diff options
Diffstat (limited to 'kopete/protocols/yahoo/libkyahoo/crypt.c')
| -rw-r--r-- | kopete/protocols/yahoo/libkyahoo/crypt.c | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/kopete/protocols/yahoo/libkyahoo/crypt.c b/kopete/protocols/yahoo/libkyahoo/crypt.c new file mode 100644 index 00000000..3aabeced --- /dev/null +++ b/kopete/protocols/yahoo/libkyahoo/crypt.c @@ -0,0 +1,210 @@ +/* One way encryption based on MD5 sum. + Copyright (C) 1996, 1997, 1999, 2000 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +/* warmenhoven took this file and made it work with the md5.[ch] we + * already had. isn't that lovely. people should just use linux or + * freebsd, crypt works properly on those systems. i hate solaris */ + +#if HAVE_CONFIG_H +# include <config.h> +#endif + +#if HAVE_STRING_H +# include <string.h> +#elif HAVE_STRINGS_H +# include <strings.h> +#endif + +#include <stdlib.h> + +#include "md5.h" +/* for MIN and MAX */ +#include "libyahoo.h" + +/* Define our magic string to mark salt for MD5 "encryption" + replacement. This is meant to be the same as for other MD5 based + encryption implementations. */ +static const char md5_salt_prefix[] = "$1$"; + +/* Table with characters for base64 transformation. */ +static const char b64t[64] = +"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"; + +char *yahoo_crypt(const char *key, const char *salt); + +char *yahoo_crypt(const char *key, const char *salt) +{ + char *buffer = NULL; + int buflen = 0; + int needed = 3 + strlen (salt) + 1 + 26 + 1; + + md5_byte_t alt_result[16]; + md5_state_t ctx; + md5_state_t alt_ctx; + size_t salt_len; + size_t key_len; + size_t cnt; + char *cp; + + if (buflen < needed) { + buflen = needed; + if ((buffer = realloc(buffer, buflen)) == NULL) + return NULL; + } + + /* Find beginning of salt string. The prefix should normally always + be present. Just in case it is not. */ + if (strncmp (md5_salt_prefix, salt, sizeof (md5_salt_prefix) - 1) == 0) + /* Skip salt prefix. */ + salt += sizeof (md5_salt_prefix) - 1; + + salt_len = MIN (strcspn (salt, "$"), 8); + key_len = strlen (key); + + /* Prepare for the real work. */ + md5_init(&ctx); + + /* Add the key string. */ + md5_append(&ctx, (md5_byte_t *)key, key_len); + + /* Because the SALT argument need not always have the salt prefix we + add it separately. */ + md5_append(&ctx, (md5_byte_t *)md5_salt_prefix, sizeof (md5_salt_prefix) - 1); + + /* The last part is the salt string. This must be at most 8 + characters and it ends at the first `$' character (for + compatibility which existing solutions). */ + md5_append(&ctx, (md5_byte_t *)salt, salt_len); + + /* Compute alternate MD5 sum with input KEY, SALT, and KEY. The + final result will be added to the first context. */ + md5_init(&alt_ctx); + + /* Add key. */ + md5_append(&alt_ctx, (md5_byte_t *)key, key_len); + + /* Add salt. */ + md5_append(&alt_ctx, (md5_byte_t *)salt, salt_len); + + /* Add key again. */ + md5_append(&alt_ctx, (md5_byte_t *)key, key_len); + + /* Now get result of this (16 bytes) and add it to the other + context. */ + md5_finish(&alt_ctx, alt_result); + + /* Add for any character in the key one byte of the alternate sum. */ + for (cnt = key_len; cnt > 16; cnt -= 16) + md5_append(&ctx, alt_result, 16); + md5_append(&ctx, alt_result, cnt); + + /* For the following code we need a NUL byte. */ + alt_result[0] = '\0'; + + /* The original implementation now does something weird: for every 1 + bit in the key the first 0 is added to the buffer, for every 0 + bit the first character of the key. This does not seem to be + what was intended but we have to follow this to be compatible. */ + for (cnt = key_len; cnt > 0; cnt >>= 1) + md5_append(&ctx, (cnt & 1) != 0 ? alt_result : (md5_byte_t *)key, 1); + + /* Create intermediate result. */ + md5_finish(&ctx, alt_result); + + /* Now comes another weirdness. In fear of password crackers here + comes a quite long loop which just processes the output of the + previous round again. We cannot ignore this here. */ + for (cnt = 0; cnt < 1000; ++cnt) { + /* New context. */ + md5_init(&ctx); + + /* Add key or last result. */ + if ((cnt & 1) != 0) + md5_append(&ctx, (md5_byte_t *)key, key_len); + else + md5_append(&ctx, alt_result, 16); + + /* Add salt for numbers not divisible by 3. */ + if (cnt % 3 != 0) + md5_append(&ctx, (md5_byte_t *)salt, salt_len); + + /* Add key for numbers not divisible by 7. */ + if (cnt % 7 != 0) + md5_append(&ctx, (md5_byte_t *)key, key_len); + + /* Add key or last result. */ + if ((cnt & 1) != 0) + md5_append(&ctx, alt_result, 16); + else + md5_append(&ctx, (md5_byte_t *)key, key_len); + + /* Create intermediate result. */ + md5_finish(&ctx, alt_result); + } + + /* Now we can construct the result string. It consists of three + parts. */ + + strncpy(buffer, md5_salt_prefix, MAX (0, buflen)); + cp = buffer + strlen(buffer); + buflen -= sizeof (md5_salt_prefix); + + strncpy(cp, salt, MIN ((size_t) buflen, salt_len)); + cp = cp + strlen(cp); + buflen -= MIN ((size_t) buflen, salt_len); + + if (buflen > 0) { + *cp++ = '$'; + --buflen; + } + +#define b64_from_24bit(B2, B1, B0, N) \ + do { \ + unsigned int w = ((B2) << 16) | ((B1) << 8) | (B0); \ + int n = (N); \ + while (n-- > 0 && buflen > 0) { \ + *cp++ = b64t[w & 0x3f]; \ + --buflen; \ + w >>= 6; \ + }\ + } while (0) + + b64_from_24bit (alt_result[0], alt_result[6], alt_result[12], 4); + b64_from_24bit (alt_result[1], alt_result[7], alt_result[13], 4); + b64_from_24bit (alt_result[2], alt_result[8], alt_result[14], 4); + b64_from_24bit (alt_result[3], alt_result[9], alt_result[15], 4); + b64_from_24bit (alt_result[4], alt_result[10], alt_result[5], 4); + b64_from_24bit (0, 0, alt_result[11], 2); + if (buflen <= 0) { + FREE(buffer); + } else + *cp = '\0'; /* Terminate the string. */ + + /* Clear the buffer for the intermediate result so that people + attaching to processes or reading core dumps cannot get any + information. We do it in this way to clear correct_words[] + inside the MD5 implementation as well. */ + md5_init(&ctx); + md5_finish(&ctx, alt_result); + memset (&ctx, '\0', sizeof (ctx)); + memset (&alt_ctx, '\0', sizeof (alt_ctx)); + + return buffer; +} |