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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "tls_protect.h"
#include "tls_filter.h"
namespace nss_test {
AeadCipher::~AeadCipher() {
if (key_) {
PK11_FreeSymKey(key_);
}
}
bool AeadCipher::Init(PK11SymKey *key, const uint8_t *iv) {
key_ = PK11_ReferenceSymKey(key);
if (!key_) return false;
memcpy(iv_, iv, sizeof(iv_));
return true;
}
void AeadCipher::FormatNonce(uint64_t seq, uint8_t *nonce) {
memcpy(nonce, iv_, 12);
for (size_t i = 0; i < 8; ++i) {
nonce[12 - (i + 1)] ^= seq & 0xff;
seq >>= 8;
}
DataBuffer d(nonce, 12);
}
bool AeadCipher::AeadInner(bool decrypt, void *params, size_t param_length,
const uint8_t *in, size_t inlen, uint8_t *out,
size_t *outlen, size_t maxlen) {
SECStatus rv;
unsigned int uoutlen = 0;
SECItem param = {
siBuffer, static_cast<unsigned char *>(params),
static_cast<unsigned int>(param_length),
};
if (decrypt) {
rv = PK11_Decrypt(key_, mech_, ¶m, out, &uoutlen, maxlen, in, inlen);
} else {
rv = PK11_Encrypt(key_, mech_, ¶m, out, &uoutlen, maxlen, in, inlen);
}
*outlen = (int)uoutlen;
return rv == SECSuccess;
}
bool AeadCipherAesGcm::Aead(bool decrypt, const uint8_t *hdr, size_t hdr_len,
uint64_t seq, const uint8_t *in, size_t inlen,
uint8_t *out, size_t *outlen, size_t maxlen) {
CK_GCM_PARAMS aeadParams;
unsigned char nonce[12];
memset(&aeadParams, 0, sizeof(aeadParams));
aeadParams.pIv = nonce;
aeadParams.ulIvLen = sizeof(nonce);
aeadParams.pAAD = const_cast<uint8_t *>(hdr);
aeadParams.ulAADLen = hdr_len;
aeadParams.ulTagBits = 128;
FormatNonce(seq, nonce);
return AeadInner(decrypt, (unsigned char *)&aeadParams, sizeof(aeadParams),
in, inlen, out, outlen, maxlen);
}
bool AeadCipherChacha20Poly1305::Aead(bool decrypt, const uint8_t *hdr,
size_t hdr_len, uint64_t seq,
const uint8_t *in, size_t inlen,
uint8_t *out, size_t *outlen,
size_t maxlen) {
CK_NSS_AEAD_PARAMS aeadParams;
unsigned char nonce[12];
memset(&aeadParams, 0, sizeof(aeadParams));
aeadParams.pNonce = nonce;
aeadParams.ulNonceLen = sizeof(nonce);
aeadParams.pAAD = const_cast<uint8_t *>(hdr);
aeadParams.ulAADLen = hdr_len;
aeadParams.ulTagLen = 16;
FormatNonce(seq, nonce);
return AeadInner(decrypt, (unsigned char *)&aeadParams, sizeof(aeadParams),
in, inlen, out, outlen, maxlen);
}
bool TlsCipherSpec::Init(uint16_t epoc, SSLCipherAlgorithm cipher,
PK11SymKey *key, const uint8_t *iv) {
epoch_ = epoc;
switch (cipher) {
case ssl_calg_aes_gcm:
aead_.reset(new AeadCipherAesGcm());
break;
case ssl_calg_chacha20:
aead_.reset(new AeadCipherChacha20Poly1305());
break;
default:
return false;
}
return aead_->Init(key, iv);
}
bool TlsCipherSpec::Unprotect(const TlsRecordHeader &header,
const DataBuffer &ciphertext,
DataBuffer *plaintext) {
// Make space.
plaintext->Allocate(ciphertext.len());
auto header_bytes = header.header();
size_t len;
bool ret =
aead_->Aead(true, header_bytes.data(), header_bytes.len(),
header.sequence_number(), ciphertext.data(), ciphertext.len(),
plaintext->data(), &len, plaintext->len());
if (!ret) return false;
plaintext->Truncate(len);
return true;
}
bool TlsCipherSpec::Protect(const TlsRecordHeader &header,
const DataBuffer &plaintext,
DataBuffer *ciphertext) {
// Make a padded buffer.
ciphertext->Allocate(plaintext.len() +
32); // Room for any plausible auth tag
size_t len;
DataBuffer header_bytes;
(void)header.WriteHeader(&header_bytes, 0, plaintext.len() + 16);
bool ret =
aead_->Aead(false, header_bytes.data(), header_bytes.len(),
header.sequence_number(), plaintext.data(), plaintext.len(),
ciphertext->data(), &len, ciphertext->len());
if (!ret) return false;
ciphertext->Truncate(len);
return true;
}
} // namespace nss_test
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