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Commit | Line | Data |
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e2770979 JK |
1 | #include "cache.h" |
2 | #include "credential.h" | |
3 | #include "unix-socket.h" | |
4 | #include "sigchain.h" | |
f5e3c0b9 | 5 | #include "parse-options.h" |
e2770979 JK |
6 | |
7 | static const char *socket_path; | |
8 | ||
9 | static void cleanup_socket(void) | |
10 | { | |
11 | if (socket_path) | |
12 | unlink(socket_path); | |
13 | } | |
14 | ||
15 | static void cleanup_socket_on_signal(int sig) | |
16 | { | |
17 | cleanup_socket(); | |
18 | sigchain_pop(sig); | |
19 | raise(sig); | |
20 | } | |
21 | ||
22 | struct credential_cache_entry { | |
23 | struct credential item; | |
24 | unsigned long expiration; | |
25 | }; | |
26 | static struct credential_cache_entry *entries; | |
27 | static int entries_nr; | |
28 | static int entries_alloc; | |
29 | ||
30 | static void cache_credential(struct credential *c, int timeout) | |
31 | { | |
32 | struct credential_cache_entry *e; | |
33 | ||
34 | ALLOC_GROW(entries, entries_nr + 1, entries_alloc); | |
35 | e = &entries[entries_nr++]; | |
36 | ||
37 | /* take ownership of pointers */ | |
38 | memcpy(&e->item, c, sizeof(*c)); | |
39 | memset(c, 0, sizeof(*c)); | |
40 | e->expiration = time(NULL) + timeout; | |
41 | } | |
42 | ||
43 | static struct credential_cache_entry *lookup_credential(const struct credential *c) | |
44 | { | |
45 | int i; | |
46 | for (i = 0; i < entries_nr; i++) { | |
47 | struct credential *e = &entries[i].item; | |
48 | if (credential_match(c, e)) | |
49 | return &entries[i]; | |
50 | } | |
51 | return NULL; | |
52 | } | |
53 | ||
54 | static void remove_credential(const struct credential *c) | |
55 | { | |
56 | struct credential_cache_entry *e; | |
57 | ||
58 | e = lookup_credential(c); | |
59 | if (e) | |
60 | e->expiration = 0; | |
61 | } | |
62 | ||
63 | static int check_expirations(void) | |
64 | { | |
65 | static unsigned long wait_for_entry_until; | |
66 | int i = 0; | |
67 | unsigned long now = time(NULL); | |
68 | unsigned long next = (unsigned long)-1; | |
69 | ||
70 | /* | |
71 | * Initially give the client 30 seconds to actually contact us | |
72 | * and store a credential before we decide there's no point in | |
73 | * keeping the daemon around. | |
74 | */ | |
75 | if (!wait_for_entry_until) | |
76 | wait_for_entry_until = now + 30; | |
77 | ||
78 | while (i < entries_nr) { | |
79 | if (entries[i].expiration <= now) { | |
80 | entries_nr--; | |
81 | credential_clear(&entries[i].item); | |
82 | if (i != entries_nr) | |
83 | memcpy(&entries[i], &entries[entries_nr], sizeof(*entries)); | |
84 | /* | |
85 | * Stick around 30 seconds in case a new credential | |
86 | * shows up (e.g., because we just removed a failed | |
87 | * one, and we will soon get the correct one). | |
88 | */ | |
89 | wait_for_entry_until = now + 30; | |
90 | } | |
91 | else { | |
92 | if (entries[i].expiration < next) | |
93 | next = entries[i].expiration; | |
94 | i++; | |
95 | } | |
96 | } | |
97 | ||
98 | if (!entries_nr) { | |
99 | if (wait_for_entry_until <= now) | |
100 | return 0; | |
101 | next = wait_for_entry_until; | |
102 | } | |
103 | ||
104 | return next - now; | |
105 | } | |
106 | ||
107 | static int read_request(FILE *fh, struct credential *c, | |
108 | struct strbuf *action, int *timeout) { | |
109 | static struct strbuf item = STRBUF_INIT; | |
110 | const char *p; | |
111 | ||
112 | strbuf_getline(&item, fh, '\n'); | |
cf4fff57 | 113 | if (!skip_prefix(item.buf, "action=", &p)) |
e2770979 JK |
114 | return error("client sent bogus action line: %s", item.buf); |
115 | strbuf_addstr(action, p); | |
116 | ||
117 | strbuf_getline(&item, fh, '\n'); | |
cf4fff57 | 118 | if (!skip_prefix(item.buf, "timeout=", &p)) |
e2770979 JK |
119 | return error("client sent bogus timeout line: %s", item.buf); |
120 | *timeout = atoi(p); | |
121 | ||
122 | if (credential_read(c, fh) < 0) | |
123 | return -1; | |
124 | return 0; | |
125 | } | |
126 | ||
127 | static void serve_one_client(FILE *in, FILE *out) | |
128 | { | |
129 | struct credential c = CREDENTIAL_INIT; | |
130 | struct strbuf action = STRBUF_INIT; | |
131 | int timeout = -1; | |
132 | ||
133 | if (read_request(in, &c, &action, &timeout) < 0) | |
134 | /* ignore error */ ; | |
135 | else if (!strcmp(action.buf, "get")) { | |
136 | struct credential_cache_entry *e = lookup_credential(&c); | |
137 | if (e) { | |
138 | fprintf(out, "username=%s\n", e->item.username); | |
139 | fprintf(out, "password=%s\n", e->item.password); | |
140 | } | |
141 | } | |
142 | else if (!strcmp(action.buf, "exit")) | |
143 | exit(0); | |
144 | else if (!strcmp(action.buf, "erase")) | |
145 | remove_credential(&c); | |
146 | else if (!strcmp(action.buf, "store")) { | |
147 | if (timeout < 0) | |
148 | warning("cache client didn't specify a timeout"); | |
149 | else if (!c.username || !c.password) | |
150 | warning("cache client gave us a partial credential"); | |
151 | else { | |
152 | remove_credential(&c); | |
153 | cache_credential(&c, timeout); | |
154 | } | |
155 | } | |
156 | else | |
157 | warning("cache client sent unknown action: %s", action.buf); | |
158 | ||
159 | credential_clear(&c); | |
160 | strbuf_release(&action); | |
161 | } | |
162 | ||
163 | static int serve_cache_loop(int fd) | |
164 | { | |
165 | struct pollfd pfd; | |
166 | unsigned long wakeup; | |
167 | ||
168 | wakeup = check_expirations(); | |
169 | if (!wakeup) | |
170 | return 0; | |
171 | ||
172 | pfd.fd = fd; | |
173 | pfd.events = POLLIN; | |
174 | if (poll(&pfd, 1, 1000 * wakeup) < 0) { | |
175 | if (errno != EINTR) | |
176 | die_errno("poll failed"); | |
177 | return 1; | |
178 | } | |
179 | ||
180 | if (pfd.revents & POLLIN) { | |
181 | int client, client2; | |
182 | FILE *in, *out; | |
183 | ||
184 | client = accept(fd, NULL, NULL); | |
185 | if (client < 0) { | |
186 | warning("accept failed: %s", strerror(errno)); | |
187 | return 1; | |
188 | } | |
189 | client2 = dup(client); | |
190 | if (client2 < 0) { | |
191 | warning("dup failed: %s", strerror(errno)); | |
192 | close(client); | |
193 | return 1; | |
194 | } | |
195 | ||
196 | in = xfdopen(client, "r"); | |
197 | out = xfdopen(client2, "w"); | |
198 | serve_one_client(in, out); | |
199 | fclose(in); | |
200 | fclose(out); | |
201 | } | |
202 | return 1; | |
203 | } | |
204 | ||
f5e3c0b9 | 205 | static void serve_cache(const char *socket_path, int debug) |
e2770979 JK |
206 | { |
207 | int fd; | |
208 | ||
209 | fd = unix_stream_listen(socket_path); | |
210 | if (fd < 0) | |
211 | die_errno("unable to bind to '%s'", socket_path); | |
212 | ||
213 | printf("ok\n"); | |
214 | fclose(stdout); | |
f5e3c0b9 JK |
215 | if (!debug) { |
216 | if (!freopen("/dev/null", "w", stderr)) | |
217 | die_errno("unable to point stderr to /dev/null"); | |
218 | } | |
e2770979 JK |
219 | |
220 | while (serve_cache_loop(fd)) | |
221 | ; /* nothing */ | |
222 | ||
223 | close(fd); | |
224 | unlink(socket_path); | |
225 | } | |
226 | ||
227 | static const char permissions_advice[] = | |
228 | "The permissions on your socket directory are too loose; other\n" | |
229 | "users may be able to read your cached credentials. Consider running:\n" | |
230 | "\n" | |
231 | " chmod 0700 %s"; | |
232 | static void check_socket_directory(const char *path) | |
233 | { | |
234 | struct stat st; | |
235 | char *path_copy = xstrdup(path); | |
236 | char *dir = dirname(path_copy); | |
237 | ||
238 | if (!stat(dir, &st)) { | |
239 | if (st.st_mode & 077) | |
240 | die(permissions_advice, dir); | |
241 | free(path_copy); | |
242 | return; | |
243 | } | |
244 | ||
245 | /* | |
246 | * We must be sure to create the directory with the correct mode, | |
247 | * not just chmod it after the fact; otherwise, there is a race | |
248 | * condition in which somebody can chdir to it, sleep, then try to open | |
249 | * our protected socket. | |
250 | */ | |
251 | if (safe_create_leading_directories_const(dir) < 0) | |
252 | die_errno("unable to create directories for '%s'", dir); | |
253 | if (mkdir(dir, 0700) < 0) | |
254 | die_errno("unable to mkdir '%s'", dir); | |
255 | free(path_copy); | |
256 | } | |
257 | ||
258 | int main(int argc, const char **argv) | |
259 | { | |
f5e3c0b9 JK |
260 | static const char *usage[] = { |
261 | "git-credential-cache--daemon [opts] <socket_path>", | |
262 | NULL | |
263 | }; | |
264 | int debug = 0; | |
265 | const struct option options[] = { | |
266 | OPT_BOOL(0, "debug", &debug, | |
267 | N_("print debugging messages to stderr")), | |
268 | OPT_END() | |
269 | }; | |
270 | ||
271 | argc = parse_options(argc, argv, NULL, options, usage, 0); | |
272 | socket_path = argv[0]; | |
e2770979 JK |
273 | |
274 | if (!socket_path) | |
f5e3c0b9 | 275 | usage_with_options(usage, options); |
e2770979 JK |
276 | check_socket_directory(socket_path); |
277 | ||
278 | atexit(cleanup_socket); | |
279 | sigchain_push_common(cleanup_socket_on_signal); | |
280 | ||
f5e3c0b9 | 281 | serve_cache(socket_path, debug); |
e2770979 JK |
282 | |
283 | return 0; | |
284 | } |