| /* |
| * Copyright 2004 The WebRTC project authors. All Rights Reserved. |
| * |
| * Use of this source code is governed by a BSD-style license |
| * that can be found in the LICENSE file in the root of the source |
| * tree. An additional intellectual property rights grant can be found |
| * in the file PATENTS. All contributing project authors may |
| * be found in the AUTHORS file in the root of the source tree. |
| */ |
| |
| #include "pc/srtp_session.h" |
| |
| #include <string.h> |
| |
| #include <cstdint> |
| #include <cstring> |
| #include <limits> |
| #include <vector> |
| |
| #include "media/base/fake_rtp.h" |
| #include "pc/test/srtp_test_util.h" |
| #include "rtc_base/buffer.h" |
| #include "rtc_base/byte_order.h" |
| #include "rtc_base/copy_on_write_buffer.h" |
| #include "rtc_base/ssl_stream_adapter.h" // For rtc::SRTP_* |
| #include "system_wrappers/include/metrics.h" |
| #include "test/gmock.h" |
| #include "test/gtest.h" |
| #include "test/scoped_key_value_config.h" |
| #include "third_party/libsrtp/include/srtp.h" |
| |
| using ::testing::ElementsAre; |
| using ::testing::Pair; |
| |
| namespace rtc { |
| |
| std::vector<int> kEncryptedHeaderExtensionIds; |
| |
| class SrtpSessionTest : public ::testing::Test { |
| public: |
| SrtpSessionTest() : s1_(field_trials_), s2_(field_trials_) { |
| webrtc::metrics::Reset(); |
| } |
| |
| protected: |
| virtual void SetUp() { |
| rtp_len_ = sizeof(kPcmuFrame); |
| rtcp_len_ = sizeof(kRtcpReport); |
| rtp_packet_.EnsureCapacity(rtp_len_ + 10); |
| rtp_packet_.SetData(kPcmuFrame, rtp_len_); |
| rtcp_packet_.EnsureCapacity(rtcp_len_ + 4 + 10); |
| rtcp_packet_.SetData(kRtcpReport, rtcp_len_); |
| } |
| void TestProtectRtp(int crypto_suite) { |
| EXPECT_TRUE(s1_.ProtectRtp(rtp_packet_)); |
| EXPECT_EQ(rtp_packet_.size(), rtp_len_ + rtp_auth_tag_len(crypto_suite)); |
| // Check that Protect changed the content (up to the original length). |
| EXPECT_NE(0, std::memcmp(kPcmuFrame, rtp_packet_.data(), rtp_len_)); |
| rtp_len_ = rtp_packet_.size(); |
| } |
| void TestProtectRtcp(int crypto_suite) { |
| EXPECT_TRUE(s1_.ProtectRtcp(rtcp_packet_)); |
| EXPECT_EQ(rtcp_packet_.size(), |
| rtcp_len_ + 4 + rtcp_auth_tag_len(crypto_suite)); |
| // Check that Protect changed the content (up to the original length). |
| EXPECT_NE(0, std::memcmp(kRtcpReport, rtcp_packet_.data(), rtcp_len_)); |
| rtcp_len_ = rtcp_packet_.size(); |
| } |
| void TestUnprotectRtp(int crypto_suite) { |
| EXPECT_TRUE(s2_.UnprotectRtp(rtp_packet_)); |
| EXPECT_EQ(rtp_packet_.size(), sizeof(kPcmuFrame)); |
| EXPECT_EQ(0, |
| std::memcmp(kPcmuFrame, rtp_packet_.data(), rtp_packet_.size())); |
| } |
| void TestUnprotectRtcp(int crypto_suite) { |
| EXPECT_TRUE(s2_.UnprotectRtcp(rtcp_packet_)); |
| EXPECT_EQ(rtcp_packet_.size(), sizeof(kRtcpReport)); |
| EXPECT_EQ( |
| 0, std::memcmp(kRtcpReport, rtcp_packet_.data(), rtcp_packet_.size())); |
| } |
| webrtc::test::ScopedKeyValueConfig field_trials_; |
| cricket::SrtpSession s1_; |
| cricket::SrtpSession s2_; |
| rtc::CopyOnWriteBuffer rtp_packet_; |
| rtc::CopyOnWriteBuffer rtcp_packet_; |
| size_t rtp_len_; |
| size_t rtcp_len_; |
| }; |
| |
| // Test that we can set up the session and keys properly. |
| TEST_F(SrtpSessionTest, TestGoodSetup) { |
| EXPECT_TRUE(s1_.SetSend(kSrtpAes128CmSha1_80, kTestKey1, |
| kEncryptedHeaderExtensionIds)); |
| EXPECT_TRUE(s2_.SetReceive(kSrtpAes128CmSha1_80, kTestKey1, |
| kEncryptedHeaderExtensionIds)); |
| } |
| |
| // Test that we can't change the keys once set. |
| TEST_F(SrtpSessionTest, TestBadSetup) { |
| EXPECT_TRUE(s1_.SetSend(kSrtpAes128CmSha1_80, kTestKey1, |
| kEncryptedHeaderExtensionIds)); |
| EXPECT_TRUE(s2_.SetReceive(kSrtpAes128CmSha1_80, kTestKey1, |
| kEncryptedHeaderExtensionIds)); |
| EXPECT_FALSE(s1_.SetSend(kSrtpAes128CmSha1_80, kTestKey2, |
| kEncryptedHeaderExtensionIds)); |
| EXPECT_FALSE(s2_.SetReceive(kSrtpAes128CmSha1_80, kTestKey2, |
| kEncryptedHeaderExtensionIds)); |
| } |
| |
| // Test that we fail keys of the wrong length. |
| TEST_F(SrtpSessionTest, TestKeysTooShort) { |
| EXPECT_FALSE(s1_.SetSend(kSrtpAes128CmSha1_80, |
| rtc::ZeroOnFreeBuffer<uint8_t>(kTestKey1.data(), 1), |
| kEncryptedHeaderExtensionIds)); |
| EXPECT_FALSE(s2_.SetReceive( |
| kSrtpAes128CmSha1_80, rtc::ZeroOnFreeBuffer<uint8_t>(kTestKey1.data(), 1), |
| kEncryptedHeaderExtensionIds)); |
| } |
| |
| // Test that we can encrypt and decrypt RTP/RTCP using AES_CM_128_HMAC_SHA1_80. |
| TEST_F(SrtpSessionTest, TestProtect_AES_CM_128_HMAC_SHA1_80) { |
| EXPECT_TRUE(s1_.SetSend(kSrtpAes128CmSha1_80, kTestKey1, |
| kEncryptedHeaderExtensionIds)); |
| EXPECT_TRUE(s2_.SetReceive(kSrtpAes128CmSha1_80, kTestKey1, |
| kEncryptedHeaderExtensionIds)); |
| TestProtectRtp(kSrtpAes128CmSha1_80); |
| TestProtectRtcp(kSrtpAes128CmSha1_80); |
| TestUnprotectRtp(kSrtpAes128CmSha1_80); |
| TestUnprotectRtcp(kSrtpAes128CmSha1_80); |
| } |
| |
| // Test that we can encrypt and decrypt RTP/RTCP using AES_CM_128_HMAC_SHA1_32. |
| TEST_F(SrtpSessionTest, TestProtect_AES_CM_128_HMAC_SHA1_32) { |
| EXPECT_TRUE(s1_.SetSend(kSrtpAes128CmSha1_32, kTestKey1, |
| kEncryptedHeaderExtensionIds)); |
| EXPECT_TRUE(s2_.SetReceive(kSrtpAes128CmSha1_32, kTestKey1, |
| kEncryptedHeaderExtensionIds)); |
| TestProtectRtp(kSrtpAes128CmSha1_32); |
| TestProtectRtcp(kSrtpAes128CmSha1_32); |
| TestUnprotectRtp(kSrtpAes128CmSha1_32); |
| TestUnprotectRtcp(kSrtpAes128CmSha1_32); |
| } |
| |
| TEST_F(SrtpSessionTest, TestGetSendStreamPacketIndex) { |
| EXPECT_TRUE(s1_.SetSend(kSrtpAes128CmSha1_32, kTestKey1, |
| kEncryptedHeaderExtensionIds)); |
| int64_t index; |
| EXPECT_TRUE(s1_.ProtectRtp(rtp_packet_, &index)); |
| // `index` will be shifted by 16. |
| int64_t be64_index = static_cast<int64_t>(NetworkToHost64(1 << 16)); |
| EXPECT_EQ(be64_index, index); |
| } |
| |
| // Test that we fail to unprotect if someone tampers with the RTP/RTCP paylaods. |
| TEST_F(SrtpSessionTest, TestTamperReject) { |
| EXPECT_TRUE(s1_.SetSend(kSrtpAes128CmSha1_80, kTestKey1, |
| kEncryptedHeaderExtensionIds)); |
| EXPECT_TRUE(s2_.SetReceive(kSrtpAes128CmSha1_80, kTestKey1, |
| kEncryptedHeaderExtensionIds)); |
| TestProtectRtp(kSrtpAes128CmSha1_80); |
| rtp_packet_.MutableData<uint8_t>()[0] = 0x12; |
| EXPECT_FALSE(s2_.UnprotectRtp(rtp_packet_)); |
| EXPECT_METRIC_THAT( |
| webrtc::metrics::Samples("WebRTC.PeerConnection.SrtpUnprotectError"), |
| ElementsAre(Pair(srtp_err_status_bad_param, 1))); |
| |
| TestProtectRtcp(kSrtpAes128CmSha1_80); |
| rtcp_packet_.MutableData<uint8_t>()[1] = 0x34; |
| EXPECT_FALSE(s2_.UnprotectRtcp(rtcp_packet_)); |
| EXPECT_METRIC_THAT( |
| webrtc::metrics::Samples("WebRTC.PeerConnection.SrtcpUnprotectError"), |
| ElementsAre(Pair(srtp_err_status_auth_fail, 1))); |
| } |
| |
| // Test that we fail to unprotect if the payloads are not authenticated. |
| TEST_F(SrtpSessionTest, TestUnencryptReject) { |
| EXPECT_TRUE(s1_.SetSend(kSrtpAes128CmSha1_80, kTestKey1, |
| kEncryptedHeaderExtensionIds)); |
| EXPECT_TRUE(s2_.SetReceive(kSrtpAes128CmSha1_80, kTestKey1, |
| kEncryptedHeaderExtensionIds)); |
| EXPECT_FALSE(s2_.UnprotectRtp(rtp_packet_)); |
| EXPECT_METRIC_THAT( |
| webrtc::metrics::Samples("WebRTC.PeerConnection.SrtpUnprotectError"), |
| ElementsAre(Pair(srtp_err_status_auth_fail, 1))); |
| EXPECT_FALSE(s2_.UnprotectRtcp(rtcp_packet_)); |
| EXPECT_METRIC_THAT( |
| webrtc::metrics::Samples("WebRTC.PeerConnection.SrtcpUnprotectError"), |
| ElementsAre(Pair(srtp_err_status_cant_check, 1))); |
| } |
| |
| // Test that we fail when using buffers that are too small. |
| TEST_F(SrtpSessionTest, TestBuffersTooSmall) { |
| EXPECT_TRUE(s1_.SetSend(kSrtpAes128CmSha1_80, kTestKey1, |
| kEncryptedHeaderExtensionIds)); |
| // This buffer does not have extra capacity which we treat as an error. |
| rtc::CopyOnWriteBuffer rtp_packet(rtp_packet_.data(), rtp_packet_.size(), |
| rtp_packet_.size()); |
| EXPECT_FALSE(s1_.ProtectRtp(rtp_packet)); |
| // This buffer does not have extra capacity which we treat as an error. |
| rtc::CopyOnWriteBuffer rtcp_packet(rtcp_packet_.data(), rtcp_packet_.size(), |
| rtcp_packet_.size()); |
| EXPECT_FALSE(s1_.ProtectRtcp(rtcp_packet)); |
| } |
| |
| TEST_F(SrtpSessionTest, TestReplay) { |
| static const uint16_t kMaxSeqnum = std::numeric_limits<uint16_t>::max() - 1; |
| static const uint16_t seqnum_big = 62275; |
| static const uint16_t seqnum_small = 10; |
| static const uint16_t replay_window = 1024; |
| |
| EXPECT_TRUE(s1_.SetSend(kSrtpAes128CmSha1_80, kTestKey1, |
| kEncryptedHeaderExtensionIds)); |
| EXPECT_TRUE(s2_.SetReceive(kSrtpAes128CmSha1_80, kTestKey1, |
| kEncryptedHeaderExtensionIds)); |
| |
| // Initial sequence number. |
| SetBE16(rtp_packet_.MutableData<uint8_t>() + 2, seqnum_big); |
| EXPECT_TRUE(s1_.ProtectRtp(rtp_packet_)); |
| rtp_packet_.SetData(kPcmuFrame, sizeof(kPcmuFrame)); |
| |
| // Replay within the 1024 window should succeed. |
| SetBE16(rtp_packet_.MutableData<uint8_t>() + 2, |
| seqnum_big - replay_window + 1); |
| EXPECT_TRUE(s1_.ProtectRtp(rtp_packet_)); |
| rtp_packet_.SetData(kPcmuFrame, sizeof(kPcmuFrame)); |
| |
| // Replay out side of the 1024 window should fail. |
| SetBE16(rtp_packet_.MutableData<uint8_t>() + 2, |
| seqnum_big - replay_window - 1); |
| EXPECT_FALSE(s1_.ProtectRtp(rtp_packet_)); |
| rtp_packet_.SetData(kPcmuFrame, sizeof(kPcmuFrame)); |
| |
| // Increment sequence number to a small number. |
| SetBE16(rtp_packet_.MutableData<uint8_t>() + 2, seqnum_small); |
| EXPECT_TRUE(s1_.ProtectRtp(rtp_packet_)); |
| |
| // Replay around 0 but out side of the 1024 window should fail. |
| SetBE16(rtp_packet_.MutableData<uint8_t>() + 2, |
| kMaxSeqnum + seqnum_small - replay_window - 1); |
| EXPECT_FALSE(s1_.ProtectRtp(rtp_packet_)); |
| rtp_packet_.SetData(kPcmuFrame, sizeof(kPcmuFrame)); |
| |
| // Replay around 0 but within the 1024 window should succeed. |
| for (uint16_t seqnum = 65000; seqnum < 65003; ++seqnum) { |
| SetBE16(rtp_packet_.MutableData<uint8_t>() + 2, seqnum); |
| EXPECT_TRUE(s1_.ProtectRtp(rtp_packet_)); |
| rtp_packet_.SetData(kPcmuFrame, sizeof(kPcmuFrame)); |
| } |
| |
| // Go back to normal sequence nubmer. |
| // NOTE: without the fix in libsrtp, this would fail. This is because |
| // without the fix, the loop above would keep incrementing local sequence |
| // number in libsrtp, eventually the new sequence number would go out side |
| // of the window. |
| SetBE16(rtp_packet_.MutableData<uint8_t>() + 2, seqnum_small + 1); |
| EXPECT_TRUE(s1_.ProtectRtp(rtp_packet_)); |
| } |
| |
| TEST_F(SrtpSessionTest, RemoveSsrc) { |
| EXPECT_TRUE(s1_.SetSend(kSrtpAes128CmSha1_80, kTestKey1, |
| kEncryptedHeaderExtensionIds)); |
| EXPECT_TRUE(s2_.SetReceive(kSrtpAes128CmSha1_80, kTestKey1, |
| kEncryptedHeaderExtensionIds)); |
| // Encrypt and decrypt the packet once. |
| EXPECT_TRUE(s1_.ProtectRtp(rtp_packet_)); |
| EXPECT_TRUE(s2_.UnprotectRtp(rtp_packet_)); |
| EXPECT_EQ(sizeof(kPcmuFrame), rtp_packet_.size()); |
| EXPECT_EQ(0, std::memcmp(kPcmuFrame, rtp_packet_.data(), rtp_packet_.size())); |
| |
| // Recreate the original packet and encrypt again. |
| rtp_packet_.SetData(kPcmuFrame, sizeof(kPcmuFrame)); |
| EXPECT_TRUE(s1_.ProtectRtp(rtp_packet_)); |
| // Attempting to decrypt will fail as a replay attack. |
| // (srtp_err_status_replay_fail) since the sequence number was already seen. |
| EXPECT_FALSE(s2_.UnprotectRtp(rtp_packet_)); |
| |
| // Remove the fake packet SSRC 1 from the session. |
| EXPECT_TRUE(s2_.RemoveSsrcFromSession(1)); |
| EXPECT_FALSE(s2_.RemoveSsrcFromSession(1)); |
| |
| // Since the SRTP state was discarded, this is no longer a replay attack. |
| EXPECT_TRUE(s2_.UnprotectRtp(rtp_packet_)); |
| EXPECT_EQ(sizeof(kPcmuFrame), rtp_packet_.size()); |
| EXPECT_EQ(0, std::memcmp(kPcmuFrame, rtp_packet_.data(), rtp_packet_.size())); |
| EXPECT_TRUE(s2_.RemoveSsrcFromSession(1)); |
| } |
| |
| TEST_F(SrtpSessionTest, ProtectUnprotectWrapAroundRocMismatch) { |
| // This unit tests demonstrates why you should be careful when |
| // choosing the initial RTP sequence number as there can be decryption |
| // failures when it wraps around with packet loss. Pick your starting |
| // sequence number in the lower half of the range for robustness reasons, |
| // see packet_sequencer.cc for the code doing so. |
| EXPECT_TRUE(s1_.SetSend(kSrtpAes128CmSha1_80, kTestKey1, |
| kEncryptedHeaderExtensionIds)); |
| EXPECT_TRUE(s2_.SetReceive(kSrtpAes128CmSha1_80, kTestKey1, |
| kEncryptedHeaderExtensionIds)); |
| // Buffers include enough room for the 10 byte SRTP auth tag so we can |
| // encrypt in place. |
| unsigned char kFrame1[] = { |
| // clang-format off |
| // PT=0, SN=65535, TS=0, SSRC=1 |
| 0x80, 0x00, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, |
| 0xBE, 0xEF, // data bytes |
| // Space for the SRTP auth tag |
| 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, |
| // clang-format on |
| }; |
| rtc::CopyOnWriteBuffer packet1(kFrame1, sizeof(kFrame1) - 10, |
| sizeof(kFrame1)); |
| unsigned char kFrame2[] = { |
| // clang-format off |
| // PT=0, SN=1, TS=0, SSRC=1 |
| 0x80, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, |
| 0xBE, 0xEF, // data bytes |
| // Space for the SRTP auth tag |
| 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, |
| // clang-format on |
| }; |
| rtc::CopyOnWriteBuffer packet2(kFrame2, sizeof(kFrame2) - 10, |
| sizeof(kFrame1)); |
| const unsigned char kPayload[] = {0xBE, 0xEF}; |
| |
| // Encrypt the frames in-order. There is a sequence number rollover from |
| // 65535 to 1 (skipping 0) and the second packet gets encrypted with a |
| // roll-over counter (ROC) of 1. See |
| // https://datatracker.ietf.org/doc/html/rfc3711#section-3.3.1 |
| EXPECT_TRUE(s1_.ProtectRtp(packet1)); |
| EXPECT_EQ(packet1.size(), 24u); |
| EXPECT_TRUE(s1_.ProtectRtp(packet2)); |
| EXPECT_EQ(packet2.size(), 24u); |
| |
| // If we decrypt frame 2 first it will have a ROC of 1 but the receiver |
| // does not know this is a rollover so will attempt with a ROC of 0. |
| // Note: If libsrtp is modified to attempt to decrypt with ROC=1 for this |
| // case, this test will fail and needs to be modified accordingly to unblock |
| // the roll. See https://issues.webrtc.org/353565743 for details. |
| EXPECT_FALSE(s2_.UnprotectRtp(packet2)); |
| // Decrypt frame 1. |
| EXPECT_TRUE(s2_.UnprotectRtp(packet1)); |
| ASSERT_EQ(packet1.size(), 14u); |
| EXPECT_EQ(0, std::memcmp(packet1.data() + 12, kPayload, sizeof(kPayload))); |
| // Now decrypt frame 2 again. A rollover is detected which increases |
| // the ROC to 1 so this succeeds. |
| EXPECT_TRUE(s2_.UnprotectRtp(packet2)); |
| ASSERT_EQ(packet2.size(), 14u); |
| EXPECT_EQ(0, std::memcmp(packet2.data() + 12, kPayload, sizeof(kPayload))); |
| } |
| |
| TEST_F(SrtpSessionTest, ProtectGetPacketIndex) { |
| EXPECT_TRUE(s1_.SetSend(kSrtpAes128CmSha1_80, kTestKey1, |
| kEncryptedHeaderExtensionIds)); |
| EXPECT_TRUE(s2_.SetReceive(kSrtpAes128CmSha1_80, kTestKey1, |
| kEncryptedHeaderExtensionIds)); |
| // Buffers include enough room for the 10 byte SRTP auth tag so we can |
| // encrypt in place. |
| unsigned char kFrame1[] = { |
| // clang-format off |
| // PT=0, SN=65535, TS=0, SSRC=1 |
| 0x80, 0x00, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, |
| 0xBE, 0xEF, // data bytes |
| // Space for the SRTP auth tag |
| 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, |
| // clang-format on |
| }; |
| rtc::CopyOnWriteBuffer packet1(kFrame1, sizeof(kFrame1) - 10, |
| sizeof(kFrame1)); |
| unsigned char kFrame2[] = { |
| // clang-format off |
| // PT=0, SN=1, TS=0, SSRC=1 |
| 0x80, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, |
| 0xBE, 0xEF, // data bytes |
| // Space for the SRTP auth tag |
| 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, |
| // clang-format on |
| }; |
| rtc::CopyOnWriteBuffer packet2(kFrame2, sizeof(kFrame2) - 10, |
| sizeof(kFrame1)); |
| |
| // Encrypt the frames in-order. There is a sequence number rollover from |
| // 65535 to 1 (skipping 0) and the second packet gets encrypted with a |
| // roll-over counter (ROC) of 1. See |
| // https://datatracker.ietf.org/doc/html/rfc3711#section-3.3.1 |
| int64_t index; |
| EXPECT_TRUE(s1_.ProtectRtp(packet1, &index)); |
| EXPECT_EQ(packet1.size(), 24u); |
| EXPECT_EQ(index, 0xffff00000000); // ntohl(65535 << 16) |
| EXPECT_TRUE(s1_.ProtectRtp(packet2, &index)); |
| EXPECT_EQ(packet2.size(), 24u); |
| EXPECT_EQ(index, 0x10001000000); // ntohl(65537 << 16) |
| } |
| |
| } // namespace rtc |
