/src/curl/lib/vtls/keylog.c
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1 | | /*************************************************************************** |
2 | | * _ _ ____ _ |
3 | | * Project ___| | | | _ \| | |
4 | | * / __| | | | |_) | | |
5 | | * | (__| |_| | _ <| |___ |
6 | | * \___|\___/|_| \_\_____| |
7 | | * |
8 | | * Copyright (C) 1998 - 2022, Daniel Stenberg, <daniel@haxx.se>, et al. |
9 | | * |
10 | | * This software is licensed as described in the file COPYING, which |
11 | | * you should have received as part of this distribution. The terms |
12 | | * are also available at https://curl.se/docs/copyright.html. |
13 | | * |
14 | | * You may opt to use, copy, modify, merge, publish, distribute and/or sell |
15 | | * copies of the Software, and permit persons to whom the Software is |
16 | | * furnished to do so, under the terms of the COPYING file. |
17 | | * |
18 | | * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY |
19 | | * KIND, either express or implied. |
20 | | * |
21 | | * SPDX-License-Identifier: curl |
22 | | * |
23 | | ***************************************************************************/ |
24 | | #include "curl_setup.h" |
25 | | |
26 | | #include "keylog.h" |
27 | | #include <curl/curl.h> |
28 | | |
29 | | /* The last #include files should be: */ |
30 | | #include "curl_memory.h" |
31 | | #include "memdebug.h" |
32 | | |
33 | 0 | #define KEYLOG_LABEL_MAXLEN (sizeof("CLIENT_HANDSHAKE_TRAFFIC_SECRET") - 1) |
34 | | |
35 | 0 | #define CLIENT_RANDOM_SIZE 32 |
36 | | |
37 | | /* |
38 | | * The master secret in TLS 1.2 and before is always 48 bytes. In TLS 1.3, the |
39 | | * secret size depends on the cipher suite's hash function which is 32 bytes |
40 | | * for SHA-256 and 48 bytes for SHA-384. |
41 | | */ |
42 | 0 | #define SECRET_MAXLEN 48 |
43 | | |
44 | | |
45 | | /* The fp for the open SSLKEYLOGFILE, or NULL if not open */ |
46 | | static FILE *keylog_file_fp; |
47 | | |
48 | | void |
49 | | Curl_tls_keylog_open(void) |
50 | 19 | { |
51 | 19 | char *keylog_file_name; |
52 | | |
53 | 19 | if(!keylog_file_fp) { |
54 | 19 | keylog_file_name = curl_getenv("SSLKEYLOGFILE"); |
55 | 19 | if(keylog_file_name) { |
56 | 0 | keylog_file_fp = fopen(keylog_file_name, FOPEN_APPENDTEXT); |
57 | 0 | if(keylog_file_fp) { |
58 | | #ifdef WIN32 |
59 | | if(setvbuf(keylog_file_fp, NULL, _IONBF, 0)) |
60 | | #else |
61 | 0 | if(setvbuf(keylog_file_fp, NULL, _IOLBF, 4096)) |
62 | 0 | #endif |
63 | 0 | { |
64 | 0 | fclose(keylog_file_fp); |
65 | 0 | keylog_file_fp = NULL; |
66 | 0 | } |
67 | 0 | } |
68 | 0 | Curl_safefree(keylog_file_name); |
69 | 0 | } |
70 | 19 | } |
71 | 19 | } |
72 | | |
73 | | void |
74 | | Curl_tls_keylog_close(void) |
75 | 0 | { |
76 | 0 | if(keylog_file_fp) { |
77 | 0 | fclose(keylog_file_fp); |
78 | 0 | keylog_file_fp = NULL; |
79 | 0 | } |
80 | 0 | } |
81 | | |
82 | | bool |
83 | | Curl_tls_keylog_enabled(void) |
84 | 0 | { |
85 | 0 | return keylog_file_fp != NULL; |
86 | 0 | } |
87 | | |
88 | | bool |
89 | | Curl_tls_keylog_write_line(const char *line) |
90 | 0 | { |
91 | | /* The current maximum valid keylog line length LF and NUL is 195. */ |
92 | 0 | size_t linelen; |
93 | 0 | char buf[256]; |
94 | |
|
95 | 0 | if(!keylog_file_fp || !line) { |
96 | 0 | return false; |
97 | 0 | } |
98 | | |
99 | 0 | linelen = strlen(line); |
100 | 0 | if(linelen == 0 || linelen > sizeof(buf) - 2) { |
101 | | /* Empty line or too big to fit in a LF and NUL. */ |
102 | 0 | return false; |
103 | 0 | } |
104 | | |
105 | 0 | memcpy(buf, line, linelen); |
106 | 0 | if(line[linelen - 1] != '\n') { |
107 | 0 | buf[linelen++] = '\n'; |
108 | 0 | } |
109 | 0 | buf[linelen] = '\0'; |
110 | | |
111 | | /* Using fputs here instead of fprintf since libcurl's fprintf replacement |
112 | | may not be thread-safe. */ |
113 | 0 | fputs(buf, keylog_file_fp); |
114 | 0 | return true; |
115 | 0 | } |
116 | | |
117 | | bool |
118 | | Curl_tls_keylog_write(const char *label, |
119 | | const unsigned char client_random[CLIENT_RANDOM_SIZE], |
120 | | const unsigned char *secret, size_t secretlen) |
121 | 0 | { |
122 | 0 | const char *hex = "0123456789ABCDEF"; |
123 | 0 | size_t pos, i; |
124 | 0 | char line[KEYLOG_LABEL_MAXLEN + 1 + 2 * CLIENT_RANDOM_SIZE + 1 + |
125 | 0 | 2 * SECRET_MAXLEN + 1 + 1]; |
126 | |
|
127 | 0 | if(!keylog_file_fp) { |
128 | 0 | return false; |
129 | 0 | } |
130 | | |
131 | 0 | pos = strlen(label); |
132 | 0 | if(pos > KEYLOG_LABEL_MAXLEN || !secretlen || secretlen > SECRET_MAXLEN) { |
133 | | /* Should never happen - sanity check anyway. */ |
134 | 0 | return false; |
135 | 0 | } |
136 | | |
137 | 0 | memcpy(line, label, pos); |
138 | 0 | line[pos++] = ' '; |
139 | | |
140 | | /* Client Random */ |
141 | 0 | for(i = 0; i < CLIENT_RANDOM_SIZE; i++) { |
142 | 0 | line[pos++] = hex[client_random[i] >> 4]; |
143 | 0 | line[pos++] = hex[client_random[i] & 0xF]; |
144 | 0 | } |
145 | 0 | line[pos++] = ' '; |
146 | | |
147 | | /* Secret */ |
148 | 0 | for(i = 0; i < secretlen; i++) { |
149 | 0 | line[pos++] = hex[secret[i] >> 4]; |
150 | 0 | line[pos++] = hex[secret[i] & 0xF]; |
151 | 0 | } |
152 | 0 | line[pos++] = '\n'; |
153 | 0 | line[pos] = '\0'; |
154 | | |
155 | | /* Using fputs here instead of fprintf since libcurl's fprintf replacement |
156 | | may not be thread-safe. */ |
157 | 0 | fputs(line, keylog_file_fp); |
158 | 0 | return true; |
159 | 0 | } |