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authormiod <>2014-07-09 08:20:08 +0000
committermiod <>2014-07-09 08:20:08 +0000
commit8cbe58f0d357b14b0ce292d336469d0554a567bc (patch)
tree07872a7ef59da8cea3b3b4a101fa3580e4d658c0 /src/lib/libcrypto/rsa/rsa_oaep.c
parentbc1209e388500a20f5e75cab35d1b543ce0bbe74 (diff)
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Diffstat (limited to 'src/lib/libcrypto/rsa/rsa_oaep.c')
-rw-r--r--src/lib/libcrypto/rsa/rsa_oaep.c155
1 files changed, 79 insertions, 76 deletions
diff --git a/src/lib/libcrypto/rsa/rsa_oaep.c b/src/lib/libcrypto/rsa/rsa_oaep.c
index 695df4e0a0..f8f9935fac 100644
--- a/src/lib/libcrypto/rsa/rsa_oaep.c
+++ b/src/lib/libcrypto/rsa/rsa_oaep.c
@@ -1,4 +1,4 @@
1/* $OpenBSD: rsa_oaep.c,v 1.16 2014/06/12 15:49:30 deraadt Exp $ */ 1/* $OpenBSD: rsa_oaep.c,v 1.17 2014/07/09 08:20:08 miod Exp $ */
2/* Written by Ulf Moeller. This software is distributed on an "AS IS" 2/* Written by Ulf Moeller. This software is distributed on an "AS IS"
3 basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. */ 3 basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. */
4 4
@@ -28,29 +28,28 @@
28#include <openssl/rand.h> 28#include <openssl/rand.h>
29#include <openssl/sha.h> 29#include <openssl/sha.h>
30 30
31static int MGF1(unsigned char *mask, long len, 31static int MGF1(unsigned char *mask, long len, const unsigned char *seed,
32 const unsigned char *seed, long seedlen); 32 long seedlen);
33 33
34int RSA_padding_add_PKCS1_OAEP(unsigned char *to, int tlen, 34int
35 const unsigned char *from, int flen, 35RSA_padding_add_PKCS1_OAEP(unsigned char *to, int tlen,
36 const unsigned char *param, int plen) 36 const unsigned char *from, int flen, const unsigned char *param, int plen)
37 { 37{
38 int i, emlen = tlen - 1; 38 int i, emlen = tlen - 1;
39 unsigned char *db, *seed; 39 unsigned char *db, *seed;
40 unsigned char *dbmask, seedmask[SHA_DIGEST_LENGTH]; 40 unsigned char *dbmask, seedmask[SHA_DIGEST_LENGTH];
41 41
42 if (flen > emlen - 2 * SHA_DIGEST_LENGTH - 1) 42 if (flen > emlen - 2 * SHA_DIGEST_LENGTH - 1) {
43 {
44 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP, 43 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP,
45 RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE); 44 RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
46 return 0; 45 return 0;
47 } 46 }
48 47
49 if (emlen < 2 * SHA_DIGEST_LENGTH + 1) 48 if (emlen < 2 * SHA_DIGEST_LENGTH + 1) {
50 { 49 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP,
51 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP, RSA_R_KEY_SIZE_TOO_SMALL); 50 RSA_R_KEY_SIZE_TOO_SMALL);
52 return 0; 51 return 0;
53 } 52 }
54 53
55 to[0] = 0; 54 to[0] = 0;
56 seed = to + 1; 55 seed = to + 1;
@@ -59,9 +58,9 @@ int RSA_padding_add_PKCS1_OAEP(unsigned char *to, int tlen,
59 if (!EVP_Digest((void *)param, plen, db, NULL, EVP_sha1(), NULL)) 58 if (!EVP_Digest((void *)param, plen, db, NULL, EVP_sha1(), NULL))
60 return 0; 59 return 0;
61 memset(db + SHA_DIGEST_LENGTH, 0, 60 memset(db + SHA_DIGEST_LENGTH, 0,
62 emlen - flen - 2 * SHA_DIGEST_LENGTH - 1); 61 emlen - flen - 2 * SHA_DIGEST_LENGTH - 1);
63 db[emlen - flen - SHA_DIGEST_LENGTH - 1] = 0x01; 62 db[emlen - flen - SHA_DIGEST_LENGTH - 1] = 0x01;
64 memcpy(db + emlen - flen - SHA_DIGEST_LENGTH, from, (unsigned int) flen); 63 memcpy(db + emlen - flen - SHA_DIGEST_LENGTH, from, (unsigned int)flen);
65 if (RAND_bytes(seed, SHA_DIGEST_LENGTH) <= 0) 64 if (RAND_bytes(seed, SHA_DIGEST_LENGTH) <= 0)
66 return 0; 65 return 0;
67#ifdef PKCS_TESTVECT 66#ifdef PKCS_TESTVECT
@@ -71,65 +70,73 @@ int RSA_padding_add_PKCS1_OAEP(unsigned char *to, int tlen,
71#endif 70#endif
72 71
73 dbmask = malloc(emlen - SHA_DIGEST_LENGTH); 72 dbmask = malloc(emlen - SHA_DIGEST_LENGTH);
74 if (dbmask == NULL) 73 if (dbmask == NULL) {
75 {
76 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP, ERR_R_MALLOC_FAILURE); 74 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP, ERR_R_MALLOC_FAILURE);
77 return 0; 75 return 0;
78 } 76 }
79 77
80 if (MGF1(dbmask, emlen - SHA_DIGEST_LENGTH, seed, SHA_DIGEST_LENGTH) < 0) 78 if (MGF1(dbmask, emlen - SHA_DIGEST_LENGTH, seed,
79 SHA_DIGEST_LENGTH) < 0)
81 return 0; 80 return 0;
82 for (i = 0; i < emlen - SHA_DIGEST_LENGTH; i++) 81 for (i = 0; i < emlen - SHA_DIGEST_LENGTH; i++)
83 db[i] ^= dbmask[i]; 82 db[i] ^= dbmask[i];
84 83
85 if (MGF1(seedmask, SHA_DIGEST_LENGTH, db, emlen - SHA_DIGEST_LENGTH) < 0) 84 if (MGF1(seedmask, SHA_DIGEST_LENGTH, db,
85 emlen - SHA_DIGEST_LENGTH) < 0)
86 return 0; 86 return 0;
87 for (i = 0; i < SHA_DIGEST_LENGTH; i++) 87 for (i = 0; i < SHA_DIGEST_LENGTH; i++)
88 seed[i] ^= seedmask[i]; 88 seed[i] ^= seedmask[i];
89 89
90 free(dbmask); 90 free(dbmask);
91 return 1; 91 return 1;
92 } 92}
93 93
94int RSA_padding_check_PKCS1_OAEP(unsigned char *to, int tlen, 94int
95 const unsigned char *from, int flen, int num, 95RSA_padding_check_PKCS1_OAEP(unsigned char *to, int tlen,
96 const unsigned char *param, int plen) 96 const unsigned char *from, int flen, int num, const unsigned char *param,
97 { 97 int plen)
98{
98 int i, dblen, mlen = -1; 99 int i, dblen, mlen = -1;
99 const unsigned char *maskeddb; 100 const unsigned char *maskeddb;
100 int lzero; 101 int lzero;
101 unsigned char *db = NULL, seed[SHA_DIGEST_LENGTH], phash[SHA_DIGEST_LENGTH]; 102 unsigned char *db = NULL;
103 unsigned char seed[SHA_DIGEST_LENGTH], phash[SHA_DIGEST_LENGTH];
102 unsigned char *padded_from; 104 unsigned char *padded_from;
103 int bad = 0; 105 int bad = 0;
104 106
105 if (--num < 2 * SHA_DIGEST_LENGTH + 1) 107 if (--num < 2 * SHA_DIGEST_LENGTH + 1)
106 /* 'num' is the length of the modulus, i.e. does not depend on the 108 /*
107 * particular ciphertext. */ 109 * 'num' is the length of the modulus, i.e. does not depend
110 * on the particular ciphertext.
111 */
108 goto decoding_err; 112 goto decoding_err;
109 113
110 lzero = num - flen; 114 lzero = num - flen;
111 if (lzero < 0) 115 if (lzero < 0) {
112 { 116 /*
113 /* signalling this error immediately after detection might allow 117 * signalling this error immediately after detection might allow
114 * for side-channel attacks (e.g. timing if 'plen' is huge 118 * for side-channel attacks (e.g. timing if 'plen' is huge
115 * -- cf. James H. Manger, "A Chosen Ciphertext Attack on RSA Optimal 119 * -- cf. James H. Manger, "A Chosen Ciphertext Attack on RSA
116 * Asymmetric Encryption Padding (OAEP) [...]", CRYPTO 2001), 120 * Optimal Asymmetric Encryption Padding (OAEP) [...]",
117 * so we use a 'bad' flag */ 121 * CRYPTO 2001), so we use a 'bad' flag
122 */
118 bad = 1; 123 bad = 1;
119 lzero = 0; 124 lzero = 0;
120 flen = num; /* don't overflow the memcpy to padded_from */ 125 flen = num; /* don't overflow the memcpy to padded_from */
121 } 126 }
122 127
123 dblen = num - SHA_DIGEST_LENGTH; 128 dblen = num - SHA_DIGEST_LENGTH;
124 db = malloc(dblen + num); 129 db = malloc(dblen + num);
125 if (db == NULL) 130 if (db == NULL) {
126 { 131 RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_OAEP,
127 RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_OAEP, ERR_R_MALLOC_FAILURE); 132 ERR_R_MALLOC_FAILURE);
128 return -1; 133 return -1;
129 } 134 }
130 135
131 /* Always do this zero-padding copy (even when lzero == 0) 136 /*
132 * to avoid leaking timing info about the value of lzero. */ 137 * Always do this zero-padding copy (even when lzero == 0)
138 * to avoid leaking timing info about the value of lzero.
139 */
133 padded_from = db + dblen; 140 padded_from = db + dblen;
134 memset(padded_from, 0, lzero); 141 memset(padded_from, 0, lzero);
135 memcpy(padded_from + lzero, from, flen); 142 memcpy(padded_from + lzero, from, flen);
@@ -151,41 +158,41 @@ int RSA_padding_check_PKCS1_OAEP(unsigned char *to, int tlen,
151 158
152 if (CRYPTO_memcmp(db, phash, SHA_DIGEST_LENGTH) != 0 || bad) 159 if (CRYPTO_memcmp(db, phash, SHA_DIGEST_LENGTH) != 0 || bad)
153 goto decoding_err; 160 goto decoding_err;
154 else 161 else {
155 {
156 for (i = SHA_DIGEST_LENGTH; i < dblen; i++) 162 for (i = SHA_DIGEST_LENGTH; i < dblen; i++)
157 if (db[i] != 0x00) 163 if (db[i] != 0x00)
158 break; 164 break;
159 if (i == dblen || db[i] != 0x01) 165 if (i == dblen || db[i] != 0x01)
160 goto decoding_err; 166 goto decoding_err;
161 else 167 else {
162 {
163 /* everything looks OK */ 168 /* everything looks OK */
164 169
165 mlen = dblen - ++i; 170 mlen = dblen - ++i;
166 if (tlen < mlen) 171 if (tlen < mlen) {
167 { 172 RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_OAEP,
168 RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_OAEP, RSA_R_DATA_TOO_LARGE); 173 RSA_R_DATA_TOO_LARGE);
169 mlen = -1; 174 mlen = -1;
170 } 175 } else
171 else
172 memcpy(to, db + i, mlen); 176 memcpy(to, db + i, mlen);
173 }
174 } 177 }
178 }
175 free(db); 179 free(db);
176 return mlen; 180 return mlen;
177 181
178decoding_err: 182decoding_err:
179 /* to avoid chosen ciphertext attacks, the error message should not reveal 183 /*
180 * which kind of decoding error happened */ 184 * To avoid chosen ciphertext attacks, the error message should not
185 * reveal which kind of decoding error happened
186 */
181 RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_OAEP, RSA_R_OAEP_DECODING_ERROR); 187 RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_OAEP, RSA_R_OAEP_DECODING_ERROR);
182 free(db); 188 free(db);
183 return -1; 189 return -1;
184 } 190}
185 191
186int PKCS1_MGF1(unsigned char *mask, long len, 192int
187 const unsigned char *seed, long seedlen, const EVP_MD *dgst) 193PKCS1_MGF1(unsigned char *mask, long len, const unsigned char *seed,
188 { 194 long seedlen, const EVP_MD *dgst)
195{
189 long i, outlen = 0; 196 long i, outlen = 0;
190 unsigned char cnt[4]; 197 unsigned char cnt[4];
191 EVP_MD_CTX c; 198 EVP_MD_CTX c;
@@ -197,39 +204,35 @@ int PKCS1_MGF1(unsigned char *mask, long len,
197 mdlen = EVP_MD_size(dgst); 204 mdlen = EVP_MD_size(dgst);
198 if (mdlen < 0) 205 if (mdlen < 0)
199 goto err; 206 goto err;
200 for (i = 0; outlen < len; i++) 207 for (i = 0; outlen < len; i++) {
201 {
202 cnt[0] = (unsigned char)((i >> 24) & 255); 208 cnt[0] = (unsigned char)((i >> 24) & 255);
203 cnt[1] = (unsigned char)((i >> 16) & 255); 209 cnt[1] = (unsigned char)((i >> 16) & 255);
204 cnt[2] = (unsigned char)((i >> 8)) & 255; 210 cnt[2] = (unsigned char)((i >> 8)) & 255;
205 cnt[3] = (unsigned char)(i & 255); 211 cnt[3] = (unsigned char)(i & 255);
206 if (!EVP_DigestInit_ex(&c,dgst, NULL) 212 if (!EVP_DigestInit_ex(&c,dgst, NULL) ||
207 || !EVP_DigestUpdate(&c, seed, seedlen) 213 !EVP_DigestUpdate(&c, seed, seedlen) ||
208 || !EVP_DigestUpdate(&c, cnt, 4)) 214 !EVP_DigestUpdate(&c, cnt, 4))
209 goto err; 215 goto err;
210 if (outlen + mdlen <= len) 216 if (outlen + mdlen <= len) {
211 {
212 if (!EVP_DigestFinal_ex(&c, mask + outlen, NULL)) 217 if (!EVP_DigestFinal_ex(&c, mask + outlen, NULL))
213 goto err; 218 goto err;
214 outlen += mdlen; 219 outlen += mdlen;
215 } 220 } else {
216 else
217 {
218 if (!EVP_DigestFinal_ex(&c, md, NULL)) 221 if (!EVP_DigestFinal_ex(&c, md, NULL))
219 goto err; 222 goto err;
220 memcpy(mask + outlen, md, len - outlen); 223 memcpy(mask + outlen, md, len - outlen);
221 outlen = len; 224 outlen = len;
222 }
223 } 225 }
226 }
224 rv = 0; 227 rv = 0;
225 err: 228err:
226 EVP_MD_CTX_cleanup(&c); 229 EVP_MD_CTX_cleanup(&c);
227 return rv; 230 return rv;
228 } 231}
229 232
230static int MGF1(unsigned char *mask, long len, const unsigned char *seed, 233static int
231 long seedlen) 234MGF1(unsigned char *mask, long len, const unsigned char *seed, long seedlen)
232 { 235{
233 return PKCS1_MGF1(mask, len, seed, seedlen, EVP_sha1()); 236 return PKCS1_MGF1(mask, len, seed, seedlen, EVP_sha1());
234 } 237}
235#endif 238#endif