Mercurial > dropbear

comparison libtomcrypt/src/pk/pkcs1/pkcs_1_pss_decode.c @ 382:0cbe8f6dbf9e

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 2af22fb4e878750b88f80f90d439b316d229796f) to branch 'au.asn.ucc.matt.dropbear' (head 02c413252c90e9de8e03d91e9939dde3029f5c0a)
author Matt Johnston <matt@ucc.asn.au>
date Thu, 11 Jan 2007 02:41:05 +0000
parents 1b9e69c058d2
children f849a5ca2efc
comparison
equal deleted inserted replaced
379:b66a00272a90 382:0cbe8f6dbf9e
4 * algorithms in a highly modular and flexible manner. 4 * algorithms in a highly modular and flexible manner.
5 * 5 *
6 * The library is free for all purposes without any express 6 * The library is free for all purposes without any express
7 * guarantee it works. 7 * guarantee it works.
8 * 8 *
9 * Tom St Denis, [email protected], http://libtomcrypt.org 9 * Tom St Denis, [email protected], http://libtomcrypt.com
10 */ 10 */
11 #include "tomcrypt.h" 11 #include "tomcrypt.h"
12 12
13 /** 13 /**
14 @file pkcs_1_pss_decode.c 14 @file pkcs_1_pss_decode.c
80 return CRYPT_MEM; 80 return CRYPT_MEM;
81 } 81 }
82 82
83 /* ensure the 0xBC byte */ 83 /* ensure the 0xBC byte */
84 if (sig[siglen-1] != 0xBC) { 84 if (sig[siglen-1] != 0xBC) {
85 err = CRYPT_OK; 85 err = CRYPT_INVALID_PACKET;
86 goto LBL_ERR; 86 goto LBL_ERR;
87 } 87 }
88 88
89 /* copy out the DB */ 89 /* copy out the DB */
90 x = 0; 90 x = 0;
95 XMEMCPY(hash, sig + x, hLen); 95 XMEMCPY(hash, sig + x, hLen);
96 x += hLen; 96 x += hLen;
97 97
98 /* check the MSB */ 98 /* check the MSB */
99 if ((sig[0] & ~(0xFF >> ((modulus_len<<3) - (modulus_bitlen-1)))) != 0) { 99 if ((sig[0] & ~(0xFF >> ((modulus_len<<3) - (modulus_bitlen-1)))) != 0) {
100 err = CRYPT_OK; 100 err = CRYPT_INVALID_PACKET;
101 goto LBL_ERR; 101 goto LBL_ERR;
102 } 102 }
103 103
104 /* generate mask of length modulus_len - hLen - 1 from hash */ 104 /* generate mask of length modulus_len - hLen - 1 from hash */
105 if ((err = pkcs_1_mgf1(hash, hLen, hash_idx, mask, modulus_len - hLen - 1)) != CRYPT_OK) { 105 if ((err = pkcs_1_mgf1(hash_idx, hash, hLen, mask, modulus_len - hLen - 1)) != CRYPT_OK) {
106 goto LBL_ERR; 106 goto LBL_ERR;
107 } 107 }
108 108
109 /* xor against DB */ 109 /* xor against DB */
110 for (y = 0; y < (modulus_len - hLen - 1); y++) { 110 for (y = 0; y < (modulus_len - hLen - 1); y++) {
117 /* DB = PS || 0x01 || salt, PS == modulus_len - saltlen - hLen - 2 zero bytes */ 117 /* DB = PS || 0x01 || salt, PS == modulus_len - saltlen - hLen - 2 zero bytes */
118 118
119 /* check for zeroes and 0x01 */ 119 /* check for zeroes and 0x01 */
120 for (x = 0; x < modulus_len - saltlen - hLen - 2; x++) { 120 for (x = 0; x < modulus_len - saltlen - hLen - 2; x++) {
121 if (DB[x] != 0x00) { 121 if (DB[x] != 0x00) {
122 err = CRYPT_OK; 122 err = CRYPT_INVALID_PACKET;
123 goto LBL_ERR; 123 goto LBL_ERR;
124 } 124 }
125 } 125 }
126 126
127 /* check for the 0x01 */ 127 /* check for the 0x01 */
128 if (DB[x++] != 0x01) { 128 if (DB[x++] != 0x01) {
129 err = CRYPT_OK; 129 err = CRYPT_INVALID_PACKET;
130 goto LBL_ERR; 130 goto LBL_ERR;
131 } 131 }
132 132
133 /* M = (eight) 0x00 || msghash || salt, mask = H(M) */ 133 /* M = (eight) 0x00 || msghash || salt, mask = H(M) */
134 if ((err = hash_descriptor[hash_idx].init(&md)) != CRYPT_OK) { 134 if ((err = hash_descriptor[hash_idx].init(&md)) != CRYPT_OK) {
147 if ((err = hash_descriptor[hash_idx].done(&md, mask)) != CRYPT_OK) { 147 if ((err = hash_descriptor[hash_idx].done(&md, mask)) != CRYPT_OK) {
148 goto LBL_ERR; 148 goto LBL_ERR;
149 } 149 }
150 150
151 /* mask == hash means valid signature */ 151 /* mask == hash means valid signature */
152 if (memcmp(mask, hash, hLen) == 0) { 152 if (XMEMCMP(mask, hash, hLen) == 0) {
153 *res = 1; 153 *res = 1;
154 } 154 }
155 155
156 err = CRYPT_OK; 156 err = CRYPT_OK;
157 LBL_ERR: 157 LBL_ERR:
171 } 171 }
172 172
173 #endif /* PKCS_1 */ 173 #endif /* PKCS_1 */
174 174
175 /* $Source: /cvs/libtom/libtomcrypt/src/pk/pkcs1/pkcs_1_pss_decode.c,v $ */ 175 /* $Source: /cvs/libtom/libtomcrypt/src/pk/pkcs1/pkcs_1_pss_decode.c,v $ */
176 /* $Revision: 1.4 $ */ 176 /* $Revision: 1.9 $ */
177 /* $Date: 2005/05/05 14:35:59 $ */ 177 /* $Date: 2006/11/30 02:37:21 $ */