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