diff options
Diffstat (limited to 'openssl-1.1.0h/crypto/rsa/rsa_oaep.c')
| -rw-r--r-- | openssl-1.1.0h/crypto/rsa/rsa_oaep.c | 286 |
1 files changed, 286 insertions, 0 deletions
diff --git a/openssl-1.1.0h/crypto/rsa/rsa_oaep.c b/openssl-1.1.0h/crypto/rsa/rsa_oaep.c new file mode 100644 index 0000000..4878d49 --- /dev/null +++ b/openssl-1.1.0h/crypto/rsa/rsa_oaep.c @@ -0,0 +1,286 @@ +/* + * Copyright 1999-2016 The OpenSSL Project Authors. All Rights Reserved. + * + * Licensed under the OpenSSL license (the "License"). You may not use + * this file except in compliance with the License. You can obtain a copy + * in the file LICENSE in the source distribution or at + * https://www.openssl.org/source/license.html + */ + +/* 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. + */ + +#include "internal/constant_time_locl.h" + +#include <stdio.h> +#include "internal/cryptlib.h" +#include <openssl/bn.h> +#include <openssl/evp.h> +#include <openssl/rand.h> +#include <openssl/sha.h> +#include "rsa_locl.h" + +int RSA_padding_add_PKCS1_OAEP(unsigned char *to, int tlen, + const unsigned char *from, int flen, + const unsigned char *param, int plen) +{ + return RSA_padding_add_PKCS1_OAEP_mgf1(to, tlen, from, flen, + param, plen, NULL, NULL); +} + +int RSA_padding_add_PKCS1_OAEP_mgf1(unsigned char *to, int tlen, + const unsigned char *from, int flen, + const unsigned char *param, int plen, + const EVP_MD *md, const EVP_MD *mgf1md) +{ + int i, emlen = tlen - 1; + unsigned char *db, *seed; + unsigned char *dbmask, seedmask[EVP_MAX_MD_SIZE]; + int mdlen; + + if (md == NULL) + md = EVP_sha1(); + if (mgf1md == NULL) + mgf1md = md; + + mdlen = EVP_MD_size(md); + + if (flen > emlen - 2 * mdlen - 1) { + RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP_MGF1, + RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE); + return 0; + } + + if (emlen < 2 * mdlen + 1) { + RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP_MGF1, + RSA_R_KEY_SIZE_TOO_SMALL); + return 0; + } + + to[0] = 0; + seed = to + 1; + db = to + mdlen + 1; + + if (!EVP_Digest((void *)param, plen, db, NULL, md, NULL)) + return 0; + memset(db + mdlen, 0, emlen - flen - 2 * mdlen - 1); + db[emlen - flen - mdlen - 1] = 0x01; + memcpy(db + emlen - flen - mdlen, from, (unsigned int)flen); + if (RAND_bytes(seed, mdlen) <= 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 + + dbmask = OPENSSL_malloc(emlen - mdlen); + if (dbmask == NULL) { + RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_OAEP_MGF1, ERR_R_MALLOC_FAILURE); + return 0; + } + + if (PKCS1_MGF1(dbmask, emlen - mdlen, seed, mdlen, mgf1md) < 0) + goto err; + for (i = 0; i < emlen - mdlen; i++) + db[i] ^= dbmask[i]; + + if (PKCS1_MGF1(seedmask, mdlen, db, emlen - mdlen, mgf1md) < 0) + goto err; + for (i = 0; i < mdlen; i++) + seed[i] ^= seedmask[i]; + + OPENSSL_free(dbmask); + return 1; + + err: + OPENSSL_free(dbmask); + return 0; +} + +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) +{ + return RSA_padding_check_PKCS1_OAEP_mgf1(to, tlen, from, flen, num, + param, plen, NULL, NULL); +} + +int RSA_padding_check_PKCS1_OAEP_mgf1(unsigned char *to, int tlen, + const unsigned char *from, int flen, + int num, const unsigned char *param, + int plen, const EVP_MD *md, + const EVP_MD *mgf1md) +{ + int i, dblen = 0, mlen = -1, one_index = 0, msg_index; + unsigned int good, found_one_byte; + const unsigned char *maskedseed, *maskeddb; + /* + * |em| is the encoded message, zero-padded to exactly |num| bytes: em = + * Y || maskedSeed || maskedDB + */ + unsigned char *db = NULL, *em = NULL, seed[EVP_MAX_MD_SIZE], + phash[EVP_MAX_MD_SIZE]; + int mdlen; + + if (md == NULL) + md = EVP_sha1(); + if (mgf1md == NULL) + mgf1md = md; + + mdlen = EVP_MD_size(md); + + if (tlen <= 0 || flen <= 0) + return -1; + /* + * |num| is the length of the modulus; |flen| is the length of the + * encoded message. Therefore, for any |from| that was obtained by + * decrypting a ciphertext, we must have |flen| <= |num|. Similarly, + * num < 2 * mdlen + 2 must hold for the modulus irrespective of + * the ciphertext, see PKCS #1 v2.2, section 7.1.2. + * This does not leak any side-channel information. + */ + if (num < flen || num < 2 * mdlen + 2) + goto decoding_err; + + dblen = num - mdlen - 1; + db = OPENSSL_malloc(dblen); + em = OPENSSL_malloc(num); + if (db == NULL || em == NULL) { + RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_OAEP_MGF1, ERR_R_MALLOC_FAILURE); + goto cleanup; + } + + /* + * Always do this zero-padding copy (even when num == flen) to avoid + * leaking that information. The copy still leaks some side-channel + * information, but it's impossible to have a fixed memory access + * pattern since we can't read out of the bounds of |from|. + * + * TODO(emilia): Consider porting BN_bn2bin_padded from BoringSSL. + */ + memset(em, 0, num); + memcpy(em + num - flen, from, flen); + + /* + * The first byte must be zero, however we must not leak if this is + * true. See James H. Manger, "A Chosen Ciphertext Attack on RSA + * Optimal Asymmetric Encryption Padding (OAEP) [...]", CRYPTO 2001). + */ + good = constant_time_is_zero(em[0]); + + maskedseed = em + 1; + maskeddb = em + 1 + mdlen; + + if (PKCS1_MGF1(seed, mdlen, maskeddb, dblen, mgf1md)) + goto cleanup; + for (i = 0; i < mdlen; i++) + seed[i] ^= maskedseed[i]; + + if (PKCS1_MGF1(db, dblen, seed, mdlen, mgf1md)) + goto cleanup; + for (i = 0; i < dblen; i++) + db[i] ^= maskeddb[i]; + + if (!EVP_Digest((void *)param, plen, phash, NULL, md, NULL)) + goto cleanup; + + good &= constant_time_is_zero(CRYPTO_memcmp(db, phash, mdlen)); + + found_one_byte = 0; + for (i = mdlen; i < dblen; i++) { + /* + * Padding consists of a number of 0-bytes, followed by a 1. + */ + unsigned int equals1 = constant_time_eq(db[i], 1); + unsigned int equals0 = constant_time_is_zero(db[i]); + one_index = constant_time_select_int(~found_one_byte & equals1, + i, one_index); + found_one_byte |= equals1; + good &= (found_one_byte | equals0); + } + + good &= found_one_byte; + + /* + * At this point |good| is zero unless the plaintext was valid, + * so plaintext-awareness ensures timing side-channels are no longer a + * concern. + */ + if (!good) + goto decoding_err; + + msg_index = one_index + 1; + mlen = dblen - msg_index; + + if (tlen < mlen) { + RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_OAEP_MGF1, RSA_R_DATA_TOO_LARGE); + mlen = -1; + } else { + memcpy(to, db + msg_index, mlen); + goto cleanup; + } + + 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_MGF1, + RSA_R_OAEP_DECODING_ERROR); + cleanup: + OPENSSL_clear_free(db, dblen); + OPENSSL_clear_free(em, num); + return mlen; +} + +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 = EVP_MD_CTX_new(); + unsigned char md[EVP_MAX_MD_SIZE]; + int mdlen; + int rv = -1; + + if (c == NULL) + goto err; + mdlen = EVP_MD_size(dgst); + if (mdlen < 0) + goto err; + 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); + if (!EVP_DigestInit_ex(c, dgst, NULL) + || !EVP_DigestUpdate(c, seed, seedlen) + || !EVP_DigestUpdate(c, cnt, 4)) + goto err; + if (outlen + mdlen <= len) { + if (!EVP_DigestFinal_ex(c, mask + outlen, NULL)) + goto err; + outlen += mdlen; + } else { + if (!EVP_DigestFinal_ex(c, md, NULL)) + goto err; + memcpy(mask + outlen, md, len - outlen); + outlen = len; + } + } + rv = 0; + err: + EVP_MD_CTX_free(c); + return rv; +} |