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