/* ==================================================================== * Copyright (c) 2001-2011 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 * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. All advertising materials mentioning features or use of this * software must display the following acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" * * 4. 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IN NO EVENT SHALL THE OpenSSL PROJECT OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED * OF THE POSSIBILITY OF SUCH DAMAGE. * ==================================================================== */ #include <openssl_grpc/aes.h> #include <assert.h> #include <limits.h> #include <string.h> #include <openssl_grpc/mem.h> #include "../../internal.h" // kDefaultIV is the default IV value given in RFC 3394, 2.2.3.1. static const uint8_t kDefaultIV[] = { 0xa6, 0xa6, 0xa6, 0xa6, 0xa6, 0xa6, 0xa6, 0xa6, }; static const unsigned kBound = 6; int AES_wrap_key(const AES_KEY *key, const uint8_t *iv, uint8_t *out, const uint8_t *in, size_t in_len) { // See RFC 3394, section 2.2.1. Additionally, note that section 2 requires the // plaintext be at least two 8-byte blocks. if (in_len > INT_MAX - 8 || in_len < 16 || in_len % 8 != 0) { return -1; } if (iv == NULL) { iv = kDefaultIV; } OPENSSL_memmove(out + 8, in, in_len); uint8_t A[AES_BLOCK_SIZE]; OPENSSL_memcpy(A, iv, 8); size_t n = in_len / 8; for (unsigned j = 0; j < kBound; j++) { for (size_t i = 1; i <= n; i++) { OPENSSL_memcpy(A + 8, out + 8 * i, 8); AES_encrypt(A, A, key); uint32_t t = (uint32_t)(n * j + i); A[7] ^= t & 0xff; A[6] ^= (t >> 8) & 0xff; A[5] ^= (t >> 16) & 0xff; A[4] ^= (t >> 24) & 0xff; OPENSSL_memcpy(out + 8 * i, A + 8, 8); } } OPENSSL_memcpy(out, A, 8); return (int)in_len + 8; } // aes_unwrap_key_inner performs steps one and two from // https://tools.ietf.org/html/rfc3394#section-2.2.2 static int aes_unwrap_key_inner(const AES_KEY *key, uint8_t *out, uint8_t out_iv[8], const uint8_t *in, size_t in_len) { // See RFC 3394, section 2.2.2. Additionally, note that section 2 requires the // plaintext be at least two 8-byte blocks, so the ciphertext must be at least // three blocks. if (in_len > INT_MAX || in_len < 24 || in_len % 8 != 0) { return 0; } uint8_t A[AES_BLOCK_SIZE]; OPENSSL_memcpy(A, in, 8); OPENSSL_memmove(out, in + 8, in_len - 8); size_t n = (in_len / 8) - 1; for (unsigned j = kBound - 1; j < kBound; j--) { for (size_t i = n; i > 0; i--) { uint32_t t = (uint32_t)(n * j + i); A[7] ^= t & 0xff; A[6] ^= (t >> 8) & 0xff; A[5] ^= (t >> 16) & 0xff; A[4] ^= (t >> 24) & 0xff; OPENSSL_memcpy(A + 8, out + 8 * (i - 1), 8); AES_decrypt(A, A, key); OPENSSL_memcpy(out + 8 * (i - 1), A + 8, 8); } } memcpy(out_iv, A, 8); return 1; } int AES_unwrap_key(const AES_KEY *key, const uint8_t *iv, uint8_t *out, const uint8_t *in, size_t in_len) { uint8_t calculated_iv[8]; if (!aes_unwrap_key_inner(key, out, calculated_iv, in, in_len)) { return -1; } if (iv == NULL) { iv = kDefaultIV; } if (CRYPTO_memcmp(calculated_iv, iv, 8) != 0) { return -1; } return (int)in_len - 8; } // kPaddingConstant is used in Key Wrap with Padding. See // https://tools.ietf.org/html/rfc5649#section-3 static const uint8_t kPaddingConstant[4] = {0xa6, 0x59, 0x59, 0xa6}; int AES_wrap_key_padded(const AES_KEY *key, uint8_t *out, size_t *out_len, size_t max_out, const uint8_t *in, size_t in_len) { // See https://tools.ietf.org/html/rfc5649#section-4.1 const uint32_t in_len32_be = CRYPTO_bswap4(in_len); const uint64_t in_len64 = in_len; const size_t padded_len = (in_len + 7) & ~7; *out_len = 0; if (in_len == 0 || in_len64 > 0xffffffffu || in_len + 7 < in_len || padded_len + 8 < padded_len || max_out < padded_len + 8) { return 0; } uint8_t block[AES_BLOCK_SIZE]; memcpy(block, kPaddingConstant, sizeof(kPaddingConstant)); memcpy(block + 4, &in_len32_be, sizeof(in_len32_be)); if (in_len <= 8) { memset(block + 8, 0, 8); memcpy(block + 8, in, in_len); AES_encrypt(block, out, key); *out_len = AES_BLOCK_SIZE; return 1; } uint8_t *padded_in = OPENSSL_malloc(padded_len); if (padded_in == NULL) { return 0; } assert(padded_len >= 8); memset(padded_in + padded_len - 8, 0, 8); memcpy(padded_in, in, in_len); const int ret = AES_wrap_key(key, block, out, padded_in, padded_len); OPENSSL_free(padded_in); if (ret < 0) { return 0; } *out_len = ret; return 1; } int AES_unwrap_key_padded(const AES_KEY *key, uint8_t *out, size_t *out_len, size_t max_out, const uint8_t *in, size_t in_len) { *out_len = 0; if (in_len < AES_BLOCK_SIZE || max_out < in_len - 8) { return 0; } uint8_t iv[8]; if (in_len == AES_BLOCK_SIZE) { uint8_t block[AES_BLOCK_SIZE]; AES_decrypt(in, block, key); memcpy(iv, block, sizeof(iv)); memcpy(out, block + 8, 8); } else if (!aes_unwrap_key_inner(key, out, iv, in, in_len)) { return 0; } assert(in_len % 8 == 0); crypto_word_t ok = constant_time_eq_int( CRYPTO_memcmp(iv, kPaddingConstant, sizeof(kPaddingConstant)), 0); uint32_t claimed_len32; memcpy(&claimed_len32, iv + 4, sizeof(claimed_len32)); const size_t claimed_len = CRYPTO_bswap4(claimed_len32); ok &= ~constant_time_is_zero_w(claimed_len); ok &= constant_time_eq_w((claimed_len - 1) >> 3, (in_len - 9) >> 3); // Check that padding bytes are all zero. for (size_t i = in_len - 15; i < in_len - 8; i++) { ok &= constant_time_is_zero_w(constant_time_ge_8(i, claimed_len) & out[i]); } *out_len = constant_time_select_w(ok, claimed_len, 0); return ok & 1; }