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Copy pathtransportlayerdtls.cpp
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transportlayerdtls.cpp
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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/. */
// Original author: ekr@rtfm.com
#include <queue>
#include <algorithm>
#include <sstream>
#include "mozilla/UniquePtr.h"
#include "logging.h"
#include "ssl.h"
#include "sslerr.h"
#include "sslproto.h"
#include "keyhi.h"
#include "nsCOMPtr.h"
#include "nsComponentManagerUtils.h"
#include "nsIEventTarget.h"
#include "nsNetCID.h"
#include "nsComponentManagerUtils.h"
#include "nsServiceManagerUtils.h"
#include "dtlsidentity.h"
#include "transportflow.h"
#include "transportlayerdtls.h"
namespace mozilla {
MOZ_MTLOG_MODULE("mtransport")
static PRDescIdentity transport_layer_identity = PR_INVALID_IO_LAYER;
// TODO: Implement a mode for this where
// the channel is not ready until confirmed externally
// (e.g., after cert check).
#define UNIMPLEMENTED \
MOZ_MTLOG(ML_ERROR, \
"Call to unimplemented function "<< __FUNCTION__); \
MOZ_ASSERT(false); \
PR_SetError(PR_NOT_IMPLEMENTED_ERROR, 0)
#define MAX_ALPN_LENGTH 255
// We need to adapt the NSPR/libssl model to the TransportFlow model.
// The former wants pull semantics and TransportFlow wants push.
//
// - A TransportLayerDtls assumes it is sitting on top of another
// TransportLayer, which means that events come in asynchronously.
// - NSS (libssl) wants to sit on top of a PRFileDesc and poll.
// - The TransportLayerNSPRAdapter is a PRFileDesc containing a
// FIFO.
// - When TransportLayerDtls.PacketReceived() is called, we insert
// the packets in the FIFO and then do a PR_Recv() on the NSS
// PRFileDesc, which eventually reads off the FIFO.
//
// All of this stuff is assumed to happen solely in a single thread
// (generally the SocketTransportService thread)
struct Packet {
Packet() : data_(nullptr), len_(0) {}
void Assign(const void *data, int32_t len) {
data_.reset(new uint8_t[len]);
memcpy(data_.get(), data, len);
len_ = len;
}
UniquePtr<uint8_t[]> data_;
int32_t len_;
};
void TransportLayerNSPRAdapter::PacketReceived(const void *data, int32_t len) {
if (enabled_) {
input_.push(new Packet());
input_.back()->Assign(data, len);
}
}
int32_t TransportLayerNSPRAdapter::Recv(void *buf, int32_t buflen) {
if (input_.empty()) {
PR_SetError(PR_WOULD_BLOCK_ERROR, 0);
return -1;
}
Packet* front = input_.front();
if (buflen < front->len_) {
MOZ_ASSERT(false, "Not enough buffer space to receive into");
PR_SetError(PR_BUFFER_OVERFLOW_ERROR, 0);
return -1;
}
int32_t count = front->len_;
memcpy(buf, front->data_.get(), count);
input_.pop();
delete front;
return count;
}
int32_t TransportLayerNSPRAdapter::Write(const void *buf, int32_t length) {
if (!enabled_) {
MOZ_MTLOG(ML_WARNING, "Writing to disabled transport layer");
return -1;
}
TransportResult r = output_->SendPacket(
static_cast<const unsigned char *>(buf), length);
if (r >= 0) {
return r;
}
if (r == TE_WOULDBLOCK) {
PR_SetError(PR_WOULD_BLOCK_ERROR, 0);
} else {
PR_SetError(PR_IO_ERROR, 0);
}
return -1;
}
// Implementation of NSPR methods
static PRStatus TransportLayerClose(PRFileDesc *f) {
f->dtor(f);
return PR_SUCCESS;
}
static int32_t TransportLayerRead(PRFileDesc *f, void *buf, int32_t length) {
UNIMPLEMENTED;
return -1;
}
static int32_t TransportLayerWrite(PRFileDesc *f, const void *buf, int32_t length) {
TransportLayerNSPRAdapter *io = reinterpret_cast<TransportLayerNSPRAdapter *>(f->secret);
return io->Write(buf, length);
}
static int32_t TransportLayerAvailable(PRFileDesc *f) {
UNIMPLEMENTED;
return -1;
}
int64_t TransportLayerAvailable64(PRFileDesc *f) {
UNIMPLEMENTED;
return -1;
}
static PRStatus TransportLayerSync(PRFileDesc *f) {
UNIMPLEMENTED;
return PR_FAILURE;
}
static int32_t TransportLayerSeek(PRFileDesc *f, int32_t offset,
PRSeekWhence how) {
UNIMPLEMENTED;
return -1;
}
static int64_t TransportLayerSeek64(PRFileDesc *f, int64_t offset,
PRSeekWhence how) {
UNIMPLEMENTED;
return -1;
}
static PRStatus TransportLayerFileInfo(PRFileDesc *f, PRFileInfo *info) {
UNIMPLEMENTED;
return PR_FAILURE;
}
static PRStatus TransportLayerFileInfo64(PRFileDesc *f, PRFileInfo64 *info) {
UNIMPLEMENTED;
return PR_FAILURE;
}
static int32_t TransportLayerWritev(PRFileDesc *f, const PRIOVec *iov,
int32_t iov_size, PRIntervalTime to) {
UNIMPLEMENTED;
return -1;
}
static PRStatus TransportLayerConnect(PRFileDesc *f, const PRNetAddr *addr,
PRIntervalTime to) {
UNIMPLEMENTED;
return PR_FAILURE;
}
static PRFileDesc *TransportLayerAccept(PRFileDesc *sd, PRNetAddr *addr,
PRIntervalTime to) {
UNIMPLEMENTED;
return nullptr;
}
static PRStatus TransportLayerBind(PRFileDesc *f, const PRNetAddr *addr) {
UNIMPLEMENTED;
return PR_FAILURE;
}
static PRStatus TransportLayerListen(PRFileDesc *f, int32_t depth) {
UNIMPLEMENTED;
return PR_FAILURE;
}
static PRStatus TransportLayerShutdown(PRFileDesc *f, int32_t how) {
// This is only called from NSS when we are the server and the client refuses
// to provide a certificate. In this case, the handshake is destined for
// failure, so we will just let this pass.
TransportLayerNSPRAdapter *io = reinterpret_cast<TransportLayerNSPRAdapter *>(f->secret);
io->SetEnabled(false);
return PR_SUCCESS;
}
// This function does not support peek, or waiting until `to`
static int32_t TransportLayerRecv(PRFileDesc *f, void *buf, int32_t buflen,
int32_t flags, PRIntervalTime to) {
MOZ_ASSERT(flags == 0);
if (flags != 0) {
PR_SetError(PR_NOT_IMPLEMENTED_ERROR, 0);
return -1;
}
TransportLayerNSPRAdapter *io = reinterpret_cast<TransportLayerNSPRAdapter *>(f->secret);
return io->Recv(buf, buflen);
}
// Note: this is always nonblocking and assumes a zero timeout.
static int32_t TransportLayerSend(PRFileDesc *f, const void *buf, int32_t amount,
int32_t flags, PRIntervalTime to) {
int32_t written = TransportLayerWrite(f, buf, amount);
return written;
}
static int32_t TransportLayerRecvfrom(PRFileDesc *f, void *buf, int32_t amount,
int32_t flags, PRNetAddr *addr, PRIntervalTime to) {
UNIMPLEMENTED;
return -1;
}
static int32_t TransportLayerSendto(PRFileDesc *f, const void *buf, int32_t amount,
int32_t flags, const PRNetAddr *addr, PRIntervalTime to) {
UNIMPLEMENTED;
return -1;
}
static int16_t TransportLayerPoll(PRFileDesc *f, int16_t in_flags, int16_t *out_flags) {
UNIMPLEMENTED;
return -1;
}
static int32_t TransportLayerAcceptRead(PRFileDesc *sd, PRFileDesc **nd,
PRNetAddr **raddr,
void *buf, int32_t amount, PRIntervalTime t) {
UNIMPLEMENTED;
return -1;
}
static int32_t TransportLayerTransmitFile(PRFileDesc *sd, PRFileDesc *f,
const void *headers, int32_t hlen,
PRTransmitFileFlags flags, PRIntervalTime t) {
UNIMPLEMENTED;
return -1;
}
static PRStatus TransportLayerGetpeername(PRFileDesc *f, PRNetAddr *addr) {
// TODO: Modify to return unique names for each channel
// somehow, as opposed to always the same static address. The current
// implementation messes up the session cache, which is why it's off
// elsewhere
addr->inet.family = PR_AF_INET;
addr->inet.port = 0;
addr->inet.ip = 0;
return PR_SUCCESS;
}
static PRStatus TransportLayerGetsockname(PRFileDesc *f, PRNetAddr *addr) {
UNIMPLEMENTED;
return PR_FAILURE;
}
static PRStatus TransportLayerGetsockoption(PRFileDesc *f, PRSocketOptionData *opt) {
switch (opt->option) {
case PR_SockOpt_Nonblocking:
opt->value.non_blocking = PR_TRUE;
return PR_SUCCESS;
default:
UNIMPLEMENTED;
break;
}
return PR_FAILURE;
}
// Imitate setting socket options. These are mostly noops.
static PRStatus TransportLayerSetsockoption(PRFileDesc *f,
const PRSocketOptionData *opt) {
switch (opt->option) {
case PR_SockOpt_Nonblocking:
return PR_SUCCESS;
case PR_SockOpt_NoDelay:
return PR_SUCCESS;
default:
UNIMPLEMENTED;
break;
}
return PR_FAILURE;
}
static int32_t TransportLayerSendfile(PRFileDesc *out, PRSendFileData *in,
PRTransmitFileFlags flags, PRIntervalTime to) {
UNIMPLEMENTED;
return -1;
}
static PRStatus TransportLayerConnectContinue(PRFileDesc *f, int16_t flags) {
UNIMPLEMENTED;
return PR_FAILURE;
}
static int32_t TransportLayerReserved(PRFileDesc *f) {
UNIMPLEMENTED;
return -1;
}
static const struct PRIOMethods TransportLayerMethods = {
PR_DESC_LAYERED,
TransportLayerClose,
TransportLayerRead,
TransportLayerWrite,
TransportLayerAvailable,
TransportLayerAvailable64,
TransportLayerSync,
TransportLayerSeek,
TransportLayerSeek64,
TransportLayerFileInfo,
TransportLayerFileInfo64,
TransportLayerWritev,
TransportLayerConnect,
TransportLayerAccept,
TransportLayerBind,
TransportLayerListen,
TransportLayerShutdown,
TransportLayerRecv,
TransportLayerSend,
TransportLayerRecvfrom,
TransportLayerSendto,
TransportLayerPoll,
TransportLayerAcceptRead,
TransportLayerTransmitFile,
TransportLayerGetsockname,
TransportLayerGetpeername,
TransportLayerReserved,
TransportLayerReserved,
TransportLayerGetsockoption,
TransportLayerSetsockoption,
TransportLayerSendfile,
TransportLayerConnectContinue,
TransportLayerReserved,
TransportLayerReserved,
TransportLayerReserved,
TransportLayerReserved
};
TransportLayerDtls::~TransportLayerDtls() {
nspr_io_adapter_->SetEnabled(false);
if (timer_) {
timer_->Cancel();
}
}
nsresult TransportLayerDtls::InitInternal() {
// Get the transport service as an event target
nsresult rv;
target_ = do_GetService(NS_SOCKETTRANSPORTSERVICE_CONTRACTID, &rv);
if (NS_FAILED(rv)) {
MOZ_MTLOG(ML_ERROR, "Couldn't get socket transport service");
return rv;
}
timer_ = do_CreateInstance(NS_TIMER_CONTRACTID, &rv);
if (NS_FAILED(rv)) {
MOZ_MTLOG(ML_ERROR, "Couldn't get timer");
return rv;
}
return NS_OK;
}
void TransportLayerDtls::WasInserted() {
// Connect to the lower layers
if (!Setup()) {
TL_SET_STATE(TS_ERROR);
}
}
// Set the permitted and default ALPN identifiers.
// The default is here to allow for peers that don't want to negotiate ALPN
// in that case, the default string will be reported from GetNegotiatedAlpn().
// Setting the default to the empty string causes the transport layer to fail
// if ALPN is not negotiated.
// Note: we only support Unicode strings here, which are encoded into UTF-8,
// even though ALPN ostensibly allows arbitrary octet sequences.
nsresult TransportLayerDtls::SetAlpn(
const std::set<std::string>& alpn_allowed,
const std::string& alpn_default) {
alpn_allowed_ = alpn_allowed;
alpn_default_ = alpn_default;
return NS_OK;
}
nsresult TransportLayerDtls::SetVerificationAllowAll() {
// Defensive programming
if (verification_mode_ != VERIFY_UNSET)
return NS_ERROR_ALREADY_INITIALIZED;
verification_mode_ = VERIFY_ALLOW_ALL;
return NS_OK;
}
nsresult
TransportLayerDtls::SetVerificationDigest(const std::string digest_algorithm,
const unsigned char *digest_value,
size_t digest_len) {
// Defensive programming
if (verification_mode_ != VERIFY_UNSET &&
verification_mode_ != VERIFY_DIGEST) {
return NS_ERROR_ALREADY_INITIALIZED;
}
// Note that we do not sanity check these values for length.
// We merely ensure they will fit into the buffer.
// TODO: is there a Data construct we could use?
if (digest_len > kMaxDigestLength)
return NS_ERROR_INVALID_ARG;
digests_.push_back(new VerificationDigest(
digest_algorithm, digest_value, digest_len));
verification_mode_ = VERIFY_DIGEST;
return NS_OK;
}
// TODO: make sure this is called from STS. Otherwise
// we have thread safety issues
bool TransportLayerDtls::Setup() {
CheckThread();
SECStatus rv;
if (!downward_) {
MOZ_MTLOG(ML_ERROR, "DTLS layer with nothing below. This is useless");
return false;
}
nspr_io_adapter_ = MakeUnique<TransportLayerNSPRAdapter>(downward_);
if (!identity_) {
MOZ_MTLOG(ML_ERROR, "Can't start DTLS without an identity");
return false;
}
if (verification_mode_ == VERIFY_UNSET) {
MOZ_MTLOG(ML_ERROR,
"Can't start DTLS without specifying a verification mode");
return false;
}
if (transport_layer_identity == PR_INVALID_IO_LAYER) {
transport_layer_identity = PR_GetUniqueIdentity("nssstreamadapter");
}
ScopedPRFileDesc pr_fd(PR_CreateIOLayerStub(transport_layer_identity,
&TransportLayerMethods));
MOZ_ASSERT(pr_fd != nullptr);
if (!pr_fd)
return false;
pr_fd->secret = reinterpret_cast<PRFilePrivate *>(nspr_io_adapter_.get());
ScopedPRFileDesc ssl_fd(DTLS_ImportFD(nullptr, pr_fd));
MOZ_ASSERT(ssl_fd != nullptr); // This should never happen
if (!ssl_fd) {
return false;
}
pr_fd.forget(); // ownership transfered to ssl_fd;
if (role_ == CLIENT) {
MOZ_MTLOG(ML_INFO, "Setting up DTLS as client");
rv = SSL_GetClientAuthDataHook(ssl_fd, GetClientAuthDataHook,
this);
if (rv != SECSuccess) {
MOZ_MTLOG(ML_ERROR, "Couldn't set identity");
return false;
}
} else {
MOZ_MTLOG(ML_INFO, "Setting up DTLS as server");
// Server side
rv = SSL_ConfigSecureServer(ssl_fd, identity_->cert(),
identity_->privkey(),
identity_->auth_type());
if (rv != SECSuccess) {
MOZ_MTLOG(ML_ERROR, "Couldn't set identity");
return false;
}
// Insist on a certificate from the client
rv = SSL_OptionSet(ssl_fd, SSL_REQUEST_CERTIFICATE, PR_TRUE);
if (rv != SECSuccess) {
MOZ_MTLOG(ML_ERROR, "Couldn't request certificate");
return false;
}
rv = SSL_OptionSet(ssl_fd, SSL_REQUIRE_CERTIFICATE, PR_TRUE);
if (rv != SECSuccess) {
MOZ_MTLOG(ML_ERROR, "Couldn't require certificate");
return false;
}
}
// Require TLS 1.1 or 1.2. Perhaps some day in the future we will allow TLS
// 1.0 for stream modes.
SSLVersionRange version_range = {
SSL_LIBRARY_VERSION_TLS_1_1,
SSL_LIBRARY_VERSION_TLS_1_2
};
rv = SSL_VersionRangeSet(ssl_fd, &version_range);
if (rv != SECSuccess) {
MOZ_MTLOG(ML_ERROR, "Can't disable SSLv3");
return false;
}
rv = SSL_OptionSet(ssl_fd, SSL_ENABLE_SESSION_TICKETS, PR_FALSE);
if (rv != SECSuccess) {
MOZ_MTLOG(ML_ERROR, "Couldn't disable session tickets");
return false;
}
rv = SSL_OptionSet(ssl_fd, SSL_NO_CACHE, PR_TRUE);
if (rv != SECSuccess) {
MOZ_MTLOG(ML_ERROR, "Couldn't disable session caching");
return false;
}
rv = SSL_OptionSet(ssl_fd, SSL_ENABLE_DEFLATE, PR_FALSE);
if (rv != SECSuccess) {
MOZ_MTLOG(ML_ERROR, "Couldn't disable deflate");
return false;
}
rv = SSL_OptionSet(ssl_fd, SSL_ENABLE_RENEGOTIATION, SSL_RENEGOTIATE_NEVER);
if (rv != SECSuccess) {
MOZ_MTLOG(ML_ERROR, "Couldn't disable renegotiation");
return false;
}
rv = SSL_OptionSet(ssl_fd, SSL_ENABLE_FALSE_START, PR_FALSE);
if (rv != SECSuccess) {
MOZ_MTLOG(ML_ERROR, "Couldn't disable false start");
return false;
}
rv = SSL_OptionSet(ssl_fd, SSL_NO_LOCKS, PR_TRUE);
if (rv != SECSuccess) {
MOZ_MTLOG(ML_ERROR, "Couldn't disable locks");
return false;
}
rv = SSL_OptionSet(ssl_fd, SSL_REUSE_SERVER_ECDHE_KEY, PR_FALSE);
if (rv != SECSuccess) {
MOZ_MTLOG(ML_ERROR, "Couldn't disable ECDHE key reuse");
return false;
}
if (!SetupCipherSuites(ssl_fd)) {
return false;
}
// Certificate validation
rv = SSL_AuthCertificateHook(ssl_fd, AuthCertificateHook,
reinterpret_cast<void *>(this));
if (rv != SECSuccess) {
MOZ_MTLOG(ML_ERROR, "Couldn't set certificate validation hook");
return false;
}
if (!SetupAlpn(ssl_fd)) {
return false;
}
// Now start the handshake
rv = SSL_ResetHandshake(ssl_fd, role_ == SERVER ? PR_TRUE : PR_FALSE);
if (rv != SECSuccess) {
MOZ_MTLOG(ML_ERROR, "Couldn't reset handshake");
return false;
}
ssl_fd_ = ssl_fd.forget();
// Finally, get ready to receive data
downward_->SignalStateChange.connect(this, &TransportLayerDtls::StateChange);
downward_->SignalPacketReceived.connect(this, &TransportLayerDtls::PacketReceived);
if (downward_->state() == TS_OPEN) {
TL_SET_STATE(TS_CONNECTING);
Handshake();
}
return true;
}
bool TransportLayerDtls::SetupAlpn(PRFileDesc* ssl_fd) const {
if (alpn_allowed_.empty()) {
return true;
}
SECStatus rv = SSL_OptionSet(ssl_fd, SSL_ENABLE_NPN, PR_FALSE);
if (rv != SECSuccess) {
MOZ_MTLOG(ML_ERROR, "Couldn't disable NPN");
return false;
}
rv = SSL_OptionSet(ssl_fd, SSL_ENABLE_ALPN, PR_TRUE);
if (rv != SECSuccess) {
MOZ_MTLOG(ML_ERROR, "Couldn't enable ALPN");
return false;
}
unsigned char buf[MAX_ALPN_LENGTH];
size_t offset = 0;
for (auto tag = alpn_allowed_.begin();
tag != alpn_allowed_.end(); ++tag) {
if ((offset + 1 + tag->length()) >= sizeof(buf)) {
MOZ_MTLOG(ML_ERROR, "ALPN too long");
return false;
}
buf[offset++] = tag->length();
memcpy(buf + offset, tag->c_str(), tag->length());
offset += tag->length();
}
rv = SSL_SetNextProtoNego(ssl_fd, buf, offset);
if (rv != SECSuccess) {
MOZ_MTLOG(ML_ERROR, "Couldn't set ALPN string");
return false;
}
return true;
}
// Ciphers we need to enable. These are on by default in standard firefox
// builds, but can be disabled with prefs and they aren't on in our unit tests
// since that uses NSS default configuration.
//
// Only override prefs to comply with MUST statements in the security-arch doc.
// Anything outside this list is governed by the usual combination of policy
// and user preferences.
static const uint32_t EnabledCiphers[] = {
TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
};
// Disable all NSS suites modes without PFS or with old and rusty ciphersuites.
// Anything outside this list is governed by the usual combination of policy
// and user preferences.
static const uint32_t DisabledCiphers[] = {
TLS_ECDHE_ECDSA_WITH_3DES_EDE_CBC_SHA,
TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA,
TLS_ECDHE_ECDSA_WITH_RC4_128_SHA,
TLS_ECDHE_RSA_WITH_RC4_128_SHA,
TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA,
TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA,
TLS_DHE_DSS_WITH_RC4_128_SHA,
TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA,
TLS_ECDH_RSA_WITH_AES_128_CBC_SHA,
TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA,
TLS_ECDH_RSA_WITH_AES_256_CBC_SHA,
TLS_ECDH_ECDSA_WITH_3DES_EDE_CBC_SHA,
TLS_ECDH_RSA_WITH_3DES_EDE_CBC_SHA,
TLS_ECDH_ECDSA_WITH_RC4_128_SHA,
TLS_ECDH_RSA_WITH_RC4_128_SHA,
TLS_RSA_WITH_AES_128_GCM_SHA256,
TLS_RSA_WITH_AES_128_CBC_SHA,
TLS_RSA_WITH_AES_128_CBC_SHA256,
TLS_RSA_WITH_CAMELLIA_128_CBC_SHA,
TLS_RSA_WITH_AES_256_CBC_SHA,
TLS_RSA_WITH_AES_256_CBC_SHA256,
TLS_RSA_WITH_CAMELLIA_256_CBC_SHA,
TLS_RSA_WITH_SEED_CBC_SHA,
SSL_RSA_FIPS_WITH_3DES_EDE_CBC_SHA,
TLS_RSA_WITH_3DES_EDE_CBC_SHA,
TLS_RSA_WITH_RC4_128_SHA,
TLS_RSA_WITH_RC4_128_MD5,
TLS_DHE_RSA_WITH_DES_CBC_SHA,
TLS_DHE_DSS_WITH_DES_CBC_SHA,
SSL_RSA_FIPS_WITH_DES_CBC_SHA,
TLS_RSA_WITH_DES_CBC_SHA,
TLS_RSA_EXPORT1024_WITH_RC4_56_SHA,
TLS_RSA_EXPORT1024_WITH_DES_CBC_SHA,
TLS_RSA_EXPORT_WITH_RC4_40_MD5,
TLS_RSA_EXPORT_WITH_RC2_CBC_40_MD5,
TLS_ECDHE_ECDSA_WITH_NULL_SHA,
TLS_ECDHE_RSA_WITH_NULL_SHA,
TLS_ECDH_ECDSA_WITH_NULL_SHA,
TLS_ECDH_RSA_WITH_NULL_SHA,
TLS_RSA_WITH_NULL_SHA,
TLS_RSA_WITH_NULL_SHA256,
TLS_RSA_WITH_NULL_MD5,
};
bool TransportLayerDtls::SetupCipherSuites(PRFileDesc* ssl_fd) const {
SECStatus rv;
// Set the SRTP ciphers
if (!srtp_ciphers_.empty()) {
// Note: std::vector is guaranteed to contiguous
rv = SSL_SetSRTPCiphers(ssl_fd, &srtp_ciphers_[0], srtp_ciphers_.size());
if (rv != SECSuccess) {
MOZ_MTLOG(ML_ERROR, "Couldn't set SRTP cipher suite");
return false;
}
}
for (size_t i = 0; i < PR_ARRAY_SIZE(EnabledCiphers); ++i) {
MOZ_MTLOG(ML_DEBUG, LAYER_INFO << "Enabling: " << EnabledCiphers[i]);
rv = SSL_CipherPrefSet(ssl_fd, EnabledCiphers[i], PR_TRUE);
if (rv != SECSuccess) {
MOZ_MTLOG(ML_ERROR, LAYER_INFO <<
"Unable to enable suite: " << EnabledCiphers[i]);
return false;
}
}
for (size_t i = 0; i < PR_ARRAY_SIZE(DisabledCiphers); ++i) {
MOZ_MTLOG(ML_DEBUG, LAYER_INFO << "Disabling: " << DisabledCiphers[i]);
PRBool enabled = false;
rv = SSL_CipherPrefGet(ssl_fd, DisabledCiphers[i], &enabled);
if (rv != SECSuccess) {
MOZ_MTLOG(ML_NOTICE, LAYER_INFO <<
"Unable to check if suite is enabled: " << DisabledCiphers[i]);
return false;
}
if (enabled) {
rv = SSL_CipherPrefSet(ssl_fd, DisabledCiphers[i], PR_FALSE);
if (rv != SECSuccess) {
MOZ_MTLOG(ML_NOTICE, LAYER_INFO <<
"Unable to disable suite: " << DisabledCiphers[i]);
return false;
}
}
}
return true;
}
nsresult TransportLayerDtls::GetCipherSuite(uint16_t* cipherSuite) const {
CheckThread();
if (!cipherSuite) {
MOZ_MTLOG(ML_ERROR, LAYER_INFO << "GetCipherSuite passed a nullptr");
return NS_ERROR_NULL_POINTER;
}
if (state_ != TS_OPEN) {
return NS_ERROR_NOT_AVAILABLE;
}
SSLChannelInfo info;
SECStatus rv = SSL_GetChannelInfo(ssl_fd_, &info, sizeof(info));
if (rv != SECSuccess) {
MOZ_MTLOG(ML_NOTICE, LAYER_INFO << "GetCipherSuite can't get channel info");
return NS_ERROR_FAILURE;
}
*cipherSuite = info.cipherSuite;
return NS_OK;
}
void TransportLayerDtls::StateChange(TransportLayer *layer, State state) {
if (state <= state_) {
MOZ_MTLOG(ML_ERROR, "Lower layer state is going backwards from ours");
TL_SET_STATE(TS_ERROR);
return;
}
switch (state) {
case TS_NONE:
MOZ_ASSERT(false); // Can't happen
break;
case TS_INIT:
MOZ_MTLOG(ML_ERROR,
LAYER_INFO << "State change of lower layer to INIT forbidden");
TL_SET_STATE(TS_ERROR);
break;
case TS_CONNECTING:
MOZ_MTLOG(ML_ERROR, LAYER_INFO << "Lower layer is connecting.");
break;
case TS_OPEN:
MOZ_MTLOG(ML_ERROR,
LAYER_INFO << "Lower layer is now open; starting TLS");
// Async, since the ICE layer might need to send a STUN response, and we
// don't want the handshake to start until that is sent.
TL_SET_STATE(TS_CONNECTING);
timer_->Cancel();
timer_->SetTarget(target_);
timer_->InitWithFuncCallback(TimerCallback,
this,
0,
nsITimer::TYPE_ONE_SHOT);
break;
case TS_CLOSED:
MOZ_MTLOG(ML_ERROR, LAYER_INFO << "Lower layer is now closed");
TL_SET_STATE(TS_CLOSED);
break;
case TS_ERROR:
MOZ_MTLOG(ML_ERROR, LAYER_INFO << "Lower layer experienced an error");
TL_SET_STATE(TS_ERROR);
break;
}
}
void TransportLayerDtls::Handshake() {
// Clear the retransmit timer
timer_->Cancel();
SECStatus rv = SSL_ForceHandshake(ssl_fd_);
if (rv == SECSuccess) {
MOZ_MTLOG(ML_NOTICE,
LAYER_INFO << "****** SSL handshake completed ******");
if (!cert_ok_) {
MOZ_MTLOG(ML_ERROR, LAYER_INFO << "Certificate check never occurred");
TL_SET_STATE(TS_ERROR);
return;
}
if (!CheckAlpn()) {
// Despite connecting, the connection doesn't have a valid ALPN label.
// Forcibly close the connection so that the peer isn't left hanging
// (assuming the close_notify isn't dropped).
ssl_fd_ = nullptr;
TL_SET_STATE(TS_ERROR);
return;
}
TL_SET_STATE(TS_OPEN);
} else {
int32_t err = PR_GetError();
switch(err) {
case SSL_ERROR_RX_MALFORMED_HANDSHAKE:
MOZ_MTLOG(ML_ERROR, LAYER_INFO << "Malformed DTLS message; ignoring");
// If this were TLS (and not DTLS), this would be fatal, but
// here we're required to ignore bad messages, so fall through
MOZ_FALLTHROUGH;
case PR_WOULD_BLOCK_ERROR:
MOZ_MTLOG(ML_NOTICE, LAYER_INFO << "Handshake would have blocked");
PRIntervalTime timeout;
rv = DTLS_GetHandshakeTimeout(ssl_fd_, &timeout);
if (rv == SECSuccess) {
uint32_t timeout_ms = PR_IntervalToMilliseconds(timeout);
MOZ_MTLOG(ML_DEBUG,
LAYER_INFO << "Setting DTLS timeout to " << timeout_ms);
timer_->SetTarget(target_);
timer_->InitWithFuncCallback(TimerCallback,
this, timeout_ms,
nsITimer::TYPE_ONE_SHOT);
}
break;
default:
const char *err_msg = PR_ErrorToName(err);
MOZ_MTLOG(ML_ERROR, LAYER_INFO << "DTLS handshake error " << err << " ("
<< err_msg << ")");
TL_SET_STATE(TS_ERROR);
break;
}
}
}
// Checks if ALPN was negotiated correctly and returns false if it wasn't.
// After this returns successfully, alpn_ will be set to the negotiated
// protocol.
bool TransportLayerDtls::CheckAlpn() {
if (alpn_allowed_.empty()) {
return true;
}
SSLNextProtoState alpnState;
char chosenAlpn[MAX_ALPN_LENGTH];
unsigned int chosenAlpnLen;
SECStatus rv = SSL_GetNextProto(ssl_fd_, &alpnState,
reinterpret_cast<unsigned char*>(chosenAlpn),
&chosenAlpnLen, sizeof(chosenAlpn));
if (rv != SECSuccess) {
MOZ_MTLOG(ML_ERROR, LAYER_INFO << "ALPN error");
return false;
}
switch (alpnState) {
case SSL_NEXT_PROTO_SELECTED:
case SSL_NEXT_PROTO_NEGOTIATED:
break; // OK
case SSL_NEXT_PROTO_NO_SUPPORT:
MOZ_MTLOG(ML_NOTICE, LAYER_INFO << "ALPN not negotiated, "
<< (alpn_default_.empty() ? "failing" : "selecting default"));
alpn_ = alpn_default_;
return !alpn_.empty();
case SSL_NEXT_PROTO_NO_OVERLAP:
// This only happens if there is a custom NPN/ALPN callback installed and
// that callback doesn't properly handle ALPN.
MOZ_MTLOG(ML_ERROR, LAYER_INFO << "error in ALPN selection callback");
return false;
case SSL_NEXT_PROTO_EARLY_VALUE:
MOZ_CRASH("Unexpected 0-RTT ALPN value");
return false;
}
// Warning: NSS won't null terminate the ALPN string for us.
std::string chosen(chosenAlpn, chosenAlpnLen);
MOZ_MTLOG(ML_NOTICE, LAYER_INFO << "Selected ALPN string: " << chosen);
if (alpn_allowed_.find(chosen) == alpn_allowed_.end()) {
// Maybe our peer chose a protocol we didn't offer (when we are client), or
// something is seriously wrong.
std::ostringstream ss;
for (auto i = alpn_allowed_.begin(); i != alpn_allowed_.end(); ++i) {
ss << (i == alpn_allowed_.begin() ? " '" : ", '") << *i << "'";
}
MOZ_MTLOG(ML_ERROR, LAYER_INFO << "Bad ALPN string: '" << chosen
<< "'; permitted:" << ss.str());
return false;
}
alpn_ = chosen;
return true;
}
void TransportLayerDtls::PacketReceived(TransportLayer* layer,
const unsigned char *data,
size_t len) {
CheckThread();
MOZ_MTLOG(ML_DEBUG, LAYER_INFO << "PacketReceived(" << len << ")");
if (state_ != TS_CONNECTING && state_ != TS_OPEN) {
MOZ_MTLOG(ML_DEBUG,
LAYER_INFO << "Discarding packet in inappropriate state");
return;
}
nspr_io_adapter_->PacketReceived(data, len);
// If we're still connecting, try to handshake
if (state_ == TS_CONNECTING) {
Handshake();
}
// Now try a recv if we're open, since there might be data left
if (state_ == TS_OPEN) {
// nICEr uses a 9216 bytes buffer to allow support for jumbo frames
unsigned char buf[9216];
int32_t rv;
// One packet might contain several DTLS packets
do {
rv = PR_Recv(ssl_fd_, buf, sizeof(buf), 0, PR_INTERVAL_NO_WAIT);
if (rv > 0) {
// We have data
MOZ_MTLOG(ML_DEBUG, LAYER_INFO << "Read " << rv << " bytes from NSS");
SignalPacketReceived(this, buf, rv);
} else if (rv == 0) {
TL_SET_STATE(TS_CLOSED);
} else {
int32_t err = PR_GetError();
if (err == PR_WOULD_BLOCK_ERROR) {
// This gets ignored
MOZ_MTLOG(ML_DEBUG, LAYER_INFO << "Receive would have blocked");
} else {
MOZ_MTLOG(ML_NOTICE, LAYER_INFO << "NSS Error " << err);
TL_SET_STATE(TS_ERROR);