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dtls_utils: skip over DTLSCiphertext from DTLS 1.3

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where we can not extract any message_seq for piggybacking.

BUG=webrtc:367395350

Change-Id: I2e42d3b1304b5cf204c34bc8a136f17c363e011c
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/372881
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Jonas Oreland <jonaso@webrtc.org>
Commit-Queue: Jonas Oreland <jonaso@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#43731}
This commit is contained in:
Philipp Hancke 2025-01-13 08:53:05 -08:00 committed by WebRTC LUCI CQ
parent 153d558c18
commit 11edd41c04
2 changed files with 101 additions and 48 deletions
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44
p2p/dtls/dtls_utils.cc
View File

@ -20,8 +20,14 @@
namespace {
// https://datatracker.ietf.org/doc/html/rfc5246#appendix-A.1
const uint8_t kDtlsHandshakeRecord = 22;
const uint8_t kDtlsChangeCipherSpecRecord = 20;
const uint8_t kDtlsHandshakeRecord = 22;
// https://www.rfc-editor.org/rfc/rfc9147.html#section-4
const uint8_t kFixedBitmask = 0b00100000;
const uint8_t kConnectionBitmask = 0b00010000;
const uint8_t kSequenceNumberBitmask = 0b00001000;
const uint8_t kLengthPresentBitmask = 0b00000100;
} // namespace
namespace cricket {
@ -61,10 +67,38 @@ std::optional<std::vector<uint16_t>> GetDtlsHandshakeAcks(
uint8_t content_type;
uint64_t epoch_and_seq;
uint16_t len;
// Read content_type(1), skip version(2), read epoch+seq(2+6),
// read len(2)
if (!(record_buf.ReadUInt8(&content_type) && record_buf.Consume(2) &&
record_buf.ReadUInt64(&epoch_and_seq) &&
// Read content_type(1).
if (!record_buf.ReadUInt8(&content_type)) {
return std::nullopt;
}
// DTLS 1.3 rules:
// https://www.rfc-editor.org/rfc/rfc9147.html#section-4.1
if ((content_type & kFixedBitmask) == kFixedBitmask) {
// Interpret as DTLSCipherText:
// https://www.rfc-editor.org/rfc/rfc9147.html#appendix-A.1
// We assume no connection id is used so C must be 0.
if ((content_type & kConnectionBitmask) != 0) {
return std::nullopt;
}
// Skip sequence_number(1 or 2 bytes depending on S bit).
if (!record_buf.Consume((content_type & kSequenceNumberBitmask) ==
kSequenceNumberBitmask
? 2
: 1)) {
return std::nullopt;
}
// If the L bit is set, consume the 16 bit length field.
if ((content_type & kLengthPresentBitmask) == kLengthPresentBitmask) {
if (!(record_buf.ReadUInt16(&len) && record_buf.Consume(len))) {
return std::nullopt;
}
}
// DTLSCipherText is encrypted so we can not read it.
continue;
}
// Skip version(2), read epoch+seq(2+6), read len(2)
if (!(record_buf.Consume(2) && record_buf.ReadUInt64(&epoch_and_seq) &&
record_buf.ReadUInt16(&len) && record_buf.Length() >= len)) {
return std::nullopt;
}

105
p2p/dtls/dtls_utils_unittest.cc
View File

@ -128,50 +128,54 @@ TEST(DtlsUtils, GetDtlsHandshakeAcksPackedRecords) {
0x40, 0x29, 0x30, 0x58, 0x37, 0x26, 0x0d, 0xe8, 0xc0, 0x2b, 0x00, 0x00,
0x18, 0x00, 0x17, 0x00, 0x00, 0xff, 0x01, 0x00, 0x01, 0x00, 0x00, 0x0b,
0x00, 0x02, 0x01, 0x00, 0x00, 0x0e, 0x00, 0x05, 0x00, 0x02, 0x00, 0x01,
0x00, 0x16, 0xfe, 0xfd, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
0x01, 0x28, 0x0b, 0x00, 0x01, 0x1c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00,
0x01, 0x1c, 0x00, 0x01, 0x19, 0x00, 0x01, 0x16, 0x30, 0x82, 0x01, 0x12,
0x30, 0x81, 0xb8, 0xa0, 0x03, 0x02, 0x01, 0x02, 0x02, 0x08, 0x15, 0xc9,
0xcc, 0xd0, 0x55, 0x57, 0xa2, 0x32, 0x30, 0x0a, 0x06, 0x08, 0x2a, 0x86,
0x48, 0xce, 0x3d, 0x04, 0x03, 0x02, 0x30, 0x0f, 0x31, 0x0d, 0x30, 0x0b,
0x00, //
0x16, 0xfe, 0xfd, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x01,
0x28, 0x0b, 0x00, 0x01, 0x1c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x01,
0x1c, 0x00, 0x01, 0x19, 0x00, 0x01, 0x16, 0x30, 0x82, 0x01, 0x12, 0x30,
0x81, 0xb8, 0xa0, 0x03, 0x02, 0x01, 0x02, 0x02, 0x08, 0x15, 0xc9, 0xcc,
0xd0, 0x55, 0x57, 0xa2, 0x32, 0x30, 0x0a, 0x06, 0x08, 0x2a, 0x86, 0x48,
0xce, 0x3d, 0x04, 0x03, 0x02, 0x30, 0x0f, 0x31, 0x0d, 0x30, 0x0b, 0x06,
0x03, 0x55, 0x04, 0x03, 0x0c, 0x04, 0x74, 0x65, 0x73, 0x74, 0x30, 0x1e,
0x17, 0x0d, 0x32, 0x34, 0x31, 0x31, 0x30, 0x35, 0x32, 0x30, 0x35, 0x33,
0x34, 0x38, 0x5a, 0x17, 0x0d, 0x32, 0x34, 0x31, 0x32, 0x30, 0x36, 0x32,
0x30, 0x35, 0x33, 0x34, 0x38, 0x5a, 0x30, 0x0f, 0x31, 0x0d, 0x30, 0x0b,
0x06, 0x03, 0x55, 0x04, 0x03, 0x0c, 0x04, 0x74, 0x65, 0x73, 0x74, 0x30,
0x1e, 0x17, 0x0d, 0x32, 0x34, 0x31, 0x31, 0x30, 0x35, 0x32, 0x30, 0x35,
0x33, 0x34, 0x38, 0x5a, 0x17, 0x0d, 0x32, 0x34, 0x31, 0x32, 0x30, 0x36,
0x32, 0x30, 0x35, 0x33, 0x34, 0x38, 0x5a, 0x30, 0x0f, 0x31, 0x0d, 0x30,
0x0b, 0x06, 0x03, 0x55, 0x04, 0x03, 0x0c, 0x04, 0x74, 0x65, 0x73, 0x74,
0x30, 0x59, 0x30, 0x13, 0x06, 0x07, 0x2a, 0x86, 0x48, 0xce, 0x3d, 0x02,
0x01, 0x06, 0x08, 0x2a, 0x86, 0x48, 0xce, 0x3d, 0x03, 0x01, 0x07, 0x03,
0x42, 0x00, 0x04, 0x8f, 0x43, 0xeb, 0x7b, 0x88, 0x73, 0x4f, 0xe7, 0x69,
0x06, 0x81, 0xb6, 0xb9, 0xf3, 0xca, 0x73, 0x32, 0x69, 0xb2, 0xc5, 0xe6,
0x4e, 0xf0, 0x8c, 0xf4, 0xdd, 0x4e, 0x5b, 0xea, 0x06, 0x52, 0x94, 0x9a,
0x12, 0x77, 0x11, 0xde, 0xf9, 0x12, 0x9a, 0xeb, 0x3c, 0x7c, 0xe4, 0xcf,
0x58, 0x4c, 0x74, 0x44, 0x84, 0x0a, 0x84, 0xeb, 0xe6, 0xa4, 0xd5, 0xd3,
0x06, 0xca, 0x52, 0x15, 0x7e, 0xeb, 0x19, 0x30, 0x0a, 0x06, 0x08, 0x2a,
0x86, 0x48, 0xce, 0x3d, 0x04, 0x03, 0x02, 0x03, 0x49, 0x00, 0x30, 0x46,
0x02, 0x21, 0x00, 0xab, 0xc7, 0x06, 0x7e, 0x36, 0x9b, 0xad, 0xe0, 0x26,
0x61, 0x6b, 0x59, 0xa0, 0x1c, 0x70, 0x0c, 0xa6, 0xd3, 0xff, 0x8a, 0xc7,
0xba, 0xe4, 0x23, 0x0a, 0x8b, 0x22, 0x82, 0xcd, 0x5a, 0x5c, 0x56, 0x02,
0x21, 0x00, 0xc7, 0xe8, 0x57, 0x04, 0xb5, 0x44, 0x69, 0x42, 0xa2, 0xa2,
0x1e, 0xde, 0x7f, 0xc4, 0x44, 0x98, 0xa4, 0x5c, 0x84, 0x41, 0xa1, 0x31,
0x38, 0x3c, 0xe5, 0x4f, 0xf5, 0xc0, 0xa9, 0xa8, 0xbc, 0x16, 0x16, 0xfe,
0xfd, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x00, 0x7a, 0x0c,
0x00, 0x00, 0x6e, 0x00, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x6e, 0x03,
0x00, 0x1d, 0x20, 0x89, 0xb9, 0xeb, 0x39, 0x29, 0xa0, 0x31, 0x08, 0x9a,
0xbf, 0xc3, 0xc0, 0x20, 0x60, 0xbb, 0xea, 0x73, 0x19, 0xcf, 0x63, 0xe4,
0x5a, 0xa8, 0xa9, 0x56, 0x77, 0xe8, 0x81, 0x48, 0xae, 0x9f, 0x34, 0x04,
0x03, 0x00, 0x46, 0x30, 0x44, 0x02, 0x20, 0x23, 0x34, 0xc6, 0x39, 0x94,
0x84, 0xcc, 0x67, 0xeb, 0x44, 0xf9, 0xc3, 0x5c, 0x52, 0xb3, 0x99, 0x52,
0xf7, 0x4f, 0xff, 0x8b, 0xc5, 0xea, 0xb5, 0xd0, 0xf9, 0x36, 0xb3, 0xe6,
0xfc, 0x37, 0x50, 0x02, 0x20, 0x4c, 0xe2, 0x29, 0xf5, 0x4a, 0x4c, 0x7a,
0x01, 0x37, 0xce, 0xc1, 0xb0, 0x15, 0x23, 0xfd, 0xa5, 0xd9, 0xac, 0x75,
0xcb, 0x55, 0x56, 0x99, 0x97, 0xe3, 0x13, 0xbd, 0x5b, 0xcc, 0x5d, 0x0c,
0xa8, 0x16, 0xfe, 0xfd, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03,
0x00, 0x25, 0x0d, 0x00, 0x00, 0x19, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00,
0x00, 0x19, 0x02, 0x01, 0x40, 0x00, 0x12, 0x04, 0x03, 0x08, 0x04, 0x04,
0x01, 0x05, 0x03, 0x08, 0x05, 0x05, 0x01, 0x08, 0x06, 0x06, 0x01, 0x02,
0x01, 0x00, 0x00, 0x16, 0xfe, 0xfd, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x04, 0x00, 0x0c, 0x0e, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00};
0x59, 0x30, 0x13, 0x06, 0x07, 0x2a, 0x86, 0x48, 0xce, 0x3d, 0x02, 0x01,
0x06, 0x08, 0x2a, 0x86, 0x48, 0xce, 0x3d, 0x03, 0x01, 0x07, 0x03, 0x42,
0x00, 0x04, 0x8f, 0x43, 0xeb, 0x7b, 0x88, 0x73, 0x4f, 0xe7, 0x69, 0x06,
0x81, 0xb6, 0xb9, 0xf3, 0xca, 0x73, 0x32, 0x69, 0xb2, 0xc5, 0xe6, 0x4e,
0xf0, 0x8c, 0xf4, 0xdd, 0x4e, 0x5b, 0xea, 0x06, 0x52, 0x94, 0x9a, 0x12,
0x77, 0x11, 0xde, 0xf9, 0x12, 0x9a, 0xeb, 0x3c, 0x7c, 0xe4, 0xcf, 0x58,
0x4c, 0x74, 0x44, 0x84, 0x0a, 0x84, 0xeb, 0xe6, 0xa4, 0xd5, 0xd3, 0x06,
0xca, 0x52, 0x15, 0x7e, 0xeb, 0x19, 0x30, 0x0a, 0x06, 0x08, 0x2a, 0x86,
0x48, 0xce, 0x3d, 0x04, 0x03, 0x02, 0x03, 0x49, 0x00, 0x30, 0x46, 0x02,
0x21, 0x00, 0xab, 0xc7, 0x06, 0x7e, 0x36, 0x9b, 0xad, 0xe0, 0x26, 0x61,
0x6b, 0x59, 0xa0, 0x1c, 0x70, 0x0c, 0xa6, 0xd3, 0xff, 0x8a, 0xc7, 0xba,
0xe4, 0x23, 0x0a, 0x8b, 0x22, 0x82, 0xcd, 0x5a, 0x5c, 0x56, 0x02, 0x21,
0x00, 0xc7, 0xe8, 0x57, 0x04, 0xb5, 0x44, 0x69, 0x42, 0xa2, 0xa2, 0x1e,
0xde, 0x7f, 0xc4, 0x44, 0x98, 0xa4, 0x5c, 0x84, 0x41, 0xa1, 0x31, 0x38,
0x3c, 0xe5, 0x4f, 0xf5, 0xc0, 0xa9, 0xa8, 0xbc, 0x16, //
0x16, 0xfe, 0xfd, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x00,
0x7a, 0x0c, 0x00, 0x00, 0x6e, 0x00, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00,
0x6e, 0x03, 0x00, 0x1d, 0x20, 0x89, 0xb9, 0xeb, 0x39, 0x29, 0xa0, 0x31,
0x08, 0x9a, 0xbf, 0xc3, 0xc0, 0x20, 0x60, 0xbb, 0xea, 0x73, 0x19, 0xcf,
0x63, 0xe4, 0x5a, 0xa8, 0xa9, 0x56, 0x77, 0xe8, 0x81, 0x48, 0xae, 0x9f,
0x34, 0x04, 0x03, 0x00, 0x46, 0x30, 0x44, 0x02, 0x20, 0x23, 0x34, 0xc6,
0x39, 0x94, 0x84, 0xcc, 0x67, 0xeb, 0x44, 0xf9, 0xc3, 0x5c, 0x52, 0xb3,
0x99, 0x52, 0xf7, 0x4f, 0xff, 0x8b, 0xc5, 0xea, 0xb5, 0xd0, 0xf9, 0x36,
0xb3, 0xe6, 0xfc, 0x37, 0x50, 0x02, 0x20, 0x4c, 0xe2, 0x29, 0xf5, 0x4a,
0x4c, 0x7a, 0x01, 0x37, 0xce, 0xc1, 0xb0, 0x15, 0x23, 0xfd, 0xa5, 0xd9,
0xac, 0x75, 0xcb, 0x55, 0x56, 0x99, 0x97, 0xe3, 0x13, 0xbd, 0x5b, 0xcc,
0x5d, 0x0c,
0xa8, //
0x16, 0xfe, 0xfd, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0x00,
0x25, 0x0d, 0x00, 0x00, 0x19, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00,
0x19, 0x02, 0x01, 0x40, 0x00, 0x12, 0x04, 0x03, 0x08, 0x04, 0x04, 0x01,
0x05, 0x03, 0x08, 0x05, 0x05, 0x01, 0x08, 0x06, 0x06, 0x01, 0x02, 0x01,
0x00, 0x00, //
0x16, 0xfe, 0xfd, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00,
0x0c, 0x0e, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00};
std::optional<std::vector<uint16_t>> acks2 = GetDtlsHandshakeAcks(packet2);
ASSERT_TRUE(acks2);
@ -179,4 +183,19 @@ TEST(DtlsUtils, GetDtlsHandshakeAcksPackedRecords) {
EXPECT_THAT(*acks2, ::testing::ElementsAreArray({0, 1, 2, 3, 4}));
}
TEST(DtlsUtils, GetDtls13HandshakeAcks) {
// DTLS 1.3 encrypted data, captured with Wireshark. This is a single
// encrypted record which can not be parsed and should be skipped.
std::vector<uint8_t> packet = {
0x2f, 0x5b, 0x4c, 0x00, 0x23, 0x47, 0xab, 0xe7, 0x90, 0x96,
0xc0, 0xac, 0x2f, 0x25, 0x40, 0x35, 0x35, 0xa3, 0x81, 0x50,
0x0c, 0x38, 0x0a, 0xf6, 0xd4, 0xd5, 0x7d, 0xbe, 0x9a, 0xa3,
0xcb, 0xcb, 0x67, 0xb0, 0x77, 0x79, 0x8b, 0x48, 0x60, 0xf8,
};
std::optional<std::vector<uint16_t>> acks = GetDtlsHandshakeAcks(packet);
ASSERT_TRUE(acks);
EXPECT_EQ(acks->size(), 0u);
}
} // namespace cricket