{
RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP,
RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
- return (0);
+ return 0;
}
if (emlen < 2 * SHA_DIGEST_LENGTH + 1)
{
RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP, RSA_R_KEY_SIZE_TOO_SMALL);
- return (0);
+ return 0;
}
-
+
dbmask = OPENSSL_malloc(emlen - SHA_DIGEST_LENGTH);
if (dbmask == NULL)
{
RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP, ERR_R_MALLOC_FAILURE);
- return (0);
+ return 0;
}
to[0] = 0;
seed = to + 1;
db = to + SHA_DIGEST_LENGTH + 1;
- EVP_Digest((void *)param, plen, db, NULL, EVP_sha1());
+ EVP_Digest((void *)param, plen, db, NULL, EVP_sha1(), NULL);
memset(db + SHA_DIGEST_LENGTH, 0,
emlen - flen - 2 * SHA_DIGEST_LENGTH - 1);
db[emlen - flen - SHA_DIGEST_LENGTH - 1] = 0x01;
memcpy(db + emlen - flen - SHA_DIGEST_LENGTH, from, (unsigned int) flen);
if (RAND_bytes(seed, SHA_DIGEST_LENGTH) <= 0)
- return (0);
+ return 0;
#ifdef PKCS_TESTVECT
memcpy(seed,
"\xaa\xfd\x12\xf6\x59\xca\xe6\x34\x89\xb4\x79\xe5\x07\x6d\xde\xc2\xf0\x6c\xb5\x8f",
MGF1(dbmask, emlen - SHA_DIGEST_LENGTH, seed, SHA_DIGEST_LENGTH);
for (i = 0; i < emlen - SHA_DIGEST_LENGTH; i++)
db[i] ^= dbmask[i];
-
+
MGF1(seedmask, SHA_DIGEST_LENGTH, db, emlen - SHA_DIGEST_LENGTH);
for (i = 0; i < SHA_DIGEST_LENGTH; i++)
seed[i] ^= seedmask[i];
const unsigned char *maskeddb;
int lzero;
unsigned char *db = NULL, seed[SHA_DIGEST_LENGTH], phash[SHA_DIGEST_LENGTH];
+ int bad = 0;
if (--num < 2 * SHA_DIGEST_LENGTH + 1)
+ /* 'num' is the length of the modulus, i.e. does not depend on the
+ * particular ciphertext. */
goto decoding_err;
lzero = num - flen;
if (lzero < 0)
- goto decoding_err;
+ {
+ /* lzero == -1 */
+
+ /* signalling this error immediately after detection might allow
+ * for side-channel attacks (e.g. timing if 'plen' is huge
+ * -- cf. James H. Manger, "A Chosen Ciphertext Attack on RSA Optimal
+ * Asymmetric Encryption Padding (OAEP) [...]", CRYPTO 2001),
+ * so we use a 'bad' flag */
+ bad = 1;
+ lzero = 0;
+ }
maskeddb = from - lzero + SHA_DIGEST_LENGTH;
-
+
dblen = num - SHA_DIGEST_LENGTH;
db = OPENSSL_malloc(dblen);
if (db == NULL)
{
- RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP, ERR_R_MALLOC_FAILURE);
- return (-1);
+ RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_OAEP, ERR_R_MALLOC_FAILURE);
+ return -1;
}
MGF1(seed, SHA_DIGEST_LENGTH, maskeddb, dblen);
for (i = 0; i < dblen; i++)
db[i] ^= maskeddb[i];
- EVP_Digest((void *)param, plen, phash, NULL, EVP_sha1());
-
- if (memcmp(db, phash, SHA_DIGEST_LENGTH) != 0)
+ EVP_Digest((void *)param, plen, phash, NULL, EVP_sha1(), NULL);
+
+ if (memcmp(db, phash, SHA_DIGEST_LENGTH) != 0 || bad)
goto decoding_err;
else
{
goto decoding_err;
else
{
+ /* everything looks OK */
+
mlen = dblen - i;
if (tlen < mlen)
{
}
OPENSSL_free(db);
return mlen;
-
+
decoding_err:
/* to avoid chosen ciphertext attacks, the error message should not reveal
* which kind of decoding error happened */
return -1;
}
-int MGF1(unsigned char *mask, long len,
- const unsigned char *seed, long seedlen)
+int PKCS1_MGF1(unsigned char *mask, long len,
+ const unsigned char *seed, long seedlen, const EVP_MD *dgst)
{
long i, outlen = 0;
unsigned char cnt[4];
EVP_MD_CTX c;
- unsigned char md[SHA_DIGEST_LENGTH];
+ unsigned char md[EVP_MAX_MD_SIZE];
+ int mdlen;
EVP_MD_CTX_init(&c);
+ mdlen = EVP_MD_size(dgst);
for (i = 0; outlen < len; i++)
{
cnt[0] = (unsigned char)((i >> 24) & 255);
cnt[1] = (unsigned char)((i >> 16) & 255);
cnt[2] = (unsigned char)((i >> 8)) & 255;
cnt[3] = (unsigned char)(i & 255);
- EVP_DigestInit(&c,EVP_sha1());
+ EVP_DigestInit_ex(&c,dgst, NULL);
EVP_DigestUpdate(&c, seed, seedlen);
EVP_DigestUpdate(&c, cnt, 4);
- if (outlen + SHA_DIGEST_LENGTH <= len)
+ if (outlen + mdlen <= len)
{
- EVP_DigestFinal(&c, mask + outlen, NULL);
- outlen += SHA_DIGEST_LENGTH;
+ EVP_DigestFinal_ex(&c, mask + outlen, NULL);
+ outlen += mdlen;
}
else
{
- EVP_DigestFinal(&c, md, NULL);
+ EVP_DigestFinal_ex(&c, md, NULL);
memcpy(mask + outlen, md, len - outlen);
outlen = len;
}
EVP_MD_CTX_cleanup(&c);
return 0;
}
+
+int MGF1(unsigned char *mask, long len, const unsigned char *seed, long seedlen)
+ {
+ return PKCS1_MGF1(mask, len, seed, seedlen, EVP_sha1());
+ }
#endif