diff options
Diffstat (limited to 'media/mtransport/transportlayerdtls.cpp')
| -rw-r--r-- | media/mtransport/transportlayerdtls.cpp | 1262 |
1 files changed, 1262 insertions, 0 deletions
diff --git a/media/mtransport/transportlayerdtls.cpp b/media/mtransport/transportlayerdtls.cpp new file mode 100644 index 000000000..55bf53f1b --- /dev/null +++ b/media/mtransport/transportlayerdtls.cpp @@ -0,0 +1,1262 @@ +/* -*- 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 "transportlayerdtls.h" + +#include <algorithm> +#include <queue> +#include <sstream> + +#include "dtlsidentity.h" +#include "keyhi.h" +#include "logging.h" +#include "mozilla/Move.h" +#include "mozilla/UniquePtr.h" +#include "mozilla/Unused.h" +#include "nsCOMPtr.h" +#include "nsComponentManagerUtils.h" +#include "nsComponentManagerUtils.h" +#include "nsIEventTarget.h" +#include "nsNetCID.h" +#include "nsServiceManagerUtils.h" +#include "ssl.h" +#include "sslerr.h" +#include "sslproto.h" +#include "transportflow.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; +} + +// These are the named groups that we will allow. +static const SSLNamedGroup NamedGroupPreferences[] = { + ssl_grp_ec_curve25519, + ssl_grp_ec_secp256r1, + ssl_grp_ec_secp384r1, + ssl_grp_ffdhe_2048, + ssl_grp_ffdhe_3072 +}; + +// 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"); + } + + UniquePRFileDesc 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()); + + UniquePRFileDesc ssl_fd(DTLS_ImportFD(nullptr, pr_fd.get())); + MOZ_ASSERT(ssl_fd != nullptr); // This should never happen + if (!ssl_fd) { + return false; + } + + Unused << pr_fd.release(); // ownership transfered to ssl_fd; + + if (role_ == CLIENT) { + MOZ_MTLOG(ML_INFO, "Setting up DTLS as client"); + rv = SSL_GetClientAuthDataHook(ssl_fd.get(), 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.get(), identity_->cert().get(), + identity_->privkey(), + identity_->auth_type()); + if (rv != SECSuccess) { + MOZ_MTLOG(ML_ERROR, "Couldn't set identity"); + return false; + } + + UniqueCERTCertList zero_certs(CERT_NewCertList()); + rv = SSL_SetTrustAnchors(ssl_fd.get(), zero_certs.get()); + if (rv != SECSuccess) { + MOZ_MTLOG(ML_ERROR, "Couldn't set trust anchors"); + return false; + } + + // Insist on a certificate from the client + rv = SSL_OptionSet(ssl_fd.get(), SSL_REQUEST_CERTIFICATE, PR_TRUE); + if (rv != SECSuccess) { + MOZ_MTLOG(ML_ERROR, "Couldn't request certificate"); + return false; + } + + rv = SSL_OptionSet(ssl_fd.get(), 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.get(), &version_range); + if (rv != SECSuccess) { + MOZ_MTLOG(ML_ERROR, "Can't disable SSLv3"); + return false; + } + + rv = SSL_OptionSet(ssl_fd.get(), 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.get(), SSL_NO_CACHE, PR_TRUE); + if (rv != SECSuccess) { + MOZ_MTLOG(ML_ERROR, "Couldn't disable session caching"); + return false; + } + + rv = SSL_OptionSet(ssl_fd.get(), SSL_ENABLE_DEFLATE, PR_FALSE); + if (rv != SECSuccess) { + MOZ_MTLOG(ML_ERROR, "Couldn't disable deflate"); + return false; + } + + rv = SSL_OptionSet(ssl_fd.get(), SSL_ENABLE_RENEGOTIATION, + SSL_RENEGOTIATE_NEVER); + if (rv != SECSuccess) { + MOZ_MTLOG(ML_ERROR, "Couldn't disable renegotiation"); + return false; + } + + rv = SSL_OptionSet(ssl_fd.get(), 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.get(), SSL_NO_LOCKS, PR_TRUE); + if (rv != SECSuccess) { + MOZ_MTLOG(ML_ERROR, "Couldn't disable locks"); + return false; + } + + rv = SSL_OptionSet(ssl_fd.get(), 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; + } + + rv = SSL_NamedGroupConfig(ssl_fd.get(), NamedGroupPreferences, + mozilla::ArrayLength(NamedGroupPreferences)); + if (rv != SECSuccess) { + MOZ_MTLOG(ML_ERROR, "Couldn't set named groups"); + return false; + } + + // Certificate validation + rv = SSL_AuthCertificateHook(ssl_fd.get(), 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.get(), role_ == SERVER ? PR_TRUE : PR_FALSE); + if (rv != SECSuccess) { + MOZ_MTLOG(ML_ERROR, "Couldn't reset handshake"); + return false; + } + ssl_fd_ = Move(ssl_fd); + + // 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(UniquePRFileDesc& ssl_fd) const { + if (alpn_allowed_.empty()) { + return true; + } + + SECStatus rv = SSL_OptionSet(ssl_fd.get(), SSL_ENABLE_NPN, PR_FALSE); + if (rv != SECSuccess) { + MOZ_MTLOG(ML_ERROR, "Couldn't disable NPN"); + return false; + } + + rv = SSL_OptionSet(ssl_fd.get(), 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.get(), 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[] = { + // Bug 1310061: disable all SHA384 ciphers until fixed + TLS_AES_256_GCM_SHA384, + TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, + TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, + TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384, + TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384, + TLS_DHE_RSA_WITH_AES_256_GCM_SHA384, + TLS_DHE_DSS_WITH_AES_256_GCM_SHA384, + + 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_256_GCM_SHA384, + 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, + 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, + TLS_RSA_WITH_DES_CBC_SHA, + + 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(UniquePRFileDesc& 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.get(), &srtp_ciphers_[0], + srtp_ciphers_.size()); + if (rv != SECSuccess) { + MOZ_MTLOG(ML_ERROR, "Couldn't set SRTP cipher suite"); + return false; + } + } + + for (const auto& cipher : EnabledCiphers) { + MOZ_MTLOG(ML_DEBUG, LAYER_INFO << "Enabling: " << cipher); + rv = SSL_CipherPrefSet(ssl_fd.get(), cipher, PR_TRUE); + if (rv != SECSuccess) { + MOZ_MTLOG(ML_ERROR, LAYER_INFO << + "Unable to enable suite: " << cipher); + return false; + } + } + + for (const auto& cipher : DisabledCiphers) { + MOZ_MTLOG(ML_DEBUG, LAYER_INFO << "Disabling: " << cipher); + + PRBool enabled = false; + rv = SSL_CipherPrefGet(ssl_fd.get(), cipher, &enabled); + if (rv != SECSuccess) { + MOZ_MTLOG(ML_NOTICE, LAYER_INFO << + "Unable to check if suite is enabled: " << cipher); + return false; + } + if (enabled) { + rv = SSL_CipherPrefSet(ssl_fd.get(), cipher, PR_FALSE); + if (rv != SECSuccess) { + MOZ_MTLOG(ML_NOTICE, LAYER_INFO << + "Unable to disable suite: " << cipher); + 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_.get(), &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_.get()); + + 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_.get(), &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_.get(), &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; + } + + // not DTLS per RFC 7983 + if (data[0] < 20 || data[0] > 63) { + 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_.get(), 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); + } + } + } while (rv > 0); + } +} + +TransportResult TransportLayerDtls::SendPacket(const unsigned char *data, + size_t len) { + CheckThread(); + if (state_ != TS_OPEN) { + MOZ_MTLOG(ML_ERROR, LAYER_INFO << "Can't call SendPacket() in state " + << state_); + return TE_ERROR; + } + + int32_t rv = PR_Send(ssl_fd_.get(), data, len, 0, PR_INTERVAL_NO_WAIT); + + if (rv > 0) { + // We have data + MOZ_MTLOG(ML_DEBUG, LAYER_INFO << "Wrote " << rv << " bytes to SSL Layer"); + return rv; + } + + if (rv == 0) { + TL_SET_STATE(TS_CLOSED); + return 0; + } + + int32_t err = PR_GetError(); + + if (err == PR_WOULD_BLOCK_ERROR) { + // This gets ignored + MOZ_MTLOG(ML_DEBUG, LAYER_INFO << "Send would have blocked"); + return TE_WOULDBLOCK; + } + + MOZ_MTLOG(ML_NOTICE, LAYER_INFO << "NSS Error " << err); + TL_SET_STATE(TS_ERROR); + return TE_ERROR; +} + +SECStatus TransportLayerDtls::GetClientAuthDataHook(void *arg, PRFileDesc *fd, + CERTDistNames *caNames, + CERTCertificate **pRetCert, + SECKEYPrivateKey **pRetKey) { + MOZ_MTLOG(ML_DEBUG, "Server requested client auth"); + + TransportLayerDtls *stream = reinterpret_cast<TransportLayerDtls *>(arg); + stream->CheckThread(); + + if (!stream->identity_) { + MOZ_MTLOG(ML_ERROR, "No identity available"); + PR_SetError(SSL_ERROR_NO_CERTIFICATE, 0); + return SECFailure; + } + + *pRetCert = CERT_DupCertificate(stream->identity_->cert().get()); + if (!*pRetCert) { + PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0); + return SECFailure; + } + + *pRetKey = SECKEY_CopyPrivateKey(stream->identity_->privkey()); + if (!*pRetKey) { + CERT_DestroyCertificate(*pRetCert); + *pRetCert = nullptr; + PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0); + return SECFailure; + } + + return SECSuccess; +} + +nsresult TransportLayerDtls::SetSrtpCiphers(std::vector<uint16_t> ciphers) { + // TODO: We should check these + srtp_ciphers_ = ciphers; + + return NS_OK; +} + +nsresult TransportLayerDtls::GetSrtpCipher(uint16_t *cipher) const { + CheckThread(); + if (state_ != TS_OPEN) { + return NS_ERROR_NOT_AVAILABLE; + } + SECStatus rv = SSL_GetSRTPCipher(ssl_fd_.get(), cipher); + if (rv != SECSuccess) { + MOZ_MTLOG(ML_DEBUG, "No SRTP cipher negotiated"); + return NS_ERROR_FAILURE; + } + + return NS_OK; +} + +nsresult TransportLayerDtls::ExportKeyingMaterial(const std::string& label, + bool use_context, + const std::string& context, + unsigned char *out, + unsigned int outlen) { + CheckThread(); + if (state_ != TS_OPEN) { + MOZ_ASSERT(false, "Transport must be open for ExportKeyingMaterial"); + return NS_ERROR_NOT_AVAILABLE; + } + SECStatus rv = SSL_ExportKeyingMaterial(ssl_fd_.get(), + label.c_str(), + label.size(), + use_context, + reinterpret_cast<const unsigned char *>( + context.c_str()), + context.size(), + out, + outlen); + if (rv != SECSuccess) { + MOZ_MTLOG(ML_ERROR, "Couldn't export SSL keying material"); + return NS_ERROR_FAILURE; + } + + return NS_OK; +} + +SECStatus TransportLayerDtls::AuthCertificateHook(void *arg, + PRFileDesc *fd, + PRBool checksig, + PRBool isServer) { + TransportLayerDtls *stream = reinterpret_cast<TransportLayerDtls *>(arg); + stream->CheckThread(); + return stream->AuthCertificateHook(fd, checksig, isServer); +} + +SECStatus +TransportLayerDtls::CheckDigest(const RefPtr<VerificationDigest>& digest, + UniqueCERTCertificate& peer_cert) const { + unsigned char computed_digest[kMaxDigestLength]; + size_t computed_digest_len; + + MOZ_MTLOG(ML_DEBUG, LAYER_INFO << "Checking digest, algorithm=" + << digest->algorithm_); + nsresult res = + DtlsIdentity::ComputeFingerprint(peer_cert, + digest->algorithm_, + computed_digest, + sizeof(computed_digest), + &computed_digest_len); + if (NS_FAILED(res)) { + MOZ_MTLOG(ML_ERROR, "Could not compute peer fingerprint for digest " << + digest->algorithm_); + // Go to end + PR_SetError(SSL_ERROR_BAD_CERTIFICATE, 0); + return SECFailure; + } + + if (computed_digest_len != digest->len_) { + MOZ_MTLOG(ML_ERROR, "Digest is wrong length " << digest->len_ << + " should be " << computed_digest_len << " for algorithm " << + digest->algorithm_); + PR_SetError(SSL_ERROR_BAD_CERTIFICATE, 0); + return SECFailure; + } + + if (memcmp(digest->value_, computed_digest, computed_digest_len) != 0) { + MOZ_MTLOG(ML_ERROR, "Digest does not match"); + PR_SetError(SSL_ERROR_BAD_CERTIFICATE, 0); + return SECFailure; + } + + return SECSuccess; +} + + +SECStatus TransportLayerDtls::AuthCertificateHook(PRFileDesc *fd, + PRBool checksig, + PRBool isServer) { + CheckThread(); + UniqueCERTCertificate peer_cert(SSL_PeerCertificate(fd)); + + // We are not set up to take this being called multiple + // times. Change this if we ever add renegotiation. + MOZ_ASSERT(!auth_hook_called_); + if (auth_hook_called_) { + PR_SetError(PR_UNKNOWN_ERROR, 0); + return SECFailure; + } + auth_hook_called_ = true; + + MOZ_ASSERT(verification_mode_ != VERIFY_UNSET); + + switch (verification_mode_) { + case VERIFY_UNSET: + // Break out to error exit + PR_SetError(PR_UNKNOWN_ERROR, 0); + break; + + case VERIFY_ALLOW_ALL: + cert_ok_ = true; + return SECSuccess; + + case VERIFY_DIGEST: + { + MOZ_ASSERT(digests_.size() != 0); + // Check all the provided digests + + // Checking functions call PR_SetError() + SECStatus rv = SECFailure; + for (size_t i = 0; i < digests_.size(); i++) { + RefPtr<VerificationDigest> digest = digests_[i]; + rv = CheckDigest(digest, peer_cert); + + // Matches a digest, we are good to go + if (rv == SECSuccess) { + cert_ok_ = true; + return SECSuccess; + } + } + } + break; + default: + MOZ_CRASH(); // Can't happen + } + + return SECFailure; +} + +void TransportLayerDtls::TimerCallback(nsITimer *timer, void *arg) { + TransportLayerDtls *dtls = reinterpret_cast<TransportLayerDtls *>(arg); + + MOZ_MTLOG(ML_DEBUG, "DTLS timer expired"); + + dtls->Handshake(); +} + +} // close namespace |