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