| /* Copyright (c) 2015, Google Inc. |
| * |
| * Permission to use, copy, modify, and/or distribute this software for any |
| * purpose with or without fee is hereby granted, provided that the above |
| * copyright notice and this permission notice appear in all copies. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
| * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
| * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY |
| * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION |
| * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN |
| * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ |
| |
| #include <openssl/ssl.h> |
| |
| #include <assert.h> |
| #include <string.h> |
| |
| #include <openssl/aead.h> |
| #include <openssl/err.h> |
| #include <openssl/rand.h> |
| |
| #include "../crypto/internal.h" |
| #include "internal.h" |
| |
| |
| #if defined(BORINGSSL_UNSAFE_FUZZER_MODE) |
| #define FUZZER_MODE true |
| #else |
| #define FUZZER_MODE false |
| #endif |
| |
| namespace bssl { |
| |
| SSLAEADContext::SSLAEADContext(uint16_t version_arg, |
| const SSL_CIPHER *cipher_arg) |
| : cipher_(cipher_arg), |
| version_(version_arg), |
| variable_nonce_included_in_record_(false), |
| random_variable_nonce_(false), |
| omit_length_in_ad_(false), |
| omit_version_in_ad_(false), |
| omit_ad_(false), |
| xor_fixed_nonce_(false) { |
| OPENSSL_memset(fixed_nonce_, 0, sizeof(fixed_nonce_)); |
| } |
| |
| SSLAEADContext::~SSLAEADContext() {} |
| |
| UniquePtr<SSLAEADContext> SSLAEADContext::CreateNullCipher() { |
| return MakeUnique<SSLAEADContext>(0 /* version */, nullptr /* cipher */); |
| } |
| |
| UniquePtr<SSLAEADContext> SSLAEADContext::Create( |
| enum evp_aead_direction_t direction, uint16_t version, int is_dtls, |
| const SSL_CIPHER *cipher, const uint8_t *enc_key, size_t enc_key_len, |
| const uint8_t *mac_key, size_t mac_key_len, const uint8_t *fixed_iv, |
| size_t fixed_iv_len) { |
| const EVP_AEAD *aead; |
| size_t expected_mac_key_len, expected_fixed_iv_len; |
| if (!ssl_cipher_get_evp_aead(&aead, &expected_mac_key_len, |
| &expected_fixed_iv_len, cipher, version, |
| is_dtls) || |
| // Ensure the caller returned correct key sizes. |
| expected_fixed_iv_len != fixed_iv_len || |
| expected_mac_key_len != mac_key_len) { |
| OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); |
| return nullptr; |
| } |
| |
| uint8_t merged_key[EVP_AEAD_MAX_KEY_LENGTH]; |
| if (mac_key_len > 0) { |
| // This is a "stateful" AEAD (for compatibility with pre-AEAD cipher |
| // suites). |
| if (mac_key_len + enc_key_len + fixed_iv_len > sizeof(merged_key)) { |
| OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); |
| return nullptr; |
| } |
| OPENSSL_memcpy(merged_key, mac_key, mac_key_len); |
| OPENSSL_memcpy(merged_key + mac_key_len, enc_key, enc_key_len); |
| OPENSSL_memcpy(merged_key + mac_key_len + enc_key_len, fixed_iv, |
| fixed_iv_len); |
| enc_key = merged_key; |
| enc_key_len += mac_key_len; |
| enc_key_len += fixed_iv_len; |
| } |
| |
| UniquePtr<SSLAEADContext> aead_ctx = |
| MakeUnique<SSLAEADContext>(version, cipher); |
| if (!aead_ctx) { |
| OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); |
| return nullptr; |
| } |
| |
| if (!EVP_AEAD_CTX_init_with_direction( |
| aead_ctx->ctx_.get(), aead, enc_key, enc_key_len, |
| EVP_AEAD_DEFAULT_TAG_LENGTH, direction)) { |
| return nullptr; |
| } |
| |
| assert(EVP_AEAD_nonce_length(aead) <= EVP_AEAD_MAX_NONCE_LENGTH); |
| static_assert(EVP_AEAD_MAX_NONCE_LENGTH < 256, |
| "variable_nonce_len doesn't fit in uint8_t"); |
| aead_ctx->variable_nonce_len_ = (uint8_t)EVP_AEAD_nonce_length(aead); |
| if (mac_key_len == 0) { |
| assert(fixed_iv_len <= sizeof(aead_ctx->fixed_nonce_)); |
| OPENSSL_memcpy(aead_ctx->fixed_nonce_, fixed_iv, fixed_iv_len); |
| aead_ctx->fixed_nonce_len_ = fixed_iv_len; |
| |
| if (cipher->algorithm_enc & SSL_CHACHA20POLY1305) { |
| // The fixed nonce into the actual nonce (the sequence number). |
| aead_ctx->xor_fixed_nonce_ = true; |
| aead_ctx->variable_nonce_len_ = 8; |
| } else { |
| // The fixed IV is prepended to the nonce. |
| assert(fixed_iv_len <= aead_ctx->variable_nonce_len_); |
| aead_ctx->variable_nonce_len_ -= fixed_iv_len; |
| } |
| |
| // AES-GCM uses an explicit nonce. |
| if (cipher->algorithm_enc & (SSL_AES128GCM | SSL_AES256GCM)) { |
| aead_ctx->variable_nonce_included_in_record_ = true; |
| } |
| |
| // The TLS 1.3 construction XORs the fixed nonce into the sequence number |
| // and omits the additional data. |
| if (version >= TLS1_3_VERSION) { |
| aead_ctx->xor_fixed_nonce_ = true; |
| aead_ctx->variable_nonce_len_ = 8; |
| aead_ctx->variable_nonce_included_in_record_ = false; |
| aead_ctx->omit_ad_ = true; |
| assert(fixed_iv_len >= aead_ctx->variable_nonce_len_); |
| } |
| } else { |
| assert(version < TLS1_3_VERSION); |
| aead_ctx->variable_nonce_included_in_record_ = true; |
| aead_ctx->random_variable_nonce_ = true; |
| aead_ctx->omit_length_in_ad_ = true; |
| aead_ctx->omit_version_in_ad_ = (version == SSL3_VERSION); |
| } |
| |
| return aead_ctx; |
| } |
| |
| size_t SSLAEADContext::ExplicitNonceLen() const { |
| if (!FUZZER_MODE && variable_nonce_included_in_record_) { |
| return variable_nonce_len_; |
| } |
| return 0; |
| } |
| |
| bool SSLAEADContext::SuffixLen(size_t *out_suffix_len, const size_t in_len, |
| const size_t extra_in_len) const { |
| if (is_null_cipher() || FUZZER_MODE) { |
| *out_suffix_len = extra_in_len; |
| return true; |
| } |
| return !!EVP_AEAD_CTX_tag_len(ctx_.get(), out_suffix_len, in_len, |
| extra_in_len); |
| } |
| |
| size_t SSLAEADContext::MaxOverhead() const { |
| return ExplicitNonceLen() + |
| (is_null_cipher() || FUZZER_MODE |
| ? 0 |
| : EVP_AEAD_max_overhead(EVP_AEAD_CTX_aead(ctx_.get()))); |
| } |
| |
| size_t SSLAEADContext::GetAdditionalData(uint8_t out[13], uint8_t type, |
| uint16_t wire_version, |
| const uint8_t seqnum[8], |
| size_t plaintext_len) { |
| if (omit_ad_) { |
| return 0; |
| } |
| |
| OPENSSL_memcpy(out, seqnum, 8); |
| size_t len = 8; |
| out[len++] = type; |
| if (!omit_version_in_ad_) { |
| out[len++] = static_cast<uint8_t>((wire_version >> 8)); |
| out[len++] = static_cast<uint8_t>(wire_version); |
| } |
| if (!omit_length_in_ad_) { |
| out[len++] = static_cast<uint8_t>((plaintext_len >> 8)); |
| out[len++] = static_cast<uint8_t>(plaintext_len); |
| } |
| return len; |
| } |
| |
| bool SSLAEADContext::Open(CBS *out, uint8_t type, uint16_t wire_version, |
| const uint8_t seqnum[8], uint8_t *in, size_t in_len) { |
| if (is_null_cipher() || FUZZER_MODE) { |
| // Handle the initial NULL cipher. |
| CBS_init(out, in, in_len); |
| return true; |
| } |
| |
| // TLS 1.2 AEADs include the length in the AD and are assumed to have fixed |
| // overhead. Otherwise the parameter is unused. |
| size_t plaintext_len = 0; |
| if (!omit_length_in_ad_) { |
| size_t overhead = MaxOverhead(); |
| if (in_len < overhead) { |
| // Publicly invalid. |
| OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_PACKET_LENGTH); |
| return false; |
| } |
| plaintext_len = in_len - overhead; |
| } |
| uint8_t ad[13]; |
| size_t ad_len = |
| GetAdditionalData(ad, type, wire_version, seqnum, plaintext_len); |
| |
| // Assemble the nonce. |
| uint8_t nonce[EVP_AEAD_MAX_NONCE_LENGTH]; |
| size_t nonce_len = 0; |
| |
| // Prepend the fixed nonce, or left-pad with zeros if XORing. |
| if (xor_fixed_nonce_) { |
| nonce_len = fixed_nonce_len_ - variable_nonce_len_; |
| OPENSSL_memset(nonce, 0, nonce_len); |
| } else { |
| OPENSSL_memcpy(nonce, fixed_nonce_, fixed_nonce_len_); |
| nonce_len += fixed_nonce_len_; |
| } |
| |
| // Add the variable nonce. |
| if (variable_nonce_included_in_record_) { |
| if (in_len < variable_nonce_len_) { |
| // Publicly invalid. |
| OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_PACKET_LENGTH); |
| return false; |
| } |
| OPENSSL_memcpy(nonce + nonce_len, in, variable_nonce_len_); |
| in += variable_nonce_len_; |
| in_len -= variable_nonce_len_; |
| } else { |
| assert(variable_nonce_len_ == 8); |
| OPENSSL_memcpy(nonce + nonce_len, seqnum, variable_nonce_len_); |
| } |
| nonce_len += variable_nonce_len_; |
| |
| // XOR the fixed nonce, if necessary. |
| if (xor_fixed_nonce_) { |
| assert(nonce_len == fixed_nonce_len_); |
| for (size_t i = 0; i < fixed_nonce_len_; i++) { |
| nonce[i] ^= fixed_nonce_[i]; |
| } |
| } |
| |
| // Decrypt in-place. |
| size_t len; |
| if (!EVP_AEAD_CTX_open(ctx_.get(), in, &len, in_len, nonce, nonce_len, in, |
| in_len, ad, ad_len)) { |
| return false; |
| } |
| CBS_init(out, in, len); |
| return true; |
| } |
| |
| bool SSLAEADContext::SealScatter(uint8_t *out_prefix, uint8_t *out, |
| uint8_t *out_suffix, uint8_t type, |
| uint16_t wire_version, const uint8_t seqnum[8], |
| const uint8_t *in, size_t in_len, |
| const uint8_t *extra_in, size_t extra_in_len) { |
| const size_t prefix_len = ExplicitNonceLen(); |
| size_t suffix_len; |
| if (!SuffixLen(&suffix_len, in_len, extra_in_len)) { |
| OPENSSL_PUT_ERROR(SSL, SSL_R_RECORD_TOO_LARGE); |
| return false; |
| } |
| if ((in != out && buffers_alias(in, in_len, out, in_len)) || |
| buffers_alias(in, in_len, out_prefix, prefix_len) || |
| buffers_alias(in, in_len, out_suffix, suffix_len)) { |
| OPENSSL_PUT_ERROR(SSL, SSL_R_OUTPUT_ALIASES_INPUT); |
| return false; |
| } |
| |
| if (is_null_cipher() || FUZZER_MODE) { |
| // Handle the initial NULL cipher. |
| OPENSSL_memmove(out, in, in_len); |
| OPENSSL_memmove(out_suffix, extra_in, extra_in_len); |
| return true; |
| } |
| |
| uint8_t ad[13]; |
| size_t ad_len = GetAdditionalData(ad, type, wire_version, seqnum, in_len); |
| |
| // Assemble the nonce. |
| uint8_t nonce[EVP_AEAD_MAX_NONCE_LENGTH]; |
| size_t nonce_len = 0; |
| |
| // Prepend the fixed nonce, or left-pad with zeros if XORing. |
| if (xor_fixed_nonce_) { |
| nonce_len = fixed_nonce_len_ - variable_nonce_len_; |
| OPENSSL_memset(nonce, 0, nonce_len); |
| } else { |
| OPENSSL_memcpy(nonce, fixed_nonce_, fixed_nonce_len_); |
| nonce_len += fixed_nonce_len_; |
| } |
| |
| // Select the variable nonce. |
| if (random_variable_nonce_) { |
| assert(variable_nonce_included_in_record_); |
| if (!RAND_bytes(nonce + nonce_len, variable_nonce_len_)) { |
| return false; |
| } |
| } else { |
| // When sending we use the sequence number as the variable part of the |
| // nonce. |
| assert(variable_nonce_len_ == 8); |
| OPENSSL_memcpy(nonce + nonce_len, seqnum, variable_nonce_len_); |
| } |
| nonce_len += variable_nonce_len_; |
| |
| // Emit the variable nonce if included in the record. |
| if (variable_nonce_included_in_record_) { |
| assert(!xor_fixed_nonce_); |
| if (buffers_alias(in, in_len, out_prefix, variable_nonce_len_)) { |
| OPENSSL_PUT_ERROR(SSL, SSL_R_OUTPUT_ALIASES_INPUT); |
| return false; |
| } |
| OPENSSL_memcpy(out_prefix, nonce + fixed_nonce_len_, |
| variable_nonce_len_); |
| } |
| |
| // XOR the fixed nonce, if necessary. |
| if (xor_fixed_nonce_) { |
| assert(nonce_len == fixed_nonce_len_); |
| for (size_t i = 0; i < fixed_nonce_len_; i++) { |
| nonce[i] ^= fixed_nonce_[i]; |
| } |
| } |
| |
| size_t written_suffix_len; |
| bool result = !!EVP_AEAD_CTX_seal_scatter( |
| ctx_.get(), out, out_suffix, &written_suffix_len, suffix_len, nonce, |
| nonce_len, in, in_len, extra_in, extra_in_len, ad, ad_len); |
| assert(!result || written_suffix_len == suffix_len); |
| return result; |
| } |
| |
| bool SSLAEADContext::Seal(uint8_t *out, size_t *out_len, size_t max_out_len, |
| uint8_t type, uint16_t wire_version, |
| const uint8_t seqnum[8], const uint8_t *in, |
| size_t in_len) { |
| const size_t prefix_len = ExplicitNonceLen(); |
| size_t suffix_len; |
| if (!SuffixLen(&suffix_len, in_len, 0)) { |
| OPENSSL_PUT_ERROR(SSL, SSL_R_RECORD_TOO_LARGE); |
| return false; |
| } |
| if (in_len + prefix_len < in_len || |
| in_len + prefix_len + suffix_len < in_len + prefix_len) { |
| OPENSSL_PUT_ERROR(CIPHER, SSL_R_RECORD_TOO_LARGE); |
| return false; |
| } |
| if (in_len + prefix_len + suffix_len > max_out_len) { |
| OPENSSL_PUT_ERROR(SSL, SSL_R_BUFFER_TOO_SMALL); |
| return false; |
| } |
| |
| if (!SealScatter(out, out + prefix_len, out + prefix_len + in_len, type, |
| wire_version, seqnum, in, in_len, 0, 0)) { |
| return false; |
| } |
| *out_len = prefix_len + in_len + suffix_len; |
| return true; |
| } |
| |
| bool SSLAEADContext::GetIV(const uint8_t **out_iv, size_t *out_iv_len) const { |
| return !is_null_cipher() && |
| EVP_AEAD_CTX_get_iv(ctx_.get(), out_iv, out_iv_len); |
| } |
| |
| } // namespace bssl |