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nghttpx: Send Retry packet

This commit is contained in:
Tatsuhiro Tsujikawa 2021-08-26 17:11:19 +09:00
parent 137da6adf6
commit dfc345756c
7 changed files with 356 additions and 11 deletions
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12
src/shrpx_http3_upstream.cc
View File

@ -403,7 +403,9 @@ int stream_stop_sending(ngtcp2_conn *conn, int64_t stream_id,
int Http3Upstream::init(const UpstreamAddr *faddr, const Address &remote_addr,
const Address &local_addr,
const ngtcp2_pkt_hd &initial_hd) {
const ngtcp2_pkt_hd &initial_hd,
const ngtcp2_cid *odcid, const uint8_t *token,
size_t tokenlen) {
int rv;
auto worker = handler_->get_worker();
@ -470,6 +472,7 @@ int Http3Upstream::init(const UpstreamAddr *faddr, const Address &remote_addr,
settings.max_stream_window = 6_m;
settings.max_udp_payload_size = SHRPX_MAX_UDP_PAYLOAD_SIZE;
settings.rand_ctx.native_handle = &worker->get_randgen();
settings.token = ngtcp2_vec{const_cast<uint8_t *>(token), tokenlen};
ngtcp2_transport_params params;
ngtcp2_transport_params_default(&params);
@ -480,7 +483,14 @@ int Http3Upstream::init(const UpstreamAddr *faddr, const Address &remote_addr,
params.initial_max_stream_data_uni = 256_k;
params.max_idle_timeout =
static_cast<ngtcp2_tstamp>(quicconf.timeout.idle * NGTCP2_SECONDS);
if (odcid) {
params.original_dcid = *odcid;
params.retry_scid = initial_hd.dcid;
params.retry_scid_present = 1;
} else {
params.original_dcid = initial_hd.dcid;
}
auto &quic_secret = worker->get_quic_secret();
auto &stateless_reset_secret = quic_secret->stateless_reset_secret;

3
src/shrpx_http3_upstream.h
View File

@ -88,7 +88,8 @@ public:
virtual void cancel_premature_downstream(Downstream *promised_downstream);
int init(const UpstreamAddr *faddr, const Address &remote_addr,
const Address &local_addr, const ngtcp2_pkt_hd &initial_hd);
const Address &local_addr, const ngtcp2_pkt_hd &initial_hd,
const ngtcp2_cid *odcid, const uint8_t *token, size_t tokenlen);
int on_read(const UpstreamAddr *faddr, const Address &remote_addr,
const Address &local_addr, const uint8_t *data, size_t datalen);

219
src/shrpx_quic.cc
View File

@ -181,11 +181,226 @@ int generate_quic_stateless_reset_token(uint8_t *token, const ngtcp2_cid *cid,
}
int generate_quic_stateless_reset_secret(uint8_t *secret) {
return RAND_bytes(secret, SHRPX_QUIC_STATELESS_RESET_SECRETLEN) == 1;
if (RAND_bytes(secret, SHRPX_QUIC_STATELESS_RESET_SECRETLEN) != 1) {
return -1;
}
return 0;
}
int generate_quic_token_secret(uint8_t *secret) {
return RAND_bytes(secret, SHRPX_QUIC_TOKEN_SECRETLEN) == 1;
if (RAND_bytes(secret, SHRPX_QUIC_TOKEN_SECRETLEN) != 1) {
return -1;
}
return 0;
}
namespace {
int derive_token_key(uint8_t *key, size_t &keylen, uint8_t *iv, size_t &ivlen,
const uint8_t *token_secret, const uint8_t *rand_data,
size_t rand_datalen, const ngtcp2_crypto_aead *aead,
const ngtcp2_crypto_md *md) {
std::array<uint8_t, 32> secret;
if (ngtcp2_crypto_hkdf_extract(secret.data(), md, token_secret,
SHRPX_QUIC_TOKEN_SECRETLEN, rand_data,
rand_datalen) != 0) {
return -1;
}
auto aead_keylen = ngtcp2_crypto_aead_keylen(aead);
if (keylen < aead_keylen) {
return -1;
}
keylen = aead_keylen;
auto aead_ivlen = ngtcp2_crypto_packet_protection_ivlen(aead);
if (ivlen < aead_ivlen) {
return -1;
}
ivlen = aead_ivlen;
if (ngtcp2_crypto_derive_packet_protection_key(
key, iv, nullptr, aead, md, secret.data(), secret.size()) != 0) {
return -1;
}
return 0;
}
} // namespace
namespace {
size_t generate_retry_token_aad(uint8_t *dest, size_t destlen,
const sockaddr *sa, socklen_t salen,
const ngtcp2_cid *retry_scid) {
assert(destlen >= salen + retry_scid->datalen);
auto p = std::copy_n(reinterpret_cast<const uint8_t *>(sa), salen, dest);
p = std::copy_n(retry_scid->data, retry_scid->datalen, p);
return p - dest;
}
} // namespace
int generate_retry_token(uint8_t *token, size_t &tokenlen, const sockaddr *sa,
socklen_t salen, const ngtcp2_cid *retry_scid,
const ngtcp2_cid *odcid, const uint8_t *token_secret) {
std::array<uint8_t, 4096> plaintext;
uint64_t t = std::chrono::duration_cast<std::chrono::nanoseconds>(
std::chrono::system_clock::now().time_since_epoch())
.count();
auto p = std::begin(plaintext);
// Host byte order
p = std::copy_n(reinterpret_cast<uint8_t *>(&t), sizeof(t), p);
p = std::copy_n(odcid->data, odcid->datalen, p);
std::array<uint8_t, SHRPX_QUIC_TOKEN_RAND_DATALEN> rand_data;
std::array<uint8_t, 32> key, iv;
auto keylen = key.size();
auto ivlen = iv.size();
if (RAND_bytes(rand_data.data(), rand_data.size()) != 1) {
return -1;
}
ngtcp2_crypto_aead aead;
ngtcp2_crypto_aead_init(&aead, const_cast<EVP_CIPHER *>(EVP_aes_128_gcm()));
ngtcp2_crypto_md md;
ngtcp2_crypto_md_init(&md, const_cast<EVP_MD *>(EVP_sha256()));
if (derive_token_key(key.data(), keylen, iv.data(), ivlen, token_secret,
rand_data.data(), rand_data.size(), &aead, &md) != 0) {
return -1;
}
auto plaintextlen = std::distance(std::begin(plaintext), p);
std::array<uint8_t, 256> aad;
auto aadlen =
generate_retry_token_aad(aad.data(), aad.size(), sa, salen, retry_scid);
token[0] = SHRPX_QUIC_RETRY_TOKEN_MAGIC;
ngtcp2_crypto_aead_ctx aead_ctx;
if (ngtcp2_crypto_aead_ctx_encrypt_init(&aead_ctx, &aead, key.data(),
ivlen) != 0) {
return -1;
}
auto rv =
ngtcp2_crypto_encrypt(token + 1, &aead, &aead_ctx, plaintext.data(),
plaintextlen, iv.data(), ivlen, aad.data(), aadlen);
ngtcp2_crypto_aead_ctx_free(&aead_ctx);
if (rv != 0) {
return -1;
}
/* 1 for magic byte */
tokenlen = 1 + plaintextlen + aead.max_overhead;
memcpy(token + tokenlen, rand_data.data(), rand_data.size());
tokenlen += rand_data.size();
return 0;
}
int verify_retry_token(ngtcp2_cid *odcid, const uint8_t *token, size_t tokenlen,
const ngtcp2_cid *dcid, const sockaddr *sa,
socklen_t salen, const uint8_t *token_secret) {
std::array<char, NI_MAXHOST> host;
std::array<char, NI_MAXSERV> port;
if (getnameinfo(sa, salen, host.data(), host.size(), port.data(), port.size(),
NI_NUMERICHOST | NI_NUMERICSERV) != 0) {
return -1;
}
/* 1 for SHRPX_QUIC_RETRY_TOKEN_MAGIC */
if (tokenlen < SHRPX_QUIC_TOKEN_RAND_DATALEN + 1) {
return -1;
}
if (tokenlen > SHRPX_QUIC_MAX_RETRY_TOKENLEN) {
return -1;
}
assert(token[0] == SHRPX_QUIC_RETRY_TOKEN_MAGIC);
auto rand_data = token + tokenlen - SHRPX_QUIC_TOKEN_RAND_DATALEN;
auto ciphertext = token + 1;
auto ciphertextlen = tokenlen - SHRPX_QUIC_TOKEN_RAND_DATALEN - 1;
std::array<uint8_t, 32> key, iv;
auto keylen = key.size();
auto ivlen = iv.size();
ngtcp2_crypto_aead aead;
ngtcp2_crypto_aead_init(&aead, const_cast<EVP_CIPHER *>(EVP_aes_128_gcm()));
ngtcp2_crypto_md md;
ngtcp2_crypto_md_init(&md, const_cast<EVP_MD *>(EVP_sha256()));
if (derive_token_key(key.data(), keylen, iv.data(), ivlen, token_secret,
rand_data, SHRPX_QUIC_TOKEN_RAND_DATALEN, &aead,
&md) != 0) {
return -1;
}
std::array<uint8_t, 256> aad;
auto aadlen =
generate_retry_token_aad(aad.data(), aad.size(), sa, salen, dcid);
ngtcp2_crypto_aead_ctx aead_ctx;
if (ngtcp2_crypto_aead_ctx_decrypt_init(&aead_ctx, &aead, key.data(),
ivlen) != 0) {
return -1;
}
std::array<uint8_t, SHRPX_QUIC_MAX_RETRY_TOKENLEN> plaintext;
auto rv = ngtcp2_crypto_decrypt(plaintext.data(), &aead, &aead_ctx,
ciphertext, ciphertextlen, iv.data(), ivlen,
aad.data(), aadlen);
ngtcp2_crypto_aead_ctx_free(&aead_ctx);
if (rv != 0) {
return -1;
}
assert(ciphertextlen >= aead.max_overhead);
auto plaintextlen = ciphertextlen - aead.max_overhead;
if (plaintextlen < sizeof(uint64_t)) {
return -1;
}
auto cil = plaintextlen - sizeof(uint64_t);
if (cil != 0 && (cil < NGTCP2_MIN_CIDLEN || cil > NGTCP2_MAX_CIDLEN)) {
return -1;
}
uint64_t t;
memcpy(&t, plaintext.data(), sizeof(uint64_t));
uint64_t now = std::chrono::duration_cast<std::chrono::nanoseconds>(
std::chrono::system_clock::now().time_since_epoch())
.count();
// Allow 10 seconds window
if (t + 10ULL * NGTCP2_SECONDS < now) {
return -1;
}
ngtcp2_cid_init(odcid, plaintext.data() + sizeof(uint64_t), cil);
return 0;
}
} // namespace shrpx

23
src/shrpx_quic.h
View File

@ -40,6 +40,21 @@ constexpr size_t SHRPX_QUIC_CID_PREFIXLEN = 8;
constexpr size_t SHRPX_MAX_UDP_PAYLOAD_SIZE = 1280;
constexpr size_t SHRPX_QUIC_STATELESS_RESET_SECRETLEN = 32;
constexpr size_t SHRPX_QUIC_TOKEN_SECRETLEN = 32;
constexpr size_t SHRPX_QUIC_TOKEN_RAND_DATALEN = 16;
// SHRPX_QUIC_RETRY_TOKEN_MAGIC is the magic byte of Retry token.
// Sent in plaintext.
constexpr uint8_t SHRPX_QUIC_RETRY_TOKEN_MAGIC = 0xb6;
constexpr size_t SHRPX_QUIC_MAX_RETRY_TOKENLEN =
/* magic */ 1 + sizeof(uint64_t) + NGTCP2_MAX_CIDLEN +
/* aead tag */ 16 + SHRPX_QUIC_TOKEN_RAND_DATALEN;
// SHRPX_QUIC_TOKEN_MAGIC is the magic byte of token which is sent in
// NEW_TOKEN frame. Sent in plaintext.
constexpr uint8_t SHRPX_QUIC_TOKEN_MAGIC = 0x36;
constexpr size_t SHRPX_QUIC_MAX_TOKENLEN =
/* magic */ 1 + sizeof(uint64_t) + /* aead tag */ 16 +
SHRPX_QUIC_TOKEN_RAND_DATALEN;
ngtcp2_tstamp quic_timestamp();
@ -61,6 +76,14 @@ int generate_quic_stateless_reset_secret(uint8_t *secret);
int generate_quic_token_secret(uint8_t *secret);
int generate_retry_token(uint8_t *token, size_t &tokenlen, const sockaddr *sa,
socklen_t salen, const ngtcp2_cid *retry_scid,
const ngtcp2_cid *odcid, const uint8_t *token_secret);
int verify_retry_token(ngtcp2_cid *odcid, const uint8_t *token, size_t tokenlen,
const ngtcp2_cid *dcid, const sockaddr *sa,
socklen_t salen, const uint8_t *token_secret);
} // namespace shrpx
#endif // SHRPX_QUIC_H

91
src/shrpx_quic_connection_handler.cc
View File

@ -27,6 +27,7 @@
#include <openssl/rand.h>
#include <ngtcp2/ngtcp2.h>
#include <ngtcp2/ngtcp2_crypto.h>
#include "shrpx_worker.h"
#include "shrpx_client_handler.h"
@ -83,12 +84,30 @@ int QUICConnectionHandler::handle_packet(const UpstreamAddr *faddr,
// new connection
ngtcp2_pkt_hd hd;
ngtcp2_cid odcid, *podcid = nullptr;
switch (ngtcp2_accept(&hd, data, datalen)) {
case 0:
case 0: {
if (hd.token.len == 0) {
break;
}
auto &quic_secret = worker_->get_quic_secret();
auto &secret = quic_secret->token_secret;
if (hd.token.base[0] == SHRPX_QUIC_RETRY_TOKEN_MAGIC) {
if (verify_retry_token(&odcid, hd.token.base, hd.token.len, &hd.dcid,
&remote_addr.su.sa, remote_addr.len,
secret.data()) == 0) {
podcid = &odcid;
}
}
break;
}
case NGTCP2_ERR_RETRY:
// TODO Send retry
send_retry(faddr, version, dcid, dcidlen, scid, scidlen, remote_addr,
local_addr);
return 0;
case NGTCP2_ERR_VERSION_NEGOTIATION:
send_version_negotiation(faddr, version, scid, scidlen, dcid, dcidlen,
@ -120,7 +139,7 @@ int QUICConnectionHandler::handle_packet(const UpstreamAddr *faddr,
return 0;
}
handler = handle_new_connection(faddr, remote_addr, local_addr, hd);
handler = handle_new_connection(faddr, remote_addr, local_addr, hd, podcid);
if (handler == nullptr) {
return 0;
}
@ -140,7 +159,8 @@ int QUICConnectionHandler::handle_packet(const UpstreamAddr *faddr,
ClientHandler *QUICConnectionHandler::handle_new_connection(
const UpstreamAddr *faddr, const Address &remote_addr,
const Address &local_addr, const ngtcp2_pkt_hd &hd) {
const Address &local_addr, const ngtcp2_pkt_hd &hd,
const ngtcp2_cid *odcid) {
std::array<char, NI_MAXHOST> host;
std::array<char, NI_MAXSERV> service;
int rv;
@ -178,8 +198,17 @@ ClientHandler *QUICConnectionHandler::handle_new_connection(
worker_, faddr->fd, ssl, StringRef{host.data()},
StringRef{service.data()}, remote_addr.su.sa.sa_family, faddr);
const uint8_t *token = nullptr;
size_t tokenlen = 0;
if (odcid) {
token = hd.token.base;
tokenlen = hd.token.len;
}
auto upstream = std::make_unique<Http3Upstream>(handler.get());
if (upstream->init(faddr, remote_addr, local_addr, hd) != 0) {
if (upstream->init(faddr, remote_addr, local_addr, hd, odcid, token,
tokenlen) != 0) {
return nullptr;
}
@ -215,6 +244,58 @@ uint32_t generate_reserved_version(const Address &addr, uint32_t version) {
}
} // namespace
int QUICConnectionHandler::send_retry(
const UpstreamAddr *faddr, uint32_t version, const uint8_t *initial_dcid,
size_t initial_dcidlen, const uint8_t *initial_scid, size_t initial_scidlen,
const Address &remote_addr, const Address &local_addr) {
std::array<char, NI_MAXHOST> host;
std::array<char, NI_MAXSERV> port;
if (getnameinfo(&remote_addr.su.sa, remote_addr.len, host.data(), host.size(),
port.data(), port.size(),
NI_NUMERICHOST | NI_NUMERICSERV) != 0) {
return -1;
}
ngtcp2_cid retry_scid;
retry_scid.datalen = SHRPX_QUIC_SCIDLEN;
// We do not steer packet based on Retry CID.
if (RAND_bytes(retry_scid.data, retry_scid.datalen) != 1) {
return -1;
}
std::array<uint8_t, SHRPX_QUIC_MAX_RETRY_TOKENLEN> token;
size_t tokenlen = token.size();
ngtcp2_cid ini_dcid, ini_scid;
ngtcp2_cid_init(&ini_dcid, initial_dcid, initial_dcidlen);
ngtcp2_cid_init(&ini_scid, initial_scid, initial_scidlen);
auto &quic_secret = worker_->get_quic_secret();
auto &secret = quic_secret->token_secret;
if (generate_retry_token(token.data(), tokenlen, &remote_addr.su.sa,
remote_addr.len, &retry_scid, &ini_dcid,
secret.data()) != 0) {
return -1;
}
std::array<uint8_t, 1280> buf;
auto nwrite =
ngtcp2_crypto_write_retry(buf.data(), buf.size(), version, &ini_scid,
&retry_scid, &ini_dcid, token.data(), tokenlen);
if (nwrite < 0) {
LOG(ERROR) << "ngtcp2_crypto_write_retry: " << ngtcp2_strerror(nwrite);
return -1;
}
return quic_send_packet(faddr, &remote_addr.su.sa, remote_addr.len,
&local_addr.su.sa, local_addr.len, buf.data(), nwrite,
0);
}
int QUICConnectionHandler::send_version_negotiation(
const UpstreamAddr *faddr, uint32_t version, const uint8_t *dcid,
size_t dcidlen, const uint8_t *scid, size_t scidlen,

11
src/shrpx_quic_connection_handler.h
View File

@ -50,6 +50,14 @@ public:
int handle_packet(const UpstreamAddr *faddr, const Address &remote_addr,
const Address &local_addr, const uint8_t *data,
size_t datalen);
// Send Retry packet. |ini_dcid| is the destination Connection ID
// which appeared in Client Initial packet and its length is
// |dcidlen|. |ini_scid| is the source Connection ID which appeared
// in Client Initial packet and its length is |scidlen|.
int send_retry(const UpstreamAddr *faddr, uint32_t version,
const uint8_t *ini_dcid, size_t ini_dcidlen,
const uint8_t *ini_scid, size_t ini_scidlen,
const Address &remote_addr, const Address &local_addr);
int send_version_negotiation(const UpstreamAddr *faddr, uint32_t version,
const uint8_t *dcid, size_t dcidlen,
const uint8_t *scid, size_t scidlen,
@ -61,7 +69,8 @@ public:
ClientHandler *handle_new_connection(const UpstreamAddr *faddr,
const Address &remote_addr,
const Address &local_addr,
const ngtcp2_pkt_hd &hd);
const ngtcp2_pkt_hd &hd,
const ngtcp2_cid *odcid);
void add_connection_id(const ngtcp2_cid *cid, ClientHandler *handler);
void remove_connection_id(const ngtcp2_cid *cid);

6
src/shrpx_worker_process.cc
View File

@ -496,6 +496,12 @@ int worker_process_event_loop(WorkerProcessConfig *wpconf) {
}
}
#ifdef ENABLE_HTTP3
if (conn_handler->create_quic_secret() != 0) {
return -1;
}
#endif // ENABLE_HTTP3
if (config->single_thread) {
rv = conn_handler->create_single_worker();
if (rv != 0) {