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Diffstat (limited to 'contrib/pgcrypto/pgp-s2k.c')
| -rw-r--r-- | contrib/pgcrypto/pgp-s2k.c | 308 |
1 files changed, 308 insertions, 0 deletions
diff --git a/contrib/pgcrypto/pgp-s2k.c b/contrib/pgcrypto/pgp-s2k.c new file mode 100644 index 0000000..81ca1f0 --- /dev/null +++ b/contrib/pgcrypto/pgp-s2k.c @@ -0,0 +1,308 @@ +/* + * pgp-s2k.c + * OpenPGP string2key functions. + * + * Copyright (c) 2005 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/pgp-s2k.c + */ + +#include "postgres.h" + +#include "pgp.h" +#include "px.h" + +static int +calc_s2k_simple(PGP_S2K *s2k, PX_MD *md, const uint8 *key, + unsigned key_len) +{ + unsigned md_rlen; + uint8 buf[PGP_MAX_DIGEST]; + unsigned preload; + unsigned remain; + uint8 *dst = s2k->key; + + md_rlen = px_md_result_size(md); + + remain = s2k->key_len; + preload = 0; + while (remain > 0) + { + px_md_reset(md); + + if (preload) + { + memset(buf, 0, preload); + px_md_update(md, buf, preload); + } + preload++; + + px_md_update(md, key, key_len); + px_md_finish(md, buf); + + if (remain > md_rlen) + { + memcpy(dst, buf, md_rlen); + dst += md_rlen; + remain -= md_rlen; + } + else + { + memcpy(dst, buf, remain); + remain = 0; + } + } + px_memset(buf, 0, sizeof(buf)); + return 0; +} + +static int +calc_s2k_salted(PGP_S2K *s2k, PX_MD *md, const uint8 *key, unsigned key_len) +{ + unsigned md_rlen; + uint8 buf[PGP_MAX_DIGEST]; + unsigned preload = 0; + uint8 *dst; + unsigned remain; + + md_rlen = px_md_result_size(md); + + dst = s2k->key; + remain = s2k->key_len; + while (remain > 0) + { + px_md_reset(md); + + if (preload > 0) + { + memset(buf, 0, preload); + px_md_update(md, buf, preload); + } + preload++; + + px_md_update(md, s2k->salt, PGP_S2K_SALT); + px_md_update(md, key, key_len); + px_md_finish(md, buf); + + if (remain > md_rlen) + { + memcpy(dst, buf, md_rlen); + remain -= md_rlen; + dst += md_rlen; + } + else + { + memcpy(dst, buf, remain); + remain = 0; + } + } + px_memset(buf, 0, sizeof(buf)); + return 0; +} + +static int +calc_s2k_iter_salted(PGP_S2K *s2k, PX_MD *md, const uint8 *key, + unsigned key_len) +{ + unsigned md_rlen; + uint8 buf[PGP_MAX_DIGEST]; + uint8 *dst; + unsigned preload = 0; + unsigned remain, + c, + curcnt, + count; + + count = s2k_decode_count(s2k->iter); + + md_rlen = px_md_result_size(md); + + remain = s2k->key_len; + dst = s2k->key; + while (remain > 0) + { + px_md_reset(md); + + if (preload) + { + memset(buf, 0, preload); + px_md_update(md, buf, preload); + } + preload++; + + px_md_update(md, s2k->salt, PGP_S2K_SALT); + px_md_update(md, key, key_len); + curcnt = PGP_S2K_SALT + key_len; + + while (curcnt < count) + { + if (curcnt + PGP_S2K_SALT < count) + c = PGP_S2K_SALT; + else + c = count - curcnt; + px_md_update(md, s2k->salt, c); + curcnt += c; + + if (curcnt + key_len < count) + c = key_len; + else if (curcnt < count) + c = count - curcnt; + else + break; + px_md_update(md, key, c); + curcnt += c; + } + px_md_finish(md, buf); + + if (remain > md_rlen) + { + memcpy(dst, buf, md_rlen); + remain -= md_rlen; + dst += md_rlen; + } + else + { + memcpy(dst, buf, remain); + remain = 0; + } + } + px_memset(buf, 0, sizeof(buf)); + return 0; +} + +/* + * Decide PGP_S2K_ISALTED iteration count (in OpenPGP one-byte representation) + * + * Too small: weak + * Too big: slow + * gpg defaults to 96 => 65536 iters + * + * For our default (count=-1) we let it float a bit: 96 + 32 => between 65536 + * and 262144 iterations. + * + * Otherwise, find the smallest number which provides at least the specified + * iteration count. + */ +static uint8 +decide_s2k_iter(unsigned rand_byte, int count) +{ + int iter; + + if (count == -1) + return 96 + (rand_byte & 0x1F); + /* this is a bit brute-force, but should be quick enough */ + for (iter = 0; iter <= 255; iter++) + if (s2k_decode_count(iter) >= count) + return iter; + return 255; +} + +int +pgp_s2k_fill(PGP_S2K *s2k, int mode, int digest_algo, int count) +{ + int res = 0; + uint8 tmp; + + s2k->mode = mode; + s2k->digest_algo = digest_algo; + + switch (s2k->mode) + { + case PGP_S2K_SIMPLE: + break; + case PGP_S2K_SALTED: + if (!pg_strong_random(s2k->salt, PGP_S2K_SALT)) + return PXE_NO_RANDOM; + break; + case PGP_S2K_ISALTED: + if (!pg_strong_random(s2k->salt, PGP_S2K_SALT)) + return PXE_NO_RANDOM; + if (!pg_strong_random(&tmp, 1)) + return PXE_NO_RANDOM; + s2k->iter = decide_s2k_iter(tmp, count); + break; + default: + res = PXE_PGP_BAD_S2K_MODE; + } + return res; +} + +int +pgp_s2k_read(PullFilter *src, PGP_S2K *s2k) +{ + int res = 0; + + GETBYTE(src, s2k->mode); + GETBYTE(src, s2k->digest_algo); + switch (s2k->mode) + { + case 0: + break; + case 1: + res = pullf_read_fixed(src, 8, s2k->salt); + break; + case 3: + res = pullf_read_fixed(src, 8, s2k->salt); + if (res < 0) + break; + GETBYTE(src, s2k->iter); + break; + default: + res = PXE_PGP_BAD_S2K_MODE; + } + return res; +} + +int +pgp_s2k_process(PGP_S2K *s2k, int cipher, const uint8 *key, int key_len) +{ + int res; + PX_MD *md; + + s2k->key_len = pgp_get_cipher_key_size(cipher); + if (s2k->key_len <= 0) + return PXE_PGP_UNSUPPORTED_CIPHER; + + res = pgp_load_digest(s2k->digest_algo, &md); + if (res < 0) + return res; + + switch (s2k->mode) + { + case 0: + res = calc_s2k_simple(s2k, md, key, key_len); + break; + case 1: + res = calc_s2k_salted(s2k, md, key, key_len); + break; + case 3: + res = calc_s2k_iter_salted(s2k, md, key, key_len); + break; + default: + res = PXE_PGP_BAD_S2K_MODE; + } + px_md_free(md); + return res; +} |