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1 | #include "cache.h" | |
2 | #include "config.h" | |
3 | #include "tempfile.h" | |
4 | #include "credential.h" | |
5 | #include "unix-socket.h" | |
6 | #include "parse-options.h" | |
7 | ||
8 | struct credential_cache_entry { | |
9 | struct credential item; | |
10 | timestamp_t expiration; | |
11 | }; | |
12 | static struct credential_cache_entry *entries; | |
13 | static int entries_nr; | |
14 | static int entries_alloc; | |
15 | ||
16 | static void cache_credential(struct credential *c, int timeout) | |
17 | { | |
18 | struct credential_cache_entry *e; | |
19 | ||
20 | ALLOC_GROW(entries, entries_nr + 1, entries_alloc); | |
21 | e = &entries[entries_nr++]; | |
22 | ||
23 | /* take ownership of pointers */ | |
24 | memcpy(&e->item, c, sizeof(*c)); | |
25 | memset(c, 0, sizeof(*c)); | |
26 | e->expiration = time(NULL) + timeout; | |
27 | } | |
28 | ||
29 | static struct credential_cache_entry *lookup_credential(const struct credential *c) | |
30 | { | |
31 | int i; | |
32 | for (i = 0; i < entries_nr; i++) { | |
33 | struct credential *e = &entries[i].item; | |
34 | if (credential_match(c, e)) | |
35 | return &entries[i]; | |
36 | } | |
37 | return NULL; | |
38 | } | |
39 | ||
40 | static void remove_credential(const struct credential *c) | |
41 | { | |
42 | struct credential_cache_entry *e; | |
43 | ||
44 | e = lookup_credential(c); | |
45 | if (e) | |
46 | e->expiration = 0; | |
47 | } | |
48 | ||
49 | static timestamp_t check_expirations(void) | |
50 | { | |
51 | static timestamp_t wait_for_entry_until; | |
52 | int i = 0; | |
53 | timestamp_t now = time(NULL); | |
54 | timestamp_t next = TIME_MAX; | |
55 | ||
56 | /* | |
57 | * Initially give the client 30 seconds to actually contact us | |
58 | * and store a credential before we decide there's no point in | |
59 | * keeping the daemon around. | |
60 | */ | |
61 | if (!wait_for_entry_until) | |
62 | wait_for_entry_until = now + 30; | |
63 | ||
64 | while (i < entries_nr) { | |
65 | if (entries[i].expiration <= now) { | |
66 | entries_nr--; | |
67 | credential_clear(&entries[i].item); | |
68 | if (i != entries_nr) | |
69 | memcpy(&entries[i], &entries[entries_nr], sizeof(*entries)); | |
70 | /* | |
71 | * Stick around 30 seconds in case a new credential | |
72 | * shows up (e.g., because we just removed a failed | |
73 | * one, and we will soon get the correct one). | |
74 | */ | |
75 | wait_for_entry_until = now + 30; | |
76 | } | |
77 | else { | |
78 | if (entries[i].expiration < next) | |
79 | next = entries[i].expiration; | |
80 | i++; | |
81 | } | |
82 | } | |
83 | ||
84 | if (!entries_nr) { | |
85 | if (wait_for_entry_until <= now) | |
86 | return 0; | |
87 | next = wait_for_entry_until; | |
88 | } | |
89 | ||
90 | return next - now; | |
91 | } | |
92 | ||
93 | static int read_request(FILE *fh, struct credential *c, | |
94 | struct strbuf *action, int *timeout) { | |
95 | static struct strbuf item = STRBUF_INIT; | |
96 | const char *p; | |
97 | ||
98 | strbuf_getline_lf(&item, fh); | |
99 | if (!skip_prefix(item.buf, "action=", &p)) | |
100 | return error("client sent bogus action line: %s", item.buf); | |
101 | strbuf_addstr(action, p); | |
102 | ||
103 | strbuf_getline_lf(&item, fh); | |
104 | if (!skip_prefix(item.buf, "timeout=", &p)) | |
105 | return error("client sent bogus timeout line: %s", item.buf); | |
106 | *timeout = atoi(p); | |
107 | ||
108 | if (credential_read(c, fh) < 0) | |
109 | return -1; | |
110 | return 0; | |
111 | } | |
112 | ||
113 | static void serve_one_client(FILE *in, FILE *out) | |
114 | { | |
115 | struct credential c = CREDENTIAL_INIT; | |
116 | struct strbuf action = STRBUF_INIT; | |
117 | int timeout = -1; | |
118 | ||
119 | if (read_request(in, &c, &action, &timeout) < 0) | |
120 | /* ignore error */ ; | |
121 | else if (!strcmp(action.buf, "get")) { | |
122 | struct credential_cache_entry *e = lookup_credential(&c); | |
123 | if (e) { | |
124 | fprintf(out, "username=%s\n", e->item.username); | |
125 | fprintf(out, "password=%s\n", e->item.password); | |
126 | } | |
127 | } | |
128 | else if (!strcmp(action.buf, "exit")) { | |
129 | /* | |
130 | * It's important that we clean up our socket first, and then | |
131 | * signal the client only once we have finished the cleanup. | |
132 | * Calling exit() directly does this, because we clean up in | |
133 | * our atexit() handler, and then signal the client when our | |
134 | * process actually ends, which closes the socket and gives | |
135 | * them EOF. | |
136 | */ | |
137 | exit(0); | |
138 | } | |
139 | else if (!strcmp(action.buf, "erase")) | |
140 | remove_credential(&c); | |
141 | else if (!strcmp(action.buf, "store")) { | |
142 | if (timeout < 0) | |
143 | warning("cache client didn't specify a timeout"); | |
144 | else if (!c.username || !c.password) | |
145 | warning("cache client gave us a partial credential"); | |
146 | else { | |
147 | remove_credential(&c); | |
148 | cache_credential(&c, timeout); | |
149 | } | |
150 | } | |
151 | else | |
152 | warning("cache client sent unknown action: %s", action.buf); | |
153 | ||
154 | credential_clear(&c); | |
155 | strbuf_release(&action); | |
156 | } | |
157 | ||
158 | static int serve_cache_loop(int fd) | |
159 | { | |
160 | struct pollfd pfd; | |
161 | timestamp_t wakeup; | |
162 | ||
163 | wakeup = check_expirations(); | |
164 | if (!wakeup) | |
165 | return 0; | |
166 | ||
167 | pfd.fd = fd; | |
168 | pfd.events = POLLIN; | |
169 | if (poll(&pfd, 1, 1000 * wakeup) < 0) { | |
170 | if (errno != EINTR) | |
171 | die_errno("poll failed"); | |
172 | return 1; | |
173 | } | |
174 | ||
175 | if (pfd.revents & POLLIN) { | |
176 | int client, client2; | |
177 | FILE *in, *out; | |
178 | ||
179 | client = accept(fd, NULL, NULL); | |
180 | if (client < 0) { | |
181 | warning_errno("accept failed"); | |
182 | return 1; | |
183 | } | |
184 | client2 = dup(client); | |
185 | if (client2 < 0) { | |
186 | warning_errno("dup failed"); | |
187 | close(client); | |
188 | return 1; | |
189 | } | |
190 | ||
191 | in = xfdopen(client, "r"); | |
192 | out = xfdopen(client2, "w"); | |
193 | serve_one_client(in, out); | |
194 | fclose(in); | |
195 | fclose(out); | |
196 | } | |
197 | return 1; | |
198 | } | |
199 | ||
200 | static void serve_cache(const char *socket_path, int debug) | |
201 | { | |
202 | int fd; | |
203 | ||
204 | fd = unix_stream_listen(socket_path); | |
205 | if (fd < 0) | |
206 | die_errno("unable to bind to '%s'", socket_path); | |
207 | ||
208 | printf("ok\n"); | |
209 | fclose(stdout); | |
210 | if (!debug) { | |
211 | if (!freopen("/dev/null", "w", stderr)) | |
212 | die_errno("unable to point stderr to /dev/null"); | |
213 | } | |
214 | ||
215 | while (serve_cache_loop(fd)) | |
216 | ; /* nothing */ | |
217 | ||
218 | close(fd); | |
219 | } | |
220 | ||
221 | static const char permissions_advice[] = N_( | |
222 | "The permissions on your socket directory are too loose; other\n" | |
223 | "users may be able to read your cached credentials. Consider running:\n" | |
224 | "\n" | |
225 | " chmod 0700 %s"); | |
226 | static void init_socket_directory(const char *path) | |
227 | { | |
228 | struct stat st; | |
229 | char *path_copy = xstrdup(path); | |
230 | char *dir = dirname(path_copy); | |
231 | ||
232 | if (!stat(dir, &st)) { | |
233 | if (st.st_mode & 077) | |
234 | die(_(permissions_advice), dir); | |
235 | } else { | |
236 | /* | |
237 | * We must be sure to create the directory with the correct mode, | |
238 | * not just chmod it after the fact; otherwise, there is a race | |
239 | * condition in which somebody can chdir to it, sleep, then try to open | |
240 | * our protected socket. | |
241 | */ | |
242 | if (safe_create_leading_directories_const(dir) < 0) | |
243 | die_errno("unable to create directories for '%s'", dir); | |
244 | if (mkdir(dir, 0700) < 0) | |
245 | die_errno("unable to mkdir '%s'", dir); | |
246 | } | |
247 | ||
248 | if (chdir(dir)) | |
249 | /* | |
250 | * We don't actually care what our cwd is; we chdir here just to | |
251 | * be a friendly daemon and avoid tying up our original cwd. | |
252 | * If this fails, it's OK to just continue without that benefit. | |
253 | */ | |
254 | ; | |
255 | ||
256 | free(path_copy); | |
257 | } | |
258 | ||
259 | int cmd_main(int argc, const char **argv) | |
260 | { | |
261 | struct tempfile *socket_file; | |
262 | const char *socket_path; | |
263 | int ignore_sighup = 0; | |
264 | static const char *usage[] = { | |
265 | "git-credential-cache--daemon [opts] <socket_path>", | |
266 | NULL | |
267 | }; | |
268 | int debug = 0; | |
269 | const struct option options[] = { | |
270 | OPT_BOOL(0, "debug", &debug, | |
271 | N_("print debugging messages to stderr")), | |
272 | OPT_END() | |
273 | }; | |
274 | ||
275 | git_config_get_bool("credentialcache.ignoresighup", &ignore_sighup); | |
276 | ||
277 | argc = parse_options(argc, argv, NULL, options, usage, 0); | |
278 | socket_path = argv[0]; | |
279 | ||
280 | if (!socket_path) | |
281 | usage_with_options(usage, options); | |
282 | ||
283 | if (!is_absolute_path(socket_path)) | |
284 | die("socket directory must be an absolute path"); | |
285 | ||
286 | init_socket_directory(socket_path); | |
287 | socket_file = register_tempfile(socket_path); | |
288 | ||
289 | if (ignore_sighup) | |
290 | signal(SIGHUP, SIG_IGN); | |
291 | ||
292 | serve_cache(socket_path, debug); | |
293 | delete_tempfile(&socket_file); | |
294 | ||
295 | return 0; | |
296 | } |