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| 1 // Copyright 2016 The Chromium Authors. All rights reserved. | 1 // Copyright 2016 The Chromium Authors. All rights reserved. |
| 2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
| 4 | 4 |
| 5 #include <assert.h> | 5 #include <assert.h> |
| 6 #include <stddef.h> | 6 #include <stddef.h> |
| 7 #include <stdint.h> | 7 #include <stdint.h> |
| 8 | 8 |
| 9 #include <algorithm> | 9 #include <algorithm> |
| 10 #include <vector> | 10 #include <vector> |
| 11 | 11 |
| 12 #include "third_party/libsrtp/include/rtp.h" | 12 #include "third_party/libsrtp/srtp/include/rtp.h" |
| 13 #include "third_party/libsrtp/include/rtp_priv.h" | 13 #include "third_party/libsrtp/srtp/include/rtp_priv.h" |
| 14 #include "third_party/libsrtp/include/srtp.h" | 14 #include "third_party/libsrtp/srtp/include/srtp.h" |
| 15 | 15 |
| 16 // TODO(katrielc) Also test the authenticated path, which is what | 16 // TODO(katrielc) Also test the authenticated path, which is what |
| 17 // WebRTC uses. This is nontrivial because you need to bypass the MAC | 17 // WebRTC uses. This is nontrivial because you need to bypass the MAC |
| 18 // check. Two options: add a UNSAFE_FUZZER_MODE flag to libsrtp (or | 18 // check. Two options: add a UNSAFE_FUZZER_MODE flag to libsrtp (or |
| 19 // the chromium fork of it), or compute the HMAC of whatever gibberish | 19 // the chromium fork of it), or compute the HMAC of whatever gibberish |
| 20 // the fuzzer produces and write it into the packet manually. | 20 // the fuzzer produces and write it into the packet manually. |
| 21 | 21 |
| 22 namespace LibSrtpFuzzer { | 22 namespace LibSrtpFuzzer { |
| 23 enum CryptoPolicy { | 23 enum CryptoPolicy { |
| 24 NONE, | 24 NONE, |
| 25 LIKE_WEBRTC, | 25 LIKE_WEBRTC, |
| 26 LIKE_WEBRTC_WITHOUT_AUTH, | 26 LIKE_WEBRTC_WITHOUT_AUTH, |
| 27 AES_GCM, | 27 AES_GCM, |
| 28 NUMBER_OF_POLICIES, | 28 NUMBER_OF_POLICIES, |
| 29 }; | 29 }; |
| 30 } | 30 } |
| 31 | 31 |
| 32 struct Environment { | 32 struct Environment { |
| 33 srtp_policy_t GetCryptoPolicy(LibSrtpFuzzer::CryptoPolicy crypto_policy, | 33 srtp_policy_t GetCryptoPolicy(LibSrtpFuzzer::CryptoPolicy crypto_policy, |
| 34 const unsigned char* replacement_key) { | 34 const unsigned char* replacement_key) { |
| 35 switch (crypto_policy) { | 35 switch (crypto_policy) { |
| 36 case LibSrtpFuzzer::NUMBER_OF_POLICIES: | 36 case LibSrtpFuzzer::NUMBER_OF_POLICIES: |
| 37 case LibSrtpFuzzer::NONE: | 37 case LibSrtpFuzzer::NONE: |
| 38 srtp_crypto_policy_set_null_cipher_null_auth(&policy.rtp); | 38 crypto_policy_set_null_cipher_null_auth(&policy.rtp); |
| 39 srtp_crypto_policy_set_null_cipher_null_auth(&policy.rtcp); | 39 crypto_policy_set_null_cipher_null_auth(&policy.rtcp); |
| 40 break; | 40 break; |
| 41 case LibSrtpFuzzer::LIKE_WEBRTC: | 41 case LibSrtpFuzzer::LIKE_WEBRTC: |
| 42 srtp_crypto_policy_set_aes_cm_128_hmac_sha1_80(&policy.rtp); | 42 crypto_policy_set_aes_cm_128_hmac_sha1_80(&policy.rtp); |
| 43 srtp_crypto_policy_set_aes_cm_128_hmac_sha1_80(&policy.rtcp); | 43 crypto_policy_set_aes_cm_128_hmac_sha1_80(&policy.rtcp); |
| 44 break; | |
| 45 case LibSrtpFuzzer::LIKE_WEBRTC_WITHOUT_AUTH: | 44 case LibSrtpFuzzer::LIKE_WEBRTC_WITHOUT_AUTH: |
| 46 srtp_crypto_policy_set_aes_cm_128_null_auth(&policy.rtp); | 45 crypto_policy_set_aes_cm_128_null_auth(&policy.rtp); |
| 47 srtp_crypto_policy_set_aes_cm_128_null_auth(&policy.rtcp); | 46 crypto_policy_set_aes_cm_128_null_auth(&policy.rtcp); |
| 48 break; | 47 break; |
| 49 case LibSrtpFuzzer::AES_GCM: | 48 case LibSrtpFuzzer::AES_GCM: |
| 50 // There was a security bug in the GCM mode in libsrtp 1.5.2. | 49 // There was a security bug in the GCM mode in libsrtp 1.5.2. |
| 51 srtp_crypto_policy_set_aes_gcm_128_8_auth(&policy.rtp); | 50 crypto_policy_set_aes_gcm_128_8_auth(&policy.rtp); |
| 52 srtp_crypto_policy_set_aes_gcm_128_8_auth(&policy.rtcp); | 51 crypto_policy_set_aes_gcm_128_8_auth(&policy.rtcp); |
| 53 break; | 52 break; |
| 54 } | 53 } |
| 55 | 54 |
| 56 memcpy(key, replacement_key, SRTP_MASTER_KEY_LEN); | 55 memcpy(key, replacement_key, SRTP_MASTER_KEY_LEN); |
| 57 return policy; | 56 return policy; |
| 58 }; | 57 }; |
| 59 | 58 |
| 60 Environment() { | 59 Environment() { |
| 61 srtp_init(); | 60 srtp_init(); |
| 62 | 61 |
| 63 memset(&policy, 0, sizeof(policy)); | 62 memset(&policy, 0, sizeof(policy)); |
| 64 policy.allow_repeat_tx = 1; | 63 policy.allow_repeat_tx = 1; |
| 65 policy.ekt = nullptr; | 64 policy.ekt = nullptr; |
| 66 policy.key = key; | 65 policy.key = key; |
| 67 policy.next = nullptr; | 66 policy.next = nullptr; |
| 68 policy.ssrc.type = ssrc_any_inbound; | 67 policy.ssrc.type = ssrc_any_inbound; |
| 69 policy.ssrc.value = 0xdeadbeef; | 68 policy.ssrc.value = 0xdeadbeef; |
| 70 policy.window_size = 1024; | 69 policy.window_size = 1024; |
| 71 } | 70 } |
| 72 | 71 |
| 73 private: | 72 private: |
| 74 srtp_policy_t policy; | 73 srtp_policy_t policy; |
| 75 unsigned char key[SRTP_MASTER_KEY_LEN] = {0}; | 74 unsigned char key[SRTP_MASTER_KEY_LEN] = {0}; |
| 76 | 75 |
| 77 static void srtp_crypto_policy_set_null_cipher_null_auth( | 76 static void crypto_policy_set_null_cipher_null_auth(crypto_policy_t* p) { |
| 78 srtp_crypto_policy_t* p) { | 77 p->cipher_type = NULL_CIPHER; |
| 79 p->cipher_type = SRTP_NULL_CIPHER; | |
| 80 p->cipher_key_len = 0; | 78 p->cipher_key_len = 0; |
| 81 p->auth_type = SRTP_NULL_AUTH; | 79 p->auth_type = NULL_AUTH; |
| 82 p->auth_key_len = 0; | 80 p->auth_key_len = 0; |
| 83 p->auth_tag_len = 0; | 81 p->auth_tag_len = 0; |
| 84 p->sec_serv = sec_serv_none; | 82 p->sec_serv = sec_serv_none; |
| 85 }; | 83 }; |
| 86 }; | 84 }; |
| 87 | 85 |
| 88 size_t ReadLength(const uint8_t* data, size_t size) { | 86 size_t ReadLength(const uint8_t* data, size_t size) { |
| 89 // Read one byte of input and interpret it as a length to read from | 87 // Read one byte of input and interpret it as a length to read from |
| 90 // data. Don't return more bytes than are available. | 88 // data. Don't return more bytes than are available. |
| 91 size_t n = static_cast<size_t>(data[0]); | 89 size_t n = static_cast<size_t>(data[0]); |
| (...skipping 12 matching lines...) Expand all Loading... |
| 104 size -= 1; | 102 size -= 1; |
| 105 | 103 |
| 106 // Read some more bytes to use as a key. | 104 // Read some more bytes to use as a key. |
| 107 if (size <= SRTP_MASTER_KEY_LEN) | 105 if (size <= SRTP_MASTER_KEY_LEN) |
| 108 return 0; | 106 return 0; |
| 109 srtp_policy_t srtp_policy = env->GetCryptoPolicy(policy, data); | 107 srtp_policy_t srtp_policy = env->GetCryptoPolicy(policy, data); |
| 110 data += SRTP_MASTER_KEY_LEN; | 108 data += SRTP_MASTER_KEY_LEN; |
| 111 size -= SRTP_MASTER_KEY_LEN; | 109 size -= SRTP_MASTER_KEY_LEN; |
| 112 | 110 |
| 113 srtp_t session; | 111 srtp_t session; |
| 114 srtp_err_status_t error = srtp_create(&session, &srtp_policy); | 112 err_status_t error = srtp_create(&session, &srtp_policy); |
| 115 if (error != srtp_err_status_ok) { | 113 assert(error == err_status_ok); |
| 116 assert(false); | |
| 117 return 0; | |
| 118 } | |
| 119 | 114 |
| 120 // Read one byte as a packet length N, then feed the next N bytes | 115 // Read one byte as a packet length N, then feed the next N bytes |
| 121 // into srtp_unprotect. Keep going until we run out of data. | 116 // into srtp_unprotect. Keep going until we run out of data. |
| 122 size_t packet_size; | 117 size_t packet_size; |
| 123 while (size > 0 && (packet_size = ReadLength(data, size)) > 0) { | 118 while (size > 0 && (packet_size = ReadLength(data, size)) > 0) { |
| 124 // One byte was used by ReadLength. | 119 // One byte was used by ReadLength. |
| 125 data++; | 120 data++; |
| 126 size--; | 121 size--; |
| 127 | 122 |
| 128 size_t header_size = std::min(sizeof(srtp_hdr_t), packet_size); | 123 size_t header_size = std::min(sizeof(srtp_hdr_t), packet_size); |
| 129 size_t body_size = packet_size - header_size; | 124 size_t body_size = packet_size - header_size; |
| 130 | 125 |
| 131 // We deliberately do not initialise this struct. MSAN will catch | 126 // We deliberately do not initialise this struct. MSAN will catch |
| 132 // usage of the uninitialised memory. | 127 // usage of the uninitialised memory. |
| 133 rtp_msg_t message; | 128 rtp_msg_t message; |
| 134 memcpy(&message.header, data, header_size); | 129 memcpy(&message.header, data, header_size); |
| 135 memcpy(&message.body, data + header_size, body_size); | 130 memcpy(&message.body, data + header_size, body_size); |
| 136 | 131 |
| 137 int out_len = static_cast<int>(packet_size); | 132 int out_len = static_cast<int>(packet_size); |
| 138 srtp_unprotect(session, &message, &out_len); | 133 srtp_unprotect(session, &message, &out_len); |
| 139 | 134 |
| 140 // |packet_size| bytes were used above. | 135 // |packet_size| bytes were used above. |
| 141 data += packet_size; | 136 data += packet_size; |
| 142 size -= packet_size; | 137 size -= packet_size; |
| 143 } | 138 } |
| 144 | 139 |
| 145 srtp_dealloc(session); | 140 srtp_dealloc(session); |
| 146 return 0; | 141 return 0; |
| 147 } | 142 } |
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