postgresql/contrib/pgcrypto/px.c
Heikki Linnakangas bf723a274c Forbid gen_random_uuid() with --disable-strong-random
Previously, gen_random_uuid() would fall back to a weak random number
generator, unlike gen_random_bytes() which would just fail. And this was
not made very clear in the docs. For consistency, also make
gen_random_uuid() fail outright, if compiled with --disable-strong-random.

Re-word the error message you get with --disable-strong-random. It is also
used by pgp functions that require random salts, and now also
gen_random_uuid().

Reported by Radek Slupik.

Discussion: https://www.postgresql.org/message-id/20170101232054.10135.50528@wrigleys.postgresql.org
2017-07-03 12:10:11 +03:00

469 lines
9.8 KiB
C

/*
* 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_ERR_GENERIC, "Some PX error (not specified)"},
{PXE_NO_HASH, "No such hash algorithm"},
{PXE_NO_CIPHER, "No such cipher algorithm"},
{PXE_NOTBLOCKSIZE, "Data not a multiple of block size"},
{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_DEV_READ_ERROR, "Error reading from random device"},
{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_MCRYPT_INTERNAL, "mcrypt internal error"},
{PXE_NO_RANDOM, "No strong random source"},
{PXE_DECRYPT_FAILED, "Decryption 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)
{
#ifdef HAVE_STRONG_RANDOM
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("could not generate a random number")));
#else
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("generating random data is not supported by this build"),
errdetail("This functionality requires a source of strong random numbers"),
errhint("You need to rebuild PostgreSQL using --enable-strong-random")));
#endif
}
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 = px_alloc(ivs);
memset(ivbuf, 0, ivs);
if (ivlen > ivs)
memcpy(ivbuf, iv, ivs);
else
memcpy(ivbuf, iv, ivlen);
}
if (klen > ks)
klen = ks;
keybuf = px_alloc(ks);
memset(keybuf, 0, ks);
memcpy(keybuf, key, klen);
err = px_cipher_init(c, keybuf, klen, ivbuf);
if (ivbuf)
px_free(ivbuf);
px_free(keybuf);
return err;
}
static int
combo_encrypt(PX_Combo *cx, const uint8 *data, unsigned dlen,
uint8 *res, unsigned *rlen)
{
int err = 0;
uint8 *bbuf;
unsigned bs,
bpos,
i,
pad;
PX_Cipher *c = cx->cipher;
bbuf = NULL;
bs = px_cipher_block_size(c);
/* encrypt */
if (bs > 1)
{
bbuf = px_alloc(bs * 4);
bpos = dlen % bs;
*rlen = dlen - bpos;
memcpy(bbuf, data + *rlen, bpos);
/* encrypt full-block data */
if (*rlen)
{
err = px_cipher_encrypt(c, data, *rlen, res);
if (err)
goto out;
}
/* bbuf has now bpos bytes of stuff */
if (cx->padding)
{
pad = bs - (bpos % bs);
for (i = 0; i < pad; i++)
bbuf[bpos++] = pad;
}
else if (bpos % bs)
{
/* ERROR? */
pad = bs - (bpos % bs);
for (i = 0; i < pad; i++)
bbuf[bpos++] = 0;
}
/* encrypt the rest - pad */
if (bpos)
{
err = px_cipher_encrypt(c, bbuf, bpos, res + *rlen);
*rlen += bpos;
}
}
else
{
/* stream cipher/mode - no pad needed */
err = px_cipher_encrypt(c, data, dlen, res);
if (err)
goto out;
*rlen = dlen;
}
out:
if (bbuf)
px_free(bbuf);
return err;
}
static int
combo_decrypt(PX_Combo *cx, const uint8 *data, unsigned dlen,
uint8 *res, unsigned *rlen)
{
unsigned bs,
i,
pad;
unsigned pad_ok;
PX_Cipher *c = cx->cipher;
/* decide whether zero-length input is allowed */
if (dlen == 0)
{
/* with padding, empty ciphertext is not allowed */
if (cx->padding)
return PXE_DECRYPT_FAILED;
/* without padding, report empty result */
*rlen = 0;
return 0;
}
bs = px_cipher_block_size(c);
if (bs > 1 && (dlen % bs) != 0)
goto block_error;
/* decrypt */
*rlen = dlen;
px_cipher_decrypt(c, data, dlen, res);
/* unpad */
if (bs > 1 && cx->padding)
{
pad = res[*rlen - 1];
pad_ok = 0;
if (pad > 0 && pad <= bs && pad <= *rlen)
{
pad_ok = 1;
for (i = *rlen - pad; i < *rlen; i++)
if (res[i] != pad)
{
pad_ok = 0;
break;
}
}
if (pad_ok)
*rlen -= pad;
}
return 0;
block_error:
return PXE_NOTBLOCKSIZE;
}
static void
combo_free(PX_Combo *cx)
{
if (cx->cipher)
px_cipher_free(cx->cipher);
px_memset(cx, 0, sizeof(*cx));
px_free(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 = px_alloc(sizeof(*cx));
memset(cx, 0, sizeof(*cx));
buf = px_alloc(strlen(name) + 1);
strcpy(buf, name);
err = parse_cipher_name(buf, &s_cipher, &s_pad);
if (err)
{
px_free(buf);
px_free(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;
px_free(buf);
*res = cx;
return 0;
err1:
if (cx->cipher)
px_cipher_free(cx->cipher);
px_free(cx);
px_free(buf);
return PXE_NO_CIPHER;
}