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author | Ken Raeburn <raeburn@mit.edu> | 2004-04-03 01:14:39 +0000 |
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committer | Ken Raeburn <raeburn@mit.edu> | 2004-04-03 01:14:39 +0000 |
commit | 9578215c7c2c6880bf7dba70cb3a5b8da0a05c48 (patch) | |
tree | 22f283455064d7982529088abb3c744a5a24468e | |
parent | 8783a5ce453c4a48f95fa4477b5d43780c4cfc7d (diff) | |
download | krb5-9578215c7c2c6880bf7dba70cb3a5b8da0a05c48.zip krb5-9578215c7c2c6880bf7dba70cb3a5b8da0a05c48.tar.gz krb5-9578215c7c2c6880bf7dba70cb3a5b8da0a05c48.tar.bz2 |
* string2key.c: Replaced with a new implementation.
(Smaller and faster, at least on gcc for x86.)
git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@16227 dc483132-0cff-0310-8789-dd5450dbe970
-rw-r--r-- | src/lib/crypto/des/ChangeLog | 4 | ||||
-rw-r--r-- | src/lib/crypto/des/string2key.c | 400 |
2 files changed, 205 insertions, 199 deletions
diff --git a/src/lib/crypto/des/ChangeLog b/src/lib/crypto/des/ChangeLog index 409e09b..faba396 100644 --- a/src/lib/crypto/des/ChangeLog +++ b/src/lib/crypto/des/ChangeLog @@ -1,3 +1,7 @@ +2004-04-02 Ken Raeburn <raeburn@mit.edu> + + * string2key.c: Replaced with a new implementation. + 2004-02-18 Ken Raeburn <raeburn@mit.edu> * afsstring2key.c, d3_cbc.c, d3_kysched.c, f_cbc.c, f_cksum.c, diff --git a/src/lib/crypto/des/string2key.c b/src/lib/crypto/des/string2key.c index 73e1ae4..4fe9e47 100644 --- a/src/lib/crypto/des/string2key.c +++ b/src/lib/crypto/des/string2key.c @@ -1,7 +1,7 @@ /* - * lib/crypto/des/string2key.c + * lib/crypto/des/des_s2k.c * - * Copyright 1990,1991 by the Massachusetts Institute of Technology. + * Copyright 2004 by the Massachusetts Institute of Technology. * All Rights Reserved. * * Export of this software from the United States of America may @@ -22,238 +22,240 @@ * 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. - */ - -/* - * Copyright (C) 1998 by the FundsXpress, INC. - * - * 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 FundsXpress. not be used in advertising or publicity pertaining - * to distribution of the software without specific, written prior - * permission. FundsXpress makes no representations about the suitability of - * this software for any purpose. It is provided "as is" without express - * or implied warranty. * - * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR - * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED - * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. + * + * Compute encryption key from salt and pass phrase. */ #include "k5-int.h" #include "des_int.h" -/* - converts the string pointed to by "data" into an encryption key - of type "enctype". *keyblock is filled in with the key info; - in particular, keyblock->contents is to be set to allocated storage. - It is the responsibility of the caller to release this storage - when the generated key no longer needed. - - The routine may use "salt" to seed or alter the conversion - algorithm. - - If the particular function called does not know how to make a - key of type "enctype", an error may be returned. - - returns: errors - */ - -/*#define PRINT_TEST_VECTORS*/ - krb5_error_code -mit_des_string_to_key_int (krb5_keyblock *keyblock, const krb5_data *data, - const krb5_data *salt) +mit_des_string_to_key_int (krb5_keyblock *key, + const krb5_data *pw, const krb5_data *salt) { - register krb5_octet *str, *copystr; - register krb5_octet *key; - - register unsigned temp; - register long i; - register int j; - register unsigned long length; - unsigned char *k_p; - int forward; - register char *p_char; - char k_char[64]; - mit_des_key_schedule key_sked; + union { + /* 8 "forward" bytes, 8 "reverse" bytes */ + unsigned char uc[16]; + krb5_ui_4 ui[4]; + mit_des_cblock cb; + } temp; + 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 errno; + 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 - unsigned char tmp_array[56]; - unsigned char *t_char; -#endif - -#ifndef min -#define min(A, B) ((A) < (B) ? (A): (B)) + { + 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 - - keyblock->magic = KV5M_KEYBLOCK; - keyblock->length = sizeof(mit_des_cblock); - key = keyblock->contents; - - if (salt) { - if (salt->length == SALT_TYPE_AFS_LENGTH || salt->length == (unsigned) -1) { - krb5_data salt2; - char *c; - c = strchr(salt->data, '@'); - if (c != NULL) *c = '\0'; /* workaround from krb5-clients/1146 */ - salt2.data = salt->data; - salt2.length = strlen (salt2.data); - /* cheat and do AFS string2key instead */ - return mit_afs_string_to_key (keyblock, data, &salt2); - } else - length = data->length + salt->length; - } else - length = data->length; - - copystr = malloc((size_t) length); - if (!copystr) { - free(keyblock->contents); - keyblock->contents = 0; - return ENOMEM; + } } - memcpy(copystr, (char *) data->data, data->length); - if (salt) - memcpy(copystr + data->length, (char *)salt->data, salt->length); - - /* convert to des key */ - forward = 1; - - /* init key array for bits */ - p_char = k_char; - memset(k_char,0,sizeof(k_char)); #ifdef PRINT_TEST_VECTORS - t_char = tmp_array; + 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 - if (mit_des_debug) - fprintf(stdout, - "\n\ninput str length = %d string = %*s\nstring = 0x ", - length,length,str); + /* 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 - str = copystr; - - /* get next 8 bytes, strip parity, xor */ - for (i = 1; i <= length; i++) { - /* get next input key byte */ - temp = (unsigned int) *str++; -#if 0 - if (mit_des_debug) - fprintf(stdout,"%02x ",temp & 0xff); -#endif - /* loop through bits within byte, ignore parity */ - for (j = 0; j <= 6; j++) { - unsigned int x = temp & 1; - if (forward) { - *p_char++ ^= x; -#ifdef PRINT_TEST_VECTORS - *t_char++ = x; -#endif - } else { - *--p_char ^= x; + 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 - *--t_char = x; + { + 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 - } - temp = temp >> 1; - } + /* 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); - /* check and flip direction */ - if ((i%8) == 0) { #ifdef PRINT_TEST_VECTORS - printf("%-20s ", - forward ? "forward block:" : "reversed block:"); - for (j = 0; j <= 7; j++) { - int k, num = 0; - for (k = 0; k <= 6; k++) - num |= tmp_array[j * 7 + k] << k; - printf(" %02x", num); - } - printf("\n"); - - printf("%-20s ", "xor result:"); - for (j = 0; j <= 7; j++) { - int k, num = 0; - for (k = 0; k <= 6; k++) - num |= k_char[j * 7 + k] << k; - printf(" %02x", num); - } - printf("\n"); -#endif - forward = !forward; - } + { + 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 - /* now stuff into the key mit_des_cblock, and force odd parity */ - p_char = k_char; - k_p = (unsigned char *) key; +#define FIXUP(K) \ + (mit_des_fixup_key_parity(K), \ + mit_des_is_weak_key(K) ? (K[7] ^= 0xF0) : 0) - for (i = 0; i <= 7; i++) { - temp = 0; - for (j = 0; j <= 6; j++) - temp |= *p_char++ << (1+j); - *k_p++ = (unsigned char) temp; - } + /* Now temp.cb is the temporary key, with invalid parity. */ + FIXUP(temp.cb); #ifdef PRINT_TEST_VECTORS - printf("%-20s ", "after fanfolding:"); - for (i = 0; i <= 7; i++) - printf(" %02x", i[(unsigned char *)key]); - printf("\n"); - - printf("%-20s ", "after shifting:"); - for (i = 0; i <= 7; i++) - printf(" %02x", i[(unsigned char *)key]); - printf("\n"); + { + 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 - /* fix key parity */ - mit_des_fixup_key_parity(key); - if (mit_des_is_weak_key(key)) - ((krb5_octet *)key)[7] ^= 0xf0; + 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 - printf("after fixing parity and weak keys: {"); - for (i = 0; i <= 7; i++) - printf(" %02x", i[(unsigned char *)key]); - printf(" }\n"); + { + int j; + printf("cbc checksum:\n\t\t"); + for (j = 0; j < 8; j++) + printf(" %02x", temp.uc[j] & 0xff); + printf("\n"); + } #endif - /* Now one-way encrypt it with the folded key */ - (void) mit_des_key_sched(key, key_sked); - (void) mit_des_cbc_cksum(copystr, key, length, key_sked, key); - /* erase key_sked */ - memset((char *)key_sked, 0, sizeof(key_sked)); + memset(sched, 0, sizeof(sched)); + FIXUP (temp.cb); - /* clean & free the input string */ - memset(copystr, 0, length); - krb5_xfree(copystr); +#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 - /* now fix up key parity again */ - mit_des_fixup_key_parity(key); - if (mit_des_is_weak_key(key)) - ((krb5_octet *)key)[7] ^= 0xf0; + memcpy(key->contents, temp.cb, 8); + memset(&temp, 0, sizeof(temp)); -#if 0 - if (mit_des_debug) - fprintf(stdout, - "\nResulting string_to_key = 0x%x 0x%x\n", - *((unsigned long *) key), - *((unsigned long *) key+1)); -#endif - return 0; } |