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quic: decrypt_crypto: Support QUIC v2

Browse source 
Attempt to refactor in order to re-use common code between the two
versions.
This commit is contained in:
Arne Welzel 2024-01-04 17:16:36 +01:00
parent 6c4a9510da
commit 0b6f4ef443
2 changed files with 217 additions and 140 deletions
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3
src/analyzer/protocol/quic/QUIC.spicy
View file

@ -8,6 +8,7 @@ import zeek;
# The interface to the C++ code that handles the decryption of the INITIAL packet payload using well-known keys
public function decrypt_crypto_payload(
version: uint32,
all_data: bytes,
connection_id: bytes,
encrypted_offset: uint64,
@ -430,6 +431,7 @@ type Packet = unit(from_client: bool, context: ConnectionIDInfo&) {
# This means that here, we can try to decrypt the initial packet!
# All data is accessible via the `long_header` unit
self.decrypted_data = decrypt_crypto_payload(
self.long_header.version,
self.all_data,
self.long_header.dest_conn_id,
self.long_header.encrypted_offset,
@ -449,6 +451,7 @@ type Packet = unit(from_client: bool, context: ConnectionIDInfo&) {
# Assuming that the client set up the connection, this can be considered the first
# received Initial from the client. So disable change of ConnectionID's afterwards
self.decrypted_data = decrypt_crypto_payload(
self.long_header.version,
self.all_data,
context.initial_destination_conn_id,
self.long_header.encrypted_offset,

354
src/analyzer/protocol/quic/decrypt_crypto.cc
View file

@ -2,15 +2,15 @@
// Copyright (c) 2023 by the Zeek Project. See COPYING for details.
/*
WARNING: THIS CODE IS NOT SAFE IN MULTI-THREADED
WARNING: THIS CODE IS NOT SAFE IN MULTI-THREADED ENVIRONMENTS:
* Initializations of static OpenSSL contexts without locking
* Use of contexts is not protected by locks.
* Use of SSL contexts is not protected by locks
The involved contexts are EVP_CIPHER_CTX and EVP_PKEY_CTX and are allocated
lazily just once and re-used for performance reasons. Previously, every
decrypt operation allocated, initialized and freed each of the used context
resulting in a significant performance hit.
The involved contexts are EVP_CIPHER_CTX and EVP_PKEY_CTX. These are allocated
lazily and re-used for performance reasons. Previously, every decrypt operation
allocated, initialized and freed these individually, resulting in a significant
performance hit. Given Zeek's single threaded nature, this is fine.
*/
/*
@ -25,6 +25,7 @@ refactors as C++ development is not our main profession.
#include <cstdint>
#include <cstdlib>
#include <cstring>
#include <memory>
#include <string>
#include <vector>
@ -51,31 +52,6 @@ struct DecryptionInformation {
// This should be alright: https://stackoverflow.com/a/15172304
inline const uint8_t* data_as_uint8(const hilti::rt::Bytes& b) { return reinterpret_cast<const uint8_t*>(b.data()); }
/*
Constants used in the HKDF functions. HKDF-Expand-Label uses labels
such as 'quic key' and 'quic hp'. These labels can obviously be
calculated dynamically, but are incluced statically for now, as the
goal of this analyser is only to analyze the INITIAL packets.
*/
std::vector<uint8_t> INITIAL_SALT_V1 = {0x38, 0x76, 0x2c, 0xf7, 0xf5, 0x59, 0x34, 0xb3, 0x4d, 0x17,
0x9a, 0xe6, 0xa4, 0xc8, 0x0c, 0xad, 0xcc, 0xbb, 0x7f, 0x0a};
std::vector<uint8_t> CLIENT_INITIAL_INFO = {0x00, 0x20, 0x0f, 0x74, 0x6c, 0x73, 0x31, 0x33, 0x20, 0x63,
0x6c, 0x69, 0x65, 0x6e, 0x74, 0x20, 0x69, 0x6e, 0x00};
std::vector<uint8_t> SERVER_INITIAL_INFO = {0x00, 0x20, 0x0f, 0x74, 0x6c, 0x73, 0x31, 0x33, 0x20, 0x73,
0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x69, 0x6e, 0x00};
std::vector<uint8_t> KEY_INFO = {0x00, 0x10, 0x0e, 0x74, 0x6c, 0x73, 0x31, 0x33, 0x20,
0x71, 0x75, 0x69, 0x63, 0x20, 0x6b, 0x65, 0x79, 0x00};
std::vector<uint8_t> IV_INFO = {0x00, 0x0c, 0x0d, 0x74, 0x6c, 0x73, 0x31, 0x33, 0x20,
0x71, 0x75, 0x69, 0x63, 0x20, 0x69, 0x76, 0x00};
std::vector<uint8_t> HP_INFO = {0x00, 0x10, 0x0d, 0x74, 0x6c, 0x73, 0x31, 0x33, 0x20,
0x71, 0x75, 0x69, 0x63, 0x20, 0x68, 0x70, 0x00};
/*
Constants used by the different functions
*/
@ -107,100 +83,6 @@ EVP_CIPHER_CTX* get_aes_128_gcm() {
return ctx;
}
/*
HKDF-Extract as described in https://www.rfc-editor.org/rfc/rfc8446.html#section-7.1
*/
std::vector<uint8_t> hkdf_extract(const hilti::rt::Bytes& connection_id) {
std::vector<uint8_t> out_temp(INITIAL_SECRET_LEN);
size_t initial_secret_len = out_temp.size();
static EVP_PKEY_CTX* ctx = nullptr;
if ( ! ctx ) {
ctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
EVP_PKEY_derive_init(ctx);
EVP_PKEY_CTX_set_hkdf_md(ctx, EVP_sha256());
EVP_PKEY_CTX_hkdf_mode(ctx, EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY);
}
EVP_PKEY_CTX_set1_hkdf_key(ctx, data_as_uint8(connection_id), connection_id.size());
EVP_PKEY_CTX_set1_hkdf_salt(ctx, INITIAL_SALT_V1.data(), INITIAL_SALT_V1.size());
EVP_PKEY_derive(ctx, out_temp.data(), &initial_secret_len);
return out_temp;
}
/*
HKDF-Expand-Label as described in https://www.rfc-editor.org/rfc/rfc8446.html#section-7.1
*/
std::vector<uint8_t> hkdf_expand(EVP_PKEY_CTX* ctx, size_t out_len, const std::vector<uint8_t>& key) {
std::vector<uint8_t> out_temp(out_len);
EVP_PKEY_CTX_set1_hkdf_key(ctx, key.data(), key.size());
EVP_PKEY_derive(ctx, out_temp.data(), &out_len);
return out_temp;
}
std::vector<uint8_t> hkdf_expand_client_initial_info(size_t out_len, const std::vector<uint8_t>& key) {
static EVP_PKEY_CTX* ctx = nullptr;
if ( ! ctx ) {
ctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
EVP_PKEY_derive_init(ctx);
EVP_PKEY_CTX_set_hkdf_md(ctx, EVP_sha256());
EVP_PKEY_CTX_hkdf_mode(ctx, EVP_PKEY_HKDEF_MODE_EXPAND_ONLY);
EVP_PKEY_CTX_add1_hkdf_info(ctx, CLIENT_INITIAL_INFO.data(), CLIENT_INITIAL_INFO.size());
}
return hkdf_expand(ctx, out_len, key);
}
std::vector<uint8_t> hkdf_expand_server_initial_info(size_t out_len, const std::vector<uint8_t>& key) {
static EVP_PKEY_CTX* ctx = nullptr;
if ( ! ctx ) {
ctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
EVP_PKEY_derive_init(ctx);
EVP_PKEY_CTX_set_hkdf_md(ctx, EVP_sha256());
EVP_PKEY_CTX_hkdf_mode(ctx, EVP_PKEY_HKDEF_MODE_EXPAND_ONLY);
EVP_PKEY_CTX_add1_hkdf_info(ctx, SERVER_INITIAL_INFO.data(), SERVER_INITIAL_INFO.size());
}
return hkdf_expand(ctx, out_len, key);
}
std::vector<uint8_t> hkdf_expand_key_info(size_t out_len, const std::vector<uint8_t>& key) {
static EVP_PKEY_CTX* ctx = nullptr;
if ( ! ctx ) {
ctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
EVP_PKEY_derive_init(ctx);
EVP_PKEY_CTX_set_hkdf_md(ctx, EVP_sha256());
EVP_PKEY_CTX_hkdf_mode(ctx, EVP_PKEY_HKDEF_MODE_EXPAND_ONLY);
EVP_PKEY_CTX_add1_hkdf_info(ctx, KEY_INFO.data(), KEY_INFO.size());
}
return hkdf_expand(ctx, out_len, key);
}
std::vector<uint8_t> hkdf_expand_iv_info(size_t out_len, const std::vector<uint8_t>& key) {
static EVP_PKEY_CTX* ctx = nullptr;
if ( ! ctx ) {
ctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
EVP_PKEY_derive_init(ctx);
EVP_PKEY_CTX_set_hkdf_md(ctx, EVP_sha256());
EVP_PKEY_CTX_hkdf_mode(ctx, EVP_PKEY_HKDEF_MODE_EXPAND_ONLY);
EVP_PKEY_CTX_add1_hkdf_info(ctx, IV_INFO.data(), IV_INFO.size());
}
return hkdf_expand(ctx, out_len, key);
}
std::vector<uint8_t> hkdf_expand_hp_info(size_t out_len, const std::vector<uint8_t>& key) {
static EVP_PKEY_CTX* ctx = nullptr;
if ( ! ctx ) {
ctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
EVP_PKEY_derive_init(ctx);
EVP_PKEY_CTX_set_hkdf_md(ctx, EVP_sha256());
EVP_PKEY_CTX_hkdf_mode(ctx, EVP_PKEY_HKDEF_MODE_EXPAND_ONLY);
EVP_PKEY_CTX_add1_hkdf_info(ctx, HP_INFO.data(), HP_INFO.size());
}
return hkdf_expand(ctx, out_len, key);
}
/*
Removes the header protection from the INITIAL packet and returns a DecryptionInformation struct
@ -268,10 +150,8 @@ std::vector<uint8_t> calculate_nonce(std::vector<uint8_t> client_iv, uint64_t pa
}
/*
Function that calls the AEAD decryption routine, and returns the
decrypted data
Function that calls the AEAD decryption routine, and returns the decrypted data.
*/
hilti::rt::Bytes decrypt(const std::vector<uint8_t>& client_key, const hilti::rt::Bytes& all_data,
uint64_t payload_length, const DecryptionInformation& decryptInfo) {
int out, out2, res;
@ -324,14 +204,203 @@ hilti::rt::Bytes decrypt(const std::vector<uint8_t>& client_key, const hilti::rt
return hilti::rt::Bytes(decrypt_buffer.data(), decrypt_buffer.data() + out);
}
// Pre-initialized SSL contexts for re-use. Not thread-safe. These are only used in expand-only mode
// and have a fixed HKDF info set.
struct HkdfCtx {
bool initialized = false;
EVP_PKEY_CTX* client_in_ctx = nullptr;
EVP_PKEY_CTX* server_in_ctx = nullptr;
EVP_PKEY_CTX* key_info_ctx = nullptr;
EVP_PKEY_CTX* iv_info_ctx = nullptr;
EVP_PKEY_CTX* hp_info_ctx = nullptr;
};
struct HkdfCtxParam {
EVP_PKEY_CTX** ctx;
std::vector<uint8_t> info;
};
/*
HKDF-Extract as described in https://www.rfc-editor.org/rfc/rfc8446.html#section-7.1
*/
std::vector<uint8_t> hkdf_extract(const std::vector<uint8_t>& salt, const hilti::rt::Bytes& connection_id) {
std::vector<uint8_t> out_temp(INITIAL_SECRET_LEN);
size_t initial_secret_len = out_temp.size();
static EVP_PKEY_CTX* ctx = nullptr;
if ( ! ctx ) {
ctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
EVP_PKEY_derive_init(ctx);
EVP_PKEY_CTX_set_hkdf_md(ctx, EVP_sha256());
EVP_PKEY_CTX_hkdf_mode(ctx, EVP_PKEY_HKDEF_MODE_EXTRACT_ONLY);
}
EVP_PKEY_CTX_set1_hkdf_key(ctx, data_as_uint8(connection_id), connection_id.size());
EVP_PKEY_CTX_set1_hkdf_salt(ctx, salt.data(), salt.size());
EVP_PKEY_derive(ctx, out_temp.data(), &initial_secret_len);
return out_temp;
}
std::vector<uint8_t> hkdf_expand(EVP_PKEY_CTX* ctx, size_t out_len, const std::vector<uint8_t>& key) {
std::vector<uint8_t> out_temp(out_len);
EVP_PKEY_CTX_set1_hkdf_key(ctx, key.data(), key.size());
EVP_PKEY_derive(ctx, out_temp.data(), &out_len);
return out_temp;
}
class QuicPacketProtection {
public:
std::vector<uint8_t> GetSecret(bool is_orig, const hilti::rt::Bytes& connection_id) {
const auto& ctxs = GetHkdfCtxs();
const auto initial_secret = hkdf_extract(GetInitialSalt(), connection_id);
EVP_PKEY_CTX* ctx = is_orig ? ctxs.client_in_ctx : ctxs.server_in_ctx;
return hkdf_expand(ctx, INITIAL_SECRET_LEN, initial_secret);
}
std::vector<uint8_t> GetKey(const std::vector<uint8_t>& secret) {
const auto& ctxs = GetHkdfCtxs();
return hkdf_expand(ctxs.key_info_ctx, AEAD_KEY_LEN, secret);
}
std::vector<uint8_t> GetIv(const std::vector<uint8_t>& secret) {
const auto& ctxs = GetHkdfCtxs();
return hkdf_expand(ctxs.iv_info_ctx, AEAD_IV_LEN, secret);
}
std::vector<uint8_t> GetHp(const std::vector<uint8_t>& secret) {
const auto& ctxs = GetHkdfCtxs();
return hkdf_expand(ctxs.hp_info_ctx, AEAD_HP_LEN, secret);
}
virtual const std::vector<uint8_t>& GetInitialSalt() = 0;
virtual HkdfCtx& GetHkdfCtxs() = 0;
virtual ~QuicPacketProtection() = default;
// Helper to initialize HKDF expand only contexts.
static void Initialize(std::vector<HkdfCtxParam>& params) {
for ( const auto& p : params ) {
*p.ctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
EVP_PKEY_derive_init(*p.ctx);
EVP_PKEY_CTX_set_hkdf_md(*p.ctx, EVP_sha256());
EVP_PKEY_CTX_hkdf_mode(*p.ctx, EVP_PKEY_HKDEF_MODE_EXPAND_ONLY);
EVP_PKEY_CTX_add1_hkdf_info(*p.ctx, p.info.data(), p.info.size());
}
}
};
// QUIC v1
//
// https://datatracker.ietf.org/doc/html/rfc9001
std::vector<uint8_t> INITIAL_SALT_V1 = {0x38, 0x76, 0x2c, 0xf7, 0xf5, 0x59, 0x34, 0xb3, 0x4d, 0x17,
0x9a, 0xe6, 0xa4, 0xc8, 0x0c, 0xad, 0xcc, 0xbb, 0x7f, 0x0a};
std::vector<uint8_t> CLIENT_INITIAL_INFO = {0x00, 0x20, 0x0f, 0x74, 0x6c, 0x73, 0x31, 0x33, 0x20, 0x63,
0x6c, 0x69, 0x65, 0x6e, 0x74, 0x20, 0x69, 0x6e, 0x00};
std::vector<uint8_t> SERVER_INITIAL_INFO = {0x00, 0x20, 0x0f, 0x74, 0x6c, 0x73, 0x31, 0x33, 0x20, 0x73,
0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x69, 0x6e, 0x00};
std::vector<uint8_t> KEY_INFO = {0x00, 0x10, 0x0e, 0x74, 0x6c, 0x73, 0x31, 0x33, 0x20,
0x71, 0x75, 0x69, 0x63, 0x20, 0x6b, 0x65, 0x79, 0x00};
std::vector<uint8_t> IV_INFO = {0x00, 0x0c, 0x0d, 0x74, 0x6c, 0x73, 0x31, 0x33, 0x20,
0x71, 0x75, 0x69, 0x63, 0x20, 0x69, 0x76, 0x00};
std::vector<uint8_t> HP_INFO = {0x00, 0x10, 0x0d, 0x74, 0x6c, 0x73, 0x31, 0x33, 0x20,
0x71, 0x75, 0x69, 0x63, 0x20, 0x68, 0x70, 0x00};
class QuicPacketProtectionV1 : public QuicPacketProtection {
public:
virtual std::vector<uint8_t>& GetInitialSalt() override { return INITIAL_SALT_V1; }
virtual HkdfCtx& GetHkdfCtxs() override { return hkdf_ctxs; }
// Pre-initialize SSL context for reuse with HKDF info set to version specific values.
static void Initialize() {
if ( hkdf_ctxs.initialized )
return;
std::vector<HkdfCtxParam> hkdf_ctx_params = {
{&hkdf_ctxs.client_in_ctx, CLIENT_INITIAL_INFO},
{&hkdf_ctxs.server_in_ctx, SERVER_INITIAL_INFO},
{&hkdf_ctxs.key_info_ctx, KEY_INFO},
{&hkdf_ctxs.iv_info_ctx, IV_INFO},
{&hkdf_ctxs.hp_info_ctx, HP_INFO},
};
QuicPacketProtection::Initialize(hkdf_ctx_params);
instance = std::make_unique<QuicPacketProtectionV1>();
hkdf_ctxs.initialized = true;
}
static HkdfCtx hkdf_ctxs;
static std::unique_ptr<QuicPacketProtectionV1> instance;
};
HkdfCtx QuicPacketProtectionV1::hkdf_ctxs = {0};
std::unique_ptr<QuicPacketProtectionV1> QuicPacketProtectionV1::instance = nullptr;
// QUIC v2
//
// https://datatracker.ietf.org/doc/rfc9369/
std::vector<uint8_t> INITIAL_SALT_V2 = {0x0d, 0xed, 0xe3, 0xde, 0xf7, 0x00, 0xa6, 0xdb, 0x81, 0x93,
0x81, 0xbe, 0x6e, 0x26, 0x9d, 0xcb, 0xf9, 0xbd, 0x2e, 0xd9};
std::vector<uint8_t> CLIENT_INITIAL_INFO_V2 = {0x00, 0x20, 0x0f, 0x74, 0x6c, 0x73, 0x31, 0x33, 0x20, 0x63,
0x6c, 0x69, 0x65, 0x6e, 0x74, 0x20, 0x69, 0x6e, 0x00};
std::vector<uint8_t> SERVER_INITIAL_INFO_V2 = {0x00, 0x20, 0x0f, 0x74, 0x6c, 0x73, 0x31, 0x33, 0x20, 0x73,
0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x69, 0x6e, 0x00};
std::vector<uint8_t> KEY_INFO_V2 = {0x00, 0x10, 0x10, 0x74, 0x6c, 0x73, 0x31, 0x33, 0x20, 0x71,
0x75, 0x69, 0x63, 0x76, 0x32, 0x20, 0x6b, 0x65, 0x79, 0x00};
std::vector<uint8_t> IV_INFO_V2 = {0x00, 0x0c, 0x0f, 0x74, 0x6c, 0x73, 0x31, 0x33, 0x20, 0x71,
0x75, 0x69, 0x63, 0x76, 0x32, 0x20, 0x69, 0x76, 0x00};
std::vector<uint8_t> HP_INFO_V2 = {0x00, 0x10, 0x0f, 0x74, 0x6c, 0x73, 0x31, 0x33, 0x20, 0x71,
0x75, 0x69, 0x63, 0x76, 0x32, 0x20, 0x68, 0x70, 0x00};
class QuicPacketProtectionV2 : public QuicPacketProtection {
public:
virtual std::vector<uint8_t>& GetInitialSalt() override { return INITIAL_SALT_V2; }
virtual HkdfCtx& GetHkdfCtxs() override { return hkdf_ctxs; }
static void Initialize() {
if ( hkdf_ctxs.initialized )
return;
std::vector<HkdfCtxParam> hkdf_ctx_params = {
{&hkdf_ctxs.client_in_ctx, CLIENT_INITIAL_INFO_V2},
{&hkdf_ctxs.server_in_ctx, SERVER_INITIAL_INFO_V2},
{&hkdf_ctxs.key_info_ctx, KEY_INFO_V2},
{&hkdf_ctxs.iv_info_ctx, IV_INFO_V2},
{&hkdf_ctxs.hp_info_ctx, HP_INFO_V2},
};
QuicPacketProtection::Initialize(hkdf_ctx_params);
instance = std::make_unique<QuicPacketProtectionV2>();
hkdf_ctxs.initialized = true;
}
static HkdfCtx hkdf_ctxs;
static std::unique_ptr<QuicPacketProtectionV2> instance;
};
HkdfCtx QuicPacketProtectionV2::hkdf_ctxs = {0};
std::unique_ptr<QuicPacketProtectionV2> QuicPacketProtectionV2::instance = nullptr;
} // namespace
/*
Function that is called from Spicy. It's a wrapper around `process_data`;
it stores all the passed data in a global struct and then calls `process_data`,
which will eventually return the decrypted data and pass it back to Spicy.
Function that is called from Spicy, decrypting an INITIAL packet and returning
the decrypted payload back to the analyzer.
*/
hilti::rt::Bytes QUIC_decrypt_crypto_payload(const hilti::rt::Bytes& all_data, const hilti::rt::Bytes& connection_id,
hilti::rt::Bytes QUIC_decrypt_crypto_payload(const hilti::rt::integer::safe<uint32_t>& version,
const hilti::rt::Bytes& all_data, const hilti::rt::Bytes& connection_id,
const hilti::rt::integer::safe<uint64_t>& encrypted_offset,
const hilti::rt::integer::safe<uint64_t>& payload_length,
const hilti::rt::Bool& from_client) {
@ -342,19 +411,24 @@ hilti::rt::Bytes QUIC_decrypt_crypto_payload(const hilti::rt::Bytes& all_data, c
throw hilti::rt::RuntimeError(
hilti::rt::fmt("packet too small %ld %ld", all_data.size(), encrypted_offset + payload_length));
std::vector<uint8_t> initial_secret = hkdf_extract(connection_id);
QuicPacketProtection* qpp = nullptr;
std::vector<uint8_t> server_client_secret;
if ( from_client ) {
server_client_secret = hkdf_expand_client_initial_info(INITIAL_SECRET_LEN, initial_secret);
if ( version == 0x00000001 ) { // quicv1
QuicPacketProtectionV1::Initialize();
qpp = QuicPacketProtectionV1::instance.get();
}
else if ( version == 0x6b3343cf ) { // quicv2
QuicPacketProtectionV2::Initialize();
qpp = QuicPacketProtectionV2::instance.get();
}
else {
server_client_secret = hkdf_expand_server_initial_info(INITIAL_SECRET_LEN, initial_secret);
throw hilti::rt::RuntimeError(hilti::rt::fmt("unable to handle version %lx", version));
}
std::vector<uint8_t> key = hkdf_expand_key_info(AEAD_KEY_LEN, server_client_secret);
std::vector<uint8_t> iv = hkdf_expand_iv_info(AEAD_IV_LEN, server_client_secret);
std::vector<uint8_t> hp = hkdf_expand_hp_info(AEAD_HP_LEN, server_client_secret);
const auto& secret = qpp->GetSecret(from_client, connection_id);
std::vector<uint8_t> key = qpp->GetKey(secret);
std::vector<uint8_t> iv = qpp->GetIv(secret);
std::vector<uint8_t> hp = qpp->GetHp(secret);
DecryptionInformation decryptInfo = remove_header_protection(hp, encrypted_offset, all_data);