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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/srtp/include/rtp.h" | 12 #include "third_party/libsrtp/include/rtp.h" |
13 #include "third_party/libsrtp/srtp/include/rtp_priv.h" | 13 #include "third_party/libsrtp/include/rtp_priv.h" |
14 #include "third_party/libsrtp/srtp/include/srtp.h" | 14 #include "third_party/libsrtp/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 crypto_policy_set_null_cipher_null_auth(&policy.rtp); | 38 srtp_crypto_policy_set_null_cipher_null_auth(&policy.rtp); |
39 crypto_policy_set_null_cipher_null_auth(&policy.rtcp); | 39 srtp_crypto_policy_set_null_cipher_null_auth(&policy.rtcp); |
40 break; | 40 break; |
41 case LibSrtpFuzzer::LIKE_WEBRTC: | 41 case LibSrtpFuzzer::LIKE_WEBRTC: |
42 crypto_policy_set_aes_cm_128_hmac_sha1_80(&policy.rtp); | 42 srtp_crypto_policy_set_aes_cm_128_hmac_sha1_80(&policy.rtp); |
43 crypto_policy_set_aes_cm_128_hmac_sha1_80(&policy.rtcp); | 43 srtp_crypto_policy_set_aes_cm_128_hmac_sha1_80(&policy.rtcp); |
| 44 break; |
44 case LibSrtpFuzzer::LIKE_WEBRTC_WITHOUT_AUTH: | 45 case LibSrtpFuzzer::LIKE_WEBRTC_WITHOUT_AUTH: |
45 crypto_policy_set_aes_cm_128_null_auth(&policy.rtp); | 46 srtp_crypto_policy_set_aes_cm_128_null_auth(&policy.rtp); |
46 crypto_policy_set_aes_cm_128_null_auth(&policy.rtcp); | 47 srtp_crypto_policy_set_aes_cm_128_null_auth(&policy.rtcp); |
47 break; | 48 break; |
48 case LibSrtpFuzzer::AES_GCM: | 49 case LibSrtpFuzzer::AES_GCM: |
49 // There was a security bug in the GCM mode in libsrtp 1.5.2. | 50 // There was a security bug in the GCM mode in libsrtp 1.5.2. |
50 crypto_policy_set_aes_gcm_128_8_auth(&policy.rtp); | 51 srtp_crypto_policy_set_aes_gcm_128_8_auth(&policy.rtp); |
51 crypto_policy_set_aes_gcm_128_8_auth(&policy.rtcp); | 52 srtp_crypto_policy_set_aes_gcm_128_8_auth(&policy.rtcp); |
52 break; | 53 break; |
53 } | 54 } |
54 | 55 |
55 memcpy(key, replacement_key, SRTP_MASTER_KEY_LEN); | 56 memcpy(key, replacement_key, SRTP_MASTER_KEY_LEN); |
56 return policy; | 57 return policy; |
57 }; | 58 }; |
58 | 59 |
59 Environment() { | 60 Environment() { |
60 srtp_init(); | 61 srtp_init(); |
61 | 62 |
62 memset(&policy, 0, sizeof(policy)); | 63 memset(&policy, 0, sizeof(policy)); |
63 policy.allow_repeat_tx = 1; | 64 policy.allow_repeat_tx = 1; |
64 policy.ekt = nullptr; | 65 policy.ekt = nullptr; |
65 policy.key = key; | 66 policy.key = key; |
66 policy.next = nullptr; | 67 policy.next = nullptr; |
67 policy.ssrc.type = ssrc_any_inbound; | 68 policy.ssrc.type = ssrc_any_inbound; |
68 policy.ssrc.value = 0xdeadbeef; | 69 policy.ssrc.value = 0xdeadbeef; |
69 policy.window_size = 1024; | 70 policy.window_size = 1024; |
70 } | 71 } |
71 | 72 |
72 private: | 73 private: |
73 srtp_policy_t policy; | 74 srtp_policy_t policy; |
74 unsigned char key[SRTP_MASTER_KEY_LEN] = {0}; | 75 unsigned char key[SRTP_MASTER_KEY_LEN] = {0}; |
75 | 76 |
76 static void crypto_policy_set_null_cipher_null_auth(crypto_policy_t* p) { | 77 static void srtp_crypto_policy_set_null_cipher_null_auth( |
77 p->cipher_type = NULL_CIPHER; | 78 srtp_crypto_policy_t* p) { |
| 79 p->cipher_type = SRTP_NULL_CIPHER; |
78 p->cipher_key_len = 0; | 80 p->cipher_key_len = 0; |
79 p->auth_type = NULL_AUTH; | 81 p->auth_type = SRTP_NULL_AUTH; |
80 p->auth_key_len = 0; | 82 p->auth_key_len = 0; |
81 p->auth_tag_len = 0; | 83 p->auth_tag_len = 0; |
82 p->sec_serv = sec_serv_none; | 84 p->sec_serv = sec_serv_none; |
83 }; | 85 }; |
84 }; | 86 }; |
85 | 87 |
86 size_t ReadLength(const uint8_t* data, size_t size) { | 88 size_t ReadLength(const uint8_t* data, size_t size) { |
87 // Read one byte of input and interpret it as a length to read from | 89 // Read one byte of input and interpret it as a length to read from |
88 // data. Don't return more bytes than are available. | 90 // data. Don't return more bytes than are available. |
89 size_t n = static_cast<size_t>(data[0]); | 91 size_t n = static_cast<size_t>(data[0]); |
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102 size -= 1; | 104 size -= 1; |
103 | 105 |
104 // Read some more bytes to use as a key. | 106 // Read some more bytes to use as a key. |
105 if (size <= SRTP_MASTER_KEY_LEN) | 107 if (size <= SRTP_MASTER_KEY_LEN) |
106 return 0; | 108 return 0; |
107 srtp_policy_t srtp_policy = env->GetCryptoPolicy(policy, data); | 109 srtp_policy_t srtp_policy = env->GetCryptoPolicy(policy, data); |
108 data += SRTP_MASTER_KEY_LEN; | 110 data += SRTP_MASTER_KEY_LEN; |
109 size -= SRTP_MASTER_KEY_LEN; | 111 size -= SRTP_MASTER_KEY_LEN; |
110 | 112 |
111 srtp_t session; | 113 srtp_t session; |
112 err_status_t error = srtp_create(&session, &srtp_policy); | 114 srtp_err_status_t error = srtp_create(&session, &srtp_policy); |
113 assert(error == err_status_ok); | 115 if (error != srtp_err_status_ok) { |
| 116 assert(false); |
| 117 return 0; |
| 118 } |
114 | 119 |
115 // Read one byte as a packet length N, then feed the next N bytes | 120 // Read one byte as a packet length N, then feed the next N bytes |
116 // into srtp_unprotect. Keep going until we run out of data. | 121 // into srtp_unprotect. Keep going until we run out of data. |
117 size_t packet_size; | 122 size_t packet_size; |
118 while (size > 0 && (packet_size = ReadLength(data, size)) > 0) { | 123 while (size > 0 && (packet_size = ReadLength(data, size)) > 0) { |
119 // One byte was used by ReadLength. | 124 // One byte was used by ReadLength. |
120 data++; | 125 data++; |
121 size--; | 126 size--; |
122 | 127 |
123 size_t header_size = std::min(sizeof(srtp_hdr_t), packet_size); | 128 size_t header_size = std::min(sizeof(srtp_hdr_t), packet_size); |
124 size_t body_size = packet_size - header_size; | 129 size_t body_size = packet_size - header_size; |
125 | 130 |
126 // We deliberately do not initialise this struct. MSAN will catch | 131 // We deliberately do not initialise this struct. MSAN will catch |
127 // usage of the uninitialised memory. | 132 // usage of the uninitialised memory. |
128 rtp_msg_t message; | 133 rtp_msg_t message; |
129 memcpy(&message.header, data, header_size); | 134 memcpy(&message.header, data, header_size); |
130 memcpy(&message.body, data + header_size, body_size); | 135 memcpy(&message.body, data + header_size, body_size); |
131 | 136 |
132 int out_len = static_cast<int>(packet_size); | 137 int out_len = static_cast<int>(packet_size); |
133 srtp_unprotect(session, &message, &out_len); | 138 srtp_unprotect(session, &message, &out_len); |
134 | 139 |
135 // |packet_size| bytes were used above. | 140 // |packet_size| bytes were used above. |
136 data += packet_size; | 141 data += packet_size; |
137 size -= packet_size; | 142 size -= packet_size; |
138 } | 143 } |
139 | 144 |
140 srtp_dealloc(session); | 145 srtp_dealloc(session); |
141 return 0; | 146 return 0; |
142 } | 147 } |
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