import openssl-0.9.7-beta1

1 files changed, 168 insertions, 124 deletions

diff --git a/src/lib/libcrypto/rsa/rsa_oaep.c b/src/lib/libcrypto/rsa/rsa_oaep.c
index 843c40c864..e3f7c608ec 100644
--- a/src/lib/libcrypto/rsa/rsa_oaep.c
+++ b/src/lib/libcrypto/rsa/rsa_oaep.c
@@ -2,161 +2,205 @@
 /* Written by Ulf Moeller. This software is distributed on an "AS IS"
    basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. */
 
-/* EME_OAEP as defined in RFC 2437 (PKCS #1 v2.0) */
-
-#if !defined(NO_SHA) && !defined(NO_SHA1)
+/* EME-OAEP as defined in RFC 2437 (PKCS #1 v2.0) */
+
+/* See Victor Shoup, "OAEP reconsidered," Nov. 2000,
+ * <URL: http://www.shoup.net/papers/oaep.ps.Z>
+ * for problems with the security proof for the
+ * original OAEP scheme, which EME-OAEP is based on.
+ * 
+ * A new proof can be found in E. Fujisaki, T. Okamoto,
+ * D. Pointcheval, J. Stern, "RSA-OEAP is Still Alive!",
+ * Dec. 2000, <URL: http://eprint.iacr.org/2000/061/>.
+ * The new proof has stronger requirements for the
+ * underlying permutation: "partial-one-wayness" instead
+ * of one-wayness.  For the RSA function, this is
+ * an equivalent notion.
+ */
+
+
+#if !defined(OPENSSL_NO_SHA) && !defined(OPENSSL_NO_SHA1)
 #include <stdio.h>
 #include "cryptlib.h"
 #include <openssl/bn.h>
 #include <openssl/rsa.h>
-#include <openssl/sha.h>
+#include <openssl/evp.h>
 #include <openssl/rand.h>
+#include <openssl/sha.h>
 
-int MGF1(unsigned char *mask, long len, unsigned char *seed, long seedlen);
+int MGF1(unsigned char *mask, long len,
+        const unsigned char *seed, long seedlen);
 
 int RSA_padding_add_PKCS1_OAEP(unsigned char *to, int tlen,
-             unsigned char *from, int flen, unsigned char *param, int plen)
-    {
-    int i, emlen = tlen - 1;
-    unsigned char *db, *seed;
-    unsigned char *dbmask, seedmask[SHA_DIGEST_LENGTH];
-
-    if (flen > emlen - 2 * SHA_DIGEST_LENGTH - 1)
+        const unsigned char *from, int flen,
+        const unsigned char *param, int plen)
         {
-        RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP,
-               RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
-        return (0);
-        }
+        int i, emlen = tlen - 1;
+        unsigned char *db, *seed;
+        unsigned char *dbmask, seedmask[SHA_DIGEST_LENGTH];
 
-    if (emlen < 2 * SHA_DIGEST_LENGTH + 1)
-        {
-        RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP, RSA_R_KEY_SIZE_TOO_SMALL);
-        return (0);
-        }
-    
-    dbmask = Malloc(emlen - SHA_DIGEST_LENGTH);
-    if (dbmask == NULL)
-        {
-        RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP, ERR_R_MALLOC_FAILURE);
-        return (0);
-        }
+        if (flen > emlen - 2 * SHA_DIGEST_LENGTH - 1)
+                {
+                RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP,
+                   RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
+                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;
+                }
 
-    to[0] = 0;
-    seed = to + 1;
-    db = to + SHA_DIGEST_LENGTH + 1;
+        dbmask = OPENSSL_malloc(emlen - SHA_DIGEST_LENGTH);
+        if (dbmask == NULL)
+                {
+                RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP, ERR_R_MALLOC_FAILURE);
+                return 0;
+                }
 
-    SHA1(param, plen, db);
-    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);
-    RAND_bytes(seed, SHA_DIGEST_LENGTH);
+        to[0] = 0;
+        seed = to + 1;
+        db = to + SHA_DIGEST_LENGTH + 1;
+
+        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;
 #ifdef PKCS_TESTVECT
-    memcpy(seed,
+        memcpy(seed,
            "\xaa\xfd\x12\xf6\x59\xca\xe6\x34\x89\xb4\x79\xe5\x07\x6d\xde\xc2\xf0\x6c\xb5\x8f",
            20);
 #endif
 
-    MGF1(dbmask, emlen - SHA_DIGEST_LENGTH, seed, SHA_DIGEST_LENGTH);
-    for (i = 0; i < emlen - SHA_DIGEST_LENGTH; i++)
-        db[i] ^= dbmask[i];
+        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];
+        MGF1(seedmask, SHA_DIGEST_LENGTH, db, emlen - SHA_DIGEST_LENGTH);
+        for (i = 0; i < SHA_DIGEST_LENGTH; i++)
+                seed[i] ^= seedmask[i];
 
-    Free(dbmask);
-    return (1);
-    }
+        OPENSSL_free(dbmask);
+        return 1;
+        }
 
 int RSA_padding_check_PKCS1_OAEP(unsigned char *to, int tlen,
-             unsigned char *from, int flen, int num, unsigned char *param,
-             int plen)
-    {
-    int i, dblen, mlen = -1;
-    unsigned char *maskeddb;
-    int lzero;
-    unsigned char *db, seed[SHA_DIGEST_LENGTH], phash[SHA_DIGEST_LENGTH];
-
-    if (--num < 2 * SHA_DIGEST_LENGTH + 1)
+        const unsigned char *from, int flen, int num,
+        const unsigned char *param, int plen)
         {
-        RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_OAEP, RSA_R_OAEP_DECODING_ERROR);
-        return (-1);
-        }
+        int i, dblen, mlen = -1;
+        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)
+                {
+                /* 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 = Malloc(dblen);
-    if (db == NULL)
-        {
-        RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP, ERR_R_MALLOC_FAILURE);
-        return (-1);
-        }
+        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;
+                }
 
-    lzero = num - flen;
-    maskeddb = from - lzero + SHA_DIGEST_LENGTH;
-    
-    MGF1(seed, SHA_DIGEST_LENGTH, maskeddb, dblen);
-    for (i = lzero; i < SHA_DIGEST_LENGTH; i++)
-        seed[i] ^= from[i - lzero];
+        MGF1(seed, SHA_DIGEST_LENGTH, maskeddb, dblen);
+        for (i = lzero; i < SHA_DIGEST_LENGTH; i++)
+                seed[i] ^= from[i - lzero];
   
-    MGF1(db, dblen, seed, SHA_DIGEST_LENGTH);
-    for (i = 0; i < dblen; i++)
-        db[i] ^= maskeddb[i];
+        MGF1(db, dblen, seed, SHA_DIGEST_LENGTH);
+        for (i = 0; i < dblen; i++)
+                db[i] ^= maskeddb[i];
 
-    SHA1(param, plen, phash);
+        EVP_Digest((void *)param, plen, phash, NULL, EVP_sha1(), NULL);
 
-    if (memcmp(db, phash, SHA_DIGEST_LENGTH) != 0)
-        RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_OAEP, RSA_R_OAEP_DECODING_ERROR);
-    else
-        {
-        for (i = SHA_DIGEST_LENGTH; i < dblen; i++)
-            if (db[i] != 0x00)
-                break;
-        if (db[i] != 0x01 || i++ >= dblen)
-            RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_OAEP,
-                   RSA_R_OAEP_DECODING_ERROR);
+        if (memcmp(db, phash, SHA_DIGEST_LENGTH) != 0 || bad)
+                goto decoding_err;
         else
-            {
-            mlen = dblen - i;
-            if (tlen < mlen)
                 {
-                RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP, RSA_R_DATA_TOO_LARGE);
-                mlen = -1;
+                for (i = SHA_DIGEST_LENGTH; i < dblen; i++)
+                        if (db[i] != 0x00)
+                                break;
+                if (db[i] != 0x01 || i++ >= dblen)
+                        goto decoding_err;
+                else
+                        {
+                        /* everything looks OK */
+
+                        mlen = dblen - i;
+                        if (tlen < mlen)
+                                {
+                                RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_OAEP, RSA_R_DATA_TOO_LARGE);
+                                mlen = -1;
+                                }
+                        else
+                                memcpy(to, db + i, mlen);
+                        }
                 }
-            else
-                memcpy(to, db + i, 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 */
+        RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_OAEP, RSA_R_OAEP_DECODING_ERROR);
+        if (db != NULL) OPENSSL_free(db);
+        return -1;
         }
-    Free(db);
-    return (mlen);
-    }
-
-int MGF1(unsigned char *mask, long len, unsigned char *seed, long seedlen)
-    {
-    long i, outlen = 0;
-    unsigned char cnt[4];
-    SHA_CTX c;
-    unsigned char md[SHA_DIGEST_LENGTH];
-
-    for (i = 0; outlen < len; i++)
+
+int MGF1(unsigned char *mask, long len,
+        const unsigned char *seed, long seedlen)
         {
-        cnt[0] = (i >> 24) & 255, cnt[1] = (i >> 16) & 255,
-          cnt[2] = (i >> 8) & 255, cnt[3] = i & 255;
-        SHA1_Init(&c);
-        SHA1_Update(&c, seed, seedlen);
-        SHA1_Update(&c, cnt, 4);
-        if (outlen + SHA_DIGEST_LENGTH <= len)
-            {
-            SHA1_Final(mask + outlen, &c);
-            outlen += SHA_DIGEST_LENGTH;
-            }
-        else
-            {
-            SHA1_Final(md, &c);
-            memcpy(mask + outlen, md, len - outlen);
-            outlen = len;
-            }
+        long i, outlen = 0;
+        unsigned char cnt[4];
+        EVP_MD_CTX c;
+        unsigned char md[SHA_DIGEST_LENGTH];
+
+        EVP_MD_CTX_init(&c);
+        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_ex(&c,EVP_sha1(), NULL);
+                EVP_DigestUpdate(&c, seed, seedlen);
+                EVP_DigestUpdate(&c, cnt, 4);
+                if (outlen + SHA_DIGEST_LENGTH <= len)
+                        {
+                        EVP_DigestFinal_ex(&c, mask + outlen, NULL);
+                        outlen += SHA_DIGEST_LENGTH;
+                        }
+                else
+                        {
+                        EVP_DigestFinal_ex(&c, md, NULL);
+                        memcpy(mask + outlen, md, len - outlen);
+                        outlen = len;
+                        }
+                }
+        EVP_MD_CTX_cleanup(&c);
+        return 0;
         }
-    return (0);
-    }
 #endif