credential.c

   1 #include "git-compat-util.h"
   2 #include "abspath.h"
   3 #include "config.h"
   4 #include "credential.h"
   5 #include "gettext.h"
   6 #include "string-list.h"
   7 #include "run-command.h"
   8 #include "url.h"
   9 #include "prompt.h"
  10 #include "sigchain.h"
  11 #include "strbuf.h"
  12 #include "urlmatch.h"
  13 #include "git-compat-util.h"
  14
  15 void credential_init(struct credential *c)
  16 {
  17         struct credential blank = CREDENTIAL_INIT;
  18         memcpy(c, &blank, sizeof(*c));
  19 }
  20
  21 void credential_clear(struct credential *c)
  22 {
  23         free(c->protocol);
  24         free(c->host);
  25         free(c->path);
  26         free(c->username);
  27         free(c->password);
  28         free(c->credential);
  29         free(c->oauth_refresh_token);
  30         free(c->authtype);
  31         string_list_clear(&c->helpers, 0);
  32         strvec_clear(&c->wwwauth_headers);
  33
  34         credential_init(c);
  35 }
  36
  37 static void credential_set_capability(struct credential_capability *capa,
  38                                       enum credential_op_type op_type)
  39 {
  40         switch (op_type) {
  41         case CREDENTIAL_OP_INITIAL:
  42                 capa->request_initial = 1;
  43                 break;
  44         case CREDENTIAL_OP_HELPER:
  45                 capa->request_helper = 1;
  46                 break;
  47         case CREDENTIAL_OP_RESPONSE:
  48                 capa->response = 1;
  49                 break;
  50         }
  51 }
  52
  53
  54 void credential_set_all_capabilities(struct credential *c,
  55                                      enum credential_op_type op_type)
  56 {
  57         credential_set_capability(&c->capa_authtype, op_type);
  58 }
  59
  60 int credential_match(const struct credential *want,
  61                      const struct credential *have, int match_password)
  62 {
  63 #define CHECK(x) (!want->x || (have->x && !strcmp(want->x, have->x)))
  64         return CHECK(protocol) &&
  65                CHECK(host) &&
  66                CHECK(path) &&
  67                CHECK(username) &&
  68                (!match_password || CHECK(password));
  69 #undef CHECK
  70 }
  71
  72
  73 static int credential_from_potentially_partial_url(struct credential *c,
  74                                                    const char *url);
  75
  76 static int credential_config_callback(const char *var, const char *value,
  77                                       const struct config_context *ctx UNUSED,
  78                                       void *data)
  79 {
  80         struct credential *c = data;
  81         const char *key;
  82
  83         if (!skip_prefix(var, "credential.", &key))
  84                 return 0;
  85
  86         if (!value)
  87                 return config_error_nonbool(var);
  88
  89         if (!strcmp(key, "helper")) {
  90                 if (*value)
  91                         string_list_append(&c->helpers, value);
  92                 else
  93                         string_list_clear(&c->helpers, 0);
  94         } else if (!strcmp(key, "username")) {
  95                 if (!c->username_from_proto) {
  96                         free(c->username);
  97                         c->username = xstrdup(value);
  98                 }
  99         }
 100         else if (!strcmp(key, "usehttppath"))
 101                 c->use_http_path = git_config_bool(var, value);
 102
 103         return 0;
 104 }
 105
 106 static int proto_is_http(const char *s)
 107 {
 108         if (!s)
 109                 return 0;
 110         return !strcmp(s, "https") || !strcmp(s, "http");
 111 }
 112
 113 static void credential_describe(struct credential *c, struct strbuf *out);
 114 static void credential_format(struct credential *c, struct strbuf *out);
 115
 116 static int select_all(const struct urlmatch_item *a UNUSED,
 117                       const struct urlmatch_item *b UNUSED)
 118 {
 119         return 0;
 120 }
 121
 122 static int match_partial_url(const char *url, void *cb)
 123 {
 124         struct credential *c = cb;
 125         struct credential want = CREDENTIAL_INIT;
 126         int matches = 0;
 127
 128         if (credential_from_potentially_partial_url(&want, url) < 0)
 129                 warning(_("skipping credential lookup for key: credential.%s"),
 130                         url);
 131         else
 132                 matches = credential_match(&want, c, 0);
 133         credential_clear(&want);
 134
 135         return matches;
 136 }
 137
 138 static void credential_apply_config(struct credential *c)
 139 {
 140         char *normalized_url;
 141         struct urlmatch_config config = URLMATCH_CONFIG_INIT;
 142         struct strbuf url = STRBUF_INIT;
 143
 144         if (!c->host)
 145                 die(_("refusing to work with credential missing host field"));
 146         if (!c->protocol)
 147                 die(_("refusing to work with credential missing protocol field"));
 148
 149         if (c->configured)
 150                 return;
 151
 152         config.section = "credential";
 153         config.key = NULL;
 154         config.collect_fn = credential_config_callback;
 155         config.cascade_fn = NULL;
 156         config.select_fn = select_all;
 157         config.fallback_match_fn = match_partial_url;
 158         config.cb = c;
 159
 160         credential_format(c, &url);
 161         normalized_url = url_normalize(url.buf, &config.url);
 162
 163         git_config(urlmatch_config_entry, &config);
 164         string_list_clear(&config.vars, 1);
 165         free(normalized_url);
 166         urlmatch_config_release(&config);
 167         strbuf_release(&url);
 168
 169         c->configured = 1;
 170
 171         if (!c->use_http_path && proto_is_http(c->protocol)) {
 172                 FREE_AND_NULL(c->path);
 173         }
 174 }
 175
 176 static void credential_describe(struct credential *c, struct strbuf *out)
 177 {
 178         if (!c->protocol)
 179                 return;
 180         strbuf_addf(out, "%s://", c->protocol);
 181         if (c->username && *c->username)
 182                 strbuf_addf(out, "%s@", c->username);
 183         if (c->host)
 184                 strbuf_addstr(out, c->host);
 185         if (c->path)
 186                 strbuf_addf(out, "/%s", c->path);
 187 }
 188
 189 static void credential_format(struct credential *c, struct strbuf *out)
 190 {
 191         if (!c->protocol)
 192                 return;
 193         strbuf_addf(out, "%s://", c->protocol);
 194         if (c->username && *c->username) {
 195                 strbuf_add_percentencode(out, c->username, STRBUF_ENCODE_SLASH);
 196                 strbuf_addch(out, '@');
 197         }
 198         if (c->host)
 199                 strbuf_addstr(out, c->host);
 200         if (c->path) {
 201                 strbuf_addch(out, '/');
 202                 strbuf_add_percentencode(out, c->path, 0);
 203         }
 204 }
 205
 206 static char *credential_ask_one(const char *what, struct credential *c,
 207                                 int flags)
 208 {
 209         struct strbuf desc = STRBUF_INIT;
 210         struct strbuf prompt = STRBUF_INIT;
 211         char *r;
 212
 213         credential_describe(c, &desc);
 214         if (desc.len)
 215                 strbuf_addf(&prompt, "%s for '%s': ", what, desc.buf);
 216         else
 217                 strbuf_addf(&prompt, "%s: ", what);
 218
 219         r = git_prompt(prompt.buf, flags);
 220
 221         strbuf_release(&desc);
 222         strbuf_release(&prompt);
 223         return xstrdup(r);
 224 }
 225
 226 static void credential_getpass(struct credential *c)
 227 {
 228         if (!c->username)
 229                 c->username = credential_ask_one("Username", c,
 230                                                  PROMPT_ASKPASS|PROMPT_ECHO);
 231         if (!c->password)
 232                 c->password = credential_ask_one("Password", c,
 233                                                  PROMPT_ASKPASS);
 234 }
 235
 236 static int credential_has_capability(const struct credential_capability *capa,
 237                                      enum credential_op_type op_type)
 238 {
 239         /*
 240          * We're checking here if each previous step indicated that we had the
 241          * capability.  If it did, then we want to pass it along; conversely, if
 242          * it did not, we don't want to report that to our caller.
 243          */
 244         switch (op_type) {
 245         case CREDENTIAL_OP_HELPER:
 246                 return capa->request_initial;
 247         case CREDENTIAL_OP_RESPONSE:
 248                 return capa->request_initial && capa->request_helper;
 249         default:
 250                 return 0;
 251         }
 252 }
 253
 254 int credential_read(struct credential *c, FILE *fp,
 255                     enum credential_op_type op_type)
 256 {
 257         struct strbuf line = STRBUF_INIT;
 258
 259         while (strbuf_getline(&line, fp) != EOF) {
 260                 char *key = line.buf;
 261                 char *value = strchr(key, '=');
 262
 263                 if (!line.len)
 264                         break;
 265
 266                 if (!value) {
 267                         warning("invalid credential line: %s", key);
 268                         strbuf_release(&line);
 269                         return -1;
 270                 }
 271                 *value++ = '\0';
 272
 273                 if (!strcmp(key, "username")) {
 274                         free(c->username);
 275                         c->username = xstrdup(value);
 276                         c->username_from_proto = 1;
 277                 } else if (!strcmp(key, "password")) {
 278                         free(c->password);
 279                         c->password = xstrdup(value);
 280                 } else if (!strcmp(key, "credential")) {
 281                         free(c->credential);
 282                         c->credential = xstrdup(value);
 283                 } else if (!strcmp(key, "protocol")) {
 284                         free(c->protocol);
 285                         c->protocol = xstrdup(value);
 286                 } else if (!strcmp(key, "host")) {
 287                         free(c->host);
 288                         c->host = xstrdup(value);
 289                 } else if (!strcmp(key, "path")) {
 290                         free(c->path);
 291                         c->path = xstrdup(value);
 292                 } else if (!strcmp(key, "ephemeral")) {
 293                         c->ephemeral = !!git_config_bool("ephemeral", value);
 294                 } else if (!strcmp(key, "wwwauth[]")) {
 295                         strvec_push(&c->wwwauth_headers, value);
 296                 } else if (!strcmp(key, "capability[]") && !strcmp(value, "authtype")) {
 297                         credential_set_capability(&c->capa_authtype, op_type);
 298                 } else if (!strcmp(key, "password_expiry_utc")) {
 299                         errno = 0;
 300                         c->password_expiry_utc = parse_timestamp(value, NULL, 10);
 301                         if (c->password_expiry_utc == 0 || errno == ERANGE)
 302                                 c->password_expiry_utc = TIME_MAX;
 303                 } else if (!strcmp(key, "oauth_refresh_token")) {
 304                         free(c->oauth_refresh_token);
 305                         c->oauth_refresh_token = xstrdup(value);
 306                 } else if (!strcmp(key, "authtype")) {
 307                         free(c->authtype);
 308                         c->authtype = xstrdup(value);
 309                 } else if (!strcmp(key, "url")) {
 310                         credential_from_url(c, value);
 311                 } else if (!strcmp(key, "quit")) {
 312                         c->quit = !!git_config_bool("quit", value);
 313                 }
 314                 /*
 315                  * Ignore other lines; we don't know what they mean, but
 316                  * this future-proofs us when later versions of git do
 317                  * learn new lines, and the helpers are updated to match.
 318                  */
 319         }
 320
 321         strbuf_release(&line);
 322         return 0;
 323 }
 324
 325 static void credential_write_item(FILE *fp, const char *key, const char *value,
 326                                   int required)
 327 {
 328         if (!value && required)
 329                 BUG("credential value for %s is missing", key);
 330         if (!value)
 331                 return;
 332         if (strchr(value, '\n'))
 333                 die("credential value for %s contains newline", key);
 334         fprintf(fp, "%s=%s\n", key, value);
 335 }
 336
 337 void credential_write(const struct credential *c, FILE *fp,
 338                       enum credential_op_type op_type)
 339 {
 340         if (credential_has_capability(&c->capa_authtype, op_type)) {
 341                 credential_write_item(fp, "capability[]", "authtype", 0);
 342                 credential_write_item(fp, "authtype", c->authtype, 0);
 343                 credential_write_item(fp, "credential", c->credential, 0);
 344                 if (c->ephemeral)
 345                         credential_write_item(fp, "ephemeral", "1", 0);
 346         }
 347         credential_write_item(fp, "protocol", c->protocol, 1);
 348         credential_write_item(fp, "host", c->host, 1);
 349         credential_write_item(fp, "path", c->path, 0);
 350         credential_write_item(fp, "username", c->username, 0);
 351         credential_write_item(fp, "password", c->password, 0);
 352         credential_write_item(fp, "oauth_refresh_token", c->oauth_refresh_token, 0);
 353         if (c->password_expiry_utc != TIME_MAX) {
 354                 char *s = xstrfmt("%"PRItime, c->password_expiry_utc);
 355                 credential_write_item(fp, "password_expiry_utc", s, 0);
 356                 free(s);
 357         }
 358         for (size_t i = 0; i < c->wwwauth_headers.nr; i++)
 359                 credential_write_item(fp, "wwwauth[]", c->wwwauth_headers.v[i], 0);
 360 }
 361
 362 static int run_credential_helper(struct credential *c,
 363                                  const char *cmd,
 364                                  int want_output)
 365 {
 366         struct child_process helper = CHILD_PROCESS_INIT;
 367         FILE *fp;
 368
 369         strvec_push(&helper.args, cmd);
 370         helper.use_shell = 1;
 371         helper.in = -1;
 372         if (want_output)
 373                 helper.out = -1;
 374         else
 375                 helper.no_stdout = 1;
 376
 377         if (start_command(&helper) < 0)
 378                 return -1;
 379
 380         fp = xfdopen(helper.in, "w");
 381         sigchain_push(SIGPIPE, SIG_IGN);
 382         credential_write(c, fp, want_output ? CREDENTIAL_OP_HELPER : CREDENTIAL_OP_RESPONSE);
 383         fclose(fp);
 384         sigchain_pop(SIGPIPE);
 385
 386         if (want_output) {
 387                 int r;
 388                 fp = xfdopen(helper.out, "r");
 389                 r = credential_read(c, fp, CREDENTIAL_OP_HELPER);
 390                 fclose(fp);
 391                 if (r < 0) {
 392                         finish_command(&helper);
 393                         return -1;
 394                 }
 395         }
 396
 397         if (finish_command(&helper))
 398                 return -1;
 399         return 0;
 400 }
 401
 402 static int credential_do(struct credential *c, const char *helper,
 403                          const char *operation)
 404 {
 405         struct strbuf cmd = STRBUF_INIT;
 406         int r;
 407
 408         if (helper[0] == '!')
 409                 strbuf_addstr(&cmd, helper + 1);
 410         else if (is_absolute_path(helper))
 411                 strbuf_addstr(&cmd, helper);
 412         else
 413                 strbuf_addf(&cmd, "git credential-%s", helper);
 414
 415         strbuf_addf(&cmd, " %s", operation);
 416         r = run_credential_helper(c, cmd.buf, !strcmp(operation, "get"));
 417
 418         strbuf_release(&cmd);
 419         return r;
 420 }
 421
 422 void credential_fill(struct credential *c, int all_capabilities)
 423 {
 424         int i;
 425
 426         if ((c->username && c->password) || c->credential)
 427                 return;
 428
 429         credential_apply_config(c);
 430         if (all_capabilities)
 431                 credential_set_all_capabilities(c, CREDENTIAL_OP_INITIAL);
 432
 433         for (i = 0; i < c->helpers.nr; i++) {
 434                 credential_do(c, c->helpers.items[i].string, "get");
 435                 if (c->password_expiry_utc < time(NULL)) {
 436                         /* Discard expired password */
 437                         FREE_AND_NULL(c->password);
 438                         /* Reset expiry to maintain consistency */
 439                         c->password_expiry_utc = TIME_MAX;
 440                 }
 441                 if ((c->username && c->password) || c->credential)
 442                         return;
 443                 if (c->quit)
 444                         die("credential helper '%s' told us to quit",
 445                             c->helpers.items[i].string);
 446         }
 447
 448         credential_getpass(c);
 449         if (!c->username && !c->password && !c->credential)
 450                 die("unable to get password from user");
 451 }
 452
 453 void credential_approve(struct credential *c)
 454 {
 455         int i;
 456
 457         if (c->approved)
 458                 return;
 459         if (((!c->username || !c->password) && !c->credential) || c->password_expiry_utc < time(NULL))
 460                 return;
 461
 462         credential_apply_config(c);
 463
 464         for (i = 0; i < c->helpers.nr; i++)
 465                 credential_do(c, c->helpers.items[i].string, "store");
 466         c->approved = 1;
 467 }
 468
 469 void credential_reject(struct credential *c)
 470 {
 471         int i;
 472
 473         credential_apply_config(c);
 474
 475         for (i = 0; i < c->helpers.nr; i++)
 476                 credential_do(c, c->helpers.items[i].string, "erase");
 477
 478         FREE_AND_NULL(c->username);
 479         FREE_AND_NULL(c->password);
 480         FREE_AND_NULL(c->credential);
 481         FREE_AND_NULL(c->oauth_refresh_token);
 482         c->password_expiry_utc = TIME_MAX;
 483         c->approved = 0;
 484 }
 485
 486 static int check_url_component(const char *url, int quiet,
 487                                const char *name, const char *value)
 488 {
 489         if (!value)
 490                 return 0;
 491         if (!strchr(value, '\n'))
 492                 return 0;
 493
 494         if (!quiet)
 495                 warning(_("url contains a newline in its %s component: %s"),
 496                         name, url);
 497         return -1;
 498 }
 499
 500 /*
 501  * Potentially-partial URLs can, but do not have to, contain
 502  *
 503  * - a protocol (or scheme) of the form "<protocol>://"
 504  *
 505  * - a host name (the part after the protocol and before the first slash after
 506  *   that, if any)
 507  *
 508  * - a user name and potentially a password (as "<user>[:<password>]@" part of
 509  *   the host name)
 510  *
 511  * - a path (the part after the host name, if any, starting with the slash)
 512  *
 513  * Missing parts will be left unset in `struct credential`. Thus, `https://`
 514  * will have only the `protocol` set, `example.com` only the host name, and
 515  * `/git` only the path.
 516  *
 517  * Note that an empty host name in an otherwise fully-qualified URL (e.g.
 518  * `cert:///path/to/cert.pem`) will be treated as unset if we expect the URL to
 519  * be potentially partial, and only then (otherwise, the empty string is used).
 520  *
 521  * The credential_from_url() function does not allow partial URLs.
 522  */
 523 static int credential_from_url_1(struct credential *c, const char *url,
 524                                  int allow_partial_url, int quiet)
 525 {
 526         const char *at, *colon, *cp, *slash, *host, *proto_end;
 527
 528         credential_clear(c);
 529
 530         /*
 531          * Match one of:
 532          *   (1) proto://<host>/...
 533          *   (2) proto://<user>@<host>/...
 534          *   (3) proto://<user>:<pass>@<host>/...
 535          */
 536         proto_end = strstr(url, "://");
 537         if (!allow_partial_url && (!proto_end || proto_end == url)) {
 538                 if (!quiet)
 539                         warning(_("url has no scheme: %s"), url);
 540                 return -1;
 541         }
 542         cp = proto_end ? proto_end + 3 : url;
 543         at = strchr(cp, '@');
 544         colon = strchr(cp, ':');
 545
 546         /*
 547          * A query or fragment marker before the slash ends the host portion.
 548          * We'll just continue to call this "slash" for simplicity. Notably our
 549          * "trim leading slashes" part won't skip over this part of the path,
 550          * but that's what we'd want.
 551          */
 552         slash = cp + strcspn(cp, "/?#");
 553
 554         if (!at || slash <= at) {
 555                 /* Case (1) */
 556                 host = cp;
 557         }
 558         else if (!colon || at <= colon) {
 559                 /* Case (2) */
 560                 c->username = url_decode_mem(cp, at - cp);
 561                 if (c->username && *c->username)
 562                         c->username_from_proto = 1;
 563                 host = at + 1;
 564         } else {
 565                 /* Case (3) */
 566                 c->username = url_decode_mem(cp, colon - cp);
 567                 if (c->username && *c->username)
 568                         c->username_from_proto = 1;
 569                 c->password = url_decode_mem(colon + 1, at - (colon + 1));
 570                 host = at + 1;
 571         }
 572
 573         if (proto_end && proto_end - url > 0)
 574                 c->protocol = xmemdupz(url, proto_end - url);
 575         if (!allow_partial_url || slash - host > 0)
 576                 c->host = url_decode_mem(host, slash - host);
 577         /* Trim leading and trailing slashes from path */
 578         while (*slash == '/')
 579                 slash++;
 580         if (*slash) {
 581                 char *p;
 582                 c->path = url_decode(slash);
 583                 p = c->path + strlen(c->path) - 1;
 584                 while (p > c->path && *p == '/')
 585                         *p-- = '\0';
 586         }
 587
 588         if (check_url_component(url, quiet, "username", c->username) < 0 ||
 589             check_url_component(url, quiet, "password", c->password) < 0 ||
 590             check_url_component(url, quiet, "protocol", c->protocol) < 0 ||
 591             check_url_component(url, quiet, "host", c->host) < 0 ||
 592             check_url_component(url, quiet, "path", c->path) < 0)
 593                 return -1;
 594
 595         return 0;
 596 }
 597
 598 static int credential_from_potentially_partial_url(struct credential *c,
 599                                                    const char *url)
 600 {
 601         return credential_from_url_1(c, url, 1, 0);
 602 }
 603
 604 int credential_from_url_gently(struct credential *c, const char *url, int quiet)
 605 {
 606         return credential_from_url_1(c, url, 0, quiet);
 607 }
 608
 609 void credential_from_url(struct credential *c, const char *url)
 610 {
 611         if (credential_from_url_gently(c, url, 0) < 0)
 612                 die(_("credential url cannot be parsed: %s"), url);
 613 }