diff options
Diffstat (limited to 'crypto/rsa')
| -rw-r--r-- | crypto/rsa/rsa_eay.c | 4 | ||||
| -rw-r--r-- | crypto/rsa/rsa_oaep.c | 46 | ||||
| -rw-r--r-- | crypto/rsa/rsa_pk1.c | 44 | ||||
| -rw-r--r-- | crypto/rsa/rsa_pmeth.c | 4 | ||||
| -rw-r--r-- | crypto/rsa/rsa_ssl.c | 55 |
5 files changed, 78 insertions, 75 deletions
diff --git a/crypto/rsa/rsa_eay.c b/crypto/rsa/rsa_eay.c index 7f20fd6738a73..b7362ad7656d5 100644 --- a/crypto/rsa/rsa_eay.c +++ b/crypto/rsa/rsa_eay.c @@ -56,7 +56,7 @@ * [including the GNU Public Licence.] */ /* ==================================================================== - * Copyright (c) 1998-2018 The OpenSSL Project. All rights reserved. + * Copyright (c) 1998-2019 The OpenSSL Project. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions @@ -589,7 +589,7 @@ static int RSA_eay_private_decrypt(int flen, const unsigned char *from, goto err; } RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, RSA_R_PADDING_CHECK_FAILED); - err_clear_last_constant_time(r >= 0); + err_clear_last_constant_time(1 & ~constant_time_msb(r)); err: if (ctx != NULL) { diff --git a/crypto/rsa/rsa_oaep.c b/crypto/rsa/rsa_oaep.c index 033ea5a520cbc..41e9c3bfe3ba7 100644 --- a/crypto/rsa/rsa_oaep.c +++ b/crypto/rsa/rsa_oaep.c @@ -144,7 +144,7 @@ int RSA_padding_check_PKCS1_OAEP_mgf1(unsigned char *to, int tlen, * |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 + * |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. */ @@ -180,17 +180,16 @@ int RSA_padding_check_PKCS1_OAEP_mgf1(unsigned char *to, int tlen, from -= 1 & mask; *--em = *from & mask; } - from = em; /* * 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(from[0]); + good = constant_time_is_zero(em[0]); - maskedseed = from + 1; - maskeddb = from + 1 + mdlen; + maskedseed = em + 1; + maskeddb = em + 1 + mdlen; if (PKCS1_MGF1(seed, mdlen, maskeddb, dblen, mgf1md)) goto cleanup; @@ -231,29 +230,30 @@ int RSA_padding_check_PKCS1_OAEP_mgf1(unsigned char *to, int tlen, mlen = dblen - msg_index; /* - * For good measure, do this check in constant tine as well. + * For good measure, do this check in constant time as well. */ good &= constant_time_ge(tlen, mlen); /* - * Even though we can't fake result's length, we can pretend copying - * |tlen| bytes where |mlen| bytes would be real. Last |tlen| of |dblen| - * bytes are viewed as circular buffer with start at |tlen|-|mlen'|, - * where |mlen'| is "saturated" |mlen| value. Deducing information - * about failure or |mlen| would take attacker's ability to observe - * memory access pattern with byte granularity *as it occurs*. It - * should be noted that failure is indistinguishable from normal - * operation if |tlen| is fixed by protocol. + * Move the result in-place by |dblen|-|mdlen|-1-|mlen| bytes to the left. + * Then if |good| move |mlen| bytes from |db|+|mdlen|+1 to |to|. + * Otherwise leave |to| unchanged. + * Copy the memory back in a way that does not reveal the size of + * the data being copied via a timing side channel. This requires copying + * parts of the buffer multiple times based on the bits set in the real + * length. Clear bits do a non-copy with identical access pattern. + * The loop below has overall complexity of O(N*log(N)). */ - tlen = constant_time_select_int(constant_time_lt(dblen, tlen), dblen, tlen); - msg_index = constant_time_select_int(good, msg_index, dblen - tlen); - mlen = dblen - msg_index; - for (from = db + msg_index, mask = good, i = 0; i < tlen; i++) { - unsigned int equals = constant_time_eq(i, mlen); - - from -= dblen & equals; /* if (i == dblen) rewind */ - mask &= mask ^ equals; /* if (i == dblen) mask = 0 */ - to[i] = constant_time_select_8(mask, from[i], to[i]); + tlen = constant_time_select_int(constant_time_lt(dblen - mdlen - 1, tlen), + dblen - mdlen - 1, tlen); + for (msg_index = 1; msg_index < dblen - mdlen - 1; msg_index <<= 1) { + mask = ~constant_time_eq(msg_index & (dblen - mdlen - 1 - mlen), 0); + for (i = mdlen + 1; i < dblen - msg_index; i++) + db[i] = constant_time_select_8(mask, db[i + msg_index], db[i]); + } + for (i = 0; i < tlen; i++) { + mask = good & constant_time_lt(i, mlen); + to[i] = constant_time_select_8(mask, db[i + mdlen + 1], to[i]); } /* diff --git a/crypto/rsa/rsa_pk1.c b/crypto/rsa/rsa_pk1.c index 074bc0a93947f..86e0debc46bb4 100644 --- a/crypto/rsa/rsa_pk1.c +++ b/crypto/rsa/rsa_pk1.c @@ -241,15 +241,14 @@ int RSA_padding_check_PKCS1_type_2(unsigned char *to, int tlen, from -= 1 & mask; *--em = *from & mask; } - from = em; - good = constant_time_is_zero(from[0]); - good &= constant_time_eq(from[1], 2); + good = constant_time_is_zero(em[0]); + good &= constant_time_eq(em[1], 2); /* scan over padding data */ found_zero_byte = 0; for (i = 2; i < num; i++) { - unsigned int equals0 = constant_time_is_zero(from[i]); + unsigned int equals0 = constant_time_is_zero(em[i]); zero_index = constant_time_select_int(~found_zero_byte & equals0, i, zero_index); @@ -257,7 +256,7 @@ int RSA_padding_check_PKCS1_type_2(unsigned char *to, int tlen, } /* - * PS must be at least 8 bytes long, and it starts two bytes into |from|. + * PS must be at least 8 bytes long, and it starts two bytes into |em|. * If we never found a 0-byte, then |zero_index| is 0 and the check * also fails. */ @@ -276,24 +275,25 @@ int RSA_padding_check_PKCS1_type_2(unsigned char *to, int tlen, good &= constant_time_ge(tlen, mlen); /* - * Even though we can't fake result's length, we can pretend copying - * |tlen| bytes where |mlen| bytes would be real. Last |tlen| of |num| - * bytes are viewed as circular buffer with start at |tlen|-|mlen'|, - * where |mlen'| is "saturated" |mlen| value. Deducing information - * about failure or |mlen| would take attacker's ability to observe - * memory access pattern with byte granularity *as it occurs*. It - * should be noted that failure is indistinguishable from normal - * operation if |tlen| is fixed by protocol. + * Move the result in-place by |num|-11-|mlen| bytes to the left. + * Then if |good| move |mlen| bytes from |em|+11 to |to|. + * Otherwise leave |to| unchanged. + * Copy the memory back in a way that does not reveal the size of + * the data being copied via a timing side channel. This requires copying + * parts of the buffer multiple times based on the bits set in the real + * length. Clear bits do a non-copy with identical access pattern. + * The loop below has overall complexity of O(N*log(N)). */ - tlen = constant_time_select_int(constant_time_lt(num, tlen), num, tlen); - msg_index = constant_time_select_int(good, msg_index, num - tlen); - mlen = num - msg_index; - for (from += msg_index, mask = good, i = 0; i < tlen; i++) { - unsigned int equals = constant_time_eq(i, mlen); - - from -= tlen & equals; /* if (i == mlen) rewind */ - mask &= mask ^ equals; /* if (i == mlen) mask = 0 */ - to[i] = constant_time_select_8(mask, from[i], to[i]); + tlen = constant_time_select_int(constant_time_lt(num - 11, tlen), + num - 11, tlen); + for (msg_index = 1; msg_index < num - 11; msg_index <<= 1) { + mask = ~constant_time_eq(msg_index & (num - 11 - mlen), 0); + for (i = 11; i < num - msg_index; i++) + em[i] = constant_time_select_8(mask, em[i + msg_index], em[i]); + } + for (i = 0; i < tlen; i++) { + mask = good & constant_time_lt(i, mlen); + to[i] = constant_time_select_8(mask, em[i + 11], to[i]); } OPENSSL_cleanse(em, num); diff --git a/crypto/rsa/rsa_pmeth.c b/crypto/rsa/rsa_pmeth.c index 00e730ffa9588..a798be5b3459a 100644 --- a/crypto/rsa/rsa_pmeth.c +++ b/crypto/rsa/rsa_pmeth.c @@ -4,7 +4,7 @@ * 2006. */ /* ==================================================================== - * Copyright (c) 2006 The OpenSSL Project. All rights reserved. + * Copyright (c) 2006-2019 The OpenSSL Project. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions @@ -103,7 +103,7 @@ static int pkey_rsa_init(EVP_PKEY_CTX *ctx) rctx = OPENSSL_malloc(sizeof(RSA_PKEY_CTX)); if (!rctx) return 0; - rctx->nbits = 1024; + rctx->nbits = 2048; rctx->pub_exp = NULL; rctx->pad_mode = RSA_PKCS1_PADDING; rctx->md = NULL; diff --git a/crypto/rsa/rsa_ssl.c b/crypto/rsa/rsa_ssl.c index e9a5fe2385b33..6f25acdac47ad 100644 --- a/crypto/rsa/rsa_ssl.c +++ b/crypto/rsa/rsa_ssl.c @@ -104,7 +104,7 @@ int RSA_padding_add_SSLv23(unsigned char *to, int tlen, /* * Copy of RSA_padding_check_PKCS1_type_2 with a twist that rejects padding - * if nul delimiter is preceded by 8 consecutive 0x03 bytes. It also + * if nul delimiter is not preceded by 8 consecutive 0x03 bytes. It also * preserves error code reporting for backward compatibility. */ int RSA_padding_check_SSLv23(unsigned char *to, int tlen, @@ -116,7 +116,10 @@ int RSA_padding_check_SSLv23(unsigned char *to, int tlen, unsigned int good, found_zero_byte, mask, threes_in_row; int zero_index = 0, msg_index, mlen = -1, err; - if (flen < 10) { + if (tlen <= 0 || flen <= 0) + return -1; + + if (flen > num || num < 11) { RSAerr(RSA_F_RSA_PADDING_CHECK_SSLV23, RSA_R_DATA_TOO_SMALL); return (-1); } @@ -138,10 +141,9 @@ int RSA_padding_check_SSLv23(unsigned char *to, int tlen, from -= 1 & mask; *--em = *from & mask; } - from = em; - good = constant_time_is_zero(from[0]); - good &= constant_time_eq(from[1], 2); + good = constant_time_is_zero(em[0]); + good &= constant_time_eq(em[1], 2); err = constant_time_select_int(good, 0, RSA_R_BLOCK_TYPE_IS_NOT_02); mask = ~good; @@ -149,18 +151,18 @@ int RSA_padding_check_SSLv23(unsigned char *to, int tlen, found_zero_byte = 0; threes_in_row = 0; for (i = 2; i < num; i++) { - unsigned int equals0 = constant_time_is_zero(from[i]); + unsigned int equals0 = constant_time_is_zero(em[i]); zero_index = constant_time_select_int(~found_zero_byte & equals0, i, zero_index); found_zero_byte |= equals0; threes_in_row += 1 & ~found_zero_byte; - threes_in_row &= found_zero_byte | constant_time_eq(from[i], 3); + threes_in_row &= found_zero_byte | constant_time_eq(em[i], 3); } /* - * PS must be at least 8 bytes long, and it starts two bytes into |from|. + * PS must be at least 8 bytes long, and it starts two bytes into |em|. * If we never found a 0-byte, then |zero_index| is 0 and the check * also fails. */ @@ -169,7 +171,7 @@ int RSA_padding_check_SSLv23(unsigned char *to, int tlen, RSA_R_NULL_BEFORE_BLOCK_MISSING); mask = ~good; - good &= constant_time_lt(threes_in_row, 8); + good &= constant_time_ge(threes_in_row, 8); err = constant_time_select_int(mask | good, err, RSA_R_SSLV3_ROLLBACK_ATTACK); mask = ~good; @@ -188,24 +190,25 @@ int RSA_padding_check_SSLv23(unsigned char *to, int tlen, err = constant_time_select_int(mask | good, err, RSA_R_DATA_TOO_LARGE); /* - * Even though we can't fake result's length, we can pretend copying - * |tlen| bytes where |mlen| bytes would be real. Last |tlen| of |num| - * bytes are viewed as circular buffer with start at |tlen|-|mlen'|, - * where |mlen'| is "saturated" |mlen| value. Deducing information - * about failure or |mlen| would take attacker's ability to observe - * memory access pattern with byte granularity *as it occurs*. It - * should be noted that failure is indistinguishable from normal - * operation if |tlen| is fixed by protocol. + * Move the result in-place by |num|-11-|mlen| bytes to the left. + * Then if |good| move |mlen| bytes from |em|+11 to |to|. + * Otherwise leave |to| unchanged. + * Copy the memory back in a way that does not reveal the size of + * the data being copied via a timing side channel. This requires copying + * parts of the buffer multiple times based on the bits set in the real + * length. Clear bits do a non-copy with identical access pattern. + * The loop below has overall complexity of O(N*log(N)). */ - tlen = constant_time_select_int(constant_time_lt(num, tlen), num, tlen); - msg_index = constant_time_select_int(good, msg_index, num - tlen); - mlen = num - msg_index; - for (from += msg_index, mask = good, i = 0; i < tlen; i++) { - unsigned int equals = constant_time_eq(i, mlen); - - from -= tlen & equals; /* if (i == mlen) rewind */ - mask &= mask ^ equals; /* if (i == mlen) mask = 0 */ - to[i] = constant_time_select_8(mask, from[i], to[i]); + tlen = constant_time_select_int(constant_time_lt(num - 11, tlen), + num - 11, tlen); + for (msg_index = 1; msg_index < num - 11; msg_index <<= 1) { + mask = ~constant_time_eq(msg_index & (num - 11 - mlen), 0); + for (i = 11; i < num - msg_index; i++) + em[i] = constant_time_select_8(mask, em[i + msg_index], em[i]); + } + for (i = 0; i < tlen; i++) { + mask = good & constant_time_lt(i, mlen); + to[i] = constant_time_select_8(mask, em[i + 11], to[i]); } OPENSSL_cleanse(em, num); |