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         string_list_clear(&c->helpers, 0);
  29         strvec_clear(&c->wwwauth_headers);
  30
  31         credential_init(c);
  32 }
  33
  34 int credential_match(const struct credential *want,
  35                      const struct credential *have)
  36 {
  37 #define CHECK(x) (!want->x || (have->x && !strcmp(want->x, have->x)))
  38         return CHECK(protocol) &&
  39                CHECK(host) &&
  40                CHECK(path) &&
  41                CHECK(username);
  42 #undef CHECK
  43 }
  44
  45
  46 static int credential_from_potentially_partial_url(struct credential *c,
  47                                                    const char *url);
  48
  49 static int credential_config_callback(const char *var, const char *value,
  50                                       void *data)
  51 {
  52         struct credential *c = data;
  53         const char *key;
  54
  55         if (!skip_prefix(var, "credential.", &key))
  56                 return 0;
  57
  58         if (!value)
  59                 return config_error_nonbool(var);
  60
  61         if (!strcmp(key, "helper")) {
  62                 if (*value)
  63                         string_list_append(&c->helpers, value);
  64                 else
  65                         string_list_clear(&c->helpers, 0);
  66         } else if (!strcmp(key, "username")) {
  67                 if (!c->username_from_proto) {
  68                         free(c->username);
  69                         c->username = xstrdup(value);
  70                 }
  71         }
  72         else if (!strcmp(key, "usehttppath"))
  73                 c->use_http_path = git_config_bool(var, value);
  74
  75         return 0;
  76 }
  77
  78 static int proto_is_http(const char *s)
  79 {
  80         if (!s)
  81                 return 0;
  82         return !strcmp(s, "https") || !strcmp(s, "http");
  83 }
  84
  85 static void credential_describe(struct credential *c, struct strbuf *out);
  86 static void credential_format(struct credential *c, struct strbuf *out);
  87
  88 static int select_all(const struct urlmatch_item *a,
  89                       const struct urlmatch_item *b)
  90 {
  91         return 0;
  92 }
  93
  94 static int match_partial_url(const char *url, void *cb)
  95 {
  96         struct credential *c = cb;
  97         struct credential want = CREDENTIAL_INIT;
  98         int matches = 0;
  99
 100         if (credential_from_potentially_partial_url(&want, url) < 0)
 101                 warning(_("skipping credential lookup for key: credential.%s"),
 102                         url);
 103         else
 104                 matches = credential_match(&want, c);
 105         credential_clear(&want);
 106
 107         return matches;
 108 }
 109
 110 static void credential_apply_config(struct credential *c)
 111 {
 112         char *normalized_url;
 113         struct urlmatch_config config = URLMATCH_CONFIG_INIT;
 114         struct strbuf url = STRBUF_INIT;
 115
 116         if (!c->host)
 117                 die(_("refusing to work with credential missing host field"));
 118         if (!c->protocol)
 119                 die(_("refusing to work with credential missing protocol field"));
 120
 121         if (c->configured)
 122                 return;
 123
 124         config.section = "credential";
 125         config.key = NULL;
 126         config.collect_fn = credential_config_callback;
 127         config.cascade_fn = NULL;
 128         config.select_fn = select_all;
 129         config.fallback_match_fn = match_partial_url;
 130         config.cb = c;
 131
 132         credential_format(c, &url);
 133         normalized_url = url_normalize(url.buf, &config.url);
 134
 135         git_config(urlmatch_config_entry, &config);
 136         string_list_clear(&config.vars, 1);
 137         free(normalized_url);
 138         urlmatch_config_release(&config);
 139         strbuf_release(&url);
 140
 141         c->configured = 1;
 142
 143         if (!c->use_http_path && proto_is_http(c->protocol)) {
 144                 FREE_AND_NULL(c->path);
 145         }
 146 }
 147
 148 static void credential_describe(struct credential *c, struct strbuf *out)
 149 {
 150         if (!c->protocol)
 151                 return;
 152         strbuf_addf(out, "%s://", c->protocol);
 153         if (c->username && *c->username)
 154                 strbuf_addf(out, "%s@", c->username);
 155         if (c->host)
 156                 strbuf_addstr(out, c->host);
 157         if (c->path)
 158                 strbuf_addf(out, "/%s", c->path);
 159 }
 160
 161 static void credential_format(struct credential *c, struct strbuf *out)
 162 {
 163         if (!c->protocol)
 164                 return;
 165         strbuf_addf(out, "%s://", c->protocol);
 166         if (c->username && *c->username) {
 167                 strbuf_add_percentencode(out, c->username, STRBUF_ENCODE_SLASH);
 168                 strbuf_addch(out, '@');
 169         }
 170         if (c->host)
 171                 strbuf_addstr(out, c->host);
 172         if (c->path) {
 173                 strbuf_addch(out, '/');
 174                 strbuf_add_percentencode(out, c->path, 0);
 175         }
 176 }
 177
 178 static char *credential_ask_one(const char *what, struct credential *c,
 179                                 int flags)
 180 {
 181         struct strbuf desc = STRBUF_INIT;
 182         struct strbuf prompt = STRBUF_INIT;
 183         char *r;
 184
 185         credential_describe(c, &desc);
 186         if (desc.len)
 187                 strbuf_addf(&prompt, "%s for '%s': ", what, desc.buf);
 188         else
 189                 strbuf_addf(&prompt, "%s: ", what);
 190
 191         r = git_prompt(prompt.buf, flags);
 192
 193         strbuf_release(&desc);
 194         strbuf_release(&prompt);
 195         return xstrdup(r);
 196 }
 197
 198 static void credential_getpass(struct credential *c)
 199 {
 200         if (!c->username)
 201                 c->username = credential_ask_one("Username", c,
 202                                                  PROMPT_ASKPASS|PROMPT_ECHO);
 203         if (!c->password)
 204                 c->password = credential_ask_one("Password", c,
 205                                                  PROMPT_ASKPASS);
 206 }
 207
 208 int credential_read(struct credential *c, FILE *fp)
 209 {
 210         struct strbuf line = STRBUF_INIT;
 211
 212         while (strbuf_getline(&line, fp) != EOF) {
 213                 char *key = line.buf;
 214                 char *value = strchr(key, '=');
 215
 216                 if (!line.len)
 217                         break;
 218
 219                 if (!value) {
 220                         warning("invalid credential line: %s", key);
 221                         strbuf_release(&line);
 222                         return -1;
 223                 }
 224                 *value++ = '\0';
 225
 226                 if (!strcmp(key, "username")) {
 227                         free(c->username);
 228                         c->username = xstrdup(value);
 229                         c->username_from_proto = 1;
 230                 } else if (!strcmp(key, "password")) {
 231                         free(c->password);
 232                         c->password = xstrdup(value);
 233                 } else if (!strcmp(key, "protocol")) {
 234                         free(c->protocol);
 235                         c->protocol = xstrdup(value);
 236                 } else if (!strcmp(key, "host")) {
 237                         free(c->host);
 238                         c->host = xstrdup(value);
 239                 } else if (!strcmp(key, "path")) {
 240                         free(c->path);
 241                         c->path = xstrdup(value);
 242                 } else if (!strcmp(key, "password_expiry_utc")) {
 243                         errno = 0;
 244                         c->password_expiry_utc = parse_timestamp(value, NULL, 10);
 245                         if (c->password_expiry_utc == 0 || errno == ERANGE)
 246                                 c->password_expiry_utc = TIME_MAX;
 247                 } else if (!strcmp(key, "url")) {
 248                         credential_from_url(c, value);
 249                 } else if (!strcmp(key, "quit")) {
 250                         c->quit = !!git_config_bool("quit", value);
 251                 }
 252                 /*
 253                  * Ignore other lines; we don't know what they mean, but
 254                  * this future-proofs us when later versions of git do
 255                  * learn new lines, and the helpers are updated to match.
 256                  */
 257         }
 258
 259         strbuf_release(&line);
 260         return 0;
 261 }
 262
 263 static void credential_write_item(FILE *fp, const char *key, const char *value,
 264                                   int required)
 265 {
 266         if (!value && required)
 267                 BUG("credential value for %s is missing", key);
 268         if (!value)
 269                 return;
 270         if (strchr(value, '\n'))
 271                 die("credential value for %s contains newline", key);
 272         fprintf(fp, "%s=%s\n", key, value);
 273 }
 274
 275 void credential_write(const struct credential *c, FILE *fp)
 276 {
 277         credential_write_item(fp, "protocol", c->protocol, 1);
 278         credential_write_item(fp, "host", c->host, 1);
 279         credential_write_item(fp, "path", c->path, 0);
 280         credential_write_item(fp, "username", c->username, 0);
 281         credential_write_item(fp, "password", c->password, 0);
 282         if (c->password_expiry_utc != TIME_MAX) {
 283                 char *s = xstrfmt("%"PRItime, c->password_expiry_utc);
 284                 credential_write_item(fp, "password_expiry_utc", s, 0);
 285                 free(s);
 286         }
 287         for (size_t i = 0; i < c->wwwauth_headers.nr; i++)
 288                 credential_write_item(fp, "wwwauth[]", c->wwwauth_headers.v[i], 0);
 289 }
 290
 291 static int run_credential_helper(struct credential *c,
 292                                  const char *cmd,
 293                                  int want_output)
 294 {
 295         struct child_process helper = CHILD_PROCESS_INIT;
 296         FILE *fp;
 297
 298         strvec_push(&helper.args, cmd);
 299         helper.use_shell = 1;
 300         helper.in = -1;
 301         if (want_output)
 302                 helper.out = -1;
 303         else
 304                 helper.no_stdout = 1;
 305
 306         if (start_command(&helper) < 0)
 307                 return -1;
 308
 309         fp = xfdopen(helper.in, "w");
 310         sigchain_push(SIGPIPE, SIG_IGN);
 311         credential_write(c, fp);
 312         fclose(fp);
 313         sigchain_pop(SIGPIPE);
 314
 315         if (want_output) {
 316                 int r;
 317                 fp = xfdopen(helper.out, "r");
 318                 r = credential_read(c, fp);
 319                 fclose(fp);
 320                 if (r < 0) {
 321                         finish_command(&helper);
 322                         return -1;
 323                 }
 324         }
 325
 326         if (finish_command(&helper))
 327                 return -1;
 328         return 0;
 329 }
 330
 331 static int credential_do(struct credential *c, const char *helper,
 332                          const char *operation)
 333 {
 334         struct strbuf cmd = STRBUF_INIT;
 335         int r;
 336
 337         if (helper[0] == '!')
 338                 strbuf_addstr(&cmd, helper + 1);
 339         else if (is_absolute_path(helper))
 340                 strbuf_addstr(&cmd, helper);
 341         else
 342                 strbuf_addf(&cmd, "git credential-%s", helper);
 343
 344         strbuf_addf(&cmd, " %s", operation);
 345         r = run_credential_helper(c, cmd.buf, !strcmp(operation, "get"));
 346
 347         strbuf_release(&cmd);
 348         return r;
 349 }
 350
 351 void credential_fill(struct credential *c)
 352 {
 353         int i;
 354
 355         if (c->username && c->password)
 356                 return;
 357
 358         credential_apply_config(c);
 359
 360         for (i = 0; i < c->helpers.nr; i++) {
 361                 credential_do(c, c->helpers.items[i].string, "get");
 362                 if (c->password_expiry_utc < time(NULL)) {
 363                         /* Discard expired password */
 364                         FREE_AND_NULL(c->password);
 365                         /* Reset expiry to maintain consistency */
 366                         c->password_expiry_utc = TIME_MAX;
 367                 }
 368                 if (c->username && c->password)
 369                         return;
 370                 if (c->quit)
 371                         die("credential helper '%s' told us to quit",
 372                             c->helpers.items[i].string);
 373         }
 374
 375         credential_getpass(c);
 376         if (!c->username && !c->password)
 377                 die("unable to get password from user");
 378 }
 379
 380 void credential_approve(struct credential *c)
 381 {
 382         int i;
 383
 384         if (c->approved)
 385                 return;
 386         if (!c->username || !c->password || c->password_expiry_utc < time(NULL))
 387                 return;
 388
 389         credential_apply_config(c);
 390
 391         for (i = 0; i < c->helpers.nr; i++)
 392                 credential_do(c, c->helpers.items[i].string, "store");
 393         c->approved = 1;
 394 }
 395
 396 void credential_reject(struct credential *c)
 397 {
 398         int i;
 399
 400         credential_apply_config(c);
 401
 402         for (i = 0; i < c->helpers.nr; i++)
 403                 credential_do(c, c->helpers.items[i].string, "erase");
 404
 405         FREE_AND_NULL(c->username);
 406         FREE_AND_NULL(c->password);
 407         c->password_expiry_utc = TIME_MAX;
 408         c->approved = 0;
 409 }
 410
 411 static int check_url_component(const char *url, int quiet,
 412                                const char *name, const char *value)
 413 {
 414         if (!value)
 415                 return 0;
 416         if (!strchr(value, '\n'))
 417                 return 0;
 418
 419         if (!quiet)
 420                 warning(_("url contains a newline in its %s component: %s"),
 421                         name, url);
 422         return -1;
 423 }
 424
 425 /*
 426  * Potentially-partial URLs can, but do not have to, contain
 427  *
 428  * - a protocol (or scheme) of the form "<protocol>://"
 429  *
 430  * - a host name (the part after the protocol and before the first slash after
 431  *   that, if any)
 432  *
 433  * - a user name and potentially a password (as "<user>[:<password>]@" part of
 434  *   the host name)
 435  *
 436  * - a path (the part after the host name, if any, starting with the slash)
 437  *
 438  * Missing parts will be left unset in `struct credential`. Thus, `https://`
 439  * will have only the `protocol` set, `example.com` only the host name, and
 440  * `/git` only the path.
 441  *
 442  * Note that an empty host name in an otherwise fully-qualified URL (e.g.
 443  * `cert:///path/to/cert.pem`) will be treated as unset if we expect the URL to
 444  * be potentially partial, and only then (otherwise, the empty string is used).
 445  *
 446  * The credential_from_url() function does not allow partial URLs.
 447  */
 448 static int credential_from_url_1(struct credential *c, const char *url,
 449                                  int allow_partial_url, int quiet)
 450 {
 451         const char *at, *colon, *cp, *slash, *host, *proto_end;
 452
 453         credential_clear(c);
 454
 455         /*
 456          * Match one of:
 457          *   (1) proto://<host>/...
 458          *   (2) proto://<user>@<host>/...
 459          *   (3) proto://<user>:<pass>@<host>/...
 460          */
 461         proto_end = strstr(url, "://");
 462         if (!allow_partial_url && (!proto_end || proto_end == url)) {
 463                 if (!quiet)
 464                         warning(_("url has no scheme: %s"), url);
 465                 return -1;
 466         }
 467         cp = proto_end ? proto_end + 3 : url;
 468         at = strchr(cp, '@');
 469         colon = strchr(cp, ':');
 470
 471         /*
 472          * A query or fragment marker before the slash ends the host portion.
 473          * We'll just continue to call this "slash" for simplicity. Notably our
 474          * "trim leading slashes" part won't skip over this part of the path,
 475          * but that's what we'd want.
 476          */
 477         slash = cp + strcspn(cp, "/?#");
 478
 479         if (!at || slash <= at) {
 480                 /* Case (1) */
 481                 host = cp;
 482         }
 483         else if (!colon || at <= colon) {
 484                 /* Case (2) */
 485                 c->username = url_decode_mem(cp, at - cp);
 486                 if (c->username && *c->username)
 487                         c->username_from_proto = 1;
 488                 host = at + 1;
 489         } else {
 490                 /* Case (3) */
 491                 c->username = url_decode_mem(cp, colon - cp);
 492                 if (c->username && *c->username)
 493                         c->username_from_proto = 1;
 494                 c->password = url_decode_mem(colon + 1, at - (colon + 1));
 495                 host = at + 1;
 496         }
 497
 498         if (proto_end && proto_end - url > 0)
 499                 c->protocol = xmemdupz(url, proto_end - url);
 500         if (!allow_partial_url || slash - host > 0)
 501                 c->host = url_decode_mem(host, slash - host);
 502         /* Trim leading and trailing slashes from path */
 503         while (*slash == '/')
 504                 slash++;
 505         if (*slash) {
 506                 char *p;
 507                 c->path = url_decode(slash);
 508                 p = c->path + strlen(c->path) - 1;
 509                 while (p > c->path && *p == '/')
 510                         *p-- = '\0';
 511         }
 512
 513         if (check_url_component(url, quiet, "username", c->username) < 0 ||
 514             check_url_component(url, quiet, "password", c->password) < 0 ||
 515             check_url_component(url, quiet, "protocol", c->protocol) < 0 ||
 516             check_url_component(url, quiet, "host", c->host) < 0 ||
 517             check_url_component(url, quiet, "path", c->path) < 0)
 518                 return -1;
 519
 520         return 0;
 521 }
 522
 523 static int credential_from_potentially_partial_url(struct credential *c,
 524                                                    const char *url)
 525 {
 526         return credential_from_url_1(c, url, 1, 0);
 527 }
 528
 529 int credential_from_url_gently(struct credential *c, const char *url, int quiet)
 530 {
 531         return credential_from_url_1(c, url, 0, quiet);
 532 }
 533
 534 void credential_from_url(struct credential *c, const char *url)
 535 {
 536         if (credential_from_url_gently(c, url, 0) < 0)
 537                 die(_("credential url cannot be parsed: %s"), url);
 538 }