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         credential_clear_secrets(c);
  24         free(c->protocol);
  25         free(c->host);
  26         free(c->path);
  27         free(c->username);
  28         free(c->oauth_refresh_token);
  29         free(c->authtype);
  30         string_list_clear(&c->helpers, 0);
  31         strvec_clear(&c->wwwauth_headers);
  32         strvec_clear(&c->state_headers);
  33         strvec_clear(&c->state_headers_to_send);
  34
  35         credential_init(c);
  36 }
  37
  38 void credential_next_state(struct credential *c)
  39 {
  40         strvec_clear(&c->state_headers_to_send);
  41         SWAP(c->state_headers, c->state_headers_to_send);
  42 }
  43
  44 void credential_clear_secrets(struct credential *c)
  45 {
  46         FREE_AND_NULL(c->password);
  47         FREE_AND_NULL(c->credential);
  48 }
  49
  50 static void credential_set_capability(struct credential_capability *capa,
  51                                       enum credential_op_type op_type)
  52 {
  53         switch (op_type) {
  54         case CREDENTIAL_OP_INITIAL:
  55                 capa->request_initial = 1;
  56                 break;
  57         case CREDENTIAL_OP_HELPER:
  58                 capa->request_helper = 1;
  59                 break;
  60         case CREDENTIAL_OP_RESPONSE:
  61                 capa->response = 1;
  62                 break;
  63         }
  64 }
  65
  66
  67 void credential_set_all_capabilities(struct credential *c,
  68                                      enum credential_op_type op_type)
  69 {
  70         credential_set_capability(&c->capa_authtype, op_type);
  71         credential_set_capability(&c->capa_state, op_type);
  72 }
  73
  74 static void announce_one(struct credential_capability *cc, const char *name, FILE *fp) {
  75         if (cc->request_initial)
  76                 fprintf(fp, "capability %s\n", name);
  77 }
  78
  79 void credential_announce_capabilities(struct credential *c, FILE *fp) {
  80         fprintf(fp, "version 0\n");
  81         announce_one(&c->capa_authtype, "authtype", fp);
  82         announce_one(&c->capa_state, "state", fp);
  83 }
  84
  85 int credential_match(const struct credential *want,
  86                      const struct credential *have, int match_password)
  87 {
  88 #define CHECK(x) (!want->x || (have->x && !strcmp(want->x, have->x)))
  89         return CHECK(protocol) &&
  90                CHECK(host) &&
  91                CHECK(path) &&
  92                CHECK(username) &&
  93                (!match_password || CHECK(password)) &&
  94                (!match_password || CHECK(credential));
  95 #undef CHECK
  96 }
  97
  98
  99 static int credential_from_potentially_partial_url(struct credential *c,
 100                                                    const char *url);
 101
 102 static int credential_config_callback(const char *var, const char *value,
 103                                       const struct config_context *ctx UNUSED,
 104                                       void *data)
 105 {
 106         struct credential *c = data;
 107         const char *key;
 108
 109         if (!skip_prefix(var, "credential.", &key))
 110                 return 0;
 111
 112         if (!value)
 113                 return config_error_nonbool(var);
 114
 115         if (!strcmp(key, "helper")) {
 116                 if (*value)
 117                         string_list_append(&c->helpers, value);
 118                 else
 119                         string_list_clear(&c->helpers, 0);
 120         } else if (!strcmp(key, "username")) {
 121                 if (!c->username_from_proto) {
 122                         free(c->username);
 123                         c->username = xstrdup(value);
 124                 }
 125         }
 126         else if (!strcmp(key, "usehttppath"))
 127                 c->use_http_path = git_config_bool(var, value);
 128
 129         return 0;
 130 }
 131
 132 static int proto_is_http(const char *s)
 133 {
 134         if (!s)
 135                 return 0;
 136         return !strcmp(s, "https") || !strcmp(s, "http");
 137 }
 138
 139 static void credential_describe(struct credential *c, struct strbuf *out);
 140 static void credential_format(struct credential *c, struct strbuf *out);
 141
 142 static int select_all(const struct urlmatch_item *a UNUSED,
 143                       const struct urlmatch_item *b UNUSED)
 144 {
 145         return 0;
 146 }
 147
 148 static int match_partial_url(const char *url, void *cb)
 149 {
 150         struct credential *c = cb;
 151         struct credential want = CREDENTIAL_INIT;
 152         int matches = 0;
 153
 154         if (credential_from_potentially_partial_url(&want, url) < 0)
 155                 warning(_("skipping credential lookup for key: credential.%s"),
 156                         url);
 157         else
 158                 matches = credential_match(&want, c, 0);
 159         credential_clear(&want);
 160
 161         return matches;
 162 }
 163
 164 static void credential_apply_config(struct credential *c)
 165 {
 166         char *normalized_url;
 167         struct urlmatch_config config = URLMATCH_CONFIG_INIT;
 168         struct strbuf url = STRBUF_INIT;
 169
 170         if (!c->host)
 171                 die(_("refusing to work with credential missing host field"));
 172         if (!c->protocol)
 173                 die(_("refusing to work with credential missing protocol field"));
 174
 175         if (c->configured)
 176                 return;
 177
 178         config.section = "credential";
 179         config.key = NULL;
 180         config.collect_fn = credential_config_callback;
 181         config.cascade_fn = NULL;
 182         config.select_fn = select_all;
 183         config.fallback_match_fn = match_partial_url;
 184         config.cb = c;
 185
 186         credential_format(c, &url);
 187         normalized_url = url_normalize(url.buf, &config.url);
 188
 189         git_config(urlmatch_config_entry, &config);
 190         string_list_clear(&config.vars, 1);
 191         free(normalized_url);
 192         urlmatch_config_release(&config);
 193         strbuf_release(&url);
 194
 195         c->configured = 1;
 196
 197         if (!c->use_http_path && proto_is_http(c->protocol)) {
 198                 FREE_AND_NULL(c->path);
 199         }
 200 }
 201
 202 static void credential_describe(struct credential *c, struct strbuf *out)
 203 {
 204         if (!c->protocol)
 205                 return;
 206         strbuf_addf(out, "%s://", c->protocol);
 207         if (c->username && *c->username)
 208                 strbuf_addf(out, "%s@", c->username);
 209         if (c->host)
 210                 strbuf_addstr(out, c->host);
 211         if (c->path)
 212                 strbuf_addf(out, "/%s", c->path);
 213 }
 214
 215 static void credential_format(struct credential *c, struct strbuf *out)
 216 {
 217         if (!c->protocol)
 218                 return;
 219         strbuf_addf(out, "%s://", c->protocol);
 220         if (c->username && *c->username) {
 221                 strbuf_add_percentencode(out, c->username, STRBUF_ENCODE_SLASH);
 222                 strbuf_addch(out, '@');
 223         }
 224         if (c->host)
 225                 strbuf_addstr(out, c->host);
 226         if (c->path) {
 227                 strbuf_addch(out, '/');
 228                 strbuf_add_percentencode(out, c->path, 0);
 229         }
 230 }
 231
 232 static char *credential_ask_one(const char *what, struct credential *c,
 233                                 int flags)
 234 {
 235         struct strbuf desc = STRBUF_INIT;
 236         struct strbuf prompt = STRBUF_INIT;
 237         char *r;
 238
 239         credential_describe(c, &desc);
 240         if (desc.len)
 241                 strbuf_addf(&prompt, "%s for '%s': ", what, desc.buf);
 242         else
 243                 strbuf_addf(&prompt, "%s: ", what);
 244
 245         r = git_prompt(prompt.buf, flags);
 246
 247         strbuf_release(&desc);
 248         strbuf_release(&prompt);
 249         return xstrdup(r);
 250 }
 251
 252 static void credential_getpass(struct credential *c)
 253 {
 254         if (!c->username)
 255                 c->username = credential_ask_one("Username", c,
 256                                                  PROMPT_ASKPASS|PROMPT_ECHO);
 257         if (!c->password)
 258                 c->password = credential_ask_one("Password", c,
 259                                                  PROMPT_ASKPASS);
 260 }
 261
 262 int credential_has_capability(const struct credential_capability *capa,
 263                               enum credential_op_type op_type)
 264 {
 265         /*
 266          * We're checking here if each previous step indicated that we had the
 267          * capability.  If it did, then we want to pass it along; conversely, if
 268          * it did not, we don't want to report that to our caller.
 269          */
 270         switch (op_type) {
 271         case CREDENTIAL_OP_HELPER:
 272                 return capa->request_initial;
 273         case CREDENTIAL_OP_RESPONSE:
 274                 return capa->request_initial && capa->request_helper;
 275         default:
 276                 return 0;
 277         }
 278 }
 279
 280 int credential_read(struct credential *c, FILE *fp,
 281                     enum credential_op_type op_type)
 282 {
 283         struct strbuf line = STRBUF_INIT;
 284
 285         while (strbuf_getline(&line, fp) != EOF) {
 286                 char *key = line.buf;
 287                 char *value = strchr(key, '=');
 288
 289                 if (!line.len)
 290                         break;
 291
 292                 if (!value) {
 293                         warning("invalid credential line: %s", key);
 294                         strbuf_release(&line);
 295                         return -1;
 296                 }
 297                 *value++ = '\0';
 298
 299                 if (!strcmp(key, "username")) {
 300                         free(c->username);
 301                         c->username = xstrdup(value);
 302                         c->username_from_proto = 1;
 303                 } else if (!strcmp(key, "password")) {
 304                         free(c->password);
 305                         c->password = xstrdup(value);
 306                 } else if (!strcmp(key, "credential")) {
 307                         free(c->credential);
 308                         c->credential = xstrdup(value);
 309                 } else if (!strcmp(key, "protocol")) {
 310                         free(c->protocol);
 311                         c->protocol = xstrdup(value);
 312                 } else if (!strcmp(key, "host")) {
 313                         free(c->host);
 314                         c->host = xstrdup(value);
 315                 } else if (!strcmp(key, "path")) {
 316                         free(c->path);
 317                         c->path = xstrdup(value);
 318                 } else if (!strcmp(key, "ephemeral")) {
 319                         c->ephemeral = !!git_config_bool("ephemeral", value);
 320                 } else if (!strcmp(key, "wwwauth[]")) {
 321                         strvec_push(&c->wwwauth_headers, value);
 322                 } else if (!strcmp(key, "state[]")) {
 323                         strvec_push(&c->state_headers, value);
 324                 } else if (!strcmp(key, "capability[]")) {
 325                         if (!strcmp(value, "authtype"))
 326                                 credential_set_capability(&c->capa_authtype, op_type);
 327                         else if (!strcmp(value, "state"))
 328                                 credential_set_capability(&c->capa_state, op_type);
 329                 } else if (!strcmp(key, "continue")) {
 330                         c->multistage = !!git_config_bool("continue", value);
 331                 } else if (!strcmp(key, "password_expiry_utc")) {
 332                         errno = 0;
 333                         c->password_expiry_utc = parse_timestamp(value, NULL, 10);
 334                         if (c->password_expiry_utc == 0 || errno == ERANGE)
 335                                 c->password_expiry_utc = TIME_MAX;
 336                 } else if (!strcmp(key, "oauth_refresh_token")) {
 337                         free(c->oauth_refresh_token);
 338                         c->oauth_refresh_token = xstrdup(value);
 339                 } else if (!strcmp(key, "authtype")) {
 340                         free(c->authtype);
 341                         c->authtype = xstrdup(value);
 342                 } else if (!strcmp(key, "url")) {
 343                         credential_from_url(c, value);
 344                 } else if (!strcmp(key, "quit")) {
 345                         c->quit = !!git_config_bool("quit", value);
 346                 }
 347                 /*
 348                  * Ignore other lines; we don't know what they mean, but
 349                  * this future-proofs us when later versions of git do
 350                  * learn new lines, and the helpers are updated to match.
 351                  */
 352         }
 353
 354         strbuf_release(&line);
 355         return 0;
 356 }
 357
 358 static void credential_write_item(FILE *fp, const char *key, const char *value,
 359                                   int required)
 360 {
 361         if (!value && required)
 362                 BUG("credential value for %s is missing", key);
 363         if (!value)
 364                 return;
 365         if (strchr(value, '\n'))
 366                 die("credential value for %s contains newline", key);
 367         fprintf(fp, "%s=%s\n", key, value);
 368 }
 369
 370 void credential_write(const struct credential *c, FILE *fp,
 371                       enum credential_op_type op_type)
 372 {
 373         if (credential_has_capability(&c->capa_authtype, op_type))
 374                 credential_write_item(fp, "capability[]", "authtype", 0);
 375         if (credential_has_capability(&c->capa_state, op_type))
 376                 credential_write_item(fp, "capability[]", "state", 0);
 377
 378         if (credential_has_capability(&c->capa_authtype, op_type)) {
 379                 credential_write_item(fp, "authtype", c->authtype, 0);
 380                 credential_write_item(fp, "credential", c->credential, 0);
 381                 if (c->ephemeral)
 382                         credential_write_item(fp, "ephemeral", "1", 0);
 383         }
 384         credential_write_item(fp, "protocol", c->protocol, 1);
 385         credential_write_item(fp, "host", c->host, 1);
 386         credential_write_item(fp, "path", c->path, 0);
 387         credential_write_item(fp, "username", c->username, 0);
 388         credential_write_item(fp, "password", c->password, 0);
 389         credential_write_item(fp, "oauth_refresh_token", c->oauth_refresh_token, 0);
 390         if (c->password_expiry_utc != TIME_MAX) {
 391                 char *s = xstrfmt("%"PRItime, c->password_expiry_utc);
 392                 credential_write_item(fp, "password_expiry_utc", s, 0);
 393                 free(s);
 394         }
 395         for (size_t i = 0; i < c->wwwauth_headers.nr; i++)
 396                 credential_write_item(fp, "wwwauth[]", c->wwwauth_headers.v[i], 0);
 397         if (credential_has_capability(&c->capa_state, op_type)) {
 398                 if (c->multistage)
 399                         credential_write_item(fp, "continue", "1", 0);
 400                 for (size_t i = 0; i < c->state_headers_to_send.nr; i++)
 401                         credential_write_item(fp, "state[]", c->state_headers_to_send.v[i], 0);
 402         }
 403 }
 404
 405 static int run_credential_helper(struct credential *c,
 406                                  const char *cmd,
 407                                  int want_output)
 408 {
 409         struct child_process helper = CHILD_PROCESS_INIT;
 410         FILE *fp;
 411
 412         strvec_push(&helper.args, cmd);
 413         helper.use_shell = 1;
 414         helper.in = -1;
 415         if (want_output)
 416                 helper.out = -1;
 417         else
 418                 helper.no_stdout = 1;
 419
 420         if (start_command(&helper) < 0)
 421                 return -1;
 422
 423         fp = xfdopen(helper.in, "w");
 424         sigchain_push(SIGPIPE, SIG_IGN);
 425         credential_write(c, fp, want_output ? CREDENTIAL_OP_HELPER : CREDENTIAL_OP_RESPONSE);
 426         fclose(fp);
 427         sigchain_pop(SIGPIPE);
 428
 429         if (want_output) {
 430                 int r;
 431                 fp = xfdopen(helper.out, "r");
 432                 r = credential_read(c, fp, CREDENTIAL_OP_HELPER);
 433                 fclose(fp);
 434                 if (r < 0) {
 435                         finish_command(&helper);
 436                         return -1;
 437                 }
 438         }
 439
 440         if (finish_command(&helper))
 441                 return -1;
 442         return 0;
 443 }
 444
 445 static int credential_do(struct credential *c, const char *helper,
 446                          const char *operation)
 447 {
 448         struct strbuf cmd = STRBUF_INIT;
 449         int r;
 450
 451         if (helper[0] == '!')
 452                 strbuf_addstr(&cmd, helper + 1);
 453         else if (is_absolute_path(helper))
 454                 strbuf_addstr(&cmd, helper);
 455         else
 456                 strbuf_addf(&cmd, "git credential-%s", helper);
 457
 458         strbuf_addf(&cmd, " %s", operation);
 459         r = run_credential_helper(c, cmd.buf, !strcmp(operation, "get"));
 460
 461         strbuf_release(&cmd);
 462         return r;
 463 }
 464
 465 void credential_fill(struct credential *c, int all_capabilities)
 466 {
 467         int i;
 468
 469         if ((c->username && c->password) || c->credential)
 470                 return;
 471
 472         credential_next_state(c);
 473         c->multistage = 0;
 474
 475         credential_apply_config(c);
 476         if (all_capabilities)
 477                 credential_set_all_capabilities(c, CREDENTIAL_OP_INITIAL);
 478
 479         for (i = 0; i < c->helpers.nr; i++) {
 480                 credential_do(c, c->helpers.items[i].string, "get");
 481
 482                 if (c->password_expiry_utc < time(NULL)) {
 483                         /*
 484                          * Don't use credential_clear() here: callers such as
 485                          * cmd_credential() expect to still be able to call
 486                          * credential_write() on a struct credential whose
 487                          * secrets have expired.
 488                          */
 489                         credential_clear_secrets(c);
 490                         /* Reset expiry to maintain consistency */
 491                         c->password_expiry_utc = TIME_MAX;
 492                 }
 493                 if ((c->username && c->password) || c->credential) {
 494                         strvec_clear(&c->wwwauth_headers);
 495                         return;
 496                 }
 497                 if (c->quit)
 498                         die("credential helper '%s' told us to quit",
 499                             c->helpers.items[i].string);
 500         }
 501
 502         credential_getpass(c);
 503         if (!c->username && !c->password && !c->credential)
 504                 die("unable to get password from user");
 505 }
 506
 507 void credential_approve(struct credential *c)
 508 {
 509         int i;
 510
 511         if (c->approved)
 512                 return;
 513         if (((!c->username || !c->password) && !c->credential) || c->password_expiry_utc < time(NULL))
 514                 return;
 515
 516         credential_next_state(c);
 517
 518         credential_apply_config(c);
 519
 520         for (i = 0; i < c->helpers.nr; i++)
 521                 credential_do(c, c->helpers.items[i].string, "store");
 522         c->approved = 1;
 523 }
 524
 525 void credential_reject(struct credential *c)
 526 {
 527         int i;
 528
 529         credential_next_state(c);
 530
 531         credential_apply_config(c);
 532
 533         for (i = 0; i < c->helpers.nr; i++)
 534                 credential_do(c, c->helpers.items[i].string, "erase");
 535
 536         credential_clear_secrets(c);
 537         FREE_AND_NULL(c->username);
 538         FREE_AND_NULL(c->oauth_refresh_token);
 539         c->password_expiry_utc = TIME_MAX;
 540         c->approved = 0;
 541 }
 542
 543 static int check_url_component(const char *url, int quiet,
 544                                const char *name, const char *value)
 545 {
 546         if (!value)
 547                 return 0;
 548         if (!strchr(value, '\n'))
 549                 return 0;
 550
 551         if (!quiet)
 552                 warning(_("url contains a newline in its %s component: %s"),
 553                         name, url);
 554         return -1;
 555 }
 556
 557 /*
 558  * Potentially-partial URLs can, but do not have to, contain
 559  *
 560  * - a protocol (or scheme) of the form "<protocol>://"
 561  *
 562  * - a host name (the part after the protocol and before the first slash after
 563  *   that, if any)
 564  *
 565  * - a user name and potentially a password (as "<user>[:<password>]@" part of
 566  *   the host name)
 567  *
 568  * - a path (the part after the host name, if any, starting with the slash)
 569  *
 570  * Missing parts will be left unset in `struct credential`. Thus, `https://`
 571  * will have only the `protocol` set, `example.com` only the host name, and
 572  * `/git` only the path.
 573  *
 574  * Note that an empty host name in an otherwise fully-qualified URL (e.g.
 575  * `cert:///path/to/cert.pem`) will be treated as unset if we expect the URL to
 576  * be potentially partial, and only then (otherwise, the empty string is used).
 577  *
 578  * The credential_from_url() function does not allow partial URLs.
 579  */
 580 static int credential_from_url_1(struct credential *c, const char *url,
 581                                  int allow_partial_url, int quiet)
 582 {
 583         const char *at, *colon, *cp, *slash, *host, *proto_end;
 584
 585         credential_clear(c);
 586
 587         /*
 588          * Match one of:
 589          *   (1) proto://<host>/...
 590          *   (2) proto://<user>@<host>/...
 591          *   (3) proto://<user>:<pass>@<host>/...
 592          */
 593         proto_end = strstr(url, "://");
 594         if (!allow_partial_url && (!proto_end || proto_end == url)) {
 595                 if (!quiet)
 596                         warning(_("url has no scheme: %s"), url);
 597                 return -1;
 598         }
 599         cp = proto_end ? proto_end + 3 : url;
 600         at = strchr(cp, '@');
 601         colon = strchr(cp, ':');
 602
 603         /*
 604          * A query or fragment marker before the slash ends the host portion.
 605          * We'll just continue to call this "slash" for simplicity. Notably our
 606          * "trim leading slashes" part won't skip over this part of the path,
 607          * but that's what we'd want.
 608          */
 609         slash = cp + strcspn(cp, "/?#");
 610
 611         if (!at || slash <= at) {
 612                 /* Case (1) */
 613                 host = cp;
 614         }
 615         else if (!colon || at <= colon) {
 616                 /* Case (2) */
 617                 c->username = url_decode_mem(cp, at - cp);
 618                 if (c->username && *c->username)
 619                         c->username_from_proto = 1;
 620                 host = at + 1;
 621         } else {
 622                 /* Case (3) */
 623                 c->username = url_decode_mem(cp, colon - cp);
 624                 if (c->username && *c->username)
 625                         c->username_from_proto = 1;
 626                 c->password = url_decode_mem(colon + 1, at - (colon + 1));
 627                 host = at + 1;
 628         }
 629
 630         if (proto_end && proto_end - url > 0)
 631                 c->protocol = xmemdupz(url, proto_end - url);
 632         if (!allow_partial_url || slash - host > 0)
 633                 c->host = url_decode_mem(host, slash - host);
 634         /* Trim leading and trailing slashes from path */
 635         while (*slash == '/')
 636                 slash++;
 637         if (*slash) {
 638                 char *p;
 639                 c->path = url_decode(slash);
 640                 p = c->path + strlen(c->path) - 1;
 641                 while (p > c->path && *p == '/')
 642                         *p-- = '\0';
 643         }
 644
 645         if (check_url_component(url, quiet, "username", c->username) < 0 ||
 646             check_url_component(url, quiet, "password", c->password) < 0 ||
 647             check_url_component(url, quiet, "protocol", c->protocol) < 0 ||
 648             check_url_component(url, quiet, "host", c->host) < 0 ||
 649             check_url_component(url, quiet, "path", c->path) < 0)
 650                 return -1;
 651
 652         return 0;
 653 }
 654
 655 static int credential_from_potentially_partial_url(struct credential *c,
 656                                                    const char *url)
 657 {
 658         return credential_from_url_1(c, url, 1, 0);
 659 }
 660
 661 int credential_from_url_gently(struct credential *c, const char *url, int quiet)
 662 {
 663         return credential_from_url_1(c, url, 0, quiet);
 664 }
 665
 666 void credential_from_url(struct credential *c, const char *url)
 667 {
 668         if (credential_from_url_gently(c, url, 0) < 0)
 669                 die(_("credential url cannot be parsed: %s"), url);
 670 }