| // Copyright (c) 2013 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "net/quic/crypto/aead_base_decrypter.h" |
| |
| #include <pk11pub.h> |
| |
| #include "base/memory/scoped_ptr.h" |
| #include "crypto/scoped_nss_types.h" |
| |
| using base::StringPiece; |
| |
| namespace net { |
| |
| AeadBaseDecrypter::AeadBaseDecrypter(CK_MECHANISM_TYPE aead_mechanism, |
| PK11_DecryptFunction pk11_decrypt, |
| size_t key_size, |
| size_t auth_tag_size, |
| size_t nonce_prefix_size) |
| : aead_mechanism_(aead_mechanism), |
| pk11_decrypt_(pk11_decrypt), |
| key_size_(key_size), |
| auth_tag_size_(auth_tag_size), |
| nonce_prefix_size_(nonce_prefix_size) { |
| DCHECK_LE(key_size_, sizeof(key_)); |
| DCHECK_LE(nonce_prefix_size_, sizeof(nonce_prefix_)); |
| } |
| |
| AeadBaseDecrypter::~AeadBaseDecrypter() {} |
| |
| bool AeadBaseDecrypter::SetKey(StringPiece key) { |
| DCHECK_EQ(key.size(), key_size_); |
| if (key.size() != key_size_) { |
| return false; |
| } |
| memcpy(key_, key.data(), key.size()); |
| return true; |
| } |
| |
| bool AeadBaseDecrypter::SetNoncePrefix(StringPiece nonce_prefix) { |
| DCHECK_EQ(nonce_prefix.size(), nonce_prefix_size_); |
| if (nonce_prefix.size() != nonce_prefix_size_) { |
| return false; |
| } |
| memcpy(nonce_prefix_, nonce_prefix.data(), nonce_prefix.size()); |
| return true; |
| } |
| |
| bool AeadBaseDecrypter::Decrypt(StringPiece nonce, |
| StringPiece associated_data, |
| StringPiece ciphertext, |
| uint8* output, |
| size_t* output_length) { |
| if (ciphertext.length() < auth_tag_size_ || |
| nonce.size() != nonce_prefix_size_ + sizeof(QuicPacketSequenceNumber)) { |
| return false; |
| } |
| // NSS 3.14.x incorrectly requires an output buffer at least as long as |
| // the ciphertext (NSS bug |
| // https://bugzilla.mozilla.org/show_bug.cgi?id= 853674). Fortunately |
| // QuicDecrypter::Decrypt() specifies that |output| must be as long as |
| // |ciphertext| on entry. |
| size_t plaintext_size = ciphertext.length() - auth_tag_size_; |
| |
| // Import key_ into NSS. |
| SECItem key_item; |
| key_item.type = siBuffer; |
| key_item.data = key_; |
| key_item.len = key_size_; |
| PK11SlotInfo* slot = PK11_GetInternalSlot(); |
| |
| // TODO(wtc): For an AES-GCM key, the correct value for |key_mechanism| is |
| // CKM_AES_GCM, but because of NSS bug |
| // https://bugzilla.mozilla.org/show_bug.cgi?id=853285, use CKM_AES_ECB as a |
| // workaround. Remove this when we require NSS 3.15. |
| CK_MECHANISM_TYPE key_mechanism = aead_mechanism_; |
| if (key_mechanism == CKM_AES_GCM) { |
| key_mechanism = CKM_AES_ECB; |
| } |
| |
| // The exact value of the |origin| argument doesn't matter to NSS as long as |
| // it's not PK11_OriginFortezzaHack, so pass PK11_OriginUnwrap as a |
| // placeholder. |
| crypto::ScopedPK11SymKey aead_key(PK11_ImportSymKey( |
| slot, key_mechanism, PK11_OriginUnwrap, CKA_DECRYPT, &key_item, NULL)); |
| PK11_FreeSlot(slot); |
| slot = NULL; |
| if (!aead_key) { |
| DVLOG(1) << "PK11_ImportSymKey failed"; |
| return false; |
| } |
| |
| AeadParams aead_params = {0}; |
| FillAeadParams(nonce, associated_data, auth_tag_size_, &aead_params); |
| |
| SECItem param; |
| param.type = siBuffer; |
| param.data = reinterpret_cast<unsigned char*>(&aead_params.data); |
| param.len = aead_params.len; |
| |
| unsigned int output_len; |
| if (pk11_decrypt_(aead_key.get(), aead_mechanism_, ¶m, |
| output, &output_len, ciphertext.length(), |
| reinterpret_cast<const unsigned char*>(ciphertext.data()), |
| ciphertext.length()) != SECSuccess) { |
| return false; |
| } |
| |
| if (output_len != plaintext_size) { |
| DVLOG(1) << "Wrong output length"; |
| return false; |
| } |
| *output_length = output_len; |
| return true; |
| } |
| |
| QuicData* AeadBaseDecrypter::DecryptPacket( |
| QuicPacketSequenceNumber sequence_number, |
| StringPiece associated_data, |
| StringPiece ciphertext) { |
| if (ciphertext.length() < auth_tag_size_) { |
| return NULL; |
| } |
| size_t plaintext_size; |
| scoped_ptr<char[]> plaintext(new char[ciphertext.length()]); |
| |
| uint8 nonce[sizeof(nonce_prefix_) + sizeof(sequence_number)]; |
| const size_t nonce_size = nonce_prefix_size_ + sizeof(sequence_number); |
| DCHECK_LE(nonce_size, sizeof(nonce)); |
| memcpy(nonce, nonce_prefix_, nonce_prefix_size_); |
| memcpy(nonce + nonce_prefix_size_, &sequence_number, sizeof(sequence_number)); |
| if (!Decrypt(StringPiece(reinterpret_cast<char*>(nonce), nonce_size), |
| associated_data, ciphertext, |
| reinterpret_cast<uint8*>(plaintext.get()), |
| &plaintext_size)) { |
| return NULL; |
| } |
| return new QuicData(plaintext.release(), plaintext_size, true); |
| } |
| |
| StringPiece AeadBaseDecrypter::GetKey() const { |
| return StringPiece(reinterpret_cast<const char*>(key_), key_size_); |
| } |
| |
| StringPiece AeadBaseDecrypter::GetNoncePrefix() const { |
| if (nonce_prefix_size_ == 0) { |
| return StringPiece(); |
| } |
| return StringPiece(reinterpret_cast<const char*>(nonce_prefix_), |
| nonce_prefix_size_); |
| } |
| |
| } // namespace net |