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