credential.c

   1 #include "cache.h"
   2 #include "config.h"
   3 #include "credential.h"
   4 #include "string-list.h"
   5 #include "run-command.h"
   6 #include "url.h"
   7 #include "prompt.h"
   8 #include "sigchain.h"
   9 #include "urlmatch.h"
  10 #include "git-compat-util.h"
  11
  12 void credential_init(struct credential *c)
  13 {
  14         struct credential blank = CREDENTIAL_INIT;
  15         memcpy(c, &blank, sizeof(*c));
  16 }
  17
  18 void credential_clear(struct credential *c)
  19 {
  20         free(c->protocol);
  21         free(c->host);
  22         free(c->path);
  23         free(c->username);
  24         free(c->password);
  25         string_list_clear(&c->helpers, 0);
  26
  27         credential_init(c);
  28 }
  29
  30 int credential_match(const struct credential *want,
  31                      const struct credential *have)
  32 {
  33 #define CHECK(x) (!want->x || (have->x && !strcmp(want->x, have->x)))
  34         return CHECK(protocol) &&
  35                CHECK(host) &&
  36                CHECK(path) &&
  37                CHECK(username);
  38 #undef CHECK
  39 }
  40
  41
  42 static int credential_from_potentially_partial_url(struct credential *c,
  43                                                    const char *url);
  44
  45 static int credential_config_callback(const char *var, const char *value,
  46                                       void *data)
  47 {
  48         struct credential *c = data;
  49         const char *key;
  50
  51         if (!skip_prefix(var, "credential.", &key))
  52                 return 0;
  53
  54         if (!value)
  55                 return config_error_nonbool(var);
  56
  57         if (!strcmp(key, "helper")) {
  58                 if (*value)
  59                         string_list_append(&c->helpers, value);
  60                 else
  61                         string_list_clear(&c->helpers, 0);
  62         } else if (!strcmp(key, "username")) {
  63                 if (!c->username_from_proto) {
  64                         free(c->username);
  65                         c->username = xstrdup(value);
  66                 }
  67         }
  68         else if (!strcmp(key, "usehttppath"))
  69                 c->use_http_path = git_config_bool(var, value);
  70
  71         return 0;
  72 }
  73
  74 static int proto_is_http(const char *s)
  75 {
  76         if (!s)
  77                 return 0;
  78         return !strcmp(s, "https") || !strcmp(s, "http");
  79 }
  80
  81 static void credential_describe(struct credential *c, struct strbuf *out);
  82 static void credential_format(struct credential *c, struct strbuf *out);
  83
  84 static int select_all(const struct urlmatch_item *a,
  85                       const struct urlmatch_item *b)
  86 {
  87         return 0;
  88 }
  89
  90 static int match_partial_url(const char *url, void *cb)
  91 {
  92         struct credential *c = cb;
  93         struct credential want = CREDENTIAL_INIT;
  94         int matches = 0;
  95
  96         if (credential_from_potentially_partial_url(&want, url) < 0)
  97                 warning(_("skipping credential lookup for key: credential.%s"),
  98                         url);
  99         else
 100                 matches = credential_match(&want, c);
 101         credential_clear(&want);
 102
 103         return matches;
 104 }
 105
 106 static void credential_apply_config(struct credential *c)
 107 {
 108         char *normalized_url;
 109         struct urlmatch_config config = URLMATCH_CONFIG_INIT;
 110         struct strbuf url = STRBUF_INIT;
 111
 112         if (!c->host)
 113                 die(_("refusing to work with credential missing host field"));
 114         if (!c->protocol)
 115                 die(_("refusing to work with credential missing protocol field"));
 116
 117         if (c->configured)
 118                 return;
 119
 120         config.section = "credential";
 121         config.key = NULL;
 122         config.collect_fn = credential_config_callback;
 123         config.cascade_fn = NULL;
 124         config.select_fn = select_all;
 125         config.fallback_match_fn = match_partial_url;
 126         config.cb = c;
 127
 128         credential_format(c, &url);
 129         normalized_url = url_normalize(url.buf, &config.url);
 130
 131         git_config(urlmatch_config_entry, &config);
 132         string_list_clear(&config.vars, 1);
 133         free(normalized_url);
 134         urlmatch_config_release(&config);
 135         strbuf_release(&url);
 136
 137         c->configured = 1;
 138
 139         if (!c->use_http_path && proto_is_http(c->protocol)) {
 140                 FREE_AND_NULL(c->path);
 141         }
 142 }
 143
 144 static void credential_describe(struct credential *c, struct strbuf *out)
 145 {
 146         if (!c->protocol)
 147                 return;
 148         strbuf_addf(out, "%s://", c->protocol);
 149         if (c->username && *c->username)
 150                 strbuf_addf(out, "%s@", c->username);
 151         if (c->host)
 152                 strbuf_addstr(out, c->host);
 153         if (c->path)
 154                 strbuf_addf(out, "/%s", c->path);
 155 }
 156
 157 static void credential_format(struct credential *c, struct strbuf *out)
 158 {
 159         if (!c->protocol)
 160                 return;
 161         strbuf_addf(out, "%s://", c->protocol);
 162         if (c->username && *c->username) {
 163                 strbuf_add_percentencode(out, c->username, STRBUF_ENCODE_SLASH);
 164                 strbuf_addch(out, '@');
 165         }
 166         if (c->host)
 167                 strbuf_addstr(out, c->host);
 168         if (c->path) {
 169                 strbuf_addch(out, '/');
 170                 strbuf_add_percentencode(out, c->path, 0);
 171         }
 172 }
 173
 174 static char *credential_ask_one(const char *what, struct credential *c,
 175                                 int flags)
 176 {
 177         struct strbuf desc = STRBUF_INIT;
 178         struct strbuf prompt = STRBUF_INIT;
 179         char *r;
 180
 181         credential_describe(c, &desc);
 182         if (desc.len)
 183                 strbuf_addf(&prompt, "%s for '%s': ", what, desc.buf);
 184         else
 185                 strbuf_addf(&prompt, "%s: ", what);
 186
 187         r = git_prompt(prompt.buf, flags);
 188
 189         strbuf_release(&desc);
 190         strbuf_release(&prompt);
 191         return xstrdup(r);
 192 }
 193
 194 static void credential_getpass(struct credential *c)
 195 {
 196         if (!c->username)
 197                 c->username = credential_ask_one("Username", c,
 198                                                  PROMPT_ASKPASS|PROMPT_ECHO);
 199         if (!c->password)
 200                 c->password = credential_ask_one("Password", c,
 201                                                  PROMPT_ASKPASS);
 202 }
 203
 204 int credential_read(struct credential *c, FILE *fp)
 205 {
 206         struct strbuf line = STRBUF_INIT;
 207
 208         while (strbuf_getline(&line, fp) != EOF) {
 209                 char *key = line.buf;
 210                 char *value = strchr(key, '=');
 211
 212                 if (!line.len)
 213                         break;
 214
 215                 if (!value) {
 216                         warning("invalid credential line: %s", key);
 217                         strbuf_release(&line);
 218                         return -1;
 219                 }
 220                 *value++ = '\0';
 221
 222                 if (!strcmp(key, "username")) {
 223                         free(c->username);
 224                         c->username = xstrdup(value);
 225                         c->username_from_proto = 1;
 226                 } else if (!strcmp(key, "password")) {
 227                         free(c->password);
 228                         c->password = xstrdup(value);
 229                 } else if (!strcmp(key, "protocol")) {
 230                         free(c->protocol);
 231                         c->protocol = xstrdup(value);
 232                 } else if (!strcmp(key, "host")) {
 233                         free(c->host);
 234                         c->host = xstrdup(value);
 235                 } else if (!strcmp(key, "path")) {
 236                         free(c->path);
 237                         c->path = xstrdup(value);
 238                 } else if (!strcmp(key, "password_expiry_utc")) {
 239                         errno = 0;
 240                         c->password_expiry_utc = parse_timestamp(value, NULL, 10);
 241                         if (c->password_expiry_utc == 0 || errno == ERANGE)
 242                                 c->password_expiry_utc = TIME_MAX;
 243                 } else if (!strcmp(key, "url")) {
 244                         credential_from_url(c, value);
 245                 } else if (!strcmp(key, "quit")) {
 246                         c->quit = !!git_config_bool("quit", value);
 247                 }
 248                 /*
 249                  * Ignore other lines; we don't know what they mean, but
 250                  * this future-proofs us when later versions of git do
 251                  * learn new lines, and the helpers are updated to match.
 252                  */
 253         }
 254
 255         strbuf_release(&line);
 256         return 0;
 257 }
 258
 259 static void credential_write_item(FILE *fp, const char *key, const char *value,
 260                                   int required)
 261 {
 262         if (!value && required)
 263                 BUG("credential value for %s is missing", key);
 264         if (!value)
 265                 return;
 266         if (strchr(value, '\n'))
 267                 die("credential value for %s contains newline", key);
 268         fprintf(fp, "%s=%s\n", key, value);
 269 }
 270
 271 void credential_write(const struct credential *c, FILE *fp)
 272 {
 273         credential_write_item(fp, "protocol", c->protocol, 1);
 274         credential_write_item(fp, "host", c->host, 1);
 275         credential_write_item(fp, "path", c->path, 0);
 276         credential_write_item(fp, "username", c->username, 0);
 277         credential_write_item(fp, "password", c->password, 0);
 278         if (c->password_expiry_utc != TIME_MAX) {
 279                 char *s = xstrfmt("%"PRItime, c->password_expiry_utc);
 280                 credential_write_item(fp, "password_expiry_utc", s, 0);
 281                 free(s);
 282         }
 283 }
 284
 285 static int run_credential_helper(struct credential *c,
 286                                  const char *cmd,
 287                                  int want_output)
 288 {
 289         struct child_process helper = CHILD_PROCESS_INIT;
 290         FILE *fp;
 291
 292         strvec_push(&helper.args, cmd);
 293         helper.use_shell = 1;
 294         helper.in = -1;
 295         if (want_output)
 296                 helper.out = -1;
 297         else
 298                 helper.no_stdout = 1;
 299
 300         if (start_command(&helper) < 0)
 301                 return -1;
 302
 303         fp = xfdopen(helper.in, "w");
 304         sigchain_push(SIGPIPE, SIG_IGN);
 305         credential_write(c, fp);
 306         fclose(fp);
 307         sigchain_pop(SIGPIPE);
 308
 309         if (want_output) {
 310                 int r;
 311                 fp = xfdopen(helper.out, "r");
 312                 r = credential_read(c, fp);
 313                 fclose(fp);
 314                 if (r < 0) {
 315                         finish_command(&helper);
 316                         return -1;
 317                 }
 318         }
 319
 320         if (finish_command(&helper))
 321                 return -1;
 322         return 0;
 323 }
 324
 325 static int credential_do(struct credential *c, const char *helper,
 326                          const char *operation)
 327 {
 328         struct strbuf cmd = STRBUF_INIT;
 329         int r;
 330
 331         if (helper[0] == '!')
 332                 strbuf_addstr(&cmd, helper + 1);
 333         else if (is_absolute_path(helper))
 334                 strbuf_addstr(&cmd, helper);
 335         else
 336                 strbuf_addf(&cmd, "git credential-%s", helper);
 337
 338         strbuf_addf(&cmd, " %s", operation);
 339         r = run_credential_helper(c, cmd.buf, !strcmp(operation, "get"));
 340
 341         strbuf_release(&cmd);
 342         return r;
 343 }
 344
 345 void credential_fill(struct credential *c)
 346 {
 347         int i;
 348
 349         if (c->username && c->password)
 350                 return;
 351
 352         credential_apply_config(c);
 353
 354         for (i = 0; i < c->helpers.nr; i++) {
 355                 credential_do(c, c->helpers.items[i].string, "get");
 356                 if (c->password_expiry_utc < time(NULL)) {
 357                         /* Discard expired password */
 358                         FREE_AND_NULL(c->password);
 359                         /* Reset expiry to maintain consistency */
 360                         c->password_expiry_utc = TIME_MAX;
 361                 }
 362                 if (c->username && c->password)
 363                         return;
 364                 if (c->quit)
 365                         die("credential helper '%s' told us to quit",
 366                             c->helpers.items[i].string);
 367         }
 368
 369         credential_getpass(c);
 370         if (!c->username && !c->password)
 371                 die("unable to get password from user");
 372 }
 373
 374 void credential_approve(struct credential *c)
 375 {
 376         int i;
 377
 378         if (c->approved)
 379                 return;
 380         if (!c->username || !c->password || c->password_expiry_utc < time(NULL))
 381                 return;
 382
 383         credential_apply_config(c);
 384
 385         for (i = 0; i < c->helpers.nr; i++)
 386                 credential_do(c, c->helpers.items[i].string, "store");
 387         c->approved = 1;
 388 }
 389
 390 void credential_reject(struct credential *c)
 391 {
 392         int i;
 393
 394         credential_apply_config(c);
 395
 396         for (i = 0; i < c->helpers.nr; i++)
 397                 credential_do(c, c->helpers.items[i].string, "erase");
 398
 399         FREE_AND_NULL(c->username);
 400         FREE_AND_NULL(c->password);
 401         c->password_expiry_utc = TIME_MAX;
 402         c->approved = 0;
 403 }
 404
 405 static int check_url_component(const char *url, int quiet,
 406                                const char *name, const char *value)
 407 {
 408         if (!value)
 409                 return 0;
 410         if (!strchr(value, '\n'))
 411                 return 0;
 412
 413         if (!quiet)
 414                 warning(_("url contains a newline in its %s component: %s"),
 415                         name, url);
 416         return -1;
 417 }
 418
 419 /*
 420  * Potentially-partial URLs can, but do not have to, contain
 421  *
 422  * - a protocol (or scheme) of the form "<protocol>://"
 423  *
 424  * - a host name (the part after the protocol and before the first slash after
 425  *   that, if any)
 426  *
 427  * - a user name and potentially a password (as "<user>[:<password>]@" part of
 428  *   the host name)
 429  *
 430  * - a path (the part after the host name, if any, starting with the slash)
 431  *
 432  * Missing parts will be left unset in `struct credential`. Thus, `https://`
 433  * will have only the `protocol` set, `example.com` only the host name, and
 434  * `/git` only the path.
 435  *
 436  * Note that an empty host name in an otherwise fully-qualified URL (e.g.
 437  * `cert:///path/to/cert.pem`) will be treated as unset if we expect the URL to
 438  * be potentially partial, and only then (otherwise, the empty string is used).
 439  *
 440  * The credential_from_url() function does not allow partial URLs.
 441  */
 442 static int credential_from_url_1(struct credential *c, const char *url,
 443                                  int allow_partial_url, int quiet)
 444 {
 445         const char *at, *colon, *cp, *slash, *host, *proto_end;
 446
 447         credential_clear(c);
 448
 449         /*
 450          * Match one of:
 451          *   (1) proto://<host>/...
 452          *   (2) proto://<user>@<host>/...
 453          *   (3) proto://<user>:<pass>@<host>/...
 454          */
 455         proto_end = strstr(url, "://");
 456         if (!allow_partial_url && (!proto_end || proto_end == url)) {
 457                 if (!quiet)
 458                         warning(_("url has no scheme: %s"), url);
 459                 return -1;
 460         }
 461         cp = proto_end ? proto_end + 3 : url;
 462         at = strchr(cp, '@');
 463         colon = strchr(cp, ':');
 464
 465         /*
 466          * A query or fragment marker before the slash ends the host portion.
 467          * We'll just continue to call this "slash" for simplicity. Notably our
 468          * "trim leading slashes" part won't skip over this part of the path,
 469          * but that's what we'd want.
 470          */
 471         slash = cp + strcspn(cp, "/?#");
 472
 473         if (!at || slash <= at) {
 474                 /* Case (1) */
 475                 host = cp;
 476         }
 477         else if (!colon || at <= colon) {
 478                 /* Case (2) */
 479                 c->username = url_decode_mem(cp, at - cp);
 480                 if (c->username && *c->username)
 481                         c->username_from_proto = 1;
 482                 host = at + 1;
 483         } else {
 484                 /* Case (3) */
 485                 c->username = url_decode_mem(cp, colon - cp);
 486                 if (c->username && *c->username)
 487                         c->username_from_proto = 1;
 488                 c->password = url_decode_mem(colon + 1, at - (colon + 1));
 489                 host = at + 1;
 490         }
 491
 492         if (proto_end && proto_end - url > 0)
 493                 c->protocol = xmemdupz(url, proto_end - url);
 494         if (!allow_partial_url || slash - host > 0)
 495                 c->host = url_decode_mem(host, slash - host);
 496         /* Trim leading and trailing slashes from path */
 497         while (*slash == '/')
 498                 slash++;
 499         if (*slash) {
 500                 char *p;
 501                 c->path = url_decode(slash);
 502                 p = c->path + strlen(c->path) - 1;
 503                 while (p > c->path && *p == '/')
 504                         *p-- = '\0';
 505         }
 506
 507         if (check_url_component(url, quiet, "username", c->username) < 0 ||
 508             check_url_component(url, quiet, "password", c->password) < 0 ||
 509             check_url_component(url, quiet, "protocol", c->protocol) < 0 ||
 510             check_url_component(url, quiet, "host", c->host) < 0 ||
 511             check_url_component(url, quiet, "path", c->path) < 0)
 512                 return -1;
 513
 514         return 0;
 515 }
 516
 517 static int credential_from_potentially_partial_url(struct credential *c,
 518                                                    const char *url)
 519 {
 520         return credential_from_url_1(c, url, 1, 0);
 521 }
 522
 523 int credential_from_url_gently(struct credential *c, const char *url, int quiet)
 524 {
 525         return credential_from_url_1(c, url, 0, quiet);
 526 }
 527
 528 void credential_from_url(struct credential *c, const char *url)
 529 {
 530         if (credential_from_url_gently(c, url, 0) < 0)
 531                 die(_("credential url cannot be parsed: %s"), url);
 532 }