px.c

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/*
 * px.c
 *      Various cryptographic stuff for PostgreSQL.
 *
 * Copyright (c) 2001 Marko Kreen
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * contrib/pgcrypto/px.c
 */
 
#include "postgres.h"
 
#include "px.h"
 
struct error_desc
{
    int         err;
    const char *desc;
};
 
static const struct error_desc px_err_list[] = {
    {PXE_OK, "Everything ok"},
    {PXE_NO_HASH, "No such hash algorithm"},
    {PXE_NO_CIPHER, "No such cipher algorithm"},
    {PXE_BAD_OPTION, "Unknown option"},
    {PXE_BAD_FORMAT, "Badly formatted type"},
    {PXE_KEY_TOO_BIG, "Key was too big"},
    {PXE_CIPHER_INIT, "Cipher cannot be initialized"},
    {PXE_HASH_UNUSABLE_FOR_HMAC, "This hash algorithm is unusable for HMAC"},
    {PXE_BUG, "pgcrypto bug"},
    {PXE_ARGUMENT_ERROR, "Illegal argument to function"},
    {PXE_UNKNOWN_SALT_ALGO, "Unknown salt algorithm"},
    {PXE_BAD_SALT_ROUNDS, "Incorrect number of rounds"},
    {PXE_NO_RANDOM, "Failed to generate strong random bits"},
    {PXE_DECRYPT_FAILED, "Decryption failed"},
    {PXE_ENCRYPT_FAILED, "Encryption failed"},
    {PXE_PGP_CORRUPT_DATA, "Wrong key or corrupt data"},
    {PXE_PGP_CORRUPT_ARMOR, "Corrupt ascii-armor"},
    {PXE_PGP_UNSUPPORTED_COMPR, "Unsupported compression algorithm"},
    {PXE_PGP_UNSUPPORTED_CIPHER, "Unsupported cipher algorithm"},
    {PXE_PGP_UNSUPPORTED_HASH, "Unsupported digest algorithm"},
    {PXE_PGP_COMPRESSION_ERROR, "Compression error"},
    {PXE_PGP_NOT_TEXT, "Not text data"},
    {PXE_PGP_UNEXPECTED_PKT, "Unexpected packet in key data"},
    {PXE_PGP_MATH_FAILED, "Math operation failed"},
    {PXE_PGP_SHORT_ELGAMAL_KEY, "Elgamal keys must be at least 1024 bits long"},
    {PXE_PGP_UNKNOWN_PUBALGO, "Unknown public-key encryption algorithm"},
    {PXE_PGP_WRONG_KEY, "Wrong key"},
    {PXE_PGP_MULTIPLE_KEYS,
    "Several keys given - pgcrypto does not handle keyring"},
    {PXE_PGP_EXPECT_PUBLIC_KEY, "Refusing to encrypt with secret key"},
    {PXE_PGP_EXPECT_SECRET_KEY, "Cannot decrypt with public key"},
    {PXE_PGP_NOT_V4_KEYPKT, "Only V4 key packets are supported"},
    {PXE_PGP_KEYPKT_CORRUPT, "Corrupt key packet"},
    {PXE_PGP_NO_USABLE_KEY, "No encryption key found"},
    {PXE_PGP_NEED_SECRET_PSW, "Need password for secret key"},
    {PXE_PGP_BAD_S2K_MODE, "Bad S2K mode"},
    {PXE_PGP_UNSUPPORTED_PUBALGO, "Unsupported public key algorithm"},
    {PXE_PGP_MULTIPLE_SUBKEYS, "Several subkeys not supported"},
 
    {0, NULL},
};
 
/*
 * Call ereport(ERROR, ...), with an error code and message corresponding to
 * the PXE_* error code given as argument.
 *
 * This is similar to px_strerror(err), but for some errors, we fill in the
 * error code and detail fields more appropriately.
 */
void
px_THROW_ERROR(int err)
{
    if (err == PXE_NO_RANDOM)
    {
        ereport(ERROR,
                (errcode(ERRCODE_INTERNAL_ERROR),
                 errmsg("could not generate a random number")));
    }
    else
    {
        /* For other errors, use the message from the above list. */
        ereport(ERROR,
                (errcode(ERRCODE_EXTERNAL_ROUTINE_INVOCATION_EXCEPTION),
                 errmsg("%s", px_strerror(err))));
    }
}
 
const char *
px_strerror(int err)
{
    const struct error_desc *e;
 
    for (e = px_err_list; e->desc; e++)
        if (e->err == err)
            return e->desc;
    return "Bad error code";
}
 
/* memset that must not be optimized away */
void
px_memset(void *ptr, int c, size_t len)
{
    memset(ptr, c, len);
}
 
const char *
px_resolve_alias(const PX_Alias *list, const char *name)
{
    while (list->name)
    {
        if (pg_strcasecmp(list->alias, name) == 0)
            return list->name;
        list++;
    }
    return name;
}
 
static void (*debug_handler) (const char *) = NULL;
 
void
px_set_debug_handler(void (*handler) (const char *))
{
    debug_handler = handler;
}
 
void
px_debug(const char *fmt,...)
{
    va_list     ap;
 
    va_start(ap, fmt);
    if (debug_handler)
    {
        char        buf[512];
 
        vsnprintf(buf, sizeof(buf), fmt, ap);
        debug_handler(buf);
    }
    va_end(ap);
}
 
/*
 * combo - cipher + padding (+ checksum)
 */
 
static unsigned
combo_encrypt_len(PX_Combo *cx, unsigned dlen)
{
    return dlen + 512;
}
 
static unsigned
combo_decrypt_len(PX_Combo *cx, unsigned dlen)
{
    return dlen;
}
 
static int
combo_init(PX_Combo *cx, const uint8 *key, unsigned klen,
           const uint8 *iv, unsigned ivlen)
{
    int         err;
    unsigned    ks,
                ivs;
    PX_Cipher  *c = cx->cipher;
    uint8      *ivbuf = NULL;
    uint8      *keybuf;
 
    ks = px_cipher_key_size(c);
 
    ivs = px_cipher_iv_size(c);
    if (ivs > 0)
    {
        ivbuf = palloc0(ivs);
        if (ivlen > ivs)
            memcpy(ivbuf, iv, ivs);
        else if (ivlen > 0)
            memcpy(ivbuf, iv, ivlen);
    }
 
    if (klen > ks)
        klen = ks;
    keybuf = palloc0(ks);
    memcpy(keybuf, key, klen);
 
    err = px_cipher_init(c, keybuf, klen, ivbuf);
 
    if (ivbuf)
        pfree(ivbuf);
    pfree(keybuf);
 
    return err;
}
 
static int
combo_encrypt(PX_Combo *cx, const uint8 *data, unsigned dlen,
              uint8 *res, unsigned *rlen)
{
    return px_cipher_encrypt(cx->cipher, cx->padding, data, dlen, res, rlen);
}
 
static int
combo_decrypt(PX_Combo *cx, const uint8 *data, unsigned dlen,
              uint8 *res, unsigned *rlen)
{
    return px_cipher_decrypt(cx->cipher, cx->padding, data, dlen, res, rlen);
}
 
static void
combo_free(PX_Combo *cx)
{
    if (cx->cipher)
        px_cipher_free(cx->cipher);
    px_memset(cx, 0, sizeof(*cx));
    pfree(cx);
}
 
/* PARSER */
 
static int
parse_cipher_name(char *full, char **cipher, char **pad)
{
    char       *p,
               *p2,
               *q;
 
    *cipher = full;
    *pad = NULL;
 
    p = strchr(full, '/');
    if (p != NULL)
        *p++ = 0;
    while (p != NULL)
    {
        if ((q = strchr(p, '/')) != NULL)
            *q++ = 0;
 
        if (!*p)
        {
            p = q;
            continue;
        }
        p2 = strchr(p, ':');
        if (p2 != NULL)
        {
            *p2++ = 0;
            if (strcmp(p, "pad") == 0)
                *pad = p2;
            else
                return PXE_BAD_OPTION;
        }
        else
            return PXE_BAD_FORMAT;
 
        p = q;
    }
    return 0;
}
 
/* provider */
 
int
px_find_combo(const char *name, PX_Combo **res)
{
    int         err;
    char       *buf,
               *s_cipher,
               *s_pad;
 
    PX_Combo   *cx;
 
    cx = palloc0(sizeof(*cx));
    buf = pstrdup(name);
 
    err = parse_cipher_name(buf, &s_cipher, &s_pad);
    if (err)
    {
        pfree(buf);
        pfree(cx);
        return err;
    }
 
    err = px_find_cipher(s_cipher, &cx->cipher);
    if (err)
        goto err1;
 
    if (s_pad != NULL)
    {
        if (strcmp(s_pad, "pkcs") == 0)
            cx->padding = 1;
        else if (strcmp(s_pad, "none") == 0)
            cx->padding = 0;
        else
            goto err1;
    }
    else
        cx->padding = 1;
 
    cx->init = combo_init;
    cx->encrypt = combo_encrypt;
    cx->decrypt = combo_decrypt;
    cx->encrypt_len = combo_encrypt_len;
    cx->decrypt_len = combo_decrypt_len;
    cx->free = combo_free;
 
    pfree(buf);
 
    *res = cx;
 
    return 0;
 
err1:
    if (cx->cipher)
        px_cipher_free(cx->cipher);
    pfree(cx);
    pfree(buf);
    return PXE_NO_CIPHER;
}