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-rw-r--r--src/lib/crypto/builtin/des/string2key.c261
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diff --git a/src/lib/crypto/builtin/des/string2key.c b/src/lib/crypto/builtin/des/string2key.c
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+/*
+ * lib/crypto/des/des_s2k.c
+ *
+ * Copyright 2004, 2008 by the Massachusetts Institute of Technology.
+ * All Rights Reserved.
+ *
+ * Export of this software from the United States of America may
+ * require a specific license from the United States Government.
+ * It is the responsibility of any person or organization contemplating
+ * export to obtain such a license before exporting.
+ *
+ * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
+ * distribute this software and its documentation for any purpose and
+ * without fee is hereby granted, provided that the above copyright
+ * notice appear in all copies and that both that copyright notice and
+ * this permission notice appear in supporting documentation, and that
+ * the name of M.I.T. not be used in advertising or publicity pertaining
+ * to distribution of the software without specific, written prior
+ * permission. Furthermore if you modify this software you must label
+ * your software as modified software and not distribute it in such a
+ * fashion that it might be confused with the original M.I.T. software.
+ * M.I.T. makes no representations about the suitability of
+ * this software for any purpose. It is provided "as is" without express
+ * or implied warranty.
+ *
+ *
+ * Compute encryption key from salt and pass phrase.
+ */
+
+#include "k5-int.h"
+#include "des_int.h"
+
+krb5_error_code
+mit_des_string_to_key_int (krb5_keyblock *key,
+ const krb5_data *pw, const krb5_data *salt)
+{
+ union {
+ /* 8 "forward" bytes, 8 "reverse" bytes */
+ unsigned char uc[16];
+ krb5_ui_4 ui[4];
+ mit_des_cblock cb;
+ } temp;
+ unsigned int i;
+ krb5_ui_4 x, y, z;
+ unsigned char *p;
+ des_key_schedule sched;
+ char *copy;
+ size_t copylen;
+
+ /* As long as the architecture is big-endian or little-endian, it
+ doesn't matter which it is. Think of it as reversing the
+ bytes, and also reversing the bits within each byte. But this
+ current algorithm is dependent on having four 8-bit char values
+ exactly overlay a 32-bit integral type. */
+ if (sizeof(temp.uc) != sizeof(temp.ui)
+ || (unsigned char)~0 != 0xFF
+ || (krb5_ui_4)~(krb5_ui_4)0 != 0xFFFFFFFF
+ || (temp.uc[0] = 1, temp.uc[1] = 2, temp.uc[2] = 3, temp.uc[3] = 4,
+ !(temp.ui[0] == 0x01020304
+ || temp.ui[0] == 0x04030201)))
+ abort();
+#define FETCH4(VAR, IDX) VAR = temp.ui[IDX/4]
+#define PUT4(VAR, IDX) temp.ui[IDX/4] = VAR
+
+ if (salt
+ && (salt->length == SALT_TYPE_AFS_LENGTH
+ /* XXX Yuck! Aren't we done with this yet? */
+ || salt->length == (unsigned) -1)) {
+ krb5_data afssalt;
+ char *at;
+
+ afssalt.data = salt->data;
+ at = strchr(afssalt.data, '@');
+ if (at) {
+ *at = 0;
+ afssalt.length = at - afssalt.data;
+ } else
+ afssalt.length = strlen(afssalt.data);
+ return mit_afs_string_to_key(key, pw, &afssalt);
+ }
+
+ copylen = pw->length + (salt ? salt->length : 0);
+ /* Don't need NUL termination, at this point we're treating it as
+ a byte array, not a string. */
+ copy = malloc(copylen);
+ if (copy == NULL)
+ return ENOMEM;
+ memcpy(copy, pw->data, pw->length);
+ if (salt)
+ memcpy(copy + pw->length, salt->data, salt->length);
+
+ memset(&temp, 0, sizeof(temp));
+ p = temp.uc;
+ /* Handle the fan-fold xor operation by splitting the data into
+ forward and reverse sections, and combine them later, rather
+ than having to do the reversal over and over again. */
+ for (i = 0; i < copylen; i++) {
+ *p++ ^= copy[i];
+ if (p == temp.uc+16) {
+ p = temp.uc;
+#ifdef PRINT_TEST_VECTORS
+ {
+ int j;
+ printf("after %d input bytes:\nforward block:\t", i+1);
+ for (j = 0; j < 8; j++)
+ printf(" %02x", temp.uc[j] & 0xff);
+ printf("\nreverse block:\t");
+ for (j = 8; j < 16; j++)
+ printf(" %02x", temp.uc[j] & 0xff);
+ printf("\n");
+ }
+#endif
+ }
+ }
+
+#ifdef PRINT_TEST_VECTORS
+ if (p != temp.uc) {
+ int j;
+ printf("at end, after %d input bytes:\nforward block:\t", i);
+ for (j = 0; j < 8; j++)
+ printf(" %02x", temp.uc[j] & 0xff);
+ printf("\nreverse block:\t");
+ for (j = 8; j < 16; j++)
+ printf(" %02x", temp.uc[j] & 0xff);
+ printf("\n");
+ }
+#endif
+#if 0
+ /* Algorithm described in Dr. Dobbs Journal 1983, reported in "bit
+ twiddling hacks" web page collected by Sean Eron Anderson; see
+ http://graphics.stanford.edu/~seander/bithacks.html for
+ details.
+
+ Avoids loops, uses 7*lg(N)=35 ops instead of 4*N=128 for the
+ obvious mask, ior, shift, shift sequence of each 32-bit
+ quantity.
+
+ If we could rely on 64-bit math, another 7 ops would save us
+ from having to do double the work. */
+#define REVERSE_STEP(VAR, SHIFT, MASK) \
+ VAR = ((VAR >> SHIFT) & MASK) | ((VAR << SHIFT) & (0xFFFFFFFFUL & ~MASK))
+#define REVERSE(VAR) \
+ REVERSE_STEP (VAR, 1, 0x55555555UL); /* swap odd/even bits */ \
+ REVERSE_STEP (VAR, 2, 0x33333333UL); /* swap bitpairs */ \
+ REVERSE_STEP (VAR, 4, 0x0F0F0F0FUL); /* swap nibbles, etc */ \
+ REVERSE_STEP (VAR, 8, 0x00FF00FFUL); \
+ REVERSE_STEP (VAR, 16, 0x0000FFFFUL);
+#else /* shorter */
+#define REVERSE(VAR) \
+ { \
+ krb5_ui_4 old = VAR, temp1 = 0; \
+ int j; \
+ for (j = 0; j < 32; j++) { \
+ temp1 = (temp1 << 1) | (old & 1); \
+ old >>= 1; \
+ } \
+ VAR = temp1; \
+ }
+#endif
+
+ FETCH4 (x, 8);
+ FETCH4 (y, 12);
+ /* Ignore high bits of each input byte. */
+ x &= 0x7F7F7F7F;
+ y &= 0x7F7F7F7F;
+ /* Reverse the bit strings -- after this, y is "before" x. */
+ REVERSE (x);
+ REVERSE (y);
+#ifdef PRINT_TEST_VECTORS
+ {
+ int j;
+ union { unsigned char uc[4]; krb5_ui_4 ui; } t2;
+ printf("after reversal, reversed block:\n\t\t");
+ t2.ui = y;
+ for (j = 0; j < 4; j++)
+ printf(" %02x", t2.uc[j] & 0xff);
+ t2.ui = x;
+ for (j = 0; j < 4; j++)
+ printf(" %02x", t2.uc[j] & 0xff);
+ printf("\n");
+ }
+#endif
+ /* Ignored bits are now at the bottom of each byte, where we'll
+ put the parity bits. Good. */
+ FETCH4 (z, 0);
+ z &= 0x7F7F7F7F;
+ /* Ignored bits for z are at the top of each byte; fix that. */
+ z <<= 1;
+ /* Finish the fan-fold xor for these four bytes. */
+ z ^= y;
+ PUT4 (z, 0);
+ /* Now do the second four bytes. */
+ FETCH4 (z, 4);
+ z &= 0x7F7F7F7F;
+ /* Ignored bits for z are at the top of each byte; fix that. */
+ z <<= 1;
+ /* Finish the fan-fold xor for these four bytes. */
+ z ^= x;
+ PUT4 (z, 4);
+
+#ifdef PRINT_TEST_VECTORS
+ {
+ int j;
+ printf("after reversal, combined block:\n\t\t");
+ for (j = 0; j < 8; j++)
+ printf(" %02x", temp.uc[j] & 0xff);
+ printf("\n");
+ }
+#endif
+
+#define FIXUP(K) \
+ (mit_des_fixup_key_parity(K), \
+ mit_des_is_weak_key(K) ? (K[7] ^= 0xF0) : 0)
+
+ /* Now temp.cb is the temporary key, with invalid parity. */
+ FIXUP(temp.cb);
+
+#ifdef PRINT_TEST_VECTORS
+ {
+ int j;
+ printf("after fixing parity and weak keys:\n\t\t");
+ for (j = 0; j < 8; j++)
+ printf(" %02x", temp.uc[j] & 0xff);
+ printf("\n");
+ }
+#endif
+
+ mit_des_key_sched(temp.cb, sched);
+ mit_des_cbc_cksum(copy, temp.cb, copylen, sched, temp.cb);
+
+ memset(copy, 0, copylen);
+ free(copy);
+
+#ifdef PRINT_TEST_VECTORS
+ {
+ int j;
+ printf("cbc checksum:\n\t\t");
+ for (j = 0; j < 8; j++)
+ printf(" %02x", temp.uc[j] & 0xff);
+ printf("\n");
+ }
+#endif
+
+ memset(sched, 0, sizeof(sched));
+ FIXUP (temp.cb);
+
+#ifdef PRINT_TEST_VECTORS
+ {
+ int j;
+ printf("after fixing parity and weak keys:\n\t\t");
+ for (j = 0; j < 8; j++)
+ printf(" %02x", temp.uc[j] & 0xff);
+ printf("\n");
+ }
+#endif
+
+ memcpy(key->contents, temp.cb, 8);
+ memset(&temp, 0, sizeof(temp));
+
+ return 0;
+}
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