/* Opie (s/key) support for FTP.
- Copyright (C) 1998 Free Software Foundation, Inc.
+ Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
+ 2007 Free Software Foundation, Inc.
This file is part of GNU Wget.
GNU Wget is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
-the Free Software Foundation; either version 2 of the License, or
+the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
GNU Wget is distributed in the hope that it will be useful,
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
-along with Wget; if not, write to the Free Software
-Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+along with Wget. If not, see <http://www.gnu.org/licenses/>.
In addition, as a special exception, the Free Software Foundation
gives permission to link the code of its release of Wget with the
file, but you are not obligated to do so. If you do not wish to do
so, delete this exception statement from your version. */
-#include <config.h>
+#include "wget.h"
#include <stdio.h>
#include <stdlib.h>
-#ifdef HAVE_STRING_H
-# include <string.h>
-#else
-# include <strings.h>
-#endif
+#include <string.h>
-#include "wget.h"
#include "gen-md5.h"
+#include "ftp.h"
-/* Dictionary for integer-word translations. */
-static char Wp[2048][4] = {
+/* Dictionary for integer-word translations. Available in appendix D
+ of rfc2289. */
+ static char Wp[2048][4] = {
{ 'A', '\0', '\0', '\0' },
{ 'A', 'B', 'E', '\0' },
{ 'A', 'C', 'E', '\0' },
};
/* Extract LENGTH bits from the char array S starting with bit number
- START. */
-static unsigned long
-extract (const char *s, int start, int length)
+ START. It always reads three consecutive octects, which means it
+ can read past end of data when START is at the edge of the region. */
+
+static uint32_t
+extract (const unsigned char *s, int start, int length)
{
unsigned char cl = s[start / 8];
unsigned char cc = s[start / 8 + 1];
unsigned char cr = s[start / 8 + 2];
- unsigned long x = ((long)(cl << 8 | cc) << 8 | cr);
-
- x = x >> (24 - (length + (start % 8)));
- x = (x & (0xffff >> (16 - length)));
+ uint32_t x;
+ x = (uint32_t)(cl << 8 | cc) << 8 | cr;
+ x >>= 24 - (length + (start % 8));
+ x &= (0xffff >> (16 - length));
return x;
}
-#define STRLEN4(s) (!*(s) ? 0 : \
- (!*(s + 1) ? 1 : \
- (!*(s + 2) ? 2 : \
- (!*(s + 3) ? 3 : 4))))
+/* Length of a string known to be at least 1 and at most 4 chars
+ long. */
+
+#define STRLEN_1_4(s) (!(s)[1] ? 1 : !(s)[2] ? 2 : !(s)[3] ? 3 : 4)
/* Encode 8 bytes in C as a string of English words and store them to
STORE. Returns STORE. */
+
static char *
-btoe (char *store, const char *c)
+btoe (char *store, const unsigned char *c)
{
- char cp[10]; /* add in room for the parity 2 bits +
- extract() slop. */
+ unsigned char cp[10]; /* add in room for the parity 2 bits +
+ extract() slop. */
int p, i;
- char *ostore = store;
+ char *store_beg = store;
*store = '\0';
+
/* Workaround for extract() reads beyond end of data */
- memset (cp, 0, sizeof(cp));
+ xzero (cp);
memcpy (cp, c, 8);
- /* Compute parity. */
+
+ /* Compute parity and append it to CP. */
for (p = 0, i = 0; i < 64; i += 2)
p += extract (cp, i, 2);
-
cp[8] = (char)p << 6;
+
+ /* The 64 bits of input and the two parity bits comprise 66 bits of
+ data that are now in CP. We convert that information, 11 bits at
+ a time, to English words indexed from Wp. Since there are 2048
+ (2^11) words in Wp, every 11-bit combination corresponds to a
+ distinct word. */
memcpy (store, &Wp[extract (cp, 0, 11)][0], 4);
- store += STRLEN4 (store);
+ store += STRLEN_1_4 (store);
*store++ = ' ';
memcpy (store, &Wp[extract (cp, 11, 11)][0], 4);
- store += STRLEN4 (store);
+ store += STRLEN_1_4 (store);
*store++ = ' ';
memcpy (store, &Wp[extract (cp, 22, 11)][0], 4);
- store += STRLEN4 (store);
+ store += STRLEN_1_4 (store);
*store++ = ' ';
memcpy (store, &Wp[extract (cp, 33, 11)][0], 4);
- store += STRLEN4 (store);
+ store += STRLEN_1_4 (store);
*store++ = ' ';
memcpy (store, &Wp[extract (cp, 44, 11)][0], 4);
- store += STRLEN4 (store);
+ store += STRLEN_1_4 (store);
*store++ = ' ';
memcpy (store, &Wp[extract (cp, 55, 11)][0], 4);
+ store[4] = '\0'; /* make sure the string is terminated */
- store[4] = '\0'; /* make sure the string is zero-terminated */
+ DEBUGP (("wrote `%s' to STORE\n", store_beg));
+ return store_beg;
+}
- DEBUGP (("store is `%s'\n", ostore));
+/* Calculate the SKEY response, based on the sequence, seed
+ (challenge), and the secret password. The calculated response is
+ used instead of the real password when logging in to SKEY-enabled
+ servers.
- return ostore;
-}
+ The result is calculated like this:
+
+ + Concatenate SEED and PASS and calculate the 16-byte MD5 checksum.
+
+ + Shorten the checksum to eight bytes by folding the second eight
+ bytes onto the first eight using XOR. The resulting eight-byte
+ sequence is the key.
+
+ + MD5-process the key, fold the checksum to eight bytes and store
+ it back to the key. Repeat this crunching SEQUENCE times.
+ (Sequence is a number that gets decremented every time the user
+ logs in to the server. Therefore an eavesdropper would have to
+ invert the hash function in order to guess the next one-time
+ password.)
+
+ + Convert the resulting 64-bit key to 6 English words separated by
+ spaces (see btoe for details) and return the resulting ASCII
+ string.
+
+ All this is described in section 6 of rfc2289 in more detail. */
-/* #### Document me! */
const char *
-calculate_skey_response (int sequence, const char *seed, const char *pass)
+skey_response (int sequence, const char *seed, const char *pass)
{
- char key[8];
- static char buf[33];
-
- ALLOCA_MD5_CONTEXT (ctx);
- unsigned long results[4]; /* #### this looks 32-bit-minded */
- char *feed = (char *) alloca (strlen (seed) + strlen (pass) + 1);
+ unsigned char key[8];
- strcpy (feed, seed);
- strcat (feed, pass);
+ /* Room to hold 6 four-letter words (heh), 5 space separators, and
+ the terminating \0. 24+5+1 == 30 */
+ static char english[30];
- gen_md5_init (ctx);
- gen_md5_update ((unsigned char *)feed, strlen (feed), ctx);
- gen_md5_finish (ctx, (unsigned char *)results);
+ ALLOCA_MD5_CONTEXT (md5_ctx);
+ uint32_t checksum[4];
- results[0] ^= results[2];
- results[1] ^= results[3];
- memcpy (key, (char *) results, 8);
+ gen_md5_init (md5_ctx);
+ gen_md5_update ((const unsigned char *)seed, strlen(seed), md5_ctx);
+ gen_md5_update ((const unsigned char *)pass, strlen(pass), md5_ctx);
+ gen_md5_finish (md5_ctx, (unsigned char *)checksum);
+ checksum[0] ^= checksum[2];
+ checksum[1] ^= checksum[3];
+ memcpy (key, checksum, 8);
- while (0 < sequence--)
+ while (sequence-- > 0)
{
- gen_md5_init (ctx);
- gen_md5_update ((unsigned char *)key, 8, ctx);
- gen_md5_finish (ctx, (unsigned char *)results);
- results[0] ^= results[2];
- results[1] ^= results[3];
- memcpy (key, (char *) results, 8);
+ gen_md5_init (md5_ctx);
+ gen_md5_update ((unsigned char *) key, 8, md5_ctx);
+ gen_md5_finish (md5_ctx, (unsigned char *) checksum);
+ checksum[0] ^= checksum[2];
+ checksum[1] ^= checksum[3];
+ memcpy (key, checksum, 8);
}
- btoe (buf, key);
- return buf;
+ return btoe (english, key);
}
projects / wget / blobdiff