nghttp2/src/shrpx_quic.cc

585 lines
17 KiB
C++

/*
* nghttp2 - HTTP/2 C Library
*
* Copyright (c) 2021 Tatsuhiro Tsujikawa
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include "shrpx_quic.h"
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/udp.h>
#include <array>
#include <chrono>
#include <ngtcp2/ngtcp2_crypto.h>
#include <nghttp3/nghttp3.h>
#include <openssl/rand.h>
#include "shrpx_config.h"
#include "shrpx_log.h"
#include "util.h"
#include "xsi_strerror.h"
using namespace nghttp2;
namespace shrpx {
ngtcp2_tstamp quic_timestamp() {
return std::chrono::duration_cast<std::chrono::nanoseconds>(
std::chrono::steady_clock::now().time_since_epoch())
.count();
}
int quic_send_packet(const UpstreamAddr *faddr, const sockaddr *remote_sa,
size_t remote_salen, const sockaddr *local_sa,
size_t local_salen, const uint8_t *data, size_t datalen,
size_t gso_size) {
iovec msg_iov = {const_cast<uint8_t *>(data), datalen};
msghdr msg{};
msg.msg_name = const_cast<sockaddr *>(remote_sa);
msg.msg_namelen = remote_salen;
msg.msg_iov = &msg_iov;
msg.msg_iovlen = 1;
uint8_t msg_ctrl[
#ifdef UDP_SEGMENT
CMSG_SPACE(sizeof(uint16_t)) +
#endif // UDP_SEGMENT
CMSG_SPACE(sizeof(in6_pktinfo))];
memset(msg_ctrl, 0, sizeof(msg_ctrl));
msg.msg_control = msg_ctrl;
msg.msg_controllen = sizeof(msg_ctrl);
size_t controllen = 0;
auto cm = CMSG_FIRSTHDR(&msg);
switch (local_sa->sa_family) {
case AF_INET: {
controllen += CMSG_SPACE(sizeof(in_pktinfo));
cm->cmsg_level = IPPROTO_IP;
cm->cmsg_type = IP_PKTINFO;
cm->cmsg_len = CMSG_LEN(sizeof(in_pktinfo));
auto pktinfo = reinterpret_cast<in_pktinfo *>(CMSG_DATA(cm));
memset(pktinfo, 0, sizeof(in_pktinfo));
auto addrin =
reinterpret_cast<sockaddr_in *>(const_cast<sockaddr *>(local_sa));
pktinfo->ipi_spec_dst = addrin->sin_addr;
break;
}
case AF_INET6: {
controllen += CMSG_SPACE(sizeof(in6_pktinfo));
cm->cmsg_level = IPPROTO_IPV6;
cm->cmsg_type = IPV6_PKTINFO;
cm->cmsg_len = CMSG_LEN(sizeof(in6_pktinfo));
auto pktinfo = reinterpret_cast<in6_pktinfo *>(CMSG_DATA(cm));
memset(pktinfo, 0, sizeof(in6_pktinfo));
auto addrin =
reinterpret_cast<sockaddr_in6 *>(const_cast<sockaddr *>(local_sa));
pktinfo->ipi6_addr = addrin->sin6_addr;
break;
}
default:
assert(0);
}
#ifdef UDP_SEGMENT
if (gso_size && datalen > gso_size) {
controllen += CMSG_SPACE(sizeof(uint16_t));
cm = CMSG_NXTHDR(&msg, cm);
cm->cmsg_level = SOL_UDP;
cm->cmsg_type = UDP_SEGMENT;
cm->cmsg_len = CMSG_LEN(sizeof(uint16_t));
*(reinterpret_cast<uint16_t *>(CMSG_DATA(cm))) = gso_size;
}
#endif // UDP_SEGMENT
msg.msg_controllen = controllen;
ssize_t nwrite;
do {
nwrite = sendmsg(faddr->fd, &msg, 0);
} while (nwrite == -1 && errno == EINTR);
if (nwrite == -1) {
return -1;
}
if (LOG_ENABLED(INFO)) {
LOG(INFO) << "QUIC sent packet: local="
<< util::to_numeric_addr(local_sa, local_salen)
<< " remote=" << util::to_numeric_addr(remote_sa, remote_salen)
<< " " << nwrite << " bytes";
}
return 0;
}
int generate_quic_connection_id(ngtcp2_cid *cid, size_t cidlen) {
if (RAND_bytes(cid->data, cidlen) != 1) {
return -1;
}
cid->datalen = cidlen;
return 0;
}
int generate_quic_connection_id(ngtcp2_cid *cid, size_t cidlen,
const uint8_t *cid_prefix) {
assert(cidlen > SHRPX_QUIC_CID_PREFIXLEN);
auto p = std::copy_n(cid_prefix, SHRPX_QUIC_CID_PREFIXLEN, cid->data);
if (RAND_bytes(p, cidlen - SHRPX_QUIC_CID_PREFIXLEN) != 1) {
return -1;
}
cid->datalen = cidlen;
return 0;
}
int generate_quic_stateless_reset_token(uint8_t *token, const ngtcp2_cid *cid,
const uint8_t *secret,
size_t secretlen) {
ngtcp2_crypto_md md;
ngtcp2_crypto_md_init(&md, const_cast<EVP_MD *>(EVP_sha256()));
if (ngtcp2_crypto_generate_stateless_reset_token(token, &md, secret,
secretlen, cid) != 0) {
return -1;
}
return 0;
}
int generate_quic_stateless_reset_secret(uint8_t *secret) {
if (RAND_bytes(secret, SHRPX_QUIC_STATELESS_RESET_SECRETLEN) != 1) {
return -1;
}
return 0;
}
int generate_quic_token_secret(uint8_t *secret) {
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 {
size_t generate_token_aad(uint8_t *dest, size_t destlen, const sockaddr *sa,
size_t salen) {
const uint8_t *addr;
size_t addrlen;
switch (sa->sa_family) {
case AF_INET:
addr = reinterpret_cast<const uint8_t *>(
&reinterpret_cast<const sockaddr_in *>(sa)->sin_addr);
addrlen = sizeof(reinterpret_cast<const sockaddr_in *>(sa)->sin_addr);
break;
case AF_INET6:
addr = reinterpret_cast<const uint8_t *>(
&reinterpret_cast<const sockaddr_in6 *>(sa)->sin6_addr);
addrlen = sizeof(reinterpret_cast<const sockaddr_in6 *>(sa)->sin6_addr);
break;
default:
return 0;
}
assert(destlen >= addrlen);
return std::copy_n(addr, addrlen, dest) - dest;
}
} // namespace
int generate_token(uint8_t *token, size_t &tokenlen, const sockaddr *sa,
size_t salen, const uint8_t *token_secret) {
std::array<uint8_t, 8> plaintext;
uint64_t t = std::chrono::duration_cast<std::chrono::nanoseconds>(
std::chrono::system_clock::now().time_since_epoch())
.count();
std::array<uint8_t, 256> aad;
auto aadlen = generate_token_aad(aad.data(), aad.size(), sa, salen);
if (aadlen == 0) {
return -1;
}
auto p = std::begin(plaintext);
// Host byte order
p = std::copy_n(reinterpret_cast<uint8_t *>(&t), sizeof(t), 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);
ngtcp2_crypto_aead_ctx aead_ctx;
if (ngtcp2_crypto_aead_ctx_encrypt_init(&aead_ctx, &aead, key.data(),
ivlen) != 0) {
return -1;
}
token[0] = SHRPX_QUIC_TOKEN_MAGIC;
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_token(const uint8_t *token, size_t tokenlen, 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 TOKEN_MAGIC */
if (tokenlen < SHRPX_QUIC_TOKEN_RAND_DATALEN + 1) {
return -1;
}
if (tokenlen > SHRPX_QUIC_MAX_TOKENLEN) {
return -1;
}
assert(token[0] == SHRPX_QUIC_TOKEN_MAGIC);
std::array<uint8_t, 256> aad;
auto aadlen = generate_token_aad(aad.data(), aad.size(), sa, salen);
if (aadlen == 0) {
return -1;
}
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;
}
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_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;
}
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 1 hour window
if (t + 3600ULL * NGTCP2_SECONDS < now) {
return -1;
}
return 0;
}
} // namespace shrpx