1 files changed, 207 insertions, 0 deletions
diff --git a/protocols/yahoo/crypt.c b/protocols/yahoo/crypt.c
new file mode 100644
index 00000000..00eed70b
--- /dev/null
+++ b/protocols/yahoo/crypt.c
@@ -0,0 +1,207 @@
+/* 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 "yahoo_util.h"
+
+#include "md5.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(char *key, 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;
+}