builtin/credential-cache--daemon.c

   1 #define USE_THE_REPOSITORY_VARIABLE
   2 #include "builtin.h"
   3 #include "abspath.h"
   4 #include "gettext.h"
   5 #include "object-file.h"
   6 #include "parse-options.h"
   7
   8 #ifndef NO_UNIX_SOCKETS
   9
  10 #include "config.h"
  11 #include "tempfile.h"
  12 #include "credential.h"
  13 #include "unix-socket.h"
  14
  15 struct credential_cache_entry {
  16         struct credential item;
  17         timestamp_t expiration;
  18 };
  19 static struct credential_cache_entry *entries;
  20 static int entries_nr;
  21 static int entries_alloc;
  22
  23 static void cache_credential(struct credential *c, int timeout)
  24 {
  25         struct credential_cache_entry *e;
  26
  27         ALLOC_GROW(entries, entries_nr + 1, entries_alloc);
  28         e = &entries[entries_nr++];
  29
  30         /* take ownership of pointers */
  31         memcpy(&e->item, c, sizeof(*c));
  32         memset(c, 0, sizeof(*c));
  33         e->expiration = time(NULL) + timeout;
  34 }
  35
  36 static struct credential_cache_entry *lookup_credential(const struct credential *c)
  37 {
  38         int i;
  39         for (i = 0; i < entries_nr; i++) {
  40                 struct credential *e = &entries[i].item;
  41                 if (credential_match(c, e, 0))
  42                         return &entries[i];
  43         }
  44         return NULL;
  45 }
  46
  47 static void remove_credential(const struct credential *c, int match_password)
  48 {
  49         struct credential_cache_entry *e;
  50
  51         int i;
  52         for (i = 0; i < entries_nr; i++) {
  53                 e = &entries[i];
  54                 if (credential_match(c, &e->item, match_password))
  55                         e->expiration = 0;
  56         }
  57 }
  58
  59 static timestamp_t check_expirations(void)
  60 {
  61         static timestamp_t wait_for_entry_until;
  62         int i = 0;
  63         timestamp_t now = time(NULL);
  64         timestamp_t next = TIME_MAX;
  65
  66         /*
  67          * Initially give the client 30 seconds to actually contact us
  68          * and store a credential before we decide there's no point in
  69          * keeping the daemon around.
  70          */
  71         if (!wait_for_entry_until)
  72                 wait_for_entry_until = now + 30;
  73
  74         while (i < entries_nr) {
  75                 if (entries[i].expiration <= now) {
  76                         entries_nr--;
  77                         credential_clear(&entries[i].item);
  78                         if (i != entries_nr)
  79                                 memcpy(&entries[i], &entries[entries_nr], sizeof(*entries));
  80                         /*
  81                          * Stick around 30 seconds in case a new credential
  82                          * shows up (e.g., because we just removed a failed
  83                          * one, and we will soon get the correct one).
  84                          */
  85                         wait_for_entry_until = now + 30;
  86                 }
  87                 else {
  88                         if (entries[i].expiration < next)
  89                                 next = entries[i].expiration;
  90                         i++;
  91                 }
  92         }
  93
  94         if (!entries_nr) {
  95                 if (wait_for_entry_until <= now)
  96                         return 0;
  97                 next = wait_for_entry_until;
  98         }
  99
 100         return next - now;
 101 }
 102
 103 static int read_request(FILE *fh, struct credential *c,
 104                         struct strbuf *action, int *timeout)
 105 {
 106         static struct strbuf item = STRBUF_INIT;
 107         const char *p;
 108
 109         strbuf_getline_lf(&item, fh);
 110         if (!skip_prefix(item.buf, "action=", &p))
 111                 return error("client sent bogus action line: %s", item.buf);
 112         strbuf_addstr(action, p);
 113
 114         strbuf_getline_lf(&item, fh);
 115         if (!skip_prefix(item.buf, "timeout=", &p))
 116                 return error("client sent bogus timeout line: %s", item.buf);
 117         *timeout = atoi(p);
 118
 119         credential_set_all_capabilities(c, CREDENTIAL_OP_INITIAL);
 120
 121         if (credential_read(c, fh, CREDENTIAL_OP_HELPER) < 0)
 122                 return -1;
 123         return 0;
 124 }
 125
 126 static void serve_one_client(FILE *in, FILE *out)
 127 {
 128         struct credential c = CREDENTIAL_INIT;
 129         struct strbuf action = STRBUF_INIT;
 130         int timeout = -1;
 131
 132         if (read_request(in, &c, &action, &timeout) < 0)
 133                 /* ignore error */ ;
 134         else if (!strcmp(action.buf, "get")) {
 135                 struct credential_cache_entry *e = lookup_credential(&c);
 136                 if (e) {
 137                         e->item.capa_authtype.request_initial = 1;
 138                         e->item.capa_authtype.request_helper = 1;
 139
 140                         fprintf(out, "capability[]=authtype\n");
 141                         if (e->item.username)
 142                                 fprintf(out, "username=%s\n", e->item.username);
 143                         if (e->item.password)
 144                                 fprintf(out, "password=%s\n", e->item.password);
 145                         if (credential_has_capability(&c.capa_authtype, CREDENTIAL_OP_HELPER) && e->item.authtype)
 146                                 fprintf(out, "authtype=%s\n", e->item.authtype);
 147                         if (credential_has_capability(&c.capa_authtype, CREDENTIAL_OP_HELPER) && e->item.credential)
 148                                 fprintf(out, "credential=%s\n", e->item.credential);
 149                         if (e->item.password_expiry_utc != TIME_MAX)
 150                                 fprintf(out, "password_expiry_utc=%"PRItime"\n",
 151                                         e->item.password_expiry_utc);
 152                         if (e->item.oauth_refresh_token)
 153                                 fprintf(out, "oauth_refresh_token=%s\n",
 154                                         e->item.oauth_refresh_token);
 155                 }
 156         }
 157         else if (!strcmp(action.buf, "exit")) {
 158                 /*
 159                  * It's important that we clean up our socket first, and then
 160                  * signal the client only once we have finished the cleanup.
 161                  * Calling exit() directly does this, because we clean up in
 162                  * our atexit() handler, and then signal the client when our
 163                  * process actually ends, which closes the socket and gives
 164                  * them EOF.
 165                  */
 166                 exit(0);
 167         }
 168         else if (!strcmp(action.buf, "erase"))
 169                 remove_credential(&c, 1);
 170         else if (!strcmp(action.buf, "store")) {
 171                 if (timeout < 0)
 172                         warning("cache client didn't specify a timeout");
 173                 else if ((!c.username || !c.password) && (!c.authtype && !c.credential))
 174                         warning("cache client gave us a partial credential");
 175                 else if (c.ephemeral)
 176                         warning("not storing ephemeral credential");
 177                 else {
 178                         remove_credential(&c, 0);
 179                         cache_credential(&c, timeout);
 180                 }
 181         }
 182         else
 183                 warning("cache client sent unknown action: %s", action.buf);
 184
 185         credential_clear(&c);
 186         strbuf_release(&action);
 187 }
 188
 189 static int serve_cache_loop(int fd)
 190 {
 191         struct pollfd pfd;
 192         timestamp_t wakeup;
 193
 194         wakeup = check_expirations();
 195         if (!wakeup)
 196                 return 0;
 197
 198         pfd.fd = fd;
 199         pfd.events = POLLIN;
 200         if (poll(&pfd, 1, 1000 * wakeup) < 0) {
 201                 if (errno != EINTR)
 202                         die_errno("poll failed");
 203                 return 1;
 204         }
 205
 206         if (pfd.revents & POLLIN) {
 207                 int client, client2;
 208                 FILE *in, *out;
 209
 210                 client = accept(fd, NULL, NULL);
 211                 if (client < 0) {
 212                         warning_errno("accept failed");
 213                         return 1;
 214                 }
 215                 client2 = dup(client);
 216                 if (client2 < 0) {
 217                         warning_errno("dup failed");
 218                         close(client);
 219                         return 1;
 220                 }
 221
 222                 in = xfdopen(client, "r");
 223                 out = xfdopen(client2, "w");
 224                 serve_one_client(in, out);
 225                 fclose(in);
 226                 fclose(out);
 227         }
 228         return 1;
 229 }
 230
 231 static void serve_cache(const char *socket_path, int debug)
 232 {
 233         struct unix_stream_listen_opts opts = UNIX_STREAM_LISTEN_OPTS_INIT;
 234         int fd;
 235
 236         fd = unix_stream_listen(socket_path, &opts);
 237         if (fd < 0)
 238                 die_errno("unable to bind to '%s'", socket_path);
 239
 240         printf("ok\n");
 241         fclose(stdout);
 242         if (!debug) {
 243                 if (!freopen("/dev/null", "w", stderr))
 244                         die_errno("unable to point stderr to /dev/null");
 245         }
 246
 247         while (serve_cache_loop(fd))
 248                 ; /* nothing */
 249
 250         close(fd);
 251 }
 252
 253 static const char permissions_advice[] = N_(
 254 "The permissions on your socket directory are too loose; other\n"
 255 "users may be able to read your cached credentials. Consider running:\n"
 256 "\n"
 257 "       chmod 0700 %s");
 258 static void init_socket_directory(const char *path)
 259 {
 260         struct stat st;
 261         char *path_copy = xstrdup(path);
 262         char *dir = dirname(path_copy);
 263
 264         if (!stat(dir, &st)) {
 265                 if (st.st_mode & 077)
 266                         die(_(permissions_advice), dir);
 267         } else {
 268                 /*
 269                  * We must be sure to create the directory with the correct mode,
 270                  * not just chmod it after the fact; otherwise, there is a race
 271                  * condition in which somebody can chdir to it, sleep, then try to open
 272                  * our protected socket.
 273                  */
 274                 if (safe_create_leading_directories_const(dir) < 0)
 275                         die_errno("unable to create directories for '%s'", dir);
 276                 if (mkdir(dir, 0700) < 0)
 277                         die_errno("unable to mkdir '%s'", dir);
 278         }
 279
 280         if (chdir(dir))
 281                 /*
 282                  * We don't actually care what our cwd is; we chdir here just to
 283                  * be a friendly daemon and avoid tying up our original cwd.
 284                  * If this fails, it's OK to just continue without that benefit.
 285                  */
 286                 ;
 287
 288         free(path_copy);
 289 }
 290
 291 int cmd_credential_cache_daemon(int argc,
 292                                 const char **argv,
 293                                 const char *prefix,
 294                                 struct repository *repo UNUSED)
 295 {
 296         struct tempfile *socket_file;
 297         const char *socket_path;
 298         int ignore_sighup = 0;
 299         static const char *usage[] = {
 300                 "git credential-cache--daemon [--debug] <socket-path>",
 301                 NULL
 302         };
 303         int debug = 0;
 304         const struct option options[] = {
 305                 OPT_BOOL(0, "debug", &debug,
 306                          N_("print debugging messages to stderr")),
 307                 OPT_END()
 308         };
 309
 310         git_config_get_bool("credentialcache.ignoresighup", &ignore_sighup);
 311
 312         argc = parse_options(argc, argv, prefix, options, usage, 0);
 313         socket_path = argv[0];
 314
 315         if (!have_unix_sockets())
 316                 die(_("credential-cache--daemon unavailable; no unix socket support"));
 317         if (!socket_path)
 318                 usage_with_options(usage, options);
 319
 320         if (!is_absolute_path(socket_path))
 321                 die("socket directory must be an absolute path");
 322
 323         init_socket_directory(socket_path);
 324         socket_file = register_tempfile(socket_path);
 325
 326         if (ignore_sighup)
 327                 signal(SIGHUP, SIG_IGN);
 328
 329         serve_cache(socket_path, debug);
 330         delete_tempfile(&socket_file);
 331
 332         return 0;
 333 }
 334
 335 #else
 336
 337 int cmd_credential_cache_daemon(int argc,
 338 const char **argv,
 339 const char *prefix,
 340 struct repository *repo UNUSED)
 341 {
 342         const char * const usage[] = {
 343                 "git credential-cache--daemon [--debug] <socket-path>",
 344                 "",
 345                 "credential-cache--daemon is disabled in this build of Git",
 346                 NULL
 347         };
 348         struct option options[] = { OPT_END() };
 349
 350         argc = parse_options(argc, argv, prefix, options, usage, 0);
 351         die(_("credential-cache--daemon unavailable; no unix socket support"));
 352 }
 353
 354 #endif /* NO_UNIX_SOCKET */