credential.c

   1 #include "cache.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 "urlmatch.h"
  12 #include "git-compat-util.h"
  13
  14 void credential_init(struct credential *c)
  15 {
  16         struct credential blank = CREDENTIAL_INIT;
  17         memcpy(c, &blank, sizeof(*c));
  18 }
  19
  20 void credential_clear(struct credential *c)
  21 {
  22         free(c->protocol);
  23         free(c->host);
  24         free(c->path);
  25         free(c->username);
  26         free(c->password);
  27         string_list_clear(&c->helpers, 0);
  28         strvec_clear(&c->wwwauth_headers);
  29
  30         credential_init(c);
  31 }
  32
  33 int credential_match(const struct credential *want,
  34                      const struct credential *have)
  35 {
  36 #define CHECK(x) (!want->x || (have->x && !strcmp(want->x, have->x)))
  37         return CHECK(protocol) &&
  38                CHECK(host) &&
  39                CHECK(path) &&
  40                CHECK(username);
  41 #undef CHECK
  42 }
  43
  44
  45 static int credential_from_potentially_partial_url(struct credential *c,
  46                                                    const char *url);
  47
  48 static int credential_config_callback(const char *var, const char *value,
  49                                       void *data)
  50 {
  51         struct credential *c = data;
  52         const char *key;
  53
  54         if (!skip_prefix(var, "credential.", &key))
  55                 return 0;
  56
  57         if (!value)
  58                 return config_error_nonbool(var);
  59
  60         if (!strcmp(key, "helper")) {
  61                 if (*value)
  62                         string_list_append(&c->helpers, value);
  63                 else
  64                         string_list_clear(&c->helpers, 0);
  65         } else if (!strcmp(key, "username")) {
  66                 if (!c->username_from_proto) {
  67                         free(c->username);
  68                         c->username = xstrdup(value);
  69                 }
  70         }
  71         else if (!strcmp(key, "usehttppath"))
  72                 c->use_http_path = git_config_bool(var, value);
  73
  74         return 0;
  75 }
  76
  77 static int proto_is_http(const char *s)
  78 {
  79         if (!s)
  80                 return 0;
  81         return !strcmp(s, "https") || !strcmp(s, "http");
  82 }
  83
  84 static void credential_describe(struct credential *c, struct strbuf *out);
  85 static void credential_format(struct credential *c, struct strbuf *out);
  86
  87 static int select_all(const struct urlmatch_item *a,
  88                       const struct urlmatch_item *b)
  89 {
  90         return 0;
  91 }
  92
  93 static int match_partial_url(const char *url, void *cb)
  94 {
  95         struct credential *c = cb;
  96         struct credential want = CREDENTIAL_INIT;
  97         int matches = 0;
  98
  99         if (credential_from_potentially_partial_url(&want, url) < 0)
 100                 warning(_("skipping credential lookup for key: credential.%s"),
 101                         url);
 102         else
 103                 matches = credential_match(&want, c);
 104         credential_clear(&want);
 105
 106         return matches;
 107 }
 108
 109 static void credential_apply_config(struct credential *c)
 110 {
 111         char *normalized_url;
 112         struct urlmatch_config config = URLMATCH_CONFIG_INIT;
 113         struct strbuf url = STRBUF_INIT;
 114
 115         if (!c->host)
 116                 die(_("refusing to work with credential missing host field"));
 117         if (!c->protocol)
 118                 die(_("refusing to work with credential missing protocol field"));
 119
 120         if (c->configured)
 121                 return;
 122
 123         config.section = "credential";
 124         config.key = NULL;
 125         config.collect_fn = credential_config_callback;
 126         config.cascade_fn = NULL;
 127         config.select_fn = select_all;
 128         config.fallback_match_fn = match_partial_url;
 129         config.cb = c;
 130
 131         credential_format(c, &url);
 132         normalized_url = url_normalize(url.buf, &config.url);
 133
 134         git_config(urlmatch_config_entry, &config);
 135         string_list_clear(&config.vars, 1);
 136         free(normalized_url);
 137         urlmatch_config_release(&config);
 138         strbuf_release(&url);
 139
 140         c->configured = 1;
 141
 142         if (!c->use_http_path && proto_is_http(c->protocol)) {
 143                 FREE_AND_NULL(c->path);
 144         }
 145 }
 146
 147 static void credential_describe(struct credential *c, struct strbuf *out)
 148 {
 149         if (!c->protocol)
 150                 return;
 151         strbuf_addf(out, "%s://", c->protocol);
 152         if (c->username && *c->username)
 153                 strbuf_addf(out, "%s@", c->username);
 154         if (c->host)
 155                 strbuf_addstr(out, c->host);
 156         if (c->path)
 157                 strbuf_addf(out, "/%s", c->path);
 158 }
 159
 160 static void credential_format(struct credential *c, struct strbuf *out)
 161 {
 162         if (!c->protocol)
 163                 return;
 164         strbuf_addf(out, "%s://", c->protocol);
 165         if (c->username && *c->username) {
 166                 strbuf_add_percentencode(out, c->username, STRBUF_ENCODE_SLASH);
 167                 strbuf_addch(out, '@');
 168         }
 169         if (c->host)
 170                 strbuf_addstr(out, c->host);
 171         if (c->path) {
 172                 strbuf_addch(out, '/');
 173                 strbuf_add_percentencode(out, c->path, 0);
 174         }
 175 }
 176
 177 static char *credential_ask_one(const char *what, struct credential *c,
 178                                 int flags)
 179 {
 180         struct strbuf desc = STRBUF_INIT;
 181         struct strbuf prompt = STRBUF_INIT;
 182         char *r;
 183
 184         credential_describe(c, &desc);
 185         if (desc.len)
 186                 strbuf_addf(&prompt, "%s for '%s': ", what, desc.buf);
 187         else
 188                 strbuf_addf(&prompt, "%s: ", what);
 189
 190         r = git_prompt(prompt.buf, flags);
 191
 192         strbuf_release(&desc);
 193         strbuf_release(&prompt);
 194         return xstrdup(r);
 195 }
 196
 197 static void credential_getpass(struct credential *c)
 198 {
 199         if (!c->username)
 200                 c->username = credential_ask_one("Username", c,
 201                                                  PROMPT_ASKPASS|PROMPT_ECHO);
 202         if (!c->password)
 203                 c->password = credential_ask_one("Password", c,
 204                                                  PROMPT_ASKPASS);
 205 }
 206
 207 int credential_read(struct credential *c, FILE *fp)
 208 {
 209         struct strbuf line = STRBUF_INIT;
 210
 211         while (strbuf_getline(&line, fp) != EOF) {
 212                 char *key = line.buf;
 213                 char *value = strchr(key, '=');
 214
 215                 if (!line.len)
 216                         break;
 217
 218                 if (!value) {
 219                         warning("invalid credential line: %s", key);
 220                         strbuf_release(&line);
 221                         return -1;
 222                 }
 223                 *value++ = '\0';
 224
 225                 if (!strcmp(key, "username")) {
 226                         free(c->username);
 227                         c->username = xstrdup(value);
 228                         c->username_from_proto = 1;
 229                 } else if (!strcmp(key, "password")) {
 230                         free(c->password);
 231                         c->password = xstrdup(value);
 232                 } else if (!strcmp(key, "protocol")) {
 233                         free(c->protocol);
 234                         c->protocol = xstrdup(value);
 235                 } else if (!strcmp(key, "host")) {
 236                         free(c->host);
 237                         c->host = xstrdup(value);
 238                 } else if (!strcmp(key, "path")) {
 239                         free(c->path);
 240                         c->path = xstrdup(value);
 241                 } else if (!strcmp(key, "password_expiry_utc")) {
 242                         errno = 0;
 243                         c->password_expiry_utc = parse_timestamp(value, NULL, 10);
 244                         if (c->password_expiry_utc == 0 || errno == ERANGE)
 245                                 c->password_expiry_utc = TIME_MAX;
 246                 } else if (!strcmp(key, "url")) {
 247                         credential_from_url(c, value);
 248                 } else if (!strcmp(key, "quit")) {
 249                         c->quit = !!git_config_bool("quit", value);
 250                 }
 251                 /*
 252                  * Ignore other lines; we don't know what they mean, but
 253                  * this future-proofs us when later versions of git do
 254                  * learn new lines, and the helpers are updated to match.
 255                  */
 256         }
 257
 258         strbuf_release(&line);
 259         return 0;
 260 }
 261
 262 static void credential_write_item(FILE *fp, const char *key, const char *value,
 263                                   int required)
 264 {
 265         if (!value && required)
 266                 BUG("credential value for %s is missing", key);
 267         if (!value)
 268                 return;
 269         if (strchr(value, '\n'))
 270                 die("credential value for %s contains newline", key);
 271         fprintf(fp, "%s=%s\n", key, value);
 272 }
 273
 274 void credential_write(const struct credential *c, FILE *fp)
 275 {
 276         credential_write_item(fp, "protocol", c->protocol, 1);
 277         credential_write_item(fp, "host", c->host, 1);
 278         credential_write_item(fp, "path", c->path, 0);
 279         credential_write_item(fp, "username", c->username, 0);
 280         credential_write_item(fp, "password", c->password, 0);
 281         if (c->password_expiry_utc != TIME_MAX) {
 282                 char *s = xstrfmt("%"PRItime, c->password_expiry_utc);
 283                 credential_write_item(fp, "password_expiry_utc", s, 0);
 284                 free(s);
 285         }
 286         for (size_t i = 0; i < c->wwwauth_headers.nr; i++)
 287                 credential_write_item(fp, "wwwauth[]", c->wwwauth_headers.v[i], 0);
 288 }
 289
 290 static int run_credential_helper(struct credential *c,
 291                                  const char *cmd,
 292                                  int want_output)
 293 {
 294         struct child_process helper = CHILD_PROCESS_INIT;
 295         FILE *fp;
 296
 297         strvec_push(&helper.args, cmd);
 298         helper.use_shell = 1;
 299         helper.in = -1;
 300         if (want_output)
 301                 helper.out = -1;
 302         else
 303                 helper.no_stdout = 1;
 304
 305         if (start_command(&helper) < 0)
 306                 return -1;
 307
 308         fp = xfdopen(helper.in, "w");
 309         sigchain_push(SIGPIPE, SIG_IGN);
 310         credential_write(c, fp);
 311         fclose(fp);
 312         sigchain_pop(SIGPIPE);
 313
 314         if (want_output) {
 315                 int r;
 316                 fp = xfdopen(helper.out, "r");
 317                 r = credential_read(c, fp);
 318                 fclose(fp);
 319                 if (r < 0) {
 320                         finish_command(&helper);
 321                         return -1;
 322                 }
 323         }
 324
 325         if (finish_command(&helper))
 326                 return -1;
 327         return 0;
 328 }
 329
 330 static int credential_do(struct credential *c, const char *helper,
 331                          const char *operation)
 332 {
 333         struct strbuf cmd = STRBUF_INIT;
 334         int r;
 335
 336         if (helper[0] == '!')
 337                 strbuf_addstr(&cmd, helper + 1);
 338         else if (is_absolute_path(helper))
 339                 strbuf_addstr(&cmd, helper);
 340         else
 341                 strbuf_addf(&cmd, "git credential-%s", helper);
 342
 343         strbuf_addf(&cmd, " %s", operation);
 344         r = run_credential_helper(c, cmd.buf, !strcmp(operation, "get"));
 345
 346         strbuf_release(&cmd);
 347         return r;
 348 }
 349
 350 void credential_fill(struct credential *c)
 351 {
 352         int i;
 353
 354         if (c->username && c->password)
 355                 return;
 356
 357         credential_apply_config(c);
 358
 359         for (i = 0; i < c->helpers.nr; i++) {
 360                 credential_do(c, c->helpers.items[i].string, "get");
 361                 if (c->password_expiry_utc < time(NULL)) {
 362                         /* Discard expired password */
 363                         FREE_AND_NULL(c->password);
 364                         /* Reset expiry to maintain consistency */
 365                         c->password_expiry_utc = TIME_MAX;
 366                 }
 367                 if (c->username && c->password)
 368                         return;
 369                 if (c->quit)
 370                         die("credential helper '%s' told us to quit",
 371                             c->helpers.items[i].string);
 372         }
 373
 374         credential_getpass(c);
 375         if (!c->username && !c->password)
 376                 die("unable to get password from user");
 377 }
 378
 379 void credential_approve(struct credential *c)
 380 {
 381         int i;
 382
 383         if (c->approved)
 384                 return;
 385         if (!c->username || !c->password || c->password_expiry_utc < time(NULL))
 386                 return;
 387
 388         credential_apply_config(c);
 389
 390         for (i = 0; i < c->helpers.nr; i++)
 391                 credential_do(c, c->helpers.items[i].string, "store");
 392         c->approved = 1;
 393 }
 394
 395 void credential_reject(struct credential *c)
 396 {
 397         int i;
 398
 399         credential_apply_config(c);
 400
 401         for (i = 0; i < c->helpers.nr; i++)
 402                 credential_do(c, c->helpers.items[i].string, "erase");
 403
 404         FREE_AND_NULL(c->username);
 405         FREE_AND_NULL(c->password);
 406         c->password_expiry_utc = TIME_MAX;
 407         c->approved = 0;
 408 }
 409
 410 static int check_url_component(const char *url, int quiet,
 411                                const char *name, const char *value)
 412 {
 413         if (!value)
 414                 return 0;
 415         if (!strchr(value, '\n'))
 416                 return 0;
 417
 418         if (!quiet)
 419                 warning(_("url contains a newline in its %s component: %s"),
 420                         name, url);
 421         return -1;
 422 }
 423
 424 /*
 425  * Potentially-partial URLs can, but do not have to, contain
 426  *
 427  * - a protocol (or scheme) of the form "<protocol>://"
 428  *
 429  * - a host name (the part after the protocol and before the first slash after
 430  *   that, if any)
 431  *
 432  * - a user name and potentially a password (as "<user>[:<password>]@" part of
 433  *   the host name)
 434  *
 435  * - a path (the part after the host name, if any, starting with the slash)
 436  *
 437  * Missing parts will be left unset in `struct credential`. Thus, `https://`
 438  * will have only the `protocol` set, `example.com` only the host name, and
 439  * `/git` only the path.
 440  *
 441  * Note that an empty host name in an otherwise fully-qualified URL (e.g.
 442  * `cert:///path/to/cert.pem`) will be treated as unset if we expect the URL to
 443  * be potentially partial, and only then (otherwise, the empty string is used).
 444  *
 445  * The credential_from_url() function does not allow partial URLs.
 446  */
 447 static int credential_from_url_1(struct credential *c, const char *url,
 448                                  int allow_partial_url, int quiet)
 449 {
 450         const char *at, *colon, *cp, *slash, *host, *proto_end;
 451
 452         credential_clear(c);
 453
 454         /*
 455          * Match one of:
 456          *   (1) proto://<host>/...
 457          *   (2) proto://<user>@<host>/...
 458          *   (3) proto://<user>:<pass>@<host>/...
 459          */
 460         proto_end = strstr(url, "://");
 461         if (!allow_partial_url && (!proto_end || proto_end == url)) {
 462                 if (!quiet)
 463                         warning(_("url has no scheme: %s"), url);
 464                 return -1;
 465         }
 466         cp = proto_end ? proto_end + 3 : url;
 467         at = strchr(cp, '@');
 468         colon = strchr(cp, ':');
 469
 470         /*
 471          * A query or fragment marker before the slash ends the host portion.
 472          * We'll just continue to call this "slash" for simplicity. Notably our
 473          * "trim leading slashes" part won't skip over this part of the path,
 474          * but that's what we'd want.
 475          */
 476         slash = cp + strcspn(cp, "/?#");
 477
 478         if (!at || slash <= at) {
 479                 /* Case (1) */
 480                 host = cp;
 481         }
 482         else if (!colon || at <= colon) {
 483                 /* Case (2) */
 484                 c->username = url_decode_mem(cp, at - cp);
 485                 if (c->username && *c->username)
 486                         c->username_from_proto = 1;
 487                 host = at + 1;
 488         } else {
 489                 /* Case (3) */
 490                 c->username = url_decode_mem(cp, colon - cp);
 491                 if (c->username && *c->username)
 492                         c->username_from_proto = 1;
 493                 c->password = url_decode_mem(colon + 1, at - (colon + 1));
 494                 host = at + 1;
 495         }
 496
 497         if (proto_end && proto_end - url > 0)
 498                 c->protocol = xmemdupz(url, proto_end - url);
 499         if (!allow_partial_url || slash - host > 0)
 500                 c->host = url_decode_mem(host, slash - host);
 501         /* Trim leading and trailing slashes from path */
 502         while (*slash == '/')
 503                 slash++;
 504         if (*slash) {
 505                 char *p;
 506                 c->path = url_decode(slash);
 507                 p = c->path + strlen(c->path) - 1;
 508                 while (p > c->path && *p == '/')
 509                         *p-- = '\0';
 510         }
 511
 512         if (check_url_component(url, quiet, "username", c->username) < 0 ||
 513             check_url_component(url, quiet, "password", c->password) < 0 ||
 514             check_url_component(url, quiet, "protocol", c->protocol) < 0 ||
 515             check_url_component(url, quiet, "host", c->host) < 0 ||
 516             check_url_component(url, quiet, "path", c->path) < 0)
 517                 return -1;
 518
 519         return 0;
 520 }
 521
 522 static int credential_from_potentially_partial_url(struct credential *c,
 523                                                    const char *url)
 524 {
 525         return credential_from_url_1(c, url, 1, 0);
 526 }
 527
 528 int credential_from_url_gently(struct credential *c, const char *url, int quiet)
 529 {
 530         return credential_from_url_1(c, url, 0, quiet);
 531 }
 532
 533 void credential_from_url(struct credential *c, const char *url)
 534 {
 535         if (credential_from_url_gently(c, url, 0) < 0)
 536                 die(_("credential url cannot be parsed: %s"), url);
 537 }