PostgreSQL Source Code  git master
auth-scram.c File Reference
#include "postgres.h"
#include <unistd.h>
#include "access/xlog.h"
#include "catalog/pg_authid.h"
#include "catalog/pg_control.h"
#include "common/base64.h"
#include "common/saslprep.h"
#include "common/scram-common.h"
#include "common/sha2.h"
#include "libpq/auth.h"
#include "libpq/crypt.h"
#include "libpq/scram.h"
#include "miscadmin.h"
#include "utils/builtins.h"
#include "utils/timestamp.h"
Include dependency graph for auth-scram.c:

Go to the source code of this file.

Data Structures

struct  scram_state
 

Enumerations

enum  scram_state_enum { SCRAM_AUTH_INIT, SCRAM_AUTH_SALT_SENT, SCRAM_AUTH_FINISHED }
 

Functions

static void read_client_first_message (scram_state *state, const char *input)
 
static void read_client_final_message (scram_state *state, const char *input)
 
static char * build_server_first_message (scram_state *state)
 
static char * build_server_final_message (scram_state *state)
 
static bool verify_client_proof (scram_state *state)
 
static bool verify_final_nonce (scram_state *state)
 
static void mock_scram_secret (const char *username, int *iterations, char **salt, uint8 *stored_key, uint8 *server_key)
 
static bool is_scram_printable (char *p)
 
static char * sanitize_char (char c)
 
static char * sanitize_str (const char *s)
 
static char * scram_mock_salt (const char *username)
 
void pg_be_scram_get_mechanisms (Port *port, StringInfo buf)
 
void * pg_be_scram_init (Port *port, const char *selected_mech, const char *shadow_pass)
 
int pg_be_scram_exchange (void *opaq, const char *input, int inputlen, char **output, int *outputlen, char **logdetail)
 
char * pg_be_scram_build_secret (const char *password)
 
bool scram_verify_plain_password (const char *username, const char *password, const char *secret)
 
bool parse_scram_secret (const char *secret, int *iterations, char **salt, uint8 *stored_key, uint8 *server_key)
 
static char * read_attr_value (char **input, char attr)
 
static char * read_any_attr (char **input, char *attr_p)
 

Enumeration Type Documentation

◆ scram_state_enum

Enumerator
SCRAM_AUTH_INIT 
SCRAM_AUTH_SALT_SENT 
SCRAM_AUTH_FINISHED 

Definition at line 112 of file auth-scram.c.

Function Documentation

◆ build_server_final_message()

static char * build_server_final_message ( scram_state state)
static

Definition at line 1341 of file auth-scram.c.

References scram_state::client_final_message_without_proof, scram_state::client_first_message_bare, elog, ERROR, palloc(), pg_b64_enc_len(), pg_b64_encode(), psprintf(), scram_HMAC_final(), scram_HMAC_init(), scram_HMAC_update(), SCRAM_KEY_LEN, scram_state::server_first_message, and scram_state::ServerKey.

Referenced by pg_be_scram_exchange().

1342 {
1343  uint8 ServerSignature[SCRAM_KEY_LEN];
1344  char *server_signature_base64;
1345  int siglen;
1346  scram_HMAC_ctx ctx;
1347 
1348  /* calculate ServerSignature */
1349  scram_HMAC_init(&ctx, state->ServerKey, SCRAM_KEY_LEN);
1350  scram_HMAC_update(&ctx,
1352  strlen(state->client_first_message_bare));
1353  scram_HMAC_update(&ctx, ",", 1);
1354  scram_HMAC_update(&ctx,
1355  state->server_first_message,
1356  strlen(state->server_first_message));
1357  scram_HMAC_update(&ctx, ",", 1);
1358  scram_HMAC_update(&ctx,
1360  strlen(state->client_final_message_without_proof));
1361  scram_HMAC_final(ServerSignature, &ctx);
1362 
1363  siglen = pg_b64_enc_len(SCRAM_KEY_LEN);
1364  /* don't forget the zero-terminator */
1365  server_signature_base64 = palloc(siglen + 1);
1366  siglen = pg_b64_encode((const char *) ServerSignature,
1367  SCRAM_KEY_LEN, server_signature_base64,
1368  siglen);
1369  if (siglen < 0)
1370  elog(ERROR, "could not encode server signature");
1371  server_signature_base64[siglen] = '\0';
1372 
1373  /*------
1374  * The syntax for the server-final-message is: (RFC 5802)
1375  *
1376  * verifier = "v=" base64
1377  * ;; base-64 encoded ServerSignature.
1378  *
1379  * server-final-message = (server-error / verifier)
1380  * ["," extensions]
1381  *
1382  *------
1383  */
1384  return psprintf("v=%s", server_signature_base64);
1385 }
int pg_b64_encode(const char *src, int len, char *dst, int dstlen)
Definition: base64.c:49
char * psprintf(const char *fmt,...)
Definition: psprintf.c:46
unsigned char uint8
Definition: c.h:357
char * client_final_message_without_proof
Definition: auth-scram.c:140
#define ERROR
Definition: elog.h:43
char * server_first_message
Definition: auth-scram.c:145
void scram_HMAC_final(uint8 *result, scram_HMAC_ctx *ctx)
Definition: scram-common.c:85
int pg_b64_enc_len(int srclen)
Definition: base64.c:224
void scram_HMAC_init(scram_HMAC_ctx *ctx, const uint8 *key, int keylen)
Definition: scram-common.c:35
void scram_HMAC_update(scram_HMAC_ctx *ctx, const char *str, int slen)
Definition: scram-common.c:75
void * palloc(Size size)
Definition: mcxt.c:949
#define elog(elevel,...)
Definition: elog.h:228
uint8 ServerKey[SCRAM_KEY_LEN]
Definition: auth-scram.c:131
#define SCRAM_KEY_LEN
Definition: scram-common.h:23
char * client_first_message_bare
Definition: auth-scram.c:135

◆ build_server_first_message()

static char * build_server_first_message ( scram_state state)
static

Definition at line 1131 of file auth-scram.c.

References scram_state::client_nonce, ereport, errcode(), errmsg(), ERROR, scram_state::iterations, palloc(), pg_b64_enc_len(), pg_b64_encode(), pg_strong_random(), psprintf(), pstrdup(), scram_state::salt, SCRAM_RAW_NONCE_LEN, scram_state::server_first_message, and scram_state::server_nonce.

Referenced by pg_be_scram_exchange().

1132 {
1133  /*------
1134  * The syntax for the server-first-message is: (RFC 5802)
1135  *
1136  * server-first-message =
1137  * [reserved-mext ","] nonce "," salt ","
1138  * iteration-count ["," extensions]
1139  *
1140  * nonce = "r=" c-nonce [s-nonce]
1141  * ;; Second part provided by server.
1142  *
1143  * c-nonce = printable
1144  *
1145  * s-nonce = printable
1146  *
1147  * salt = "s=" base64
1148  *
1149  * iteration-count = "i=" posit-number
1150  * ;; A positive number.
1151  *
1152  * Example:
1153  *
1154  * r=fyko+d2lbbFgONRv9qkxdawL3rfcNHYJY1ZVvWVs7j,s=QSXCR+Q6sek8bf92,i=4096
1155  *------
1156  */
1157 
1158  /*
1159  * Per the spec, the nonce may consist of any printable ASCII characters.
1160  * For convenience, however, we don't use the whole range available,
1161  * rather, we generate some random bytes, and base64 encode them.
1162  */
1163  char raw_nonce[SCRAM_RAW_NONCE_LEN];
1164  int encoded_len;
1165 
1166  if (!pg_strong_random(raw_nonce, SCRAM_RAW_NONCE_LEN))
1167  ereport(ERROR,
1168  (errcode(ERRCODE_INTERNAL_ERROR),
1169  errmsg("could not generate random nonce")));
1170 
1171  encoded_len = pg_b64_enc_len(SCRAM_RAW_NONCE_LEN);
1172  /* don't forget the zero-terminator */
1173  state->server_nonce = palloc(encoded_len + 1);
1174  encoded_len = pg_b64_encode(raw_nonce, SCRAM_RAW_NONCE_LEN,
1175  state->server_nonce, encoded_len);
1176  if (encoded_len < 0)
1177  ereport(ERROR,
1178  (errcode(ERRCODE_INTERNAL_ERROR),
1179  errmsg("could not encode random nonce")));
1180  state->server_nonce[encoded_len] = '\0';
1181 
1182  state->server_first_message =
1183  psprintf("r=%s%s,s=%s,i=%u",
1184  state->client_nonce, state->server_nonce,
1185  state->salt, state->iterations);
1186 
1187  return pstrdup(state->server_first_message);
1188 }
int pg_b64_encode(const char *src, int len, char *dst, int dstlen)
Definition: base64.c:49
char * pstrdup(const char *in)
Definition: mcxt.c:1186
char * psprintf(const char *fmt,...)
Definition: psprintf.c:46
int errcode(int sqlerrcode)
Definition: elog.c:608
char * client_nonce
Definition: auth-scram.c:137
#define ERROR
Definition: elog.h:43
int iterations
Definition: auth-scram.c:128
char * salt
Definition: auth-scram.c:129
char * server_first_message
Definition: auth-scram.c:145
#define ereport(elevel, rest)
Definition: elog.h:141
#define SCRAM_RAW_NONCE_LEN
Definition: scram-common.h:33
bool pg_strong_random(void *buf, size_t len)
char * server_nonce
Definition: auth-scram.c:146
int pg_b64_enc_len(int srclen)
Definition: base64.c:224
void * palloc(Size size)
Definition: mcxt.c:949
int errmsg(const char *fmt,...)
Definition: elog.c:822

◆ is_scram_printable()

static bool is_scram_printable ( char *  p)
static

Definition at line 721 of file auth-scram.c.

Referenced by read_client_first_message().

722 {
723  /*------
724  * Printable characters, as defined by SCRAM spec: (RFC 5802)
725  *
726  * printable = %x21-2B / %x2D-7E
727  * ;; Printable ASCII except ",".
728  * ;; Note that any "printable" is also
729  * ;; a valid "value".
730  *------
731  */
732  for (; *p; p++)
733  {
734  if (*p < 0x21 || *p > 0x7E || *p == 0x2C /* comma */ )
735  return false;
736  }
737  return true;
738 }

◆ mock_scram_secret()

static void mock_scram_secret ( const char *  username,
int *  iterations,
char **  salt,
uint8 stored_key,
uint8 server_key 
)
static

Definition at line 647 of file auth-scram.c.

References elog, ERROR, palloc(), pg_b64_enc_len(), pg_b64_encode(), SCRAM_DEFAULT_ITERATIONS, SCRAM_DEFAULT_SALT_LEN, SCRAM_KEY_LEN, and scram_mock_salt().

Referenced by pg_be_scram_init().

649 {
650  char *raw_salt;
651  char *encoded_salt;
652  int encoded_len;
653 
654  /* Generate deterministic salt */
655  raw_salt = scram_mock_salt(username);
656 
657  encoded_len = pg_b64_enc_len(SCRAM_DEFAULT_SALT_LEN);
658  /* don't forget the zero-terminator */
659  encoded_salt = (char *) palloc(encoded_len + 1);
660  encoded_len = pg_b64_encode(raw_salt, SCRAM_DEFAULT_SALT_LEN, encoded_salt,
661  encoded_len);
662 
663  /*
664  * Note that we cannot reveal any information to an attacker here so the
665  * error message needs to remain generic. This should never fail anyway
666  * as the salt generated for mock authentication uses the cluster's nonce
667  * value.
668  */
669  if (encoded_len < 0)
670  elog(ERROR, "could not encode salt");
671  encoded_salt[encoded_len] = '\0';
672 
673  *salt = encoded_salt;
674  *iterations = SCRAM_DEFAULT_ITERATIONS;
675 
676  /* StoredKey and ServerKey are not used in a doomed authentication */
677  memset(stored_key, 0, SCRAM_KEY_LEN);
678  memset(server_key, 0, SCRAM_KEY_LEN);
679 }
static char * scram_mock_salt(const char *username)
Definition: auth-scram.c:1394
int pg_b64_encode(const char *src, int len, char *dst, int dstlen)
Definition: base64.c:49
#define ERROR
Definition: elog.h:43
#define SCRAM_DEFAULT_SALT_LEN
Definition: scram-common.h:40
static char * username
Definition: initdb.c:133
#define SCRAM_DEFAULT_ITERATIONS
Definition: scram-common.h:46
int pg_b64_enc_len(int srclen)
Definition: base64.c:224
void * palloc(Size size)
Definition: mcxt.c:949
#define elog(elevel,...)
Definition: elog.h:228
#define SCRAM_KEY_LEN
Definition: scram-common.h:23

◆ parse_scram_secret()

bool parse_scram_secret ( const char *  secret,
int *  iterations,
char **  salt,
uint8 stored_key,
uint8 server_key 
)

Definition at line 556 of file auth-scram.c.

References palloc(), pg_b64_dec_len(), pg_b64_decode(), pstrdup(), and SCRAM_KEY_LEN.

Referenced by get_password_type(), pg_be_scram_init(), and scram_verify_plain_password().

558 {
559  char *v;
560  char *p;
561  char *scheme_str;
562  char *salt_str;
563  char *iterations_str;
564  char *storedkey_str;
565  char *serverkey_str;
566  int decoded_len;
567  char *decoded_salt_buf;
568  char *decoded_stored_buf;
569  char *decoded_server_buf;
570 
571  /*
572  * The secret is of form:
573  *
574  * SCRAM-SHA-256$<iterations>:<salt>$<storedkey>:<serverkey>
575  */
576  v = pstrdup(secret);
577  if ((scheme_str = strtok(v, "$")) == NULL)
578  goto invalid_secret;
579  if ((iterations_str = strtok(NULL, ":")) == NULL)
580  goto invalid_secret;
581  if ((salt_str = strtok(NULL, "$")) == NULL)
582  goto invalid_secret;
583  if ((storedkey_str = strtok(NULL, ":")) == NULL)
584  goto invalid_secret;
585  if ((serverkey_str = strtok(NULL, "")) == NULL)
586  goto invalid_secret;
587 
588  /* Parse the fields */
589  if (strcmp(scheme_str, "SCRAM-SHA-256") != 0)
590  goto invalid_secret;
591 
592  errno = 0;
593  *iterations = strtol(iterations_str, &p, 10);
594  if (*p || errno != 0)
595  goto invalid_secret;
596 
597  /*
598  * Verify that the salt is in Base64-encoded format, by decoding it,
599  * although we return the encoded version to the caller.
600  */
601  decoded_len = pg_b64_dec_len(strlen(salt_str));
602  decoded_salt_buf = palloc(decoded_len);
603  decoded_len = pg_b64_decode(salt_str, strlen(salt_str),
604  decoded_salt_buf, decoded_len);
605  if (decoded_len < 0)
606  goto invalid_secret;
607  *salt = pstrdup(salt_str);
608 
609  /*
610  * Decode StoredKey and ServerKey.
611  */
612  decoded_len = pg_b64_dec_len(strlen(storedkey_str));
613  decoded_stored_buf = palloc(decoded_len);
614  decoded_len = pg_b64_decode(storedkey_str, strlen(storedkey_str),
615  decoded_stored_buf, decoded_len);
616  if (decoded_len != SCRAM_KEY_LEN)
617  goto invalid_secret;
618  memcpy(stored_key, decoded_stored_buf, SCRAM_KEY_LEN);
619 
620  decoded_len = pg_b64_dec_len(strlen(serverkey_str));
621  decoded_server_buf = palloc(decoded_len);
622  decoded_len = pg_b64_decode(serverkey_str, strlen(serverkey_str),
623  decoded_server_buf, decoded_len);
624  if (decoded_len != SCRAM_KEY_LEN)
625  goto invalid_secret;
626  memcpy(server_key, decoded_server_buf, SCRAM_KEY_LEN);
627 
628  return true;
629 
630 invalid_secret:
631  *salt = NULL;
632  return false;
633 }
char * pstrdup(const char *in)
Definition: mcxt.c:1186
int pg_b64_dec_len(int srclen)
Definition: base64.c:239
int pg_b64_decode(const char *src, int len, char *dst, int dstlen)
Definition: base64.c:116
void * palloc(Size size)
Definition: mcxt.c:949
#define SCRAM_KEY_LEN
Definition: scram-common.h:23

◆ pg_be_scram_build_secret()

char* pg_be_scram_build_secret ( const char *  password)

Definition at line 451 of file auth-scram.c.

References ereport, errcode(), errmsg(), ERROR, pfree(), pg_saslprep(), pg_strong_random(), SASLPREP_SUCCESS, scram_build_secret(), SCRAM_DEFAULT_ITERATIONS, and SCRAM_DEFAULT_SALT_LEN.

Referenced by encrypt_password().

452 {
453  char *prep_password;
454  pg_saslprep_rc rc;
455  char saltbuf[SCRAM_DEFAULT_SALT_LEN];
456  char *result;
457 
458  /*
459  * Normalize the password with SASLprep. If that doesn't work, because
460  * the password isn't valid UTF-8 or contains prohibited characters, just
461  * proceed with the original password. (See comments at top of file.)
462  */
463  rc = pg_saslprep(password, &prep_password);
464  if (rc == SASLPREP_SUCCESS)
465  password = (const char *) prep_password;
466 
467  /* Generate random salt */
469  ereport(ERROR,
470  (errcode(ERRCODE_INTERNAL_ERROR),
471  errmsg("could not generate random salt")));
472 
473  result = scram_build_secret(saltbuf, SCRAM_DEFAULT_SALT_LEN,
475 
476  if (prep_password)
477  pfree(prep_password);
478 
479  return result;
480 }
static char password[100]
Definition: streamutil.c:53
int errcode(int sqlerrcode)
Definition: elog.c:608
char * scram_build_secret(const char *salt, int saltlen, int iterations, const char *password)
Definition: scram-common.c:192
pg_saslprep_rc pg_saslprep(const char *input, char **output)
Definition: saslprep.c:1071
pg_saslprep_rc
Definition: saslprep.h:20
void pfree(void *pointer)
Definition: mcxt.c:1056
#define ERROR
Definition: elog.h:43
#define ereport(elevel, rest)
Definition: elog.h:141
#define SCRAM_DEFAULT_SALT_LEN
Definition: scram-common.h:40
bool pg_strong_random(void *buf, size_t len)
#define SCRAM_DEFAULT_ITERATIONS
Definition: scram-common.h:46
int errmsg(const char *fmt,...)
Definition: elog.c:822

◆ pg_be_scram_exchange()

int pg_be_scram_exchange ( void *  opaq,
const char *  input,
int  inputlen,
char **  output,
int *  outputlen,
char **  logdetail 
)

Definition at line 328 of file auth-scram.c.

References Assert, build_server_final_message(), build_server_first_message(), scram_state::doomed, elog, ereport, errcode(), errdetail(), errmsg(), ERROR, scram_state::logdetail, pstrdup(), read_client_final_message(), read_client_first_message(), SASL_EXCHANGE_CONTINUE, SASL_EXCHANGE_FAILURE, SASL_EXCHANGE_SUCCESS, SCRAM_AUTH_FINISHED, SCRAM_AUTH_INIT, SCRAM_AUTH_SALT_SENT, scram_state::state, verify_client_proof(), and verify_final_nonce().

Referenced by CheckSCRAMAuth().

330 {
331  scram_state *state = (scram_state *) opaq;
332  int result;
333 
334  *output = NULL;
335 
336  /*
337  * If the client didn't include an "Initial Client Response" in the
338  * SASLInitialResponse message, send an empty challenge, to which the
339  * client will respond with the same data that usually comes in the
340  * Initial Client Response.
341  */
342  if (input == NULL)
343  {
344  Assert(state->state == SCRAM_AUTH_INIT);
345 
346  *output = pstrdup("");
347  *outputlen = 0;
348  return SASL_EXCHANGE_CONTINUE;
349  }
350 
351  /*
352  * Check that the input length agrees with the string length of the input.
353  * We can ignore inputlen after this.
354  */
355  if (inputlen == 0)
356  ereport(ERROR,
357  (errcode(ERRCODE_PROTOCOL_VIOLATION),
358  errmsg("malformed SCRAM message"),
359  errdetail("The message is empty.")));
360  if (inputlen != strlen(input))
361  ereport(ERROR,
362  (errcode(ERRCODE_PROTOCOL_VIOLATION),
363  errmsg("malformed SCRAM message"),
364  errdetail("Message length does not match input length.")));
365 
366  switch (state->state)
367  {
368  case SCRAM_AUTH_INIT:
369 
370  /*
371  * Initialization phase. Receive the first message from client
372  * and be sure that it parsed correctly. Then send the challenge
373  * to the client.
374  */
375  read_client_first_message(state, input);
376 
377  /* prepare message to send challenge */
379 
380  state->state = SCRAM_AUTH_SALT_SENT;
381  result = SASL_EXCHANGE_CONTINUE;
382  break;
383 
385 
386  /*
387  * Final phase for the server. Receive the response to the
388  * challenge previously sent, verify, and let the client know that
389  * everything went well (or not).
390  */
391  read_client_final_message(state, input);
392 
393  if (!verify_final_nonce(state))
394  ereport(ERROR,
395  (errcode(ERRCODE_PROTOCOL_VIOLATION),
396  errmsg("invalid SCRAM response"),
397  errdetail("Nonce does not match.")));
398 
399  /*
400  * Now check the final nonce and the client proof.
401  *
402  * If we performed a "mock" authentication that we knew would fail
403  * from the get go, this is where we fail.
404  *
405  * The SCRAM specification includes an error code,
406  * "invalid-proof", for authentication failure, but it also allows
407  * erroring out in an application-specific way. We choose to do
408  * the latter, so that the error message for invalid password is
409  * the same for all authentication methods. The caller will call
410  * ereport(), when we return SASL_EXCHANGE_FAILURE with no output.
411  *
412  * NB: the order of these checks is intentional. We calculate the
413  * client proof even in a mock authentication, even though it's
414  * bound to fail, to thwart timing attacks to determine if a role
415  * with the given name exists or not.
416  */
417  if (!verify_client_proof(state) || state->doomed)
418  {
419  result = SASL_EXCHANGE_FAILURE;
420  break;
421  }
422 
423  /* Build final message for client */
425 
426  /* Success! */
427  result = SASL_EXCHANGE_SUCCESS;
428  state->state = SCRAM_AUTH_FINISHED;
429  break;
430 
431  default:
432  elog(ERROR, "invalid SCRAM exchange state");
433  result = SASL_EXCHANGE_FAILURE;
434  }
435 
436  if (result == SASL_EXCHANGE_FAILURE && state->logdetail && logdetail)
437  *logdetail = state->logdetail;
438 
439  if (*output)
440  *outputlen = strlen(*output);
441 
442  return result;
443 }
static void output(uint64 loop_count)
char * pstrdup(const char *in)
Definition: mcxt.c:1186
#define SASL_EXCHANGE_FAILURE
Definition: scram.h:22
#define SASL_EXCHANGE_SUCCESS
Definition: scram.h:21
int errcode(int sqlerrcode)
Definition: elog.c:608
#define ERROR
Definition: elog.h:43
static void read_client_first_message(scram_state *state, const char *input)
Definition: auth-scram.c:855
static bool verify_client_proof(scram_state *state)
Definition: auth-scram.c:1090
int errdetail(const char *fmt,...)
Definition: elog.c:955
#define ereport(elevel, rest)
Definition: elog.h:141
scram_state_enum state
Definition: auth-scram.c:121
#define Assert(condition)
Definition: c.h:739
Definition: regguts.h:298
static char * build_server_final_message(scram_state *state)
Definition: auth-scram.c:1341
static void read_client_final_message(scram_state *state, const char *input)
Definition: auth-scram.c:1195
int errmsg(const char *fmt,...)
Definition: elog.c:822
#define elog(elevel,...)
Definition: elog.h:228
static bool verify_final_nonce(scram_state *state)
Definition: auth-scram.c:1069
char * logdetail
Definition: auth-scram.c:155
static char * build_server_first_message(scram_state *state)
Definition: auth-scram.c:1131
#define SASL_EXCHANGE_CONTINUE
Definition: scram.h:20

◆ pg_be_scram_get_mechanisms()

void pg_be_scram_get_mechanisms ( Port port,
StringInfo  buf 
)

Definition at line 181 of file auth-scram.c.

References appendStringInfoChar(), appendStringInfoString(), SCRAM_SHA_256_NAME, SCRAM_SHA_256_PLUS_NAME, and Port::ssl_in_use.

Referenced by CheckSCRAMAuth().

182 {
183  /*
184  * Advertise the mechanisms in decreasing order of importance. So the
185  * channel-binding variants go first, if they are supported. Channel
186  * binding is only supported with SSL, and only if the SSL implementation
187  * has a function to get the certificate's hash.
188  */
189 #ifdef HAVE_BE_TLS_GET_CERTIFICATE_HASH
190  if (port->ssl_in_use)
191  {
193  appendStringInfoChar(buf, '\0');
194  }
195 #endif
197  appendStringInfoChar(buf, '\0');
198 }
#define SCRAM_SHA_256_NAME
Definition: scram-common.h:19
bool ssl_in_use
Definition: libpq-be.h:190
void appendStringInfoString(StringInfo str, const char *s)
Definition: stringinfo.c:176
#define SCRAM_SHA_256_PLUS_NAME
Definition: scram-common.h:20
void appendStringInfoChar(StringInfo str, char ch)
Definition: stringinfo.c:188

◆ pg_be_scram_init()

void* pg_be_scram_init ( Port port,
const char *  selected_mech,
const char *  shadow_pass 
)

Definition at line 218 of file auth-scram.c.

References _, scram_state::channel_binding_in_use, scram_state::doomed, ereport, errcode(), errmsg(), ERROR, get_password_type(), scram_state::iterations, LOG, scram_state::logdetail, mock_scram_secret(), palloc0(), parse_scram_secret(), PASSWORD_TYPE_SCRAM_SHA_256, port, scram_state::port, psprintf(), scram_state::salt, SCRAM_AUTH_INIT, SCRAM_SHA_256_NAME, SCRAM_SHA_256_PLUS_NAME, scram_state::ServerKey, Port::ssl_in_use, scram_state::state, scram_state::StoredKey, and Port::user_name.

Referenced by CheckSCRAMAuth().

221 {
223  bool got_secret;
224 
225  state = (scram_state *) palloc0(sizeof(scram_state));
226  state->port = port;
227  state->state = SCRAM_AUTH_INIT;
228 
229  /*
230  * Parse the selected mechanism.
231  *
232  * Note that if we don't support channel binding, either because the SSL
233  * implementation doesn't support it or we're not using SSL at all, we
234  * would not have advertised the PLUS variant in the first place. If the
235  * client nevertheless tries to select it, it's a protocol violation like
236  * selecting any other SASL mechanism we don't support.
237  */
238 #ifdef HAVE_BE_TLS_GET_CERTIFICATE_HASH
239  if (strcmp(selected_mech, SCRAM_SHA_256_PLUS_NAME) == 0 && port->ssl_in_use)
240  state->channel_binding_in_use = true;
241  else
242 #endif
243  if (strcmp(selected_mech, SCRAM_SHA_256_NAME) == 0)
244  state->channel_binding_in_use = false;
245  else
246  ereport(ERROR,
247  (errcode(ERRCODE_PROTOCOL_VIOLATION),
248  errmsg("client selected an invalid SASL authentication mechanism")));
249 
250  /*
251  * Parse the stored secret.
252  */
253  if (shadow_pass)
254  {
255  int password_type = get_password_type(shadow_pass);
256 
257  if (password_type == PASSWORD_TYPE_SCRAM_SHA_256)
258  {
259  if (parse_scram_secret(shadow_pass, &state->iterations, &state->salt,
260  state->StoredKey, state->ServerKey))
261  got_secret = true;
262  else
263  {
264  /*
265  * The password looked like a SCRAM secret, but could not be
266  * parsed.
267  */
268  ereport(LOG,
269  (errmsg("invalid SCRAM secret for user \"%s\"",
270  state->port->user_name)));
271  got_secret = false;
272  }
273  }
274  else
275  {
276  /*
277  * The user doesn't have SCRAM secret. (You cannot do SCRAM
278  * authentication with an MD5 hash.)
279  */
280  state->logdetail = psprintf(_("User \"%s\" does not have a valid SCRAM secret."),
281  state->port->user_name);
282  got_secret = false;
283  }
284  }
285  else
286  {
287  /*
288  * The caller requested us to perform a dummy authentication. This is
289  * considered normal, since the caller requested it, so don't set log
290  * detail.
291  */
292  got_secret = false;
293  }
294 
295  /*
296  * If the user did not have a valid SCRAM secret, we still go through
297  * the motions with a mock one, and fail as if the client supplied an
298  * incorrect password. This is to avoid revealing information to an
299  * attacker.
300  */
301  if (!got_secret)
302  {
303  mock_scram_secret(state->port->user_name, &state->iterations,
304  &state->salt, state->StoredKey, state->ServerKey);
305  state->doomed = true;
306  }
307 
308  return state;
309 }
Port * port
Definition: auth-scram.c:125
static void mock_scram_secret(const char *username, int *iterations, char **salt, uint8 *stored_key, uint8 *server_key)
Definition: auth-scram.c:647
#define SCRAM_SHA_256_NAME
Definition: scram-common.h:19
uint8 StoredKey[SCRAM_KEY_LEN]
Definition: auth-scram.c:130
char * psprintf(const char *fmt,...)
Definition: psprintf.c:46
int errcode(int sqlerrcode)
Definition: elog.c:608
bool ssl_in_use
Definition: libpq-be.h:190
#define LOG
Definition: elog.h:26
#define ERROR
Definition: elog.h:43
int iterations
Definition: auth-scram.c:128
char * salt
Definition: auth-scram.c:129
#define SCRAM_SHA_256_PLUS_NAME
Definition: scram-common.h:20
char * user_name
Definition: libpq-be.h:141
#define ereport(elevel, rest)
Definition: elog.h:141
static int port
Definition: pg_regress.c:91
scram_state_enum state
Definition: auth-scram.c:121
void * palloc0(Size size)
Definition: mcxt.c:980
Definition: regguts.h:298
bool parse_scram_secret(const char *secret, int *iterations, char **salt, uint8 *stored_key, uint8 *server_key)
Definition: auth-scram.c:556
int errmsg(const char *fmt,...)
Definition: elog.c:822
PasswordType get_password_type(const char *shadow_pass)
Definition: crypt.c:89
char * logdetail
Definition: auth-scram.c:155
bool channel_binding_in_use
Definition: auth-scram.c:126
uint8 ServerKey[SCRAM_KEY_LEN]
Definition: auth-scram.c:131
#define _(x)
Definition: elog.c:87

◆ read_any_attr()

static char* read_any_attr ( char **  input,
char *  attr_p 
)
static

Definition at line 797 of file auth-scram.c.

References ereport, errcode(), errdetail(), errmsg(), ERROR, and sanitize_char().

Referenced by read_client_final_message(), and read_client_first_message().

798 {
799  char *begin = *input;
800  char *end;
801  char attr = *begin;
802 
803  if (attr == '\0')
804  ereport(ERROR,
805  (errcode(ERRCODE_PROTOCOL_VIOLATION),
806  errmsg("malformed SCRAM message"),
807  errdetail("Attribute expected, but found end of string.")));
808 
809  /*------
810  * attr-val = ALPHA "=" value
811  * ;; Generic syntax of any attribute sent
812  * ;; by server or client
813  *------
814  */
815  if (!((attr >= 'A' && attr <= 'Z') ||
816  (attr >= 'a' && attr <= 'z')))
817  ereport(ERROR,
818  (errcode(ERRCODE_PROTOCOL_VIOLATION),
819  errmsg("malformed SCRAM message"),
820  errdetail("Attribute expected, but found invalid character \"%s\".",
821  sanitize_char(attr))));
822  if (attr_p)
823  *attr_p = attr;
824  begin++;
825 
826  if (*begin != '=')
827  ereport(ERROR,
828  (errcode(ERRCODE_PROTOCOL_VIOLATION),
829  errmsg("malformed SCRAM message"),
830  errdetail("Expected character \"=\" for attribute \"%c\".", attr)));
831  begin++;
832 
833  end = begin;
834  while (*end && *end != ',')
835  end++;
836 
837  if (*end)
838  {
839  *end = '\0';
840  *input = end + 1;
841  }
842  else
843  *input = end;
844 
845  return begin;
846 }
int errcode(int sqlerrcode)
Definition: elog.c:608
#define ERROR
Definition: elog.h:43
int errdetail(const char *fmt,...)
Definition: elog.c:955
#define ereport(elevel, rest)
Definition: elog.h:141
static char * sanitize_char(char c)
Definition: auth-scram.c:749
int errmsg(const char *fmt,...)
Definition: elog.c:822

◆ read_attr_value()

static char* read_attr_value ( char **  input,
char  attr 
)
static

Definition at line 685 of file auth-scram.c.

References ereport, errcode(), errdetail(), errmsg(), ERROR, and sanitize_char().

Referenced by read_client_final_message(), and read_client_first_message().

686 {
687  char *begin = *input;
688  char *end;
689 
690  if (*begin != attr)
691  ereport(ERROR,
692  (errcode(ERRCODE_PROTOCOL_VIOLATION),
693  errmsg("malformed SCRAM message"),
694  errdetail("Expected attribute \"%c\" but found \"%s\".",
695  attr, sanitize_char(*begin))));
696  begin++;
697 
698  if (*begin != '=')
699  ereport(ERROR,
700  (errcode(ERRCODE_PROTOCOL_VIOLATION),
701  errmsg("malformed SCRAM message"),
702  errdetail("Expected character \"=\" for attribute \"%c\".", attr)));
703  begin++;
704 
705  end = begin;
706  while (*end && *end != ',')
707  end++;
708 
709  if (*end)
710  {
711  *end = '\0';
712  *input = end + 1;
713  }
714  else
715  *input = end;
716 
717  return begin;
718 }
int errcode(int sqlerrcode)
Definition: elog.c:608
#define ERROR
Definition: elog.h:43
int errdetail(const char *fmt,...)
Definition: elog.c:955
#define ereport(elevel, rest)
Definition: elog.h:141
static char * sanitize_char(char c)
Definition: auth-scram.c:749
int errmsg(const char *fmt,...)
Definition: elog.c:822

◆ read_client_final_message()

static void read_client_final_message ( scram_state state,
const char *  input 
)
static

Definition at line 1195 of file auth-scram.c.

References Assert, scram_state::cbind_flag, scram_state::channel_binding_in_use, scram_state::client_final_message_without_proof, scram_state::client_final_nonce, scram_state::ClientProof, elog, ereport, errcode(), errdetail(), errmsg(), ERROR, palloc(), pfree(), pg_b64_dec_len(), pg_b64_decode(), pg_b64_enc_len(), pg_b64_encode(), scram_state::port, pstrdup(), read_any_attr(), read_attr_value(), SCRAM_KEY_LEN, snprintf, and value.

Referenced by pg_be_scram_exchange().

1196 {
1197  char attr;
1198  char *channel_binding;
1199  char *value;
1200  char *begin,
1201  *proof;
1202  char *p;
1203  char *client_proof;
1204  int client_proof_len;
1205 
1206  begin = p = pstrdup(input);
1207 
1208  /*------
1209  * The syntax for the server-first-message is: (RFC 5802)
1210  *
1211  * gs2-header = gs2-cbind-flag "," [ authzid ] ","
1212  * ;; GS2 header for SCRAM
1213  * ;; (the actual GS2 header includes an optional
1214  * ;; flag to indicate that the GSS mechanism is not
1215  * ;; "standard", but since SCRAM is "standard", we
1216  * ;; don't include that flag).
1217  *
1218  * cbind-input = gs2-header [ cbind-data ]
1219  * ;; cbind-data MUST be present for
1220  * ;; gs2-cbind-flag of "p" and MUST be absent
1221  * ;; for "y" or "n".
1222  *
1223  * channel-binding = "c=" base64
1224  * ;; base64 encoding of cbind-input.
1225  *
1226  * proof = "p=" base64
1227  *
1228  * client-final-message-without-proof =
1229  * channel-binding "," nonce [","
1230  * extensions]
1231  *
1232  * client-final-message =
1233  * client-final-message-without-proof "," proof
1234  *------
1235  */
1236 
1237  /*
1238  * Read channel binding. This repeats the channel-binding flags and is
1239  * then followed by the actual binding data depending on the type.
1240  */
1241  channel_binding = read_attr_value(&p, 'c');
1242  if (state->channel_binding_in_use)
1243  {
1244 #ifdef HAVE_BE_TLS_GET_CERTIFICATE_HASH
1245  const char *cbind_data = NULL;
1246  size_t cbind_data_len = 0;
1247  size_t cbind_header_len;
1248  char *cbind_input;
1249  size_t cbind_input_len;
1250  char *b64_message;
1251  int b64_message_len;
1252 
1253  Assert(state->cbind_flag == 'p');
1254 
1255  /* Fetch hash data of server's SSL certificate */
1256  cbind_data = be_tls_get_certificate_hash(state->port,
1257  &cbind_data_len);
1258 
1259  /* should not happen */
1260  if (cbind_data == NULL || cbind_data_len == 0)
1261  elog(ERROR, "could not get server certificate hash");
1262 
1263  cbind_header_len = strlen("p=tls-server-end-point,,"); /* p=type,, */
1264  cbind_input_len = cbind_header_len + cbind_data_len;
1265  cbind_input = palloc(cbind_input_len);
1266  snprintf(cbind_input, cbind_input_len, "p=tls-server-end-point,,");
1267  memcpy(cbind_input + cbind_header_len, cbind_data, cbind_data_len);
1268 
1269  b64_message_len = pg_b64_enc_len(cbind_input_len);
1270  /* don't forget the zero-terminator */
1271  b64_message = palloc(b64_message_len + 1);
1272  b64_message_len = pg_b64_encode(cbind_input, cbind_input_len,
1273  b64_message, b64_message_len);
1274  if (b64_message_len < 0)
1275  elog(ERROR, "could not encode channel binding data");
1276  b64_message[b64_message_len] = '\0';
1277 
1278  /*
1279  * Compare the value sent by the client with the value expected by the
1280  * server.
1281  */
1282  if (strcmp(channel_binding, b64_message) != 0)
1283  ereport(ERROR,
1284  (errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),
1285  (errmsg("SCRAM channel binding check failed"))));
1286 #else
1287  /* shouldn't happen, because we checked this earlier already */
1288  elog(ERROR, "channel binding not supported by this build");
1289 #endif
1290  }
1291  else
1292  {
1293  /*
1294  * If we are not using channel binding, the binding data is expected
1295  * to always be "biws", which is "n,," base64-encoded, or "eSws",
1296  * which is "y,,". We also have to check whether the flag is the same
1297  * one that the client originally sent.
1298  */
1299  if (!(strcmp(channel_binding, "biws") == 0 && state->cbind_flag == 'n') &&
1300  !(strcmp(channel_binding, "eSws") == 0 && state->cbind_flag == 'y'))
1301  ereport(ERROR,
1302  (errcode(ERRCODE_PROTOCOL_VIOLATION),
1303  (errmsg("unexpected SCRAM channel-binding attribute in client-final-message"))));
1304  }
1305 
1306  state->client_final_nonce = read_attr_value(&p, 'r');
1307 
1308  /* ignore optional extensions, read until we find "p" attribute */
1309  do
1310  {
1311  proof = p - 1;
1312  value = read_any_attr(&p, &attr);
1313  } while (attr != 'p');
1314 
1315  client_proof_len = pg_b64_dec_len(strlen(value));
1316  client_proof = palloc(client_proof_len);
1317  if (pg_b64_decode(value, strlen(value), client_proof,
1318  client_proof_len) != SCRAM_KEY_LEN)
1319  ereport(ERROR,
1320  (errcode(ERRCODE_PROTOCOL_VIOLATION),
1321  errmsg("malformed SCRAM message"),
1322  errdetail("Malformed proof in client-final-message.")));
1323  memcpy(state->ClientProof, client_proof, SCRAM_KEY_LEN);
1324  pfree(client_proof);
1325 
1326  if (*p != '\0')
1327  ereport(ERROR,
1328  (errcode(ERRCODE_PROTOCOL_VIOLATION),
1329  errmsg("malformed SCRAM message"),
1330  errdetail("Garbage found at the end of client-final-message.")));
1331 
1332  state->client_final_message_without_proof = palloc(proof - begin + 1);
1333  memcpy(state->client_final_message_without_proof, input, proof - begin);
1334  state->client_final_message_without_proof[proof - begin] = '\0';
1335 }
Port * port
Definition: auth-scram.c:125
int pg_b64_encode(const char *src, int len, char *dst, int dstlen)
Definition: base64.c:49
char * pstrdup(const char *in)
Definition: mcxt.c:1186
static struct @145 value
int errcode(int sqlerrcode)
Definition: elog.c:608
char ClientProof[SCRAM_KEY_LEN]
Definition: auth-scram.c:142
char * client_final_message_without_proof
Definition: auth-scram.c:140
int pg_b64_dec_len(int srclen)
Definition: base64.c:239
void pfree(void *pointer)
Definition: mcxt.c:1056
#define ERROR
Definition: elog.h:43
int errdetail(const char *fmt,...)
Definition: elog.c:955
#define ereport(elevel, rest)
Definition: elog.h:141
int pg_b64_decode(const char *src, int len, char *dst, int dstlen)
Definition: base64.c:116
char cbind_flag
Definition: auth-scram.c:134
char * client_final_nonce
Definition: auth-scram.c:141
#define Assert(condition)
Definition: c.h:739
static char * read_any_attr(char **input, char *attr_p)
Definition: auth-scram.c:797
int pg_b64_enc_len(int srclen)
Definition: base64.c:224
static char * read_attr_value(char **input, char attr)
Definition: auth-scram.c:685
void * palloc(Size size)
Definition: mcxt.c:949
int errmsg(const char *fmt,...)
Definition: elog.c:822
#define elog(elevel,...)
Definition: elog.h:228
bool channel_binding_in_use
Definition: auth-scram.c:126
#define SCRAM_KEY_LEN
Definition: scram-common.h:23
#define snprintf
Definition: port.h:192

◆ read_client_first_message()

static void read_client_first_message ( scram_state state,
const char *  input 
)
static

Definition at line 855 of file auth-scram.c.

References scram_state::cbind_flag, scram_state::channel_binding_in_use, scram_state::client_first_message_bare, scram_state::client_nonce, scram_state::client_username, ereport, errcode(), errdetail(), errmsg(), ERROR, is_scram_printable(), scram_state::port, pstrdup(), read_any_attr(), read_attr_value(), sanitize_char(), sanitize_str(), and Port::ssl_in_use.

Referenced by pg_be_scram_exchange().

856 {
857  char *p = pstrdup(input);
858  char *channel_binding_type;
859 
860 
861  /*------
862  * The syntax for the client-first-message is: (RFC 5802)
863  *
864  * saslname = 1*(value-safe-char / "=2C" / "=3D")
865  * ;; Conforms to <value>.
866  *
867  * authzid = "a=" saslname
868  * ;; Protocol specific.
869  *
870  * cb-name = 1*(ALPHA / DIGIT / "." / "-")
871  * ;; See RFC 5056, Section 7.
872  * ;; E.g., "tls-server-end-point" or
873  * ;; "tls-unique".
874  *
875  * gs2-cbind-flag = ("p=" cb-name) / "n" / "y"
876  * ;; "n" -> client doesn't support channel binding.
877  * ;; "y" -> client does support channel binding
878  * ;; but thinks the server does not.
879  * ;; "p" -> client requires channel binding.
880  * ;; The selected channel binding follows "p=".
881  *
882  * gs2-header = gs2-cbind-flag "," [ authzid ] ","
883  * ;; GS2 header for SCRAM
884  * ;; (the actual GS2 header includes an optional
885  * ;; flag to indicate that the GSS mechanism is not
886  * ;; "standard", but since SCRAM is "standard", we
887  * ;; don't include that flag).
888  *
889  * username = "n=" saslname
890  * ;; Usernames are prepared using SASLprep.
891  *
892  * reserved-mext = "m=" 1*(value-char)
893  * ;; Reserved for signaling mandatory extensions.
894  * ;; The exact syntax will be defined in
895  * ;; the future.
896  *
897  * nonce = "r=" c-nonce [s-nonce]
898  * ;; Second part provided by server.
899  *
900  * c-nonce = printable
901  *
902  * client-first-message-bare =
903  * [reserved-mext ","]
904  * username "," nonce ["," extensions]
905  *
906  * client-first-message =
907  * gs2-header client-first-message-bare
908  *
909  * For example:
910  * n,,n=user,r=fyko+d2lbbFgONRv9qkxdawL
911  *
912  * The "n,," in the beginning means that the client doesn't support
913  * channel binding, and no authzid is given. "n=user" is the username.
914  * However, in PostgreSQL the username is sent in the startup packet, and
915  * the username in the SCRAM exchange is ignored. libpq always sends it
916  * as an empty string. The last part, "r=fyko+d2lbbFgONRv9qkxdawL" is
917  * the client nonce.
918  *------
919  */
920 
921  /*
922  * Read gs2-cbind-flag. (For details see also RFC 5802 Section 6 "Channel
923  * Binding".)
924  */
925  state->cbind_flag = *p;
926  switch (*p)
927  {
928  case 'n':
929 
930  /*
931  * The client does not support channel binding or has simply
932  * decided to not use it. In that case just let it go.
933  */
934  if (state->channel_binding_in_use)
935  ereport(ERROR,
936  (errcode(ERRCODE_PROTOCOL_VIOLATION),
937  errmsg("malformed SCRAM message"),
938  errdetail("The client selected SCRAM-SHA-256-PLUS, but the SCRAM message does not include channel binding data.")));
939 
940  p++;
941  if (*p != ',')
942  ereport(ERROR,
943  (errcode(ERRCODE_PROTOCOL_VIOLATION),
944  errmsg("malformed SCRAM message"),
945  errdetail("Comma expected, but found character \"%s\".",
946  sanitize_char(*p))));
947  p++;
948  break;
949  case 'y':
950 
951  /*
952  * The client supports channel binding and thinks that the server
953  * does not. In this case, the server must fail authentication if
954  * it supports channel binding.
955  */
956  if (state->channel_binding_in_use)
957  ereport(ERROR,
958  (errcode(ERRCODE_PROTOCOL_VIOLATION),
959  errmsg("malformed SCRAM message"),
960  errdetail("The client selected SCRAM-SHA-256-PLUS, but the SCRAM message does not include channel binding data.")));
961 
962 #ifdef HAVE_BE_TLS_GET_CERTIFICATE_HASH
963  if (state->port->ssl_in_use)
964  ereport(ERROR,
965  (errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),
966  errmsg("SCRAM channel binding negotiation error"),
967  errdetail("The client supports SCRAM channel binding but thinks the server does not. "
968  "However, this server does support channel binding.")));
969 #endif
970  p++;
971  if (*p != ',')
972  ereport(ERROR,
973  (errcode(ERRCODE_PROTOCOL_VIOLATION),
974  errmsg("malformed SCRAM message"),
975  errdetail("Comma expected, but found character \"%s\".",
976  sanitize_char(*p))));
977  p++;
978  break;
979  case 'p':
980 
981  /*
982  * The client requires channel binding. Channel binding type
983  * follows, e.g., "p=tls-server-end-point".
984  */
985  if (!state->channel_binding_in_use)
986  ereport(ERROR,
987  (errcode(ERRCODE_PROTOCOL_VIOLATION),
988  errmsg("malformed SCRAM message"),
989  errdetail("The client selected SCRAM-SHA-256 without channel binding, but the SCRAM message includes channel binding data.")));
990 
991  channel_binding_type = read_attr_value(&p, 'p');
992 
993  /*
994  * The only channel binding type we support is
995  * tls-server-end-point.
996  */
997  if (strcmp(channel_binding_type, "tls-server-end-point") != 0)
998  ereport(ERROR,
999  (errcode(ERRCODE_PROTOCOL_VIOLATION),
1000  (errmsg("unsupported SCRAM channel-binding type \"%s\"",
1001  sanitize_str(channel_binding_type)))));
1002  break;
1003  default:
1004  ereport(ERROR,
1005  (errcode(ERRCODE_PROTOCOL_VIOLATION),
1006  errmsg("malformed SCRAM message"),
1007  errdetail("Unexpected channel-binding flag \"%s\".",
1008  sanitize_char(*p))));
1009  }
1010 
1011  /*
1012  * Forbid optional authzid (authorization identity). We don't support it.
1013  */
1014  if (*p == 'a')
1015  ereport(ERROR,
1016  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1017  errmsg("client uses authorization identity, but it is not supported")));
1018  if (*p != ',')
1019  ereport(ERROR,
1020  (errcode(ERRCODE_PROTOCOL_VIOLATION),
1021  errmsg("malformed SCRAM message"),
1022  errdetail("Unexpected attribute \"%s\" in client-first-message.",
1023  sanitize_char(*p))));
1024  p++;
1025 
1026  state->client_first_message_bare = pstrdup(p);
1027 
1028  /*
1029  * Any mandatory extensions would go here. We don't support any.
1030  *
1031  * RFC 5802 specifies error code "e=extensions-not-supported" for this,
1032  * but it can only be sent in the server-final message. We prefer to fail
1033  * immediately (which the RFC also allows).
1034  */
1035  if (*p == 'm')
1036  ereport(ERROR,
1037  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1038  errmsg("client requires an unsupported SCRAM extension")));
1039 
1040  /*
1041  * Read username. Note: this is ignored. We use the username from the
1042  * startup message instead, still it is kept around if provided as it
1043  * proves to be useful for debugging purposes.
1044  */
1045  state->client_username = read_attr_value(&p, 'n');
1046 
1047  /* read nonce and check that it is made of only printable characters */
1048  state->client_nonce = read_attr_value(&p, 'r');
1049  if (!is_scram_printable(state->client_nonce))
1050  ereport(ERROR,
1051  (errcode(ERRCODE_PROTOCOL_VIOLATION),
1052  errmsg("non-printable characters in SCRAM nonce")));
1053 
1054  /*
1055  * There can be any number of optional extensions after this. We don't
1056  * support any extensions, so ignore them.
1057  */
1058  while (*p != '\0')
1059  read_any_attr(&p, NULL);
1060 
1061  /* success! */
1062 }
Port * port
Definition: auth-scram.c:125
char * pstrdup(const char *in)
Definition: mcxt.c:1186
static bool is_scram_printable(char *p)
Definition: auth-scram.c:721
int errcode(int sqlerrcode)
Definition: elog.c:608
bool ssl_in_use
Definition: libpq-be.h:190
char * client_nonce
Definition: auth-scram.c:137
#define ERROR
Definition: elog.h:43
int errdetail(const char *fmt,...)
Definition: elog.c:955
char * client_username
Definition: auth-scram.c:136
#define ereport(elevel, rest)
Definition: elog.h:141
char cbind_flag
Definition: auth-scram.c:134
static char * sanitize_str(const char *s)
Definition: auth-scram.c:769
static char * read_any_attr(char **input, char *attr_p)
Definition: auth-scram.c:797
static char * sanitize_char(char c)
Definition: auth-scram.c:749
static char * read_attr_value(char **input, char attr)
Definition: auth-scram.c:685
int errmsg(const char *fmt,...)
Definition: elog.c:822
bool channel_binding_in_use
Definition: auth-scram.c:126
char * client_first_message_bare
Definition: auth-scram.c:135

◆ sanitize_char()

static char * sanitize_char ( char  c)
static

Definition at line 749 of file auth-scram.c.

References buf, and snprintf.

Referenced by read_any_attr(), read_attr_value(), and read_client_first_message().

750 {
751  static char buf[5];
752 
753  if (c >= 0x21 && c <= 0x7E)
754  snprintf(buf, sizeof(buf), "'%c'", c);
755  else
756  snprintf(buf, sizeof(buf), "0x%02x", (unsigned char) c);
757  return buf;
758 }
char * c
static char * buf
Definition: pg_test_fsync.c:67
#define snprintf
Definition: port.h:192

◆ sanitize_str()

static char * sanitize_str ( const char *  s)
static

Definition at line 769 of file auth-scram.c.

References buf, and i.

Referenced by read_client_first_message().

770 {
771  static char buf[30 + 1];
772  int i;
773 
774  for (i = 0; i < sizeof(buf) - 1; i++)
775  {
776  char c = s[i];
777 
778  if (c == '\0')
779  break;
780 
781  if (c >= 0x21 && c <= 0x7E)
782  buf[i] = c;
783  else
784  buf[i] = '?';
785  }
786  buf[i] = '\0';
787  return buf;
788 }
char * c
static char * buf
Definition: pg_test_fsync.c:67
int i

◆ scram_mock_salt()

static char * scram_mock_salt ( const char *  username)
static

Definition at line 1394 of file auth-scram.c.

References GetMockAuthenticationNonce(), MOCK_AUTH_NONCE_LEN, PG_SHA256_DIGEST_LENGTH, pg_sha256_final(), pg_sha256_init(), pg_sha256_update(), SCRAM_DEFAULT_SALT_LEN, and StaticAssertStmt.

Referenced by mock_scram_secret().

1395 {
1396  pg_sha256_ctx ctx;
1397  static uint8 sha_digest[PG_SHA256_DIGEST_LENGTH];
1398  char *mock_auth_nonce = GetMockAuthenticationNonce();
1399 
1400  /*
1401  * Generate salt using a SHA256 hash of the username and the cluster's
1402  * mock authentication nonce. (This works as long as the salt length is
1403  * not larger the SHA256 digest length. If the salt is smaller, the caller
1404  * will just ignore the extra data.)
1405  */
1407  "salt length greater than SHA256 digest length");
1408 
1409  pg_sha256_init(&ctx);
1410  pg_sha256_update(&ctx, (uint8 *) username, strlen(username));
1411  pg_sha256_update(&ctx, (uint8 *) mock_auth_nonce, MOCK_AUTH_NONCE_LEN);
1412  pg_sha256_final(&ctx, sha_digest);
1413 
1414  return (char *) sha_digest;
1415 }
#define PG_SHA256_DIGEST_LENGTH
Definition: sha2.h:62
unsigned char uint8
Definition: c.h:357
void pg_sha256_init(pg_sha256_ctx *context)
Definition: sha2.c:268
#define MOCK_AUTH_NONCE_LEN
Definition: pg_control.h:28
#define StaticAssertStmt(condition, errmessage)
Definition: c.h:849
#define SCRAM_DEFAULT_SALT_LEN
Definition: scram-common.h:40
void pg_sha256_update(pg_sha256_ctx *context, const uint8 *data, size_t len)
Definition: sha2.c:465
static char * username
Definition: initdb.c:133
char * GetMockAuthenticationNonce(void)
Definition: xlog.c:4809
void pg_sha256_final(pg_sha256_ctx *context, uint8 *digest)
Definition: sha2.c:566

◆ scram_verify_plain_password()

bool scram_verify_plain_password ( const char *  username,
const char *  password,
const char *  secret 
)

Definition at line 488 of file auth-scram.c.

References ereport, errmsg(), LOG, palloc(), parse_scram_secret(), pfree(), pg_b64_dec_len(), pg_b64_decode(), pg_saslprep(), SASLPREP_SUCCESS, SCRAM_KEY_LEN, scram_SaltedPassword(), and scram_ServerKey().

Referenced by plain_crypt_verify().

490 {
491  char *encoded_salt;
492  char *salt;
493  int saltlen;
494  int iterations;
495  uint8 salted_password[SCRAM_KEY_LEN];
496  uint8 stored_key[SCRAM_KEY_LEN];
497  uint8 server_key[SCRAM_KEY_LEN];
498  uint8 computed_key[SCRAM_KEY_LEN];
499  char *prep_password;
500  pg_saslprep_rc rc;
501 
502  if (!parse_scram_secret(secret, &iterations, &encoded_salt,
503  stored_key, server_key))
504  {
505  /*
506  * The password looked like a SCRAM secret, but could not be parsed.
507  */
508  ereport(LOG,
509  (errmsg("invalid SCRAM secret for user \"%s\"", username)));
510  return false;
511  }
512 
513  saltlen = pg_b64_dec_len(strlen(encoded_salt));
514  salt = palloc(saltlen);
515  saltlen = pg_b64_decode(encoded_salt, strlen(encoded_salt), salt,
516  saltlen);
517  if (saltlen < 0)
518  {
519  ereport(LOG,
520  (errmsg("invalid SCRAM secret for user \"%s\"", username)));
521  return false;
522  }
523 
524  /* Normalize the password */
525  rc = pg_saslprep(password, &prep_password);
526  if (rc == SASLPREP_SUCCESS)
527  password = prep_password;
528 
529  /* Compute Server Key based on the user-supplied plaintext password */
530  scram_SaltedPassword(password, salt, saltlen, iterations, salted_password);
531  scram_ServerKey(salted_password, computed_key);
532 
533  if (prep_password)
534  pfree(prep_password);
535 
536  /*
537  * Compare the secret's Server Key with the one computed from the
538  * user-supplied password.
539  */
540  return memcmp(computed_key, server_key, SCRAM_KEY_LEN) == 0;
541 }
static char password[100]
Definition: streamutil.c:53
unsigned char uint8
Definition: c.h:357
void scram_SaltedPassword(const char *password, const char *salt, int saltlen, int iterations, uint8 *result)
Definition: scram-common.c:104
pg_saslprep_rc pg_saslprep(const char *input, char **output)
Definition: saslprep.c:1071
#define LOG
Definition: elog.h:26
int pg_b64_dec_len(int srclen)
Definition: base64.c:239
void scram_ServerKey(const uint8 *salted_password, uint8 *result)
Definition: scram-common.c:173
pg_saslprep_rc
Definition: saslprep.h:20
void pfree(void *pointer)
Definition: mcxt.c:1056
#define ereport(elevel, rest)
Definition: elog.h:141
int pg_b64_decode(const char *src, int len, char *dst, int dstlen)
Definition: base64.c:116
static char * username
Definition: initdb.c:133
bool parse_scram_secret(const char *secret, int *iterations, char **salt, uint8 *stored_key, uint8 *server_key)
Definition: auth-scram.c:556
void * palloc(Size size)
Definition: mcxt.c:949
int errmsg(const char *fmt,...)
Definition: elog.c:822
#define SCRAM_KEY_LEN
Definition: scram-common.h:23

◆ verify_client_proof()

static bool verify_client_proof ( scram_state state)
static

Definition at line 1090 of file auth-scram.c.

References scram_state::client_final_message_without_proof, scram_state::client_first_message_bare, scram_state::ClientProof, i, scram_H(), scram_HMAC_final(), scram_HMAC_init(), scram_HMAC_update(), SCRAM_KEY_LEN, scram_state::server_first_message, and scram_state::StoredKey.

Referenced by pg_be_scram_exchange().

1091 {
1092  uint8 ClientSignature[SCRAM_KEY_LEN];
1093  uint8 ClientKey[SCRAM_KEY_LEN];
1094  uint8 client_StoredKey[SCRAM_KEY_LEN];
1095  scram_HMAC_ctx ctx;
1096  int i;
1097 
1098  /* calculate ClientSignature */
1099  scram_HMAC_init(&ctx, state->StoredKey, SCRAM_KEY_LEN);
1100  scram_HMAC_update(&ctx,
1102  strlen(state->client_first_message_bare));
1103  scram_HMAC_update(&ctx, ",", 1);
1104  scram_HMAC_update(&ctx,
1105  state->server_first_message,
1106  strlen(state->server_first_message));
1107  scram_HMAC_update(&ctx, ",", 1);
1108  scram_HMAC_update(&ctx,
1110  strlen(state->client_final_message_without_proof));
1111  scram_HMAC_final(ClientSignature, &ctx);
1112 
1113  /* Extract the ClientKey that the client calculated from the proof */
1114  for (i = 0; i < SCRAM_KEY_LEN; i++)
1115  ClientKey[i] = state->ClientProof[i] ^ ClientSignature[i];
1116 
1117  /* Hash it one more time, and compare with StoredKey */
1118  scram_H(ClientKey, SCRAM_KEY_LEN, client_StoredKey);
1119 
1120  if (memcmp(client_StoredKey, state->StoredKey, SCRAM_KEY_LEN) != 0)
1121  return false;
1122 
1123  return true;
1124 }
void scram_H(const uint8 *input, int len, uint8 *result)
Definition: scram-common.c:147
uint8 StoredKey[SCRAM_KEY_LEN]
Definition: auth-scram.c:130
unsigned char uint8
Definition: c.h:357
char ClientProof[SCRAM_KEY_LEN]
Definition: auth-scram.c:142
char * client_final_message_without_proof
Definition: auth-scram.c:140
char * server_first_message
Definition: auth-scram.c:145
void scram_HMAC_final(uint8 *result, scram_HMAC_ctx *ctx)
Definition: scram-common.c:85
void scram_HMAC_init(scram_HMAC_ctx *ctx, const uint8 *key, int keylen)
Definition: scram-common.c:35
void scram_HMAC_update(scram_HMAC_ctx *ctx, const char *str, int slen)
Definition: scram-common.c:75
int i
#define SCRAM_KEY_LEN
Definition: scram-common.h:23
char * client_first_message_bare
Definition: auth-scram.c:135

◆ verify_final_nonce()

static bool verify_final_nonce ( scram_state state)
static

Definition at line 1069 of file auth-scram.c.

References scram_state::client_final_nonce, scram_state::client_nonce, and scram_state::server_nonce.

Referenced by pg_be_scram_exchange().

1070 {
1071  int client_nonce_len = strlen(state->client_nonce);
1072  int server_nonce_len = strlen(state->server_nonce);
1073  int final_nonce_len = strlen(state->client_final_nonce);
1074 
1075  if (final_nonce_len != client_nonce_len + server_nonce_len)
1076  return false;
1077  if (memcmp(state->client_final_nonce, state->client_nonce, client_nonce_len) != 0)
1078  return false;
1079  if (memcmp(state->client_final_nonce + client_nonce_len, state->server_nonce, server_nonce_len) != 0)
1080  return false;
1081 
1082  return true;
1083 }
char * client_nonce
Definition: auth-scram.c:137
char * client_final_nonce
Definition: auth-scram.c:141
char * server_nonce
Definition: auth-scram.c:146