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