+++ /dev/null
-/* crypto/rsa/rsa_oaep.c */
-/* 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) */
-
-/* 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/evp.h>
-#include <openssl/rand.h>
-#include <openssl/sha.h>
-
-int MGF1(unsigned char *mask, long len,
- const unsigned char *seed, long seedlen);
-
-int RSA_padding_add_PKCS1_OAEP(unsigned char *to, int tlen,
- const unsigned char *from, int flen,
- const 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)
- {
- 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;
- }
-
- dbmask = OPENSSL_malloc(emlen - SHA_DIGEST_LENGTH);
- if (dbmask == NULL)
- {
- RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP, ERR_R_MALLOC_FAILURE);
- return 0;
- }
-
- 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,
- "\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(seedmask, SHA_DIGEST_LENGTH, db, emlen - SHA_DIGEST_LENGTH);
- for (i = 0; i < SHA_DIGEST_LENGTH; i++)
- seed[i] ^= seedmask[i];
-
- OPENSSL_free(dbmask);
- return 1;
- }
-
-int RSA_padding_check_PKCS1_OAEP(unsigned char *to, int tlen,
- const unsigned char *from, int flen, int num,
- const unsigned char *param, int plen)
- {
- 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 = OPENSSL_malloc(dblen);
- if (db == NULL)
- {
- RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP, ERR_R_MALLOC_FAILURE);
- return -1;
- }
-
- 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];
-
- EVP_Digest((void *)param, plen, phash, NULL, EVP_sha1(), NULL);
-
- if (memcmp(db, phash, SHA_DIGEST_LENGTH) != 0 || bad)
- goto decoding_err;
- else
- {
- 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);
- }
- }
- 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;
- }
-
-int MGF1(unsigned char *mask, long len,
- const unsigned char *seed, long seedlen)
- {
- 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;
- }
-#endif
projects / bcm963xx.git / blobdiff