From d31fed73e25391cd71a0de488d88724db78f6f8a Mon Sep 17 00:00:00 2001 From: "Dr. Stephen Henson" Date: Fri, 18 Jul 2014 13:52:03 +0100 Subject: [PATCH] RFC 5649 support. Add support for RFC5649 key wrapping with padding. Add RFC5649 tests to evptests.txt Based on PR#3434 contribution by Petr Spacek . EVP support and minor changes added by Stephen Henson. Doxygen comment block updates by Tim Hudson. Reviewed-by: Tim Hudson --- crypto/evp/c_allc.c | 3 + crypto/evp/e_aes.c | 96 +++++++++++++-- crypto/evp/evp.h | 3 + crypto/evp/evptests.txt | 4 + crypto/modes/modes.h | 6 + crypto/modes/wrap128.c | 250 ++++++++++++++++++++++++++++++++++++++-- 6 files changed, 342 insertions(+), 20 deletions(-) diff --git a/crypto/evp/c_allc.c b/crypto/evp/c_allc.c index 4cfe5a9835..a714f1246b 100644 --- a/crypto/evp/c_allc.c +++ b/crypto/evp/c_allc.c @@ -175,6 +175,7 @@ void OpenSSL_add_all_ciphers(void) EVP_add_cipher(EVP_aes_128_xts()); EVP_add_cipher(EVP_aes_128_ccm()); EVP_add_cipher(EVP_aes_128_wrap()); + EVP_add_cipher(EVP_aes_128_wrap_pad()); EVP_add_cipher_alias(SN_aes_128_cbc,"AES128"); EVP_add_cipher_alias(SN_aes_128_cbc,"aes128"); EVP_add_cipher(EVP_aes_192_ecb()); @@ -187,6 +188,7 @@ void OpenSSL_add_all_ciphers(void) EVP_add_cipher(EVP_aes_192_gcm()); EVP_add_cipher(EVP_aes_192_ccm()); EVP_add_cipher(EVP_aes_192_wrap()); + EVP_add_cipher(EVP_aes_192_wrap_pad()); EVP_add_cipher_alias(SN_aes_192_cbc,"AES192"); EVP_add_cipher_alias(SN_aes_192_cbc,"aes192"); EVP_add_cipher(EVP_aes_256_ecb()); @@ -200,6 +202,7 @@ void OpenSSL_add_all_ciphers(void) EVP_add_cipher(EVP_aes_256_xts()); EVP_add_cipher(EVP_aes_256_ccm()); EVP_add_cipher(EVP_aes_256_wrap()); + EVP_add_cipher(EVP_aes_256_wrap_pad()); EVP_add_cipher_alias(SN_aes_256_cbc,"AES256"); EVP_add_cipher_alias(SN_aes_256_cbc,"aes256"); #if !defined(OPENSSL_NO_SHA) && !defined(OPENSSL_NO_SHA1) diff --git a/crypto/evp/e_aes.c b/crypto/evp/e_aes.c index 3501066b07..89178bc16d 100644 --- a/crypto/evp/e_aes.c +++ b/crypto/evp/e_aes.c @@ -1,5 +1,5 @@ /* ==================================================================== - * Copyright (c) 2001-2011 The OpenSSL Project. All rights reserved. + * Copyright (c) 2001-2014 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 @@ -2086,7 +2086,7 @@ static int aes_wrap_init_key(EVP_CIPHER_CTX *ctx, const unsigned char *key, } if (iv) { - memcpy(ctx->iv, iv, 8); + memcpy(ctx->iv, iv, EVP_CIPHER_CTX_iv_length(ctx)); wctx->iv = ctx->iv; } return 1; @@ -2097,27 +2097,62 @@ static int aes_wrap_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out, { EVP_AES_WRAP_CTX *wctx = ctx->cipher_data; size_t rv; + /* AES wrap with padding has IV length of 4, without padding 8 */ + int pad = EVP_CIPHER_CTX_iv_length(ctx) == 4; + /* No final operation so always return zero length */ if (!in) return 0; - if (inlen % 8) + /* Input length must always be non-zero */ + if (!inlen) return -1; - if (ctx->encrypt && inlen < 8) + /* If decrypting need at least 16 bytes and multiple of 8 */ + if (!ctx->encrypt && (inlen < 16 || inlen & 0x7)) return -1; - if (!ctx->encrypt && inlen < 16) + /* If not padding input must be multiple of 8 */ + if (!pad && inlen & 0x7) return -1; if (!out) { if (ctx->encrypt) + { + /* If padding round up to multiple of 8 */ + if (pad) + inlen = (inlen + 7)/8 * 8; + /* 8 byte prefix */ return inlen + 8; + } else + { + /* If not padding output will be exactly 8 bytes + * smaller than input. If padding it will be at + * least 8 bytes smaller but we don't know how + * much. + */ return inlen - 8; + } } - if (ctx->encrypt) - rv = CRYPTO_128_wrap(&wctx->ks.ks, wctx->iv, out, in, inlen, + if (pad) + { + if (ctx->encrypt) + rv = CRYPTO_128_wrap_pad(&wctx->ks.ks, wctx->iv, + out, in, inlen, (block128_f)AES_encrypt); + else + rv = CRYPTO_128_unwrap_pad(&wctx->ks.ks, wctx->iv, + out, in, inlen, + (block128_f)AES_decrypt); + } else - rv = CRYPTO_128_unwrap(&wctx->ks.ks, wctx->iv, out, in, inlen, + { + if (ctx->encrypt) + rv = CRYPTO_128_wrap(&wctx->ks.ks, wctx->iv, + out, in, inlen, + (block128_f)AES_encrypt); + else + rv = CRYPTO_128_unwrap(&wctx->ks.ks, wctx->iv, + out, in, inlen, (block128_f)AES_decrypt); + } return rv ? (int)rv : -1; } @@ -2129,7 +2164,7 @@ static const EVP_CIPHER aes_128_wrap = { NID_id_aes128_wrap, 8, 16, 8, WRAP_FLAGS, aes_wrap_init_key, aes_wrap_cipher, - NULL, + NULL, sizeof(EVP_AES_WRAP_CTX), NULL,NULL,NULL,NULL }; @@ -2142,7 +2177,7 @@ static const EVP_CIPHER aes_192_wrap = { NID_id_aes192_wrap, 8, 24, 8, WRAP_FLAGS, aes_wrap_init_key, aes_wrap_cipher, - NULL, + NULL, sizeof(EVP_AES_WRAP_CTX), NULL,NULL,NULL,NULL }; @@ -2155,7 +2190,7 @@ static const EVP_CIPHER aes_256_wrap = { NID_id_aes256_wrap, 8, 32, 8, WRAP_FLAGS, aes_wrap_init_key, aes_wrap_cipher, - NULL, + NULL, sizeof(EVP_AES_WRAP_CTX), NULL,NULL,NULL,NULL }; @@ -2164,4 +2199,43 @@ const EVP_CIPHER *EVP_aes_256_wrap(void) return &aes_256_wrap; } +static const EVP_CIPHER aes_128_wrap_pad = { + NID_id_aes128_wrap_pad, + 8, 16, 4, WRAP_FLAGS, + aes_wrap_init_key, aes_wrap_cipher, + NULL, + sizeof(EVP_AES_WRAP_CTX), + NULL,NULL,NULL,NULL }; + +const EVP_CIPHER *EVP_aes_128_wrap_pad(void) + { + return &aes_128_wrap_pad; + } + +static const EVP_CIPHER aes_192_wrap_pad = { + NID_id_aes192_wrap_pad, + 8, 24, 4, WRAP_FLAGS, + aes_wrap_init_key, aes_wrap_cipher, + NULL, + sizeof(EVP_AES_WRAP_CTX), + NULL,NULL,NULL,NULL }; + +const EVP_CIPHER *EVP_aes_192_wrap_pad(void) + { + return &aes_192_wrap_pad; + } + +static const EVP_CIPHER aes_256_wrap_pad = { + NID_id_aes256_wrap_pad, + 8, 32, 4, WRAP_FLAGS, + aes_wrap_init_key, aes_wrap_cipher, + NULL, + sizeof(EVP_AES_WRAP_CTX), + NULL,NULL,NULL,NULL }; + +const EVP_CIPHER *EVP_aes_256_wrap_pad(void) + { + return &aes_256_wrap_pad; + } + #endif diff --git a/crypto/evp/evp.h b/crypto/evp/evp.h index ea92aa28d8..bafe339f06 100644 --- a/crypto/evp/evp.h +++ b/crypto/evp/evp.h @@ -849,6 +849,7 @@ const EVP_CIPHER *EVP_aes_128_ccm(void); const EVP_CIPHER *EVP_aes_128_gcm(void); const EVP_CIPHER *EVP_aes_128_xts(void); const EVP_CIPHER *EVP_aes_128_wrap(void); +const EVP_CIPHER *EVP_aes_128_wrap_pad(void); const EVP_CIPHER *EVP_aes_192_ecb(void); const EVP_CIPHER *EVP_aes_192_cbc(void); const EVP_CIPHER *EVP_aes_192_cfb1(void); @@ -860,6 +861,7 @@ const EVP_CIPHER *EVP_aes_192_ctr(void); const EVP_CIPHER *EVP_aes_192_ccm(void); const EVP_CIPHER *EVP_aes_192_gcm(void); const EVP_CIPHER *EVP_aes_192_wrap(void); +const EVP_CIPHER *EVP_aes_192_wrap_pad(void); const EVP_CIPHER *EVP_aes_256_ecb(void); const EVP_CIPHER *EVP_aes_256_cbc(void); const EVP_CIPHER *EVP_aes_256_cfb1(void); @@ -872,6 +874,7 @@ const EVP_CIPHER *EVP_aes_256_ccm(void); const EVP_CIPHER *EVP_aes_256_gcm(void); const EVP_CIPHER *EVP_aes_256_xts(void); const EVP_CIPHER *EVP_aes_256_wrap(void); +const EVP_CIPHER *EVP_aes_256_wrap_pad(void); # if !defined(OPENSSL_NO_SHA) && !defined(OPENSSL_NO_SHA1) const EVP_CIPHER *EVP_aes_128_cbc_hmac_sha1(void); const EVP_CIPHER *EVP_aes_256_cbc_hmac_sha1(void); diff --git a/crypto/evp/evptests.txt b/crypto/evp/evptests.txt index 4744fefa33..42eb42e4f8 100644 --- a/crypto/evp/evptests.txt +++ b/crypto/evp/evptests.txt @@ -401,3 +401,7 @@ id-aes256-wrap:000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F: id-aes192-wrap:000102030405060708090A0B0C0D0E0F1011121314151617::00112233445566778899AABBCCDDEEFF0001020304050607:031D33264E15D33268F24EC260743EDCE1C6C7DDEE725A936BA814915C6762D2 id-aes256-wrap:000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F::00112233445566778899AABBCCDDEEFF0001020304050607:A8F9BC1612C68B3FF6E6F4FBE30E71E4769C8B80A32CB8958CD5D17D6B254DA1 id-aes256-wrap:000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F::00112233445566778899AABBCCDDEEFF000102030405060708090A0B0C0D0E0F:28C9F404C4B810F4CBCCB35CFB87F8263F5786E2D80ED326CBC7F0E71A99F43BFB988B9B7A02DD21 +# AES wrap tests from RFC5649 +id-aes192-wrap-pad:5840df6e29b02af1ab493b705bf16ea1ae8338f4dcc176a8::c37b7e6492584340bed12207808941155068f738:138bdeaa9b8fa7fc61f97742e72248ee5ae6ae5360d1ae6a5f54f373fa543b6a +id-aes192-wrap-pad:5840df6e29b02af1ab493b705bf16ea1ae8338f4dcc176a8::466f7250617369:afbeb0f07dfbf5419200f2ccb50bb24f + diff --git a/crypto/modes/modes.h b/crypto/modes/modes.h index 9912550a21..50dc01852d 100644 --- a/crypto/modes/modes.h +++ b/crypto/modes/modes.h @@ -141,3 +141,9 @@ size_t CRYPTO_128_wrap(void *key, const unsigned char *iv, size_t CRYPTO_128_unwrap(void *key, const unsigned char *iv, unsigned char *out, const unsigned char *in, size_t inlen, block128_f block); +size_t CRYPTO_128_wrap_pad(void *key, const unsigned char *icv, + unsigned char *out, + const unsigned char *in, size_t inlen, block128_f block); +size_t CRYPTO_128_unwrap_pad(void *key, const unsigned char *icv, + unsigned char *out, + const unsigned char *in, size_t inlen, block128_f block); diff --git a/crypto/modes/wrap128.c b/crypto/modes/wrap128.c index c6c14cdaaa..315fe8fc8f 100644 --- a/crypto/modes/wrap128.c +++ b/crypto/modes/wrap128.c @@ -1,6 +1,7 @@ /* crypto/modes/wrap128.c */ /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL * project. + * Mode with padding contributed by Petr Spacek (pspacek@redhat.com). */ /* ==================================================================== * Copyright (c) 2013 The OpenSSL Project. All rights reserved. @@ -51,28 +52,55 @@ * ==================================================================== */ +/** Beware! + * + * Following wrapping modes were designed for AES but this implementation + * allows you to use them for any 128 bit block cipher. + */ + #include "cryptlib.h" #include +/** RFC 3394 section 2.2.3.1 Default Initial Value */ static const unsigned char default_iv[] = { 0xA6, 0xA6, 0xA6, 0xA6, 0xA6, 0xA6, 0xA6, 0xA6, }; -/* Input size limit: lower than maximum of standards but far larger than - * anything that will be used in practice. + +/** RFC 5649 section 3 Alternative Initial Value 32-bit constant */ +static const unsigned char default_aiv[] = { + 0xA6, 0x59, 0x59, 0xA6 +}; + +/** Input size limit: lower than maximum of standards but far larger than + * anything that will be used in practice. */ #define CRYPTO128_WRAP_MAX (1UL << 31) +/** Wrapping according to RFC 3394 section 2.2.1. + * + * @param[in] key Key value. + * @param[in] iv IV value. Length = 8 bytes. NULL = use default_iv. + * @param[in] in Plain text as n 64-bit blocks, n >= 2. + * @param[in] inlen Length of in. + * @param[out] out Cipher text. Minimal buffer length = (inlen + 8) bytes. + * Input and output buffers can overlap if block function + * supports that. + * @param[in] block Block processing function. + * @return 0 if inlen does not consist of n 64-bit blocks, n >= 2. + * or if inlen > CRYPTO128_WRAP_MAX. + * Output length if wrapping succeeded. + */ size_t CRYPTO_128_wrap(void *key, const unsigned char *iv, unsigned char *out, const unsigned char *in, size_t inlen, block128_f block) { unsigned char *A, B[16], *R; size_t i, j, t; - if ((inlen & 0x7) || (inlen < 8) || (inlen > CRYPTO128_WRAP_MAX)) + if ((inlen & 0x7) || (inlen < 16) || (inlen > CRYPTO128_WRAP_MAX)) return 0; A = B; t = 1; - memcpy(out + 8, in, inlen); + memmove(out + 8, in, inlen); if (!iv) iv = default_iv; @@ -99,9 +127,26 @@ size_t CRYPTO_128_wrap(void *key, const unsigned char *iv, return inlen + 8; } -size_t CRYPTO_128_unwrap(void *key, const unsigned char *iv, - unsigned char *out, - const unsigned char *in, size_t inlen, block128_f block) + +/** Unwrapping according to RFC 3394 section 2.2.2 steps 1-2. + * IV check (step 3) is responsibility of the caller. + * + * @param[in] key Key value. + * @param[out] iv Unchecked IV value. Minimal buffer length = 8 bytes. + * @param[out] out Plain text without IV. + * Minimal buffer length = (inlen - 8) bytes. + * Input and output buffers can overlap if block function + * supports that. + * @param[in] in Ciphertext text as n 64-bit blocks + * @param[in] inlen Length of in. + * @param[in] block Block processing function. + * @return 0 if inlen is out of range [24, CRYPTO128_WRAP_MAX] + * or if inlen is not multiply of 8. + * Output length otherwise. + */ +static size_t crypto_128_unwrap_raw(void *key, unsigned char *iv, + unsigned char *out, const unsigned char *in, + size_t inlen, block128_f block) { unsigned char *A, B[16], *R; size_t i, j, t; @@ -111,7 +156,7 @@ size_t CRYPTO_128_unwrap(void *key, const unsigned char *iv, A = B; t = 6 * (inlen >> 3); memcpy(A, in, 8); - memcpy(out, in + 8, inlen); + memmove(out, in + 8, inlen); for (j = 0; j < 6; j++) { R = out + inlen - 8; @@ -129,12 +174,199 @@ size_t CRYPTO_128_unwrap(void *key, const unsigned char *iv, memcpy(R, B + 8, 8); } } + memcpy(iv, A, 8); + return inlen; + } + +/** Unwrapping according to RFC 3394 section 2.2.2 including IV check. + * First block of plain text have to match supplied IV otherwise an error is + * returned. + * + * @param[in] key Key value. + * @param[out] iv Unchecked IV value. Minimal buffer length = 8 bytes. + * @param[out] out Plain text without IV. + * Minimal buffer length = (inlen - 8) bytes. + * Input and output buffers can overlap if block function + * supports that. + * @param[in] in Ciphertext text as n 64-bit blocks + * @param[in] inlen Length of in. + * @param[in] block Block processing function. + * @return 0 if inlen is out of range [24, CRYPTO128_WRAP_MAX] + * or if inlen is not multiply of 8 + * or if IV doesn't match expected value. + * Output length otherwise. + */ +size_t CRYPTO_128_unwrap(void *key, const unsigned char *iv, + unsigned char *out, const unsigned char *in, size_t inlen, + block128_f block) + { + size_t ret; + unsigned char got_iv[8]; + + ret = crypto_128_unwrap_raw(key, got_iv, out, in, inlen, block); + if (ret != inlen) + return ret; + if (!iv) iv = default_iv; - if (memcmp(A, iv, 8)) + if (CRYPTO_memcmp(out, iv, 8)) { OPENSSL_cleanse(out, inlen); return 0; } return inlen; } + +/** Wrapping according to RFC 5649 section 4.1. + * + * @param[in] key Key value. + * @param[in] icv (Non-standard) IV, 4 bytes. NULL = use default_aiv. + * @param[out] out Cipher text. Minimal buffer length = (inlen + 15) bytes. + * Input and output buffers can overlap if block function + * supports that. + * @param[in] in Plain text as n 64-bit blocks, n >= 2. + * @param[in] inlen Length of in. + * @param[in] block Block processing function. + * @return 0 if inlen is out of range [1, CRYPTO128_WRAP_MAX]. + * Output length if wrapping succeeded. + */ +size_t CRYPTO_128_wrap_pad(void *key, const unsigned char *icv, + unsigned char *out, + const unsigned char *in, size_t inlen, block128_f block) + { + /* n: number of 64-bit blocks in the padded key data */ + const size_t blocks_padded = (inlen + 8) / 8; + const size_t padded_len = blocks_padded * 8; + const size_t padding_len = padded_len - inlen; + /* RFC 5649 section 3: Alternative Initial Value */ + unsigned char aiv[8]; + int ret; + + /* Section 1: use 32-bit fixed field for plaintext octet length */ + if (inlen == 0 || inlen >= CRYPTO128_WRAP_MAX) + return 0; + + /* Section 3: Alternative Initial Value */ + if (!icv) + memcpy(aiv, default_aiv, 4); + else + memcpy(aiv, icv, 4); /* Standard doesn't mention this. */ + + aiv[4] = (inlen >> 24) & 0xFF; + aiv[5] = (inlen >> 16) & 0xFF; + aiv[6] = (inlen >> 8) & 0xFF; + aiv[7] = inlen & 0xFF; + + if (padded_len == 8) + { + /* Section 4.1 - special case in step 2: + * If the padded plaintext contains exactly eight octets, then + * prepend the AIV and encrypt the resulting 128-bit block + * using AES in ECB mode. */ + memmove(out + 8, in, inlen); + memcpy(out, aiv, 8); + memset(out + 8 + inlen, 0, padding_len); + block(out, out, key); + ret = 16; /* AIV + padded input */ + } + else + { + memmove(out, in, inlen); + memset(out + inlen, 0, padding_len); /* Section 4.1 step 1 */ + ret = CRYPTO_128_wrap(key, aiv, out, out, padded_len, block); + } + + return ret; + } + +/** Unwrapping according to RFC 5649 section 4.2. + * + * @param[in] key Key value. + * @param[in] icv (Non-standard) IV, 4 bytes. NULL = use default_aiv. + * @param[out] out Plain text. Minimal buffer length = inlen bytes. + * Input and output buffers can overlap if block function + * supports that. + * @param[in] in Ciphertext text as n 64-bit blocks + * @param[in] inlen Length of in. + * @param[in] block Block processing function. + * @return 0 if inlen is out of range [16, CRYPTO128_WRAP_MAX], + * or if inlen is not multiply of 8 + * or if IV and message length indicator doesn't match. + * Output length if unwrapping succeeded and IV matches. + */ +size_t CRYPTO_128_unwrap_pad(void *key, const unsigned char *icv, + unsigned char *out, + const unsigned char *in, size_t inlen, block128_f block) + { + /* n: number of 64-bit blocks in the padded key data */ + size_t n = inlen / 8 - 1; + size_t padded_len; + size_t padding_len; + size_t ptext_len; + /* RFC 5649 section 3: Alternative Initial Value */ + unsigned char aiv[8]; + static unsigned char zeros[8] = {0x0}; + size_t ret; + + /* Section 4.2: Cipher text length has to be (n+1) 64-bit blocks. */ + if ((inlen & 0x7) != 0 || inlen < 16 || inlen >= CRYPTO128_WRAP_MAX) + return 0; + + memmove(out, in, inlen); + if (inlen == 16) + { + /* Section 4.2 - special case in step 1: + * When n=1, the ciphertext contains exactly two 64-bit + * blocks and they are decrypted as a single AES + * block using AES in ECB mode: + * AIV | P[1] = DEC(K, C[0] | C[1]) + */ + block(out, out, key); + memcpy(aiv, out, 8); + /* Remove AIV */ + memmove(out, out + 8, 8); + padded_len = 8; + } + else + { + padded_len = inlen - 8; + ret = crypto_128_unwrap_raw(key, aiv, out, out, inlen, block); + if (padded_len != ret) + { + OPENSSL_cleanse(out, inlen); + return 0; + } + } + + /* Section 3: AIV checks: Check that MSB(32,A) = A65959A6. + * Optionally a user-supplied value can be used + * (even if standard doesn't mention this). */ + if ((!icv && CRYPTO_memcmp(aiv, default_aiv, 4)) + || (icv && CRYPTO_memcmp(aiv, icv, 4))) + { + OPENSSL_cleanse(out, inlen); + return 0; + } + + /* Check that 8*(n-1) < LSB(32,AIV) <= 8*n. + * If so, let ptext_len = LSB(32,AIV). */ + + ptext_len = (aiv[4] << 24) | (aiv[5] << 16) | (aiv[6] << 8) | aiv[7]; + if (8*(n-1) >= ptext_len || ptext_len > 8*n) + { + OPENSSL_cleanse(out, inlen); + return 0; + } + + /* Check that the rightmost padding_len octets of the output data + * are zero. */ + padding_len = padded_len - ptext_len; + if (CRYPTO_memcmp(out + ptext_len, zeros, padding_len) != 0) + { + OPENSSL_cleanse(out, inlen); + return 0; + } + + /* Section 4.2 step 3: Remove padding */ + return ptext_len; + } -- 2.25.1