method;     /* test method */
    SockAddr   *raddr;          /* client's actual address */
    bool        result;         /* set to true if match */
} check_network_data;


#define token_is_keyword(t, k)  (!t->quoted && strcmp(t->string, k) == 0)
#define token_matches(t, k)  (strcmp(t->string, k) == 0)

/*
 * A single string token lexed from a config file, together with whether
 * the token had been quoted.
 */
typedef struct HbaToken
{
    char       *string;
    bool        quoted;
} HbaToken;

/*
 * TokenizedLine represents one line lexed from a config file.
 * Each item in the "fields" list is a sub-list of HbaTokens.
 * We don't emit a TokenizedLine for empty or all-comment lines,
 * so "fields" is never NIL (nor are any of its sub-lists).
 * Exception: if an error occurs during tokenization, we might
 * have fields == NIL, in which case err_msg != NULL.
 */
typedef struct TokenizedLine
{
    List       *fields;         /* List of lists of HbaTokens */
    int         line_num;       /* Line number */
    char       *raw_line;       /* Raw line text */
    char       *err_msg;        /* Error message if any */
} TokenizedLine;

/*
 * pre-parsed content of HBA config file: list of HbaLine structs.
 * parsed_hba_context is the memory context where it lives.
 */
static List *parsed_hba_lines = NIL;
static MemoryContext parsed_hba_context = NULL;

/*
 * pre-parsed content of ident mapping file: list of IdentLine structs.
 * parsed_ident_context is the memory context where it lives.
 *
 * NOTE: the IdentLine structs can contain pre-compiled regular expressions
 * that live outside the memory context. Before destroying or resetting the
 * memory context, they need to be explicitly free'd.
 */
static List *parsed_ident_lines = NIL;
static MemoryContext parsed_ident_context = NULL;

/*
 * The following character array represents the names of the authentication
 * methods that are supported by PostgreSQL.
 *
 * Note: keep this in sync with the UserAuth enum in hba.h.
 */
static const char *const UserAuthName[] =
{
    "reject",
    "implicit reject",          /* Not a user-visible option */
    "trust",
    "ident",
    "password",
    "md5",
    "scram-sha-256",
    "gss",
    "sspi",
    "pam",
    "bsd",
    "ldap",
    "cert",
    "radius",
    "peer"
};


static MemoryContext tokenize_file(const char *filename, FILE *file,
              List **tok_lines, int elevel);
static List *tokenize_inc_file(List *tokens, const char *outer_filename,
                  const char *inc_filename, int elevel, char **err_msg);
static bool parse_hba_auth_opt(char *name, char *val, HbaLine *hbaline,
                   int elevel, char **err_msg);
static bool verify_option_list_length(List *options, const char *optionname,
                          List *masters, const char *mastername, int line_num);
static ArrayType *gethba_options(HbaLine *hba);
static void fill_hba_line(Tuplestorestate *tuple_store, TupleDesc tupdesc,
              int lineno, HbaLine *hba, const char *err_msg);
static void fill_hba_view(Tuplestorestate *tuple_store, TupleDesc tupdesc);


/*
 * isblank() exists in the ISO C99 spec, but it's not very portable yet,
 * so provide our own version.
 */
bool
pg_isblank(const char c)
{
    return c == ' ' || c == '\t' || c == '\r';
}


/*
 * Grab one token out of the string pointed to by *lineptr.
 *
 * Tokens are strings of non-blank
 * characters bounded by blank characters, commas, beginning of line, and
 * end of line. Blank means space or tab. Tokens can be delimited by
 * double quotes (this allows the inclusion of blanks, but not newlines).
 * Comments (started by an unquoted '#') are skipped.
 *
 * The token, if any, is returned at *buf (a buffer of size bufsz), and
 * *lineptr is advanced past the token.
 *
 * Also, we set *initial_quote to indicate whether there was quoting before
 * the first character.  (We use that to prevent "@x" from being treated
 * as a file inclusion request.  Note that @"x" should be so treated;
 * we want to allow that to support embedded spaces in file paths.)
 *
 * We set *terminating_comma to indicate whether the token is terminated by a
 * comma (which is not returned).
 *
 * In event of an error, log a message at ereport level elevel, and also
 * set *err_msg to a string describing the error.  Currently the only
 * possible error is token too long for buf.
 *
 * If successful: store null-terminated token at *buf and return true.
 * If no more tokens on line: set *buf = '\0' and return false.
 * If error: fill buf with truncated or misformatted token and return false.
 */
static bool
next_token(char **lineptr, char *buf, int bufsz,
           bool *initial_quote, bool *terminating_comma,
           int elevel, char **err_msg)
{
    int         c;
    char       *start_buf = buf;
    char       *end_buf = buf + (bufsz - 1);
    bool        in_quote = false;
    bool        was_quote = false;
    bool        saw_quote = false;

    Assert(end_buf > start_buf);

    *initial_quote = false;
    *terminating_comma = false;

    /* Move over any whitespace and commas preceding the next token */
    while ((c = (*(*lineptr)++)) != '\0' && (pg_isblank(c) || c == ','))
        ;

    /*
     * Build a token in buf of next characters up to EOL, unquoted comma, or
     * unquoted whitespace.
     */
    while (c != '\0' &&
           (!pg_isblank(c) || in_quote))
    {
        /* skip comments to EOL */
        if (c == '#' && !in_quote)
        {
            while ((c = (*(*lineptr)++)) != '\0')
                ;
            break;
        }

        if (buf >= end_buf)
        {
            *buf = '\0';
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("authentication file token too long, skipping: \"%s\"",
                            start_buf)));
            *err_msg = "authentication file token too long";
            /* Discard remainder of line */
            while ((c = (*(*lineptr)++)) != '\0')
                ;
            /* Un-eat the '\0', in case we're called again */
            (*lineptr)--;
            return false;
        }

        /* we do not pass back a terminating comma in the token */
        if (c == ',' && !in_quote)
        {
            *terminating_comma = true;
            break;
        }

        if (c != '"' || was_quote)
            *buf++ = c;

        /* Literal double-quote is two double-quotes */
        if (in_quote && c == '"')
            was_quote = !was_quote;
        else
            was_quote = false;

        if (c == '"')
        {
            in_quote = !in_quote;
            saw_quote = true;
            if (buf == start_buf)
                *initial_quote = true;
        }

        c = *(*lineptr)++;
    }

    /*
     * Un-eat the char right after the token (critical in case it is '\0',
     * else next call will read past end of string).
     */
    (*lineptr)--;

    *buf = '\0';

    return (saw_quote || buf > start_buf);
}

/*
 * Construct a palloc'd HbaToken struct, copying the given string.
 */
static HbaToken *
make_hba_token(const char *token, bool quoted)
{
    HbaToken   *hbatoken;
    int         toklen;

    toklen = strlen(token);
    /* we copy string into same palloc block as the struct */
    hbatoken = (HbaToken *) palloc(sizeof(HbaToken) + toklen + 1);
    hbatoken->string = (char *) hbatoken + sizeof(HbaToken);
    hbatoken->quoted = quoted;
    memcpy(hbatoken->string, token, toklen + 1);

    return hbatoken;
}

/*
 * Copy a HbaToken struct into freshly palloc'd memory.
 */
static HbaToken *
copy_hba_token(HbaToken *in)
{
    HbaToken   *out = make_hba_token(in->string, in->quoted);

    return out;
}


/*
 * Tokenize one HBA field from a line, handling file inclusion and comma lists.
 *
 * filename: current file's pathname (needed to resolve relative pathnames)
 * *lineptr: current line pointer, which will be advanced past field
 *
 * In event of an error, log a message at ereport level elevel, and also
 * set *err_msg to a string describing the error.  Note that the result
 * may be non-NIL anyway, so *err_msg must be tested to determine whether
 * there was an error.
 *
 * The result is a List of HbaToken structs, one for each token in the field,
 * or NIL if we reached EOL.
 */
static List *
next_field_expand(const char *filename, char **lineptr,
                  int elevel, char **err_msg)
{
    char        buf[MAX_TOKEN];
    bool        trailing_comma;
    bool        initial_quote;
    List       *tokens = NIL;

    do
    {
        if (!next_token(lineptr, buf, sizeof(buf),
                        &initial_quote, &trailing_comma,
                        elevel, err_msg))
            break;

        /* Is this referencing a file? */
        if (!initial_quote && buf[0] == '@' && buf[1] != '\0')
            tokens = tokenize_inc_file(tokens, filename, buf + 1,
                                       elevel, err_msg);
        else
            tokens = lappend(tokens, make_hba_token(buf, initial_quote));
    } while (trailing_comma && (*err_msg == NULL));

    return tokens;
}

/*
 * tokenize_inc_file
 *      Expand a file included from another file into an hba "field"
 *
 * Opens and tokenises a file included from another HBA config file with @,
 * and returns all values found therein as a flat list of HbaTokens.  If a
 * @-token is found, recursively expand it.  The newly read tokens are
 * appended to "tokens" (so that foo,bar,@baz does what you expect).
 * All new tokens are allocated in caller's memory context.
 *
 * In event of an error, log a message at ereport level elevel, and also
 * set *err_msg to a string describing the error.  Note that the result
 * may be non-NIL anyway, so *err_msg must be tested to determine whether
 * there was an error.
 */
static List *
tokenize_inc_file(List *tokens,
                  const char *outer_filename,
                  const char *inc_filename,
                  int elevel,
                  char **err_msg)
{
    char       *inc_fullname;
    FILE       *inc_file;
    List       *inc_lines;
    ListCell   *inc_line;
    MemoryContext linecxt;

    if (is_absolute_path(inc_filename))
    {
        /* absolute path is taken as-is */
        inc_fullname = pstrdup(inc_filename);
    }
    else
    {
        /* relative path is relative to dir of calling file */
        inc_fullname = (char *) palloc(strlen(outer_filename) + 1 +
                                       strlen(inc_filename) + 1);
        strcpy(inc_fullname, outer_filename);
        get_parent_directory(inc_fullname);
        join_path_components(inc_fullname, inc_fullname, inc_filename);
        canonicalize_path(inc_fullname);
    }

    inc_file = AllocateFile(inc_fullname, "r");
    if (inc_file == NULL)
    {
        int         save_errno = errno;

        ereport(elevel,
                (errcode_for_file_access(),
                 errmsg("could not open secondary authentication file \"@%s\" as \"%s\": %m",
                        inc_filename, inc_fullname)));
        *err_msg = psprintf("could not open secondary authentication file \"@%s\" as \"%s\": %s",
                            inc_filename, inc_fullname, strerror(save_errno));
        pfree(inc_fullname);
        return tokens;
    }

    /* There is possible recursion here if the file contains @ */
    linecxt = tokenize_file(inc_fullname, inc_file, &inc_lines, elevel);

    FreeFile(inc_file);
    pfree(inc_fullname);

    /* Copy all tokens found in the file and append to the tokens list */
    foreach(inc_line, inc_lines)
    {
        TokenizedLine *tok_line = (TokenizedLine *) lfirst(inc_line);
        ListCell   *inc_field;

        /* If any line has an error, propagate that up to caller */
        if (tok_line->err_msg)
        {
            *err_msg = pstrdup(tok_line->err_msg);
            break;
        }

        foreach(inc_field, tok_line->fields)
        {
            List       *inc_tokens = lfirst(inc_field);
            ListCell   *inc_token;

            foreach(inc_token, inc_tokens)
            {
                HbaToken   *token = lfirst(inc_token);

                tokens = lappend(tokens, copy_hba_token(token));
            }
        }
    }

    MemoryContextDelete(linecxt);
    return tokens;
}

/*
 * Tokenize the given file.
 *
 * The output is a list of TokenizedLine structs; see struct definition above.
 *
 * filename: the absolute path to the target file
 * file: the already-opened target file
 * tok_lines: receives output list
 * elevel: message logging level
 *
 * Errors are reported by logging messages at ereport level elevel and by
 * adding TokenizedLine structs containing non-null err_msg fields to the
 * output list.
 *
 * Return value is a memory context which contains all memory allocated by
 * this function (it's a child of caller's context).
 */
static MemoryContext
tokenize_file(const char *filename, FILE *file, List **tok_lines, int elevel)
{
    int         line_number = 1;
    MemoryContext linecxt;
    MemoryContext oldcxt;

    linecxt = AllocSetContextCreate(CurrentMemoryContext,
                                    "tokenize_file",
                                    ALLOCSET_SMALL_SIZES);
    oldcxt = MemoryContextSwitchTo(linecxt);

    *tok_lines = NIL;

    while (!feof(file) && !ferror(file))
    {
        char        rawline[MAX_LINE];
        char       *lineptr;
        List       *current_line = NIL;
        char       *err_msg = NULL;

        if (!fgets(rawline, sizeof(rawline), file))
        {
            int         save_errno = errno;

            if (!ferror(file))
                break;          /* normal EOF */
            /* I/O error! */
            ereport(elevel,
                    (errcode_for_file_access(),
                     errmsg("could not read file \"%s\": %m", filename)));
            err_msg = psprintf("could not read file \"%s\": %s",
                               filename, strerror(save_errno));
            rawline[0] = '\0';
        }
        if (strlen(rawline) == MAX_LINE - 1)
        {
            /* Line too long! */
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("authentication file line too long"),
                     errcontext("line %d of configuration file \"%s\"",
                                line_number, filename)));
            err_msg = "authentication file line too long";
        }

        /* Strip trailing linebreak from rawline */
        lineptr = rawline + strlen(rawline) - 1;
        while (lineptr >= rawline && (*lineptr == '\n' || *lineptr == '\r'))
            *lineptr-- = '\0';

        /* Parse fields */
        lineptr = rawline;
        while (*lineptr && err_msg == NULL)
        {
            List       *current_field;

            current_field = next_field_expand(filename, &lineptr,
                                              elevel, &err_msg);
            /* add field to line, unless we are at EOL or comment start */
            if (current_field != NIL)
                current_line = lappend(current_line, current_field);
        }

        /* Reached EOL; emit line to TokenizedLine list unless it's boring */
        if (current_line != NIL || err_msg != NULL)
        {
            TokenizedLine *tok_line;

            tok_line = (TokenizedLine *) palloc(sizeof(TokenizedLine));
            tok_line->fields = current_line;
            tok_line->line_num = line_number;
            tok_line->raw_line = pstrdup(rawline);
            tok_line->err_msg = err_msg;
            *tok_lines = lappend(*tok_lines, tok_line);
        }

        line_number++;
    }

    MemoryContextSwitchTo(oldcxt);

    return linecxt;
}


/*
 * Does user belong to role?
 *
 * userid is the OID of the role given as the attempted login identifier.
 * We check to see if it is a member of the specified role name.
 */
static bool
is_member(Oid userid, const char *role)
{
    Oid         roleid;

    if (!OidIsValid(userid))
        return false;           /* if user not exist, say "no" */

    roleid = get_role_oid(role, true);

    if (!OidIsValid(roleid))
        return false;           /* if target role not exist, say "no" */

    /*
     * See if user is directly or indirectly a member of role. For this
     * purpose, a superuser is not considered to be automatically a member of
     * the role, so group auth only applies to explicit membership.
     */
    return is_member_of_role_nosuper(userid, roleid);
}

/*
 * Check HbaToken list for a match to role, allowing group names.
 */
static bool
check_role(const char *role, Oid roleid, List *tokens)
{
    ListCell   *cell;
    HbaToken   *tok;

    foreach(cell, tokens)
    {
        tok = lfirst(cell);
        if (!tok->quoted && tok->string[0] == '+')
        {
            if (is_member(roleid, tok->string + 1))
                return true;
        }
        else if (token_matches(tok, role) ||
                 token_is_keyword(tok, "all"))
            return true;
    }
    return false;
}

/*
 * Check to see if db/role combination matches HbaToken list.
 */
static bool
check_db(const char *dbname, const char *role, Oid roleid, List *tokens)
{
    ListCell   *cell;
    HbaToken   *tok;

    foreach(cell, tokens)
    {
        tok = lfirst(cell);
        if (am_walsender && !am_db_walsender)
        {
            /*
             * physical replication walsender connections can only match
             * replication keyword
             */
            if (token_is_keyword(tok, "replication"))
                return true;
        }
        else if (token_is_keyword(tok, "all"))
            return true;
        else if (token_is_keyword(tok, "sameuser"))
        {
            if (strcmp(dbname, role) == 0)
                return true;
        }
        else if (token_is_keyword(tok, "samegroup") ||
                 token_is_keyword(tok, "samerole"))
        {
            if (is_member(roleid, dbname))
                return true;
        }
        else if (token_is_keyword(tok, "replication"))
            continue;           /* never match this if not walsender */
        else if (token_matches(tok, dbname))
            return true;
    }
    return false;
}

static bool
ipv4eq(struct sockaddr_in *a, struct sockaddr_in *b)
{
    return (a->sin_addr.s_addr == b->sin_addr.s_addr);
}

#ifdef HAVE_IPV6

static bool
ipv6eq(struct sockaddr_in6 *a, struct sockaddr_in6 *b)
{
    int         i;

    for (i = 0; i < 16; i++)
        if (a->sin6_addr.s6_addr[i] != b->sin6_addr.s6_addr[i])
            return false;

    return true;
}
#endif                          /* HAVE_IPV6 */

/*
 * Check whether host name matches pattern.
 */
static bool
hostname_match(const char *pattern, const char *actual_hostname)
{
    if (pattern[0] == '.')      /* suffix match */
    {
        size_t      plen = strlen(pattern);
        size_t      hlen = strlen(actual_hostname);

        if (hlen < plen)
            return false;

        return (pg_strcasecmp(pattern, actual_hostname + (hlen - plen)) == 0);
    }
    else
        return (pg_strcasecmp(pattern, actual_hostname) == 0);
}

/*
 * Check to see if a connecting IP matches a given host name.
 */
static bool
check_hostname(hbaPort *port, const char *hostname)
{
    struct addrinfo *gai_result,
               *gai;
    int         ret;
    bool        found;

    /* Quick out if remote host name already known bad */
    if (port->remote_hostname_resolv < 0)
        return false;

    /* Lookup remote host name if not already done */
    if (!port->remote_hostname)
    {
        char        remote_hostname[NI_MAXHOST];

        ret = pg_getnameinfo_all(&port->raddr.addr, port->raddr.salen,
                                 remote_hostname, sizeof(remote_hostname),
                                 NULL, 0,
                                 NI_NAMEREQD);
        if (ret != 0)
        {
            /* remember failure; don't complain in the postmaster log yet */
            port->remote_hostname_resolv = -2;
            port->remote_hostname_errcode = ret;
            return false;
        }

        port->remote_hostname = pstrdup(remote_hostname);
    }

    /* Now see if remote host name matches this pg_hba line */
    if (!hostname_match(hostname, port->remote_hostname))
        return false;

    /* If we already verified the forward lookup, we're done */
    if (port->remote_hostname_resolv == +1)
        return true;

    /* Lookup IP from host name and check against original IP */
    ret = getaddrinfo(port->remote_hostname, NULL, NULL, &gai_result);
    if (ret != 0)
    {
        /* remember failure; don't complain in the postmaster log yet */
        port->remote_hostname_resolv = -2;
        port->remote_hostname_errcode = ret;
        return false;
    }

    found = false;
    for (gai = gai_result; gai; gai = gai->ai_next)
    {
        if (gai->ai_addr->sa_family == port->raddr.addr.ss_family)
        {
            if (gai->ai_addr->sa_family == AF_INET)
            {
                if (ipv4eq((struct sockaddr_in *) gai->ai_addr,
                           (struct sockaddr_in *) &port->raddr.addr))
                {
                    found = true;
                    break;
                }
            }
#ifdef HAVE_IPV6
            else if (gai->ai_addr->sa_family == AF_INET6)
            {
                if (ipv6eq((struct sockaddr_in6 *) gai->ai_addr,
                           (struct sockaddr_in6 *) &port->raddr.addr))
                {
                    found = true;
                    break;
                }
            }
#endif
        }
    }

    if (gai_result)
        freeaddrinfo(gai_result);

    if (!found)
        elog(DEBUG2, "pg_hba.conf host name \"%s\" rejected because address resolution did not return a match with IP address of client",
             hostname);

    port->remote_hostname_resolv = found ? +1 : -1;

    return found;
}

/*
 * Check to see if a connecting IP matches the given address and netmask.
 */
static bool
check_ip(SockAddr *raddr, struct sockaddr *addr, struct sockaddr *mask)
{
    if (raddr->addr.ss_family == addr->sa_family &&
        pg_range_sockaddr(&raddr->addr,
                          (struct sockaddr_storage *) addr,
                          (struct sockaddr_storage *) mask))
        return true;
    return false;
}

/*
 * pg_foreach_ifaddr callback: does client addr match this machine interface?
 */
static void
check_network_callback(struct sockaddr *addr, struct sockaddr *netmask,
                       void *cb_data)
{
    check_network_data *cn = (check_network_data *) cb_data;
    struct sockaddr_storage mask;

    /* Already found a match? */
    if (cn->result)
        return;

    if (cn->method == ipCmpSameHost)
    {
        /* Make an all-ones netmask of appropriate length for family */
        pg_sockaddr_cidr_mask(&mask, NULL, addr->sa_family);
        cn->result = check_ip(cn->raddr, addr, (struct sockaddr *) &mask);
    }
    else
    {
        /* Use the netmask of the interface itself */
        cn->result = check_ip(cn->raddr, addr, netmask);
    }
}

/*
 * Use pg_foreach_ifaddr to check a samehost or samenet match
 */
static bool
check_same_host_or_net(SockAddr *raddr, IPCompareMethod method)
{
    check_network_data cn;

    cn.method = method;
    cn.raddr = raddr;
    cn.result = false;

    errno = 0;
    if (pg_foreach_ifaddr(check_network_callback, &cn) < 0)
    {
        elog(LOG, "error enumerating network interfaces: %m");
        return false;
    }

    return cn.result;
}


/*
 * Macros used to check and report on invalid configuration options.
 * On error: log a message at level elevel, set *err_msg, and exit the function.
 * These macros are not as general-purpose as they look, because they know
 * what the calling function's error-exit value is.
 *
 * INVALID_AUTH_OPTION = reports when an option is specified for a method where it's
 *                       not supported.
 * REQUIRE_AUTH_OPTION = same as INVALID_AUTH_OPTION, except it also checks if the
 *                       method is actually the one specified. Used as a shortcut when
 *                       the option is only valid for one authentication method.
 * MANDATORY_AUTH_ARG  = check if a required option is set for an authentication method,
 *                       reporting error if it's not.
 */
#define INVALID_AUTH_OPTION(optname, validmethods) \
do { \
    ereport(elevel, \
            (errcode(ERRCODE_CONFIG_FILE_ERROR), \
             /* translator: the second %s is a list of auth methods */ \
             errmsg("authentication option \"%s\" is only valid for authentication methods %s", \
                    optname, _(validmethods)), \
             errcontext("line %d of configuration file \"%s\"", \
                    line_num, HbaFileName))); \
    *err_msg = psprintf("authentication option \"%s\" is only valid for authentication methods %s", \
                        optname, validmethods); \
    return false; \
} while (0)

#define REQUIRE_AUTH_OPTION(methodval, optname, validmethods) \
do { \
    if (hbaline->auth_method != methodval) \
        INVALID_AUTH_OPTION(optname, validmethods); \
} while (0)

#define MANDATORY_AUTH_ARG(argvar, argname, authname) \
do { \
    if (argvar == NULL) { \
        ereport(elevel, \
                (errcode(ERRCODE_CONFIG_FILE_ERROR), \
                 errmsg("authentication method \"%s\" requires argument \"%s\" to be set", \
                        authname, argname), \
                 errcontext("line %d of configuration file \"%s\"", \
                        line_num, HbaFileName))); \
        *err_msg = psprintf("authentication method \"%s\" requires argument \"%s\" to be set", \
                            authname, argname); \
        return NULL; \
    } \
} while (0)

/*
 * Macros for handling pg_ident problems.
 * Much as above, but currently the message level is hardwired as LOG
 * and there is no provision for an err_msg string.
 *
 * IDENT_FIELD_ABSENT:
 * Log a message and exit the function if the given ident field ListCell is
 * not populated.
 *
 * IDENT_MULTI_VALUE:
 * Log a message and exit the function if the given ident token List has more
 * than one element.
 */
#define IDENT_FIELD_ABSENT(field) \
do { \
    if (!field) { \
        ereport(LOG, \
                (errcode(ERRCODE_CONFIG_FILE_ERROR), \
                 errmsg("missing entry in file \"%s\" at end of line %d", \
                        IdentFileName, line_num))); \
        return NULL; \
    } \
} while (0)

#define IDENT_MULTI_VALUE(tokens) \
do { \
    if (tokens->length > 1) { \
        ereport(LOG, \
                (errcode(ERRCODE_CONFIG_FILE_ERROR), \
                 errmsg("multiple values in ident field"), \
                 errcontext("line %d of configuration file \"%s\"", \
                            line_num, IdentFileName))); \
        return NULL; \
    } \
} while (0)


/*
 * Parse one tokenised line from the hba config file and store the result in a
 * HbaLine structure.
 *
 * If parsing fails, log a message at ereport level elevel, store an error
 * string in tok_line->err_msg, and return NULL.  (Some non-error conditions
 * can also result in such messages.)
 *
 * Note: this function leaks memory when an error occurs.  Caller is expected
 * to have set a memory context that will be reset if this function returns
 * NULL.
 */
static HbaLine *
parse_hba_line(TokenizedLine *tok_line, int elevel)
{
    int         line_num = tok_line->line_num;
    char      **err_msg = &tok_line->err_msg;
    char       *str;
    struct addrinfo *gai_result;
    struct addrinfo hints;
    int         ret;
    char       *cidr_slash;
    char       *unsupauth;
    ListCell   *field;
    List       *tokens;
    ListCell   *tokencell;
    HbaToken   *token;
    HbaLine    *parsedline;

    parsedline = palloc0(sizeof(HbaLine));
    parsedline->linenumber = line_num;
    parsedline->rawline = pstrdup(tok_line->raw_line);

    /* Check the record type. */
    Assert(tok_line->fields != NIL);
    field = list_head(tok_line->fields);
    tokens = lfirst(field);
    if (tokens->length > 1)
    {
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("multiple values specified for connection type"),
                 errhint("Specify exactly one connection type per line."),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, HbaFileName)));
        *err_msg = "multiple values specified for connection type";
        return NULL;
    }
    token = linitial(tokens);
    if (strcmp(token->string, "local") == 0)
    {
#ifdef HAVE_UNIX_SOCKETS
        parsedline->conntype = ctLocal;
#else
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("local connections are not supported by this build"),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, HbaFileName)));
        *err_msg = "local connections are not supported by this build";
        return NULL;
#endif
    }
    else if (strcmp(token->string, "host") == 0 ||
             strcmp(token->string, "hostssl") == 0 ||
             strcmp(token->string, "hostnossl") == 0)
    {

        if (token->string[4] == 's')    /* "hostssl" */
        {
            parsedline->conntype = ctHostSSL;
            /* Log a warning if SSL support is not active */
#ifdef USE_SSL
            if (!EnableSSL)
            {
                ereport(elevel,
                        (errcode(ERRCODE_CONFIG_FILE_ERROR),
                         errmsg("hostssl record cannot match because SSL is disabled"),
                         errhint("Set ssl = on in postgresql.conf."),
                         errcontext("line %d of configuration file \"%s\"",
                                    line_num, HbaFileName)));
                *err_msg = "hostssl record cannot match because SSL is disabled";
            }
#else
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("hostssl record cannot match because SSL is not supported by this build"),
                     errhint("Compile with --with-openssl to use SSL connections."),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, HbaFileName)));
            *err_msg = "hostssl record cannot match because SSL is not supported by this build";
#endif
        }
        else if (token->string[4] == 'n')   /* "hostnossl" */
        {
            parsedline->conntype = ctHostNoSSL;
        }
        else
        {
            /* "host" */
            parsedline->conntype = ctHost;
        }
    }                           /* record type */
    else
    {
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("invalid connection type \"%s\"",
                        token->string),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, HbaFileName)));
        *err_msg = psprintf("invalid connection type \"%s\"", token->string);
        return NULL;
    }

    /* Get the databases. */
    field = lnext(field);
    if (!field)
    {
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("end-of-line before database specification"),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, HbaFileName)));
        *err_msg = "end-of-line before database specification";
        return NULL;
    }
    parsedline->databases = NIL;
    tokens = lfirst(field);
    foreach(tokencell, tokens)
    {
        parsedline->databases = lappend(parsedline->databases,
                                        copy_hba_token(lfirst(tokencell)));
    }

    /* Get the roles. */
    field = lnext(field);
    if (!field)
    {
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("end-of-line before role specification"),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, HbaFileName)));
        *err_msg = "end-of-line before role specification";
        return NULL;
    }
    parsedline->roles = NIL;
    tokens = lfirst(field);
    foreach(tokencell, tokens)
    {
        parsedline->roles = lappend(parsedline->roles,
                                    copy_hba_token(lfirst(tokencell)));
    }

    if (parsedline->conntype != ctLocal)
    {
        /* Read the IP address field. (with or without CIDR netmask) */
        field = lnext(field);
        if (!field)
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("end-of-line before IP address specification"),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, HbaFileName)));
            *err_msg = "end-of-line before IP address specification";
            return NULL;
        }
        tokens = lfirst(field);
        if (tokens->length > 1)
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("multiple values specified for host address"),
                     errhint("Specify one address range per line."),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, HbaFileName)));
            *err_msg = "multiple values specified for host address";
            return NULL;
        }
        token = linitial(tokens);

        if (token_is_keyword(token, "all"))
        {
            parsedline->ip_cmp_method = ipCmpAll;
        }
        else if (token_is_keyword(token, "samehost"))
        {
            /* Any IP on this host is allowed to connect */
            parsedline->ip_cmp_method = ipCmpSameHost;
        }
        else if (token_is_keyword(token, "samenet"))
        {
            /* Any IP on the host's subnets is allowed to connect */
            parsedline->ip_cmp_method = ipCmpSameNet;
        }
        else
        {
            /* IP and netmask are specified */
            parsedline->ip_cmp_method = ipCmpMask;

            /* need a modifiable copy of token */
            str = pstrdup(token->string);

            /* Check if it has a CIDR suffix and if so isolate it */
            cidr_slash = strchr(str, '/');
            if (cidr_slash)
                *cidr_slash = '\0';

            /* Get the IP address either way */
            hints.ai_flags = AI_NUMERICHOST;
            hints.ai_family = AF_UNSPEC;
            hints.ai_socktype = 0;
            hints.ai_protocol = 0;
            hints.ai_addrlen = 0;
            hints.ai_canonname = NULL;
            hints.ai_addr = NULL;
            hints.ai_next = NULL;

            ret = pg_getaddrinfo_all(str, NULL, &hints, &gai_result);
            if (ret == 0 && gai_result)
                memcpy(&parsedline->addr, gai_result->ai_addr,
                       gai_result->ai_addrlen);
            else if (ret == EAI_NONAME)
                parsedline->hostname = str;
            else
            {
                ereport(elevel,
                        (errcode(ERRCODE_CONFIG_FILE_ERROR),
                         errmsg("invalid IP address \"%s\": %s",
                                str, gai_strerror(ret)),
                         errcontext("line %d of configuration file \"%s\"",
                                    line_num, HbaFileName)));
                *err_msg = psprintf("invalid IP address \"%s\": %s",
                                    str, gai_strerror(ret));
                if (gai_result)
                    pg_freeaddrinfo_all(hints.ai_family, gai_result);
                return NULL;
            }

            pg_freeaddrinfo_all(hints.ai_family, gai_result);

            /* Get the netmask */
            if (cidr_slash)
            {
                if (parsedline->hostname)
                {
                    ereport(elevel,
                            (errcode(ERRCODE_CONFIG_FILE_ERROR),
                             errmsg("specifying both host name and CIDR mask is invalid: \"%s\"",
                                    token->string),
                             errcontext("line %d of configuration file \"%s\"",
                                        line_num, HbaFileName)));
                    *err_msg = psprintf("specifying both host name and CIDR mask is invalid: \"%s\"",
                                        token->string);
                    return NULL;
                }

                if (pg_sockaddr_cidr_mask(&parsedline->mask, cidr_slash + 1,
                                          parsedline->addr.ss_family) < 0)
                {
                    ereport(elevel,
                            (errcode(ERRCODE_CONFIG_FILE_ERROR),
                             errmsg("invalid CIDR mask in address \"%s\"",
                                    token->string),
                             errcontext("line %d of configuration file \"%s\"",
                                        line_num, HbaFileName)));
                    *err_msg = psprintf("invalid CIDR mask in address \"%s\"",
                                        token->string);
                    return NULL;
                }
                pfree(str);
            }
            else if (!parsedline->hostname)
            {
                /* Read the mask field. */
                pfree(str);
                field = lnext(field);
                if (!field)
                {
                    ereport(elevel,
                            (errcode(ERRCODE_CONFIG_FILE_ERROR),
                             errmsg("end-of-line before netmask specification"),
                             errhint("Specify an address range in CIDR notation, or provide a separate netmask."),
                             errcontext("line %d of configuration file \"%s\"",
                                        line_num, HbaFileName)));
                    *err_msg = "end-of-line before netmask specification";
                    return NULL;
                }
                tokens = lfirst(field);
                if (tokens->length > 1)
                {
                    ereport(elevel,
                            (errcode(ERRCODE_CONFIG_FILE_ERROR),
                             errmsg("multiple values specified for netmask"),
                             errcontext("line %d of configuration file \"%s\"",
                                        line_num, HbaFileName)));
                    *err_msg = "multiple values specified for netmask";
                    return NULL;
                }
                token = linitial(tokens);

                ret = pg_getaddrinfo_all(token->string, NULL,
                                         &hints, &gai_result);
                if (ret || !gai_result)
                {
                    ereport(elevel,
                            (errcode(ERRCODE_CONFIG_FILE_ERROR),
                             errmsg("invalid IP mask \"%s\": %s",
                                    token->string, gai_strerror(ret)),
                             errcontext("line %d of configuration file \"%s\"",
                                        line_num, HbaFileName)));
                    *err_msg = psprintf("invalid IP mask \"%s\": %s",
                                        token->string, gai_strerror(ret));
                    if (gai_result)
                        pg_freeaddrinfo_all(hints.ai_family, gai_result);
                    return NULL;
                }

                memcpy(&parsedline->mask, gai_result->ai_addr,
                       gai_result->ai_addrlen);
                pg_freeaddrinfo_all(hints.ai_family, gai_result);

                if (parsedline->addr.ss_family != parsedline->mask.ss_family)
                {
                    ereport(elevel,
                            (errcode(ERRCODE_CONFIG_FILE_ERROR),
                             errmsg("IP address and mask do not match"),
                             errcontext("line %d of configuration file \"%s\"",
                                        line_num, HbaFileName)));
                    *err_msg = "IP address and mask do not match";
                    return NULL;
                }
            }
        }
    }                           /* != ctLocal */

    /* Get the authentication method */
    field = lnext(field);
    if (!field)
    {
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("end-of-line before authentication method"),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, HbaFileName)));
        *err_msg = "end-of-line before authentication method";
        return NULL;
    }
    tokens = lfirst(field);
    if (tokens->length > 1)
    {
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("multiple values specified for authentication type"),
                 errhint("Specify exactly one authentication type per line."),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, HbaFileName)));
        *err_msg = "multiple values specified for authentication type";
        return NULL;
    }
    token = linitial(tokens);

    unsupauth = NULL;
    if (strcmp(token->string, "trust") == 0)
        parsedline->auth_method = uaTrust;
    else if (strcmp(token->string, "ident") == 0)
        parsedline->auth_method = uaIdent;
    else if (strcmp(token->string, "peer") == 0)
        parsedline->auth_method = uaPeer;
    else if (strcmp(token->string, "password") == 0)
        parsedline->auth_method = uaPassword;
    else if (strcmp(token->string, "gss") == 0)
#ifdef ENABLE_GSS
        parsedline->auth_method = uaGSS;
#else
        unsupauth = "gss";
#endif
    else if (strcmp(token->string, "sspi") == 0)
#ifdef ENABLE_SSPI
        parsedline->auth_method = uaSSPI;
#else
        unsupauth = "sspi";
#endif
    else if (strcmp(token->string, "reject") == 0)
        parsedline->auth_method = uaReject;
    else if (strcmp(token->string, "md5") == 0)
    {
        if (Db_user_namespace)
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("MD5 authentication is not supported when \"db_user_namespace\" is enabled"),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, HbaFileName)));
            *err_msg = "MD5 authentication is not supported when \"db_user_namespace\" is enabled";
            return NULL;
        }
        parsedline->auth_method = uaMD5;
    }
    else if (strcmp(token->string, "scram-sha-256") == 0)
        parsedline->auth_method = uaSCRAM;
    else if (strcmp(token->string, "pam") == 0)
#ifdef USE_PAM
        parsedline->auth_method = uaPAM;
#else
        unsupauth = "pam";
#endif
    else if (strcmp(token->string, "bsd") == 0)
#ifdef USE_BSD_AUTH
        parsedline->auth_method = uaBSD;
#else
        unsupauth = "bsd";
#endif
    else if (strcmp(token->string, "ldap") == 0)
#ifdef USE_LDAP
        parsedline->auth_method = uaLDAP;
#else
        unsupauth = "ldap";
#endif
    else if (strcmp(token->string, "cert") == 0)
#ifdef USE_SSL
        parsedline->auth_method = uaCert;
#else
        unsupauth = "cert";
#endif
    else if (strcmp(token->string, "radius") == 0)
        parsedline->auth_method = uaRADIUS;
    else
    {
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("invalid authentication method \"%s\"",
                        token->string),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, HbaFileName)));
        *err_msg = psprintf("invalid authentication method \"%s\"",
                            token->string);
        return NULL;
    }

    if (unsupauth)
    {
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("invalid authentication method \"%s\": not supported by this build",
                        token->string),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, HbaFileName)));
        *err_msg = psprintf("invalid authentication method \"%s\": not supported by this build",
                            token->string);
        return NULL;
    }

    /*
     * XXX: When using ident on local connections, change it to peer, for
     * backwards compatibility.
     */
    if (parsedline->conntype == ctLocal &&
        parsedline->auth_method == uaIdent)
        parsedline->auth_method = uaPeer;

    /* Invalid authentication combinations */
    if (parsedline->conntype == ctLocal &&
        parsedline->auth_method == uaGSS)
    {
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("gssapi authentication is not supported on local sockets"),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, HbaFileName)));
        *err_msg = "gssapi authentication is not supported on local sockets";
        return NULL;
    }

    if (parsedline->conntype != ctLocal &&
        parsedline->auth_method == uaPeer)
    {
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("peer authentication is only supported on local sockets"),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, HbaFileName)));
        *err_msg = "peer authentication is only supported on local sockets";
        return NULL;
    }

    /*
     * SSPI authentication can never be enabled on ctLocal connections,
     * because it's only supported on Windows, where ctLocal isn't supported.
     */


    if (parsedline->conntype != ctHostSSL &&
        parsedline->auth_method == uaCert)
    {
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("cert authentication is only supported on hostssl connections"),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, HbaFileName)));
        *err_msg = "cert authentication is only supported on hostssl connections";
        return NULL;
    }

    /*
     * For GSS and SSPI, set the default value of include_realm to true.
     * Having include_realm set to false is dangerous in multi-realm
     * situations and is generally considered bad practice.  We keep the
     * capability around for backwards compatibility, but we might want to
     * remove it at some point in the future.  Users who still need to strip
     * the realm off would be better served by using an appropriate regex in a
     * pg_ident.conf mapping.
     */
    if (parsedline->auth_method == uaGSS ||
        parsedline->auth_method == uaSSPI)
        parsedline->include_realm = true;

    /*
     * For SSPI, include_realm defaults to the SAM-compatible domain (aka
     * NetBIOS name) and user names instead of the Kerberos principal name for
     * compatibility.
     */
    if (parsedline->auth_method == uaSSPI)
    {
        parsedline->compat_realm = true;
        parsedline->upn_username = false;
    }

    /* Parse remaining arguments */
    while ((field = lnext(field)) != NULL)
    {
        tokens = lfirst(field);
        foreach(tokencell, tokens)
        {
            char       *val;

            token = lfirst(tokencell);

            str = pstrdup(token->string);
            val = strchr(str, '=');
            if (val == NULL)
            {
                /*
                 * Got something that's not a name=value pair.
                 */
                ereport(elevel,
                        (errcode(ERRCODE_CONFIG_FILE_ERROR),
                         errmsg("authentication option not in name=value format: %s", token->string),
                         errcontext("line %d of configuration file \"%s\"",
                                    line_num, HbaFileName)));
                *err_msg = psprintf("authentication option not in name=value format: %s",
                                    token->string);
                return NULL;
            }

            *val++ = '\0';      /* str now holds "name", val holds "value" */
            if (!parse_hba_auth_opt(str, val, parsedline, elevel, err_msg))
                /* parse_hba_auth_opt already logged the error message */
                return NULL;
            pfree(str);
        }
    }

    /*
     * Check if the selected authentication method has any mandatory arguments
     * that are not set.
     */
    if (parsedline->auth_method == uaLDAP)
    {
        MANDATORY_AUTH_ARG(parsedline->ldapserver, "ldapserver", "ldap");

        /*
         * LDAP can operate in two modes: either with a direct bind, using
         * ldapprefix and ldapsuffix, or using a search+bind, using
         * ldapbasedn, ldapbinddn, ldapbindpasswd and one of
         * ldapsearchattribute or ldapsearchfilter.  Disallow mixing these
         * parameters.
         */
        if (parsedline->ldapprefix || parsedline->ldapsuffix)
        {
            if (parsedline->ldapbasedn ||
                parsedline->ldapbinddn ||
                parsedline->ldapbindpasswd ||
                parsedline->ldapsearchattribute ||
                parsedline->ldapsearchfilter)
            {
                ereport(elevel,
                        (errcode(ERRCODE_CONFIG_FILE_ERROR),
                         errmsg("cannot use ldapbasedn, ldapbinddn, ldapbindpasswd, ldapsearchattribute, ldapsearchfilter or ldapurl together with ldapprefix"),
                         errcontext("line %d of configuration file \"%s\"",
                                    line_num, HbaFileName)));
                *err_msg = "cannot use ldapbasedn, ldapbinddn, ldapbindpasswd, ldapsearchattribute, ldapsearchfilter or ldapurl together with ldapprefix";
                return NULL;
            }
        }
        else if (!parsedline->ldapbasedn)
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("authentication method \"ldap\" requires argument \"ldapbasedn\", \"ldapprefix\", or \"ldapsuffix\" to be set"),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, HbaFileName)));
            *err_msg = "authentication method \"ldap\" requires argument \"ldapbasedn\", \"ldapprefix\", or \"ldapsuffix\" to be set";
            return NULL;
        }

        /*
         * When using search+bind, you can either use a simple attribute
         * (defaulting to "uid") or a fully custom search filter.  You can't
         * do both.
         */
        if (parsedline->ldapsearchattribute && parsedline->ldapsearchfilter)
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("cannot use ldapsearchattribute together with ldapsearchfilter"),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, HbaFileName)));
            *err_msg = "cannot use ldapsearchattribute together with ldapsearchfilter";
            return NULL;
        }
    }

    if (parsedline->auth_method == uaRADIUS)
    {
        MANDATORY_AUTH_ARG(parsedline->radiusservers, "radiusservers", "radius");
        MANDATORY_AUTH_ARG(parsedline->radiussecrets, "radiussecrets", "radius");

        if (list_length(parsedline->radiusservers) < 1)
        {
            ereport(LOG,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("list of RADIUS servers cannot be empty"),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, HbaFileName)));
            return NULL;
        }

        if (list_length(parsedline->radiussecrets) < 1)
        {
            ereport(LOG,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("list of RADIUS secrets cannot be empty"),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, HbaFileName)));
            return NULL;
        }

        /*
         * Verify length of option lists - each can be 0 (except for secrets,
         * but that's already checked above), 1 (use the same value
         * everywhere) or the same as the number of servers.
         */
        if (!verify_option_list_length(parsedline->radiussecrets,
                                       "RADIUS secrets",
                                       parsedline->radiusservers,
                                       "RADIUS servers",
                                       line_num))
            return NULL;
        if (!verify_option_list_length(parsedline->radiusports,
                                       "RADIUS ports",
                                       parsedline->radiusservers,
                                       "RADIUS servers",
                                       line_num))
            return NULL;
        if (!verify_option_list_length(parsedline->radiusidentifiers,
                                       "RADIUS identifiers",
                                       parsedline->radiusservers,
                                       "RADIUS servers",
                                       line_num))
            return NULL;
    }

    /*
     * Enforce any parameters implied by other settings.
     */
    if (parsedline->auth_method == uaCert)
    {
        parsedline->clientcert = true;
    }

    return parsedline;
}


static bool
verify_option_list_length(List *options, const char *optionname, List *masters, const char *mastername, int line_num)
{
    if (list_length(options) == 0 ||
        list_length(options) == 1 ||
        list_length(options) == list_length(masters))
        return true;

    ereport(LOG,
            (errcode(ERRCODE_CONFIG_FILE_ERROR),
             errmsg("the number of %s (%d) must be 1 or the same as the number of %s (%d)",
                    optionname,
                    list_length(options),
                    mastername,
                    list_length(masters)
                    ),
             errcontext("line %d of configuration file \"%s\"",
                        line_num, HbaFileName)));
    return false;
}

/*
 * Parse one name-value pair as an authentication option into the given
 * HbaLine.  Return true if we successfully parse the option, false if we
 * encounter an error.  In the event of an error, also log a message at
 * ereport level elevel, and store a message string into *err_msg.
 */
static bool
parse_hba_auth_opt(char *name, char *val, HbaLine *hbaline,
                   int elevel, char **err_msg)
{
    int         line_num = hbaline->linenumber;

#ifdef USE_LDAP
    hbaline->ldapscope = LDAP_SCOPE_SUBTREE;
#endif

    if (strcmp(name, "map") == 0)
    {
        if (hbaline->auth_method != uaIdent &&
            hbaline->auth_method != uaPeer &&
            hbaline->auth_method != uaGSS &&
            hbaline->auth_method != uaSSPI &&
            hbaline->auth_method != uaCert)
            INVALID_AUTH_OPTION("map", gettext_noop("ident, peer, gssapi, sspi, and cert"));
        hbaline->usermap = pstrdup(val);
    }
    else if (strcmp(name, "clientcert") == 0)
    {
        if (hbaline->conntype != ctHostSSL)
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("clientcert can only be configured for \"hostssl\" rows"),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, HbaFileName)));
            *err_msg = "clientcert can only be configured for \"hostssl\" rows";
            return false;
        }
        if (strcmp(val, "1") == 0)
        {
            hbaline->clientcert = true;
        }
        else
        {
            if (hbaline->auth_method == uaCert)
            {
                ereport(elevel,
                        (errcode(ERRCODE_CONFIG_FILE_ERROR),
                         errmsg("clientcert can not be set to 0 when using \"cert\" authentication"),
                         errcontext("line %d of configuration file \"%s\"",
                                    line_num, HbaFileName)));
                *err_msg = "clientcert can not be set to 0 when using \"cert\" authentication";
                return false;
            }
            hbaline->clientcert = false;
        }
    }
    else if (strcmp(name, "pamservice") == 0)
    {
        REQUIRE_AUTH_OPTION(uaPAM, "pamservice", "pam");
        hbaline->pamservice = pstrdup(val);
    }
    else if (strcmp(name, "pam_use_hostname") == 0)
    {
        REQUIRE_AUTH_OPTION(uaPAM, "pam_use_hostname", "pam");
        if (strcmp(val, "1") == 0)
            hbaline->pam_use_hostname = true;
        else
            hbaline->pam_use_hostname = false;

    }
    else if (strcmp(name, "ldapurl") == 0)
    {
#ifdef LDAP_API_FEATURE_X_OPENLDAP
        LDAPURLDesc *urldata;
        int         rc;
#endif

        REQUIRE_AUTH_OPTION(uaLDAP, "ldapurl", "ldap");
#ifdef LDAP_API_FEATURE_X_OPENLDAP
        rc = ldap_url_parse(val, &urldata);
        if (rc != LDAP_SUCCESS)
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("could not parse LDAP URL \"%s\": %s", val, ldap_err2string(rc))));
            *err_msg = psprintf("could not parse LDAP URL \"%s\": %s",
                                val, ldap_err2string(rc));
            return false;
        }

        if (strcmp(urldata->lud_scheme, "ldap") != 0 &&
            strcmp(urldata->lud_scheme, "ldaps") != 0)
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("unsupported LDAP URL scheme: %s", urldata->lud_scheme)));
            *err_msg = psprintf("unsupported LDAP URL scheme: %s",
                                urldata->lud_scheme);
            ldap_free_urldesc(urldata);
            return false;
        }

        if (urldata->lud_scheme)
            hbaline->ldapscheme = pstrdup(urldata->lud_scheme);
        if (urldata->lud_host)
            hbaline->ldapserver = pstrdup(urldata->lud_host);
        hbaline->ldapport = urldata->lud_port;
        if (urldata->lud_dn)
            hbaline->ldapbasedn = pstrdup(urldata->lud_dn);

        if (urldata->lud_attrs)
            hbaline->ldapsearchattribute = pstrdup(urldata->lud_attrs[0]);  /* only use first one */
        hbaline->ldapscope = urldata->lud_scope;
        if (urldata->lud_filter)
            hbaline->ldapsearchfilter = pstrdup(urldata->lud_filter);
        ldap_free_urldesc(urldata);
#else                           /* not OpenLDAP */
        ereport(elevel,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("LDAP URLs not supported on this platform")));
        *err_msg = "LDAP URLs not supported on this platform";
#endif                          /* not OpenLDAP */
    }
    else if (strcmp(name, "ldaptls") == 0)
    {
        REQUIRE_AUTH_OPTION(uaLDAP, "ldaptls", "ldap");
        if (strcmp(val, "1") == 0)
            hbaline->ldaptls = true;
        else
            hbaline->ldaptls = false;
    }
    else if (strcmp(name, "ldapscheme") == 0)
    {
        REQUIRE_AUTH_OPTION(uaLDAP, "ldapscheme", "ldap");
        if (strcmp(val, "ldap") != 0 && strcmp(val, "ldaps") != 0)
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("invalid ldapscheme value: \"%s\"", val),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, HbaFileName)));
        hbaline->ldapscheme = pstrdup(val);
    }
    else if (strcmp(name, "ldapserver") == 0)
    {
        REQUIRE_AUTH_OPTION(uaLDAP, "ldapserver", "ldap");
        hbaline->ldapserver = pstrdup(val);
    }
    else if (strcmp(name, "ldapport") == 0)
    {
        REQUIRE_AUTH_OPTION(uaLDAP, "ldapport", "ldap");
        hbaline->ldapport = atoi(val);
        if (hbaline->ldapport == 0)
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("invalid LDAP port number: \"%s\"", val),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, HbaFileName)));
            *err_msg = psprintf("invalid LDAP port number: \"%s\"", val);
            return false;
        }
    }
    else if (strcmp(name, "ldapbinddn") == 0)
    {
        REQUIRE_AUTH_OPTION(uaLDAP, "ldapbinddn", "ldap");
        hbaline->ldapbinddn = pstrdup(val);
    }
    else if (strcmp(name, "ldapbindpasswd") == 0)
    {
        REQUIRE_AUTH_OPTION(uaLDAP, "ldapbindpasswd", "ldap");
        hbaline->ldapbindpasswd = pstrdup(val);
    }
    else if (strcmp(name, "ldapsearchattribute") == 0)
    {
        REQUIRE_AUTH_OPTION(uaLDAP, "ldapsearchattribute", "ldap");
        hbaline->ldapsearchattribute = pstrdup(val);
    }
    else if (strcmp(name, "ldapsearchfilter") == 0)
    {
        REQUIRE_AUTH_OPTION(uaLDAP, "ldapsearchfilter", "ldap");
        hbaline->ldapsearchfilter = pstrdup(val);
    }
    else if (strcmp(name, "ldapbasedn") == 0)
    {
        REQUIRE_AUTH_OPTION(uaLDAP, "ldapbasedn", "ldap");
        hbaline->ldapbasedn = pstrdup(val);
    }
    else if (strcmp(name, "ldapprefix") == 0)
    {
        REQUIRE_AUTH_OPTION(uaLDAP, "ldapprefix", "ldap");
        hbaline->ldapprefix = pstrdup(val);
    }
    else if (strcmp(name, "ldapsuffix") == 0)
    {
        REQUIRE_AUTH_OPTION(uaLDAP, "ldapsuffix", "ldap");
        hbaline->ldapsuffix = pstrdup(val);
    }
    else if (strcmp(name, "krb_realm") == 0)
    {
        if (hbaline->auth_method != uaGSS &&
            hbaline->auth_method != uaSSPI)
            INVALID_AUTH_OPTION("krb_realm", gettext_noop("gssapi and sspi"));
        hbaline->krb_realm = pstrdup(val);
    }
    else if (strcmp(name, "include_realm") == 0)
    {
        if (hbaline->auth_method != uaGSS &&
            hbaline->auth_method != uaSSPI)
            INVALID_AUTH_OPTION("include_realm", gettext_noop("gssapi and sspi"));
        if (strcmp(val, "1") == 0)
            hbaline->include_realm = true;
        else
            hbaline->include_realm = false;
    }
    else if (strcmp(name, "compat_realm") == 0)
    {
        if (hbaline->auth_method != uaSSPI)
            INVALID_AUTH_OPTION("compat_realm", gettext_noop("sspi"));
        if (strcmp(val, "1") == 0)
            hbaline->compat_realm = true;
        else
            hbaline->compat_realm = false;
    }
    else if (strcmp(name, "upn_username") == 0)
    {
        if (hbaline->auth_method != uaSSPI)
            INVALID_AUTH_OPTION("upn_username", gettext_noop("sspi"));
        if (strcmp(val, "1") == 0)
            hbaline->upn_username = true;
        else
            hbaline->upn_username = false;
    }
    else if (strcmp(name, "radiusservers") == 0)
    {
        struct addrinfo *gai_result;
        struct addrinfo hints;
        int         ret;
        List       *parsed_servers;
        ListCell   *l;
        char       *dupval = pstrdup(val);

        REQUIRE_AUTH_OPTION(uaRADIUS, "radiusservers", "radius");

        if (!SplitIdentifierString(dupval, ',', &parsed_servers))
        {
            /* syntax error in list */
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("could not parse RADIUS server list \"%s\"",
                            val),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, HbaFileName)));
            return false;
        }

        /* For each entry in the list, translate it */
        foreach(l, parsed_servers)
        {
            MemSet(&hints, 0, sizeof(hints));
            hints.ai_socktype = SOCK_DGRAM;
            hints.ai_family = AF_UNSPEC;

            ret = pg_getaddrinfo_all((char *) lfirst(l), NULL, &hints, &gai_result);
            if (ret || !gai_result)
            {
                ereport(elevel,
                        (errcode(ERRCODE_CONFIG_FILE_ERROR),
                         errmsg("could not translate RADIUS server name \"%s\" to address: %s",
                                (char *) lfirst(l), gai_strerror(ret)),
                         errcontext("line %d of configuration file \"%s\"",
                                    line_num, HbaFileName)));
                if (gai_result)
                    pg_freeaddrinfo_all(hints.ai_family, gai_result);

                list_free(parsed_servers);
                return false;
            }
            pg_freeaddrinfo_all(hints.ai_family, gai_result);
        }

        /* All entries are OK, so store them */
        hbaline->radiusservers = parsed_servers;
        hbaline->radiusservers_s = pstrdup(val);
    }
    else if (strcmp(name, "radiusports") == 0)
    {
        List       *parsed_ports;
        ListCell   *l;
        char       *dupval = pstrdup(val);

        REQUIRE_AUTH_OPTION(uaRADIUS, "radiusports", "radius");

        if (!SplitIdentifierString(dupval, ',', &parsed_ports))
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("could not parse RADIUS port list \"%s\"",
                            val),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, HbaFileName)));
            *err_msg = psprintf("invalid RADIUS port number: \"%s\"", val);
            return false;
        }

        foreach(l, parsed_ports)
        {
            if (atoi(lfirst(l)) == 0)
            {
                ereport(elevel,
                        (errcode(ERRCODE_CONFIG_FILE_ERROR),
                         errmsg("invalid RADIUS port number: \"%s\"", val),
                         errcontext("line %d of configuration file \"%s\"",
                                    line_num, HbaFileName)));

                return false;
            }
        }
        hbaline->radiusports = parsed_ports;
        hbaline->radiusports_s = pstrdup(val);
    }
    else if (strcmp(name, "radiussecrets") == 0)
    {
        List       *parsed_secrets;
        char       *dupval = pstrdup(val);

        REQUIRE_AUTH_OPTION(uaRADIUS, "radiussecrets", "radius");

        if (!SplitIdentifierString(dupval, ',', &parsed_secrets))
        {
            /* syntax error in list */
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("could not parse RADIUS secret list \"%s\"",
                            val),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, HbaFileName)));
            return false;
        }

        hbaline->radiussecrets = parsed_secrets;
        hbaline->radiussecrets_s = pstrdup(val);
    }
    else if (strcmp(name, "radiusidentifiers") == 0)
    {
        List       *parsed_identifiers;
        char       *dupval = pstrdup(val);

        REQUIRE_AUTH_OPTION(uaRADIUS, "radiusidentifiers", "radius");

        if (!SplitIdentifierString(dupval, ',', &parsed_identifiers))
        {
            /* syntax error in list */
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("could not parse RADIUS identifiers list \"%s\"",
                            val),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, HbaFileName)));
            return false;
        }

        hbaline->radiusidentifiers = parsed_identifiers;
        hbaline->radiusidentifiers_s = pstrdup(val);
    }
    else
    {
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("unrecognized authentication option name: \"%s\"",
                        name),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, HbaFileName)));
        *err_msg = psprintf("unrecognized authentication option name: \"%s\"",
                            name);
        return false;
    }
    return true;
}

/*
 *  Scan the pre-parsed hba file, looking for a match to the port's connection
 *  request.
 */
static void
check_hba(hbaPort *port)
{
    Oid         roleid;
    ListCell   *line;
    HbaLine    *hba;

    /* Get the target role's OID.  Note we do not error out for bad role. */
    roleid = get_role_oid(port->user_name, true);

    foreach(line, parsed_hba_lines)
    {
        hba = (HbaLine *) lfirst(line);

        /* Check connection type */
        if (hba->conntype == ctLocal)
        {
            if (!IS_AF_UNIX(port->raddr.addr.ss_family))
                continue;
        }
        else
        {
            if (IS_AF_UNIX(port->raddr.addr.ss_family))
                continue;

            /* Check SSL state */
            if (port->ssl_in_use)
            {
                /* Connection is SSL, match both "host" and "hostssl" */
                if (hba->conntype == ctHostNoSSL)
                    continue;
            }
            else
            {
                /* Connection is not SSL, match both "host" and "hostnossl" */
                if (hba->conntype == ctHostSSL)
                    continue;
            }

            /* Check IP address */
            switch (hba->ip_cmp_method)
            {
                case ipCmpMask:
                    if (hba->hostname)
                    {
                        if (!check_hostname(port,
                                            hba->hostname))
                            continue;
                    }
                    else
                    {
                        if (!check_ip(&port->raddr,
                                      (struct sockaddr *) &hba->addr,
                                      (struct sockaddr *) &hba->mask))
                            continue;
                    }
                    break;
                case ipCmpAll:
                    break;
                case ipCmpSameHost:
                case ipCmpSameNet:
                    if (!check_same_host_or_net(&port->raddr,
                                                hba->ip_cmp_method))
                        continue;
                    break;
                default:
                    /* shouldn't get here, but deem it no-match if so */
                    continue;
            }
        }                       /* != ctLocal */

        /* Check database and role */
        if (!check_db(port->database_name, port->user_name, roleid,
                      hba->databases))
            continue;

        if (!check_role(port->user_name, roleid, hba->roles))
            continue;

        /* Found a record that matched! */
        port->hba = hba;
        return;
    }

    /* If no matching entry was found, then implicitly reject. */
    hba = palloc0(sizeof(HbaLine));
    hba->auth_method = uaImplicitReject;
    port->hba = hba;
}

/*
 * Read the config file and create a List of HbaLine records for the contents.
 *
 * The configuration is read into a temporary list, and if any parse error
 * occurs the old list is kept in place and false is returned.  Only if the
 * whole file parses OK is the list replaced, and the function returns true.
 *
 * On a false result, caller will take care of reporting a FATAL error in case
 * this is the initial startup.  If it happens on reload, we just keep running
 * with the old data.
 */
bool
load_hba(void)
{
    FILE       *file;
    List       *hba_lines = NIL;
    ListCell   *line;
    List       *new_parsed_lines = NIL;
    bool        ok = true;
    MemoryContext linecxt;
    MemoryContext oldcxt;
    MemoryContext hbacxt;

    file = AllocateFile(HbaFileName, "r");
    if (file == NULL)
    {
        ereport(LOG,
                (errcode_for_file_access(),
                 errmsg("could not open configuration file \"%s\": %m",
                        HbaFileName)));
        return false;
    }

    linecxt = tokenize_file(HbaFileName, file, &hba_lines, LOG);
    FreeFile(file);

    /* Now parse all the lines */
    Assert(PostmasterContext);
    hbacxt = AllocSetContextCreate(PostmasterContext,
                                   "hba parser context",
                                   ALLOCSET_SMALL_SIZES);
    oldcxt = MemoryContextSwitchTo(hbacxt);
    foreach(line, hba_lines)
    {
        TokenizedLine *tok_line = (TokenizedLine *) lfirst(line);
        HbaLine    *newline;

        /* don't parse lines that already have errors */
        if (tok_line->err_msg != NULL)
        {
            ok = false;
            continue;
        }

        if ((newline = parse_hba_line(tok_line, LOG)) == NULL)
        {
            /* Parse error; remember there's trouble */
            ok = false;

            /*
             * Keep parsing the rest of the file so we can report errors on
             * more than the first line.  Error has already been logged, no
             * need for more chatter here.
             */
            continue;
        }

        new_parsed_lines = lappend(new_parsed_lines, newline);
    }

    /*
     * A valid HBA file must have at least one entry; else there's no way to
     * connect to the postmaster.  But only complain about this if we didn't
     * already have parsing errors.
     */
    if (ok && new_parsed_lines == NIL)
    {
        ereport(LOG,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("configuration file \"%s\" contains no entries",
                        HbaFileName)));
        ok = false;
    }

    /* Free tokenizer memory */
    MemoryContextDelete(linecxt);
    MemoryContextSwitchTo(oldcxt);

    if (!ok)
    {
        /* File contained one or more errors, so bail out */
        MemoryContextDelete(hbacxt);
        return false;
    }

    /* Loaded new file successfully, replace the one we use */
    if (parsed_hba_context != NULL)
        MemoryContextDelete(parsed_hba_context);
    parsed_hba_context = hbacxt;
    parsed_hba_lines = new_parsed_lines;

    return true;
}

/*
 * This macro specifies the maximum number of authentication options
 * that are possible with any given authentication method that is supported.
 * Currently LDAP supports 10, so the macro value is well above the most any
 * method needs.
 */
#define MAX_HBA_OPTIONS 12

/*
 * Create a text array listing the options specified in the HBA line.
 * Return NULL if no options are specified.
 */
static ArrayType *
gethba_options(HbaLine *hba)
{
    int         noptions;
    Datum       options[MAX_HBA_OPTIONS];

    noptions = 0;

    if (hba->auth_method == uaGSS || hba->auth_method == uaSSPI)
    {
        if (hba->include_realm)
            options[noptions++] =
                CStringGetTextDatum("include_realm=true");

        if (hba->krb_realm)
            options[noptions++] =
                CStringGetTextDatum(psprintf("krb_realm=%s", hba->krb_realm));
    }

    if (hba->usermap)
        options[noptions++] =
            CStringGetTextDatum(psprintf("map=%s", hba->usermap));

    if (hba->clientcert)
        options[noptions++] =
            CStringGetTextDatum("clientcert=true");

    if (hba->pamservice)
        options[noptions++] =
            CStringGetTextDatum(psprintf("pamservice=%s", hba->pamservice));

    if (hba->auth_method == uaLDAP)
    {
        if (hba->ldapserver)
            options[noptions++] =
                CStringGetTextDatum(psprintf("ldapserver=%s", hba->ldapserver));

        if (hba->ldapport)
            options[noptions++] =
                CStringGetTextDatum(psprintf("ldapport=%d", hba->ldapport));

        if (hba->ldaptls)
            options[noptions++] =
                CStringGetTextDatum("ldaptls=true");

        if (hba->ldapprefix)
            options[noptions++] =
                CStringGetTextDatum(psprintf("ldapprefix=%s", hba->ldapprefix));

        if (hba->ldapsuffix)
            options[noptions++] =
                CStringGetTextDatum(psprintf("ldapsuffix=%s", hba->ldapsuffix));

        if (hba->ldapbasedn)
            options[noptions++] =
                CStringGetTextDatum(psprintf("ldapbasedn=%s", hba->ldapbasedn));

        if (hba->ldapbinddn)
            options[noptions++] =
                CStringGetTextDatum(psprintf("ldapbinddn=%s", hba->ldapbinddn));

        if (hba->ldapbindpasswd)
            options[noptions++] =
                CStringGetTextDatum(psprintf("ldapbindpasswd=%s",
                                             hba->ldapbindpasswd));

        if (hba->ldapsearchattribute)
            options[noptions++] =
                CStringGetTextDatum(psprintf("ldapsearchattribute=%s",
                                             hba->ldapsearchattribute));

        if (hba->ldapsearchfilter)
            options[noptions++] =
                CStringGetTextDatum(psprintf("ldapsearchfilter=%s",
                                             hba->ldapsearchfilter));

        if (hba->ldapscope)
            options[noptions++] =
                CStringGetTextDatum(psprintf("ldapscope=%d", hba->ldapscope));
    }

    if (hba->auth_method == uaRADIUS)
    {
        if (hba->radiusservers_s)
            options[noptions++] =
                CStringGetTextDatum(psprintf("radiusservers=%s", hba->radiusservers_s));

        if (hba->radiussecrets_s)
            options[noptions++] =
                CStringGetTextDatum(psprintf("radiussecrets=%s", hba->radiussecrets_s));

        if (hba->radiusidentifiers_s)
            options[noptions++] =
                CStringGetTextDatum(psprintf("radiusidentifiers=%s", hba->radiusidentifiers_s));

        if (hba->radiusports_s)
            options[noptions++] =
                CStringGetTextDatum(psprintf("radiusports=%s", hba->radiusports_s));
    }

    Assert(noptions <= MAX_HBA_OPTIONS);

    if (noptions > 0)
        return construct_array(options, noptions, TEXTOID, -1, false, 'i');
    else
        return NULL;
}

/* Number of columns in pg_hba_file_rules view */
#define NUM_PG_HBA_FILE_RULES_ATTS   9

/*
 * fill_hba_line: build one row of pg_hba_file_rules view, add it to tuplestore
 *
 * tuple_store: where to store data
 * tupdesc: tuple descriptor for the view
 * lineno: pg_hba.conf line number (must always be valid)
 * hba: parsed line data (can be NULL, in which case err_msg should be set)
 * err_msg: error message (NULL if none)
 *
 * Note: leaks memory, but we don't care since this is run in a short-lived
 * memory context.
 */
static void
fill_hba_line(Tuplestorestate *tuple_store, TupleDesc tupdesc,
              int lineno, HbaLine *hba, const char *err_msg)
{
    Datum       values[NUM_PG_HBA_FILE_RULES_ATTS];
    bool        nulls[NUM_PG_HBA_FILE_RULES_ATTS];
    char        buffer[NI_MAXHOST];
    HeapTuple   tuple;
    int         index;
    ListCell   *lc;
    const char *typestr;
    const char *addrstr;
    const char *maskstr;
    ArrayType  *options;

    Assert(tupdesc->natts == NUM_PG_HBA_FILE_RULES_ATTS);

    memset(values, 0, sizeof(values));
    memset(nulls, 0, sizeof(nulls));
    index = 0;

    /* line_number */
    values[index++] = Int32GetDatum(lineno);

    if (hba != NULL)
    {
        /* type */
        /* Avoid a default: case so compiler will warn about missing cases */
        typestr = NULL;
        switch (hba->conntype)
        {
            case ctLocal:
                typestr = "local";
                break;
            case ctHost:
                typestr = "host";
                break;
            case ctHostSSL:
                typestr = "hostssl";
                break;
            case ctHostNoSSL:
                typestr = "hostnossl";
                break;
        }
        if (typestr)
            values[index++] = CStringGetTextDatum(typestr);
        else
            nulls[index++] = true;

        /* database */
        if (hba->databases)
        {
            /*
             * Flatten HbaToken list to string list.  It might seem that we
             * should re-quote any quoted tokens, but that has been rejected
             * on the grounds that it makes it harder to compare the array
             * elements to other system catalogs.  That makes entries like
             * "all" or "samerole" formally ambiguous ... but users who name
             * databases/roles that way are inflicting their own pain.
             */
            List       *names = NIL;

            foreach(lc, hba->databases)
            {
                HbaToken   *tok = lfirst(lc);

                names = lappend(names, tok->string);
            }
            values[index++] = PointerGetDatum(strlist_to_textarray(names));
        }
        else
            nulls[index++] = true;

        /* user */
        if (hba->roles)
        {
            /* Flatten HbaToken list to string list; see comment above */
            List       *roles = NIL;

            foreach(lc, hba->roles)
            {
                HbaToken   *tok = lfirst(lc);

                roles = lappend(roles, tok->string);
            }
            values[index++] = PointerGetDatum(strlist_to_textarray(roles));
        }
        else
            nulls[index++] = true;

        /* address and netmask */
        /* Avoid a default: case so compiler will warn about missing cases */
        addrstr = maskstr = NULL;
        switch (hba->ip_cmp_method)
        {
            case ipCmpMask:
                if (hba->hostname)
                {
                    addrstr = hba->hostname;
                }
                else
                {
                    if (pg_getnameinfo_all(&hba->addr, sizeof(hba->addr),
                                           buffer, sizeof(buffer),
                                           NULL, 0,
                                           NI_NUMERICHOST) == 0)
                    {
                        clean_ipv6_addr(hba->addr.ss_family, buffer);
                        addrstr = pstrdup(buffer);
                    }
                    if (pg_getnameinfo_all(&hba->mask, sizeof(hba->mask),
                                           buffer, sizeof(buffer),
                                           NULL, 0,
                                           NI_NUMERICHOST) == 0)
                    {
                        clean_ipv6_addr(hba->mask.ss_family, buffer);
                        maskstr = pstrdup(buffer);
                    }
                }
                break;
            case ipCmpAll:
                addrstr = "all";
                break;
            case ipCmpSameHost:
                addrstr = "samehost";
                break;
            case ipCmpSameNet:
                addrstr = "samenet";
                break;
        }
        if (addrstr)
            values[index++] = CStringGetTextDatum(addrstr);
        else
            nulls[index++] = true;
        if (maskstr)
            values[index++] = CStringGetTextDatum(maskstr);
        else
            nulls[index++] = true;

        /*
         * Make sure UserAuthName[] tracks additions to the UserAuth enum
         */
        StaticAssertStmt(lengthof(UserAuthName) == USER_AUTH_LAST + 1,
                         "UserAuthName[] must match the UserAuth enum");

        /* auth_method */
        values[index++] = CStringGetTextDatum(UserAuthName[hba->auth_method]);

        /* options */
        options = gethba_options(hba);
        if (options)
            values[index++] = PointerGetDatum(options);
        else
            nulls[index++] = true;
    }
    else
    {
        /* no parsing result, so set relevant fields to nulls */
        memset(&nulls[1], true, (NUM_PG_HBA_FILE_RULES_ATTS - 2) * sizeof(bool));
    }

    /* error */
    if (err_msg)
        values[NUM_PG_HBA_FILE_RULES_ATTS - 1] = CStringGetTextDatum(err_msg);
    else
        nulls[NUM_PG_HBA_FILE_RULES_ATTS - 1] = true;

    tuple = heap_form_tuple(tupdesc, values, nulls);
    tuplestore_puttuple(tuple_store, tuple);
}

/*
 * Read the pg_hba.conf file and fill the tuplestore with view records.
 */
static void
fill_hba_view(Tuplestorestate *tuple_store, TupleDesc tupdesc)
{
    FILE       *file;
    List       *hba_lines = NIL;
    ListCell   *line;
    MemoryContext linecxt;
    MemoryContext hbacxt;
    MemoryContext oldcxt;

    /*
     * In the unlikely event that we can't open pg_hba.conf, we throw an
     * error, rather than trying to report it via some sort of view entry.
     * (Most other error conditions should result in a message in a view
     * entry.)
     */
    file = AllocateFile(HbaFileName, "r");
    if (file == NULL)
        ereport(ERROR,
                (errcode_for_file_access(),
                 errmsg("could not open configuration file \"%s\": %m",
                        HbaFileName)));

    linecxt = tokenize_file(HbaFileName, file, &hba_lines, DEBUG3);
    FreeFile(file);

    /* Now parse all the lines */
    hbacxt = AllocSetContextCreate(CurrentMemoryContext,
                                   "hba parser context",
                                   ALLOCSET_SMALL_SIZES);
    oldcxt = MemoryContextSwitchTo(hbacxt);
    foreach(line, hba_lines)
    {
        TokenizedLine *tok_line = (TokenizedLine *) lfirst(line);
        HbaLine    *hbaline = NULL;

        /* don't parse lines that already have errors */
        if (tok_line->err_msg == NULL)
            hbaline = parse_hba_line(tok_line, DEBUG3);

        fill_hba_line(tuple_store, tupdesc, tok_line->line_num,
                      hbaline, tok_line->err_msg);
    }

    /* Free tokenizer memory */
    MemoryContextDelete(linecxt);
    /* Free parse_hba_line memory */
    MemoryContextSwitchTo(oldcxt);
    MemoryContextDelete(hbacxt);
}

/*
 * SQL-accessible SRF to return all the entries in the pg_hba.conf file.
 */
Datum
pg_hba_file_rules(PG_FUNCTION_ARGS)
{
    Tuplestorestate *tuple_store;
    TupleDesc   tupdesc;
    MemoryContext old_cxt;
    ReturnSetInfo *rsi;

    /*
     * We must use the Materialize mode to be safe against HBA file changes
     * while the cursor is open. It's also more efficient than having to look
     * up our current position in the parsed list every time.
     */
    rsi = (ReturnSetInfo *) fcinfo->resultinfo;

    /* Check to see if caller supports us returning a tuplestore */
    if (rsi == NULL || !IsA(rsi, ReturnSetInfo))
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("set-valued function called in context that cannot accept a set")));
    if (!(rsi->allowedModes & SFRM_Materialize))
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("materialize mode required, but it is not " \
                        "allowed in this context")));

    rsi->returnMode = SFRM_Materialize;

    /* Build a tuple descriptor for our result type */
    if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
        elog(ERROR, "return type must be a row type");

    /* Build tuplestore to hold the result rows */
    old_cxt = MemoryContextSwitchTo(rsi->econtext->ecxt_per_query_memory);

    tuple_store =
        tuplestore_begin_heap(rsi->allowedModes & SFRM_Materialize_Random,
                              false, work_mem);
    rsi->setDesc = tupdesc;
    rsi->setResult = tuple_store;

    MemoryContextSwitchTo(old_cxt);

    /* Fill the tuplestore */
    fill_hba_view(tuple_store, tupdesc);

    PG_RETURN_NULL();
}


/*
 * Parse one tokenised line from the ident config file and store the result in
 * an IdentLine structure.
 *
 * If parsing fails, log a message and return NULL.
 *
 * If ident_user is a regular expression (ie. begins with a slash), it is
 * compiled and stored in IdentLine structure.
 *
 * Note: this function leaks memory when an error occurs.  Caller is expected
 * to have set a memory context that will be reset if this function returns
 * NULL.
 */
static IdentLine *
parse_ident_line(TokenizedLine *tok_line)
{
    int         line_num = tok_line->line_num;
    ListCell   *field;
    List       *tokens;
    HbaToken   *token;
    IdentLine  *parsedline;

    Assert(tok_line->fields != NIL);
    field = list_head(tok_line->fields);

    parsedline = palloc0(sizeof(IdentLine));
    parsedline->linenumber = line_num;

    /* Get the map token (must exist) */
    tokens = lfirst(field);
    IDENT_MULTI_VALUE(tokens);
    token = linitial(tokens);
    parsedline->usermap = pstrdup(token->string);

    /* Get the ident user token */
    field = lnext(field);
    IDENT_FIELD_ABSENT(field);
    tokens = lfirst(field);
    IDENT_MULTI_VALUE(tokens);
    token = linitial(tokens);
    parsedline->ident_user = pstrdup(token->string);

    /* Get the PG rolename token */
    field = lnext(field);
    IDENT_FIELD_ABSENT(field);
    tokens = lfirst(field);
    IDENT_MULTI_VALUE(tokens);
    token = linitial(tokens);
    parsedline->pg_role = pstrdup(token->string);

    if (parsedline->ident_user[0] == '/')
    {
        /*
         * When system username starts with a slash, treat it as a regular
         * expression. Pre-compile it.
         */
        int         r;
        pg_wchar   *wstr;
        int         wlen;

        wstr = palloc((strlen(parsedline->ident_user + 1) + 1) * sizeof(pg_wchar));
        wlen = pg_mb2wchar_with_len(parsedline->ident_user + 1,
                                    wstr, strlen(parsedline->ident_user + 1));

        r = pg_regcomp(&parsedline->re, wstr, wlen, REG_ADVANCED, C_COLLATION_OID);
        if (r)
        {
            char        errstr[100];

            pg_regerror(r, &parsedline->re, errstr, sizeof(errstr));
            ereport(LOG,
                    (errcode(ERRCODE_INVALID_REGULAR_EXPRESSION),
                     errmsg("invalid regular expression \"%s\": %s",
                            parsedline->ident_user + 1, errstr)));

            pfree(wstr);
            return NULL;
        }
        pfree(wstr);
    }

    return parsedline;
}

/*
 *  Process one line from the parsed ident config lines.
 *
 *  Compare input parsed ident line to the needed map, pg_role and ident_user.
 *  *found_p and *error_p are set according to our results.
 */
static void
check_ident_usermap(IdentLine *identLine, const char *usermap_name,
                    const char *pg_role, const char *ident_user,
                    bool case_insensitive, bool *found_p, bool *error_p)
{
    *found_p = false;
    *error_p = false;

    if (strcmp(identLine->usermap, usermap_name) != 0)
        /* Line does not match the map name we're looking for, so just abort */
        return;

    /* Match? */
    if (identLine->ident_user[0] == '/')
    {
        /*
         * When system username starts with a slash, treat it as a regular
         * expression. In this case, we process the system username as a
         * regular expression that returns exactly one match. This is replaced
         * for \1 in the database username string, if present.
         */
        int         r;
        regmatch_t  matches[2];
        pg_wchar   *wstr;
        int         wlen;
        char       *ofs;
        char       *regexp_pgrole;

        wstr = palloc((strlen(ident_user) + 1) * sizeof(pg_wchar));
        wlen = pg_mb2wchar_with_len(ident_user, wstr, strlen(ident_user));

        r = pg_regexec(&identLine->re, wstr, wlen, 0, NULL, 2, matches, 0);
        if (r)
        {
            char        errstr[100];

            if (r != REG_NOMATCH)
            {
                /* REG_NOMATCH is not an error, everything else is */
                pg_regerror(r, &identLine->re, errstr, sizeof(errstr));
                ereport(LOG,
                        (errcode(ERRCODE_INVALID_REGULAR_EXPRESSION),
                         errmsg("regular expression match for \"%s\" failed: %s",
                                identLine->ident_user + 1, errstr)));
                *error_p = true;
            }

            pfree(wstr);
            return;
        }
        pfree(wstr);

        if ((ofs = strstr(identLine->pg_role, "\\1")) != NULL)
        {
            int         offset;

            /* substitution of the first argument requested */
            if (matches[1].rm_so < 0)
            {
                ereport(LOG,
                        (errcode(ERRCODE_INVALID_REGULAR_EXPRESSION),
                         errmsg("regular expression \"%s\" has no subexpressions as requested by backreference in \"%s\"",
                                identLine->ident_user + 1, identLine->pg_role)));
                *error_p = true;
                return;
            }

            /*
             * length: original length minus length of \1 plus length of match
             * plus null terminator
             */
            regexp_pgrole = palloc0(strlen(identLine->pg_role) - 2 + (matches[1].rm_eo - matches[1].rm_so) + 1);
            offset = ofs - identLine->pg_role;
            memcpy(regexp_pgrole, identLine->pg_role, offset);
            memcpy(regexp_pgrole + offset,
                   ident_user + matches[1].rm_so,
                   matches[1].rm_eo - matches[1].rm_so);
            strcat(regexp_pgrole, ofs + 2);
        }
        else
        {
            /* no substitution, so copy the match */
            regexp_pgrole = pstrdup(identLine->pg_role);
        }

        /*
         * now check if the username actually matched what the user is trying
         * to connect as
         */
        if (case_insensitive)
        {
            if (pg_strcasecmp(regexp_pgrole, pg_role) == 0)
                *found_p = true;
        }
        else
        {
            if (strcmp(regexp_pgrole, pg_role) == 0)
                *found_p = true;
        }
        pfree(regexp_pgrole);

        return;
    }
    else
    {
        /* Not regular expression, so make complete match */
        if (case_insensitive)
        {
            if (pg_strcasecmp(identLine->pg_role, pg_role) == 0 &&
                pg_strcasecmp(identLine->ident_user, ident_user) == 0)
                *found_p = true;
        }
        else
        {
            if (strcmp(identLine->pg_role, pg_role) == 0 &&
                strcmp(identLine->ident_user, ident_user) == 0)
                *found_p = true;
        }
    }
    return;
}


/*
 *  Scan the (pre-parsed) ident usermap file line by line, looking for a match
 *
 *  See if the user with ident username "auth_user" is allowed to act
 *  as Postgres user "pg_role" according to usermap "usermap_name".
 *
 *  Special case: Usermap NULL, equivalent to what was previously called
 *  "sameuser" or "samerole", means don't look in the usermap file.
 *  That's an implied map wherein "pg_role" must be identical to
 *  "auth_user" in order to be authorized.
 *
 *  Iff authorized, return STATUS_OK, otherwise return STATUS_ERROR.
 */
int
check_usermap(const char *usermap_name,
              const char *pg_role,
              const char *auth_user,
              bool case_insensitive)
{
    bool        found_entry = false,
                error = false;

    if (usermap_name == NULL || usermap_name[0] == '\0')
    {
        if (case_insensitive)
        {
            if (pg_strcasecmp(pg_role, auth_user) == 0)
                return STATUS_OK;
        }
        else
        {
            if (strcmp(pg_role, auth_user) == 0)
                return STATUS_OK;
        }
        ereport(LOG,
                (errmsg("provided user name (%s) and authenticated user name (%s) do not match",
                        pg_role, auth_user)));
        return STATUS_ERROR;
    }
    else
    {
        ListCell   *line_cell;

        foreach(line_cell, parsed_ident_lines)
        {
            check_ident_usermap(lfirst(line_cell), usermap_name,
                                pg_role, auth_user, case_insensitive,
                                &found_entry, &error);
            if (found_entry || error)
                break;
        }
    }
    if (!found_entry && !error)
    {
        ereport(LOG,
                (errmsg("no match in usermap \"%s\" for user \"%s\" authenticated as \"%s\"",
                        usermap_name, pg_role, auth_user)));
    }
    return found_entry ? STATUS_OK : STATUS_ERROR;
}


/*
 * Read the ident config file and create a List of IdentLine records for
 * the contents.
 *
 * This works the same as load_hba(), but for the user config file.
 */
bool
load_ident(void)
{
    FILE       *file;
    List       *ident_lines = NIL;
    ListCell   *line_cell,
               *parsed_line_cell;
    List       *new_parsed_lines = NIL;
    bool        ok = true;
    MemoryContext linecxt;
    MemoryContext oldcxt;
    MemoryContext ident_context;
    IdentLine  *newline;

    file = AllocateFile(IdentFileName, "r");
    if (file == NULL)
    {
        /* not fatal ... we just won't do any special ident maps */
        ereport(LOG,
                (errcode_for_file_access(),
                 errmsg("could not open usermap file \"%s\": %m",
                        IdentFileName)));
        return false;
    }

    linecxt = tokenize_file(IdentFileName, file, &ident_lines, LOG);
    FreeFile(file);

    /* Now parse all the lines */
    Assert(PostmasterContext);
    ident_context = AllocSetContextCreate(PostmasterContext,
                                          "ident parser context",
                                          ALLOCSET_SMALL_SIZES);
    oldcxt = MemoryContextSwitchTo(ident_context);
    foreach(line_cell, ident_lines)
    {
        TokenizedLine *tok_line = (TokenizedLine *) lfirst(line_cell);

        /* don't parse lines that already have errors */
        if (tok_line->err_msg != NULL)
        {
            ok = false;
            continue;
        }

        if ((newline = parse_ident_line(tok_line)) == NULL)
        {
            /* Parse error; remember there's trouble */
            ok = false;

            /*
             * Keep parsing the rest of the file so we can report errors on
             * more than the first line.  Error has already been logged, no
             * need for more chatter here.
             */
            continue;
        }

        new_parsed_lines = lappend(new_parsed_lines, newline);
    }

    /* Free tokenizer memory */
    MemoryContextDelete(linecxt);
    MemoryContextSwitchTo(oldcxt);

    if (!ok)
    {
        /*
         * File contained one or more errors, so bail out, first being careful
         * to clean up whatever we allocated.  Most stuff will go away via
         * MemoryContextDelete, but we have to clean up regexes explicitly.
         */
        foreach(parsed_line_cell, new_parsed_lines)
        {
            newline = (IdentLine *) lfirst(parsed_line_cell);
            if (newline->ident_user[0] == '/')
                pg_regfree(&newline->re);
        }
        MemoryContextDelete(ident_context);
        return false;
    }

    /* Loaded new file successfully, replace the one we use */
    if (parsed_ident_lines != NIL)
    {
        foreach(parsed_line_cell, parsed_ident_lines)
        {
            newline = (IdentLine *) lfirst(parsed_line_cell);
            if (newline->ident_user[0] == '/')
                pg_regfree(&newline->re);
        }
    }
    if (parsed_ident_context != NULL)
        MemoryContextDelete(parsed_ident_context);

    parsed_ident_context = ident_context;
    parsed_ident_lines = new_parsed_lines;

    return true;
}



/*
 *  Determine what authentication method should be used when accessing database
 *  "database" from frontend "raddr", user "user".  Return the method and
 *  an optional argument (stored in fields of *port), and STATUS_OK.
 *
 *  If the file does not contain any entry matching the request, we return
 *  method = uaImplicitReject.
 */
void
hba_getauthmethod(hbaPort *port)
{
    check_hba(port);
}