credential.c

   1 #include "cache.h"
   2 #include "config.h"
   3 #include "credential.h"
   4 #include "string-list.h"
   5 #include "run-command.h"
   6 #include "url.h"
   7 #include "prompt.h"
   8 #include "sigchain.h"
   9 #include "urlmatch.h"
  10 #include "git-compat-util.h"
  11
  12 void credential_init(struct credential *c)
  13 {
  14         struct credential blank = CREDENTIAL_INIT;
  15         memcpy(c, &blank, sizeof(*c));
  16 }
  17
  18 void credential_clear(struct credential *c)
  19 {
  20         free(c->protocol);
  21         free(c->host);
  22         free(c->path);
  23         free(c->username);
  24         free(c->password);
  25         string_list_clear(&c->helpers, 0);
  26         strvec_clear(&c->wwwauth_headers);
  27
  28         credential_init(c);
  29 }
  30
  31 int credential_match(const struct credential *want,
  32                      const struct credential *have)
  33 {
  34 #define CHECK(x) (!want->x || (have->x && !strcmp(want->x, have->x)))
  35         return CHECK(protocol) &&
  36                CHECK(host) &&
  37                CHECK(path) &&
  38                CHECK(username);
  39 #undef CHECK
  40 }
  41
  42
  43 static int credential_from_potentially_partial_url(struct credential *c,
  44                                                    const char *url);
  45
  46 static int credential_config_callback(const char *var, const char *value,
  47                                       void *data)
  48 {
  49         struct credential *c = data;
  50         const char *key;
  51
  52         if (!skip_prefix(var, "credential.", &key))
  53                 return 0;
  54
  55         if (!value)
  56                 return config_error_nonbool(var);
  57
  58         if (!strcmp(key, "helper")) {
  59                 if (*value)
  60                         string_list_append(&c->helpers, value);
  61                 else
  62                         string_list_clear(&c->helpers, 0);
  63         } else if (!strcmp(key, "username")) {
  64                 if (!c->username_from_proto) {
  65                         free(c->username);
  66                         c->username = xstrdup(value);
  67                 }
  68         }
  69         else if (!strcmp(key, "usehttppath"))
  70                 c->use_http_path = git_config_bool(var, value);
  71
  72         return 0;
  73 }
  74
  75 static int proto_is_http(const char *s)
  76 {
  77         if (!s)
  78                 return 0;
  79         return !strcmp(s, "https") || !strcmp(s, "http");
  80 }
  81
  82 static void credential_describe(struct credential *c, struct strbuf *out);
  83 static void credential_format(struct credential *c, struct strbuf *out);
  84
  85 static int select_all(const struct urlmatch_item *a,
  86                       const struct urlmatch_item *b)
  87 {
  88         return 0;
  89 }
  90
  91 static int match_partial_url(const char *url, void *cb)
  92 {
  93         struct credential *c = cb;
  94         struct credential want = CREDENTIAL_INIT;
  95         int matches = 0;
  96
  97         if (credential_from_potentially_partial_url(&want, url) < 0)
  98                 warning(_("skipping credential lookup for key: credential.%s"),
  99                         url);
 100         else
 101                 matches = credential_match(&want, c);
 102         credential_clear(&want);
 103
 104         return matches;
 105 }
 106
 107 static void credential_apply_config(struct credential *c)
 108 {
 109         char *normalized_url;
 110         struct urlmatch_config config = URLMATCH_CONFIG_INIT;
 111         struct strbuf url = STRBUF_INIT;
 112
 113         if (!c->host)
 114                 die(_("refusing to work with credential missing host field"));
 115         if (!c->protocol)
 116                 die(_("refusing to work with credential missing protocol field"));
 117
 118         if (c->configured)
 119                 return;
 120
 121         config.section = "credential";
 122         config.key = NULL;
 123         config.collect_fn = credential_config_callback;
 124         config.cascade_fn = NULL;
 125         config.select_fn = select_all;
 126         config.fallback_match_fn = match_partial_url;
 127         config.cb = c;
 128
 129         credential_format(c, &url);
 130         normalized_url = url_normalize(url.buf, &config.url);
 131
 132         git_config(urlmatch_config_entry, &config);
 133         string_list_clear(&config.vars, 1);
 134         free(normalized_url);
 135         urlmatch_config_release(&config);
 136         strbuf_release(&url);
 137
 138         c->configured = 1;
 139
 140         if (!c->use_http_path && proto_is_http(c->protocol)) {
 141                 FREE_AND_NULL(c->path);
 142         }
 143 }
 144
 145 static void credential_describe(struct credential *c, struct strbuf *out)
 146 {
 147         if (!c->protocol)
 148                 return;
 149         strbuf_addf(out, "%s://", c->protocol);
 150         if (c->username && *c->username)
 151                 strbuf_addf(out, "%s@", c->username);
 152         if (c->host)
 153                 strbuf_addstr(out, c->host);
 154         if (c->path)
 155                 strbuf_addf(out, "/%s", c->path);
 156 }
 157
 158 static void credential_format(struct credential *c, struct strbuf *out)
 159 {
 160         if (!c->protocol)
 161                 return;
 162         strbuf_addf(out, "%s://", c->protocol);
 163         if (c->username && *c->username) {
 164                 strbuf_add_percentencode(out, c->username, STRBUF_ENCODE_SLASH);
 165                 strbuf_addch(out, '@');
 166         }
 167         if (c->host)
 168                 strbuf_addstr(out, c->host);
 169         if (c->path) {
 170                 strbuf_addch(out, '/');
 171                 strbuf_add_percentencode(out, c->path, 0);
 172         }
 173 }
 174
 175 static char *credential_ask_one(const char *what, struct credential *c,
 176                                 int flags)
 177 {
 178         struct strbuf desc = STRBUF_INIT;
 179         struct strbuf prompt = STRBUF_INIT;
 180         char *r;
 181
 182         credential_describe(c, &desc);
 183         if (desc.len)
 184                 strbuf_addf(&prompt, "%s for '%s': ", what, desc.buf);
 185         else
 186                 strbuf_addf(&prompt, "%s: ", what);
 187
 188         r = git_prompt(prompt.buf, flags);
 189
 190         strbuf_release(&desc);
 191         strbuf_release(&prompt);
 192         return xstrdup(r);
 193 }
 194
 195 static void credential_getpass(struct credential *c)
 196 {
 197         if (!c->username)
 198                 c->username = credential_ask_one("Username", c,
 199                                                  PROMPT_ASKPASS|PROMPT_ECHO);
 200         if (!c->password)
 201                 c->password = credential_ask_one("Password", c,
 202                                                  PROMPT_ASKPASS);
 203 }
 204
 205 int credential_read(struct credential *c, FILE *fp)
 206 {
 207         struct strbuf line = STRBUF_INIT;
 208
 209         while (strbuf_getline(&line, fp) != EOF) {
 210                 char *key = line.buf;
 211                 char *value = strchr(key, '=');
 212
 213                 if (!line.len)
 214                         break;
 215
 216                 if (!value) {
 217                         warning("invalid credential line: %s", key);
 218                         strbuf_release(&line);
 219                         return -1;
 220                 }
 221                 *value++ = '\0';
 222
 223                 if (!strcmp(key, "username")) {
 224                         free(c->username);
 225                         c->username = xstrdup(value);
 226                         c->username_from_proto = 1;
 227                 } else if (!strcmp(key, "password")) {
 228                         free(c->password);
 229                         c->password = xstrdup(value);
 230                 } else if (!strcmp(key, "protocol")) {
 231                         free(c->protocol);
 232                         c->protocol = xstrdup(value);
 233                 } else if (!strcmp(key, "host")) {
 234                         free(c->host);
 235                         c->host = xstrdup(value);
 236                 } else if (!strcmp(key, "path")) {
 237                         free(c->path);
 238                         c->path = xstrdup(value);
 239                 } else if (!strcmp(key, "password_expiry_utc")) {
 240                         errno = 0;
 241                         c->password_expiry_utc = parse_timestamp(value, NULL, 10);
 242                         if (c->password_expiry_utc == 0 || errno == ERANGE)
 243                                 c->password_expiry_utc = TIME_MAX;
 244                 } else if (!strcmp(key, "url")) {
 245                         credential_from_url(c, value);
 246                 } else if (!strcmp(key, "quit")) {
 247                         c->quit = !!git_config_bool("quit", value);
 248                 }
 249                 /*
 250                  * Ignore other lines; we don't know what they mean, but
 251                  * this future-proofs us when later versions of git do
 252                  * learn new lines, and the helpers are updated to match.
 253                  */
 254         }
 255
 256         strbuf_release(&line);
 257         return 0;
 258 }
 259
 260 static void credential_write_item(FILE *fp, const char *key, const char *value,
 261                                   int required)
 262 {
 263         if (!value && required)
 264                 BUG("credential value for %s is missing", key);
 265         if (!value)
 266                 return;
 267         if (strchr(value, '\n'))
 268                 die("credential value for %s contains newline", key);
 269         fprintf(fp, "%s=%s\n", key, value);
 270 }
 271
 272 void credential_write(const struct credential *c, FILE *fp)
 273 {
 274         credential_write_item(fp, "protocol", c->protocol, 1);
 275         credential_write_item(fp, "host", c->host, 1);
 276         credential_write_item(fp, "path", c->path, 0);
 277         credential_write_item(fp, "username", c->username, 0);
 278         credential_write_item(fp, "password", c->password, 0);
 279         if (c->password_expiry_utc != TIME_MAX) {
 280                 char *s = xstrfmt("%"PRItime, c->password_expiry_utc);
 281                 credential_write_item(fp, "password_expiry_utc", s, 0);
 282                 free(s);
 283         }
 284         for (size_t i = 0; i < c->wwwauth_headers.nr; i++)
 285                 credential_write_item(fp, "wwwauth[]", c->wwwauth_headers.v[i], 0);
 286 }
 287
 288 static int run_credential_helper(struct credential *c,
 289                                  const char *cmd,
 290                                  int want_output)
 291 {
 292         struct child_process helper = CHILD_PROCESS_INIT;
 293         FILE *fp;
 294
 295         strvec_push(&helper.args, cmd);
 296         helper.use_shell = 1;
 297         helper.in = -1;
 298         if (want_output)
 299                 helper.out = -1;
 300         else
 301                 helper.no_stdout = 1;
 302
 303         if (start_command(&helper) < 0)
 304                 return -1;
 305
 306         fp = xfdopen(helper.in, "w");
 307         sigchain_push(SIGPIPE, SIG_IGN);
 308         credential_write(c, fp);
 309         fclose(fp);
 310         sigchain_pop(SIGPIPE);
 311
 312         if (want_output) {
 313                 int r;
 314                 fp = xfdopen(helper.out, "r");
 315                 r = credential_read(c, fp);
 316                 fclose(fp);
 317                 if (r < 0) {
 318                         finish_command(&helper);
 319                         return -1;
 320                 }
 321         }
 322
 323         if (finish_command(&helper))
 324                 return -1;
 325         return 0;
 326 }
 327
 328 static int credential_do(struct credential *c, const char *helper,
 329                          const char *operation)
 330 {
 331         struct strbuf cmd = STRBUF_INIT;
 332         int r;
 333
 334         if (helper[0] == '!')
 335                 strbuf_addstr(&cmd, helper + 1);
 336         else if (is_absolute_path(helper))
 337                 strbuf_addstr(&cmd, helper);
 338         else
 339                 strbuf_addf(&cmd, "git credential-%s", helper);
 340
 341         strbuf_addf(&cmd, " %s", operation);
 342         r = run_credential_helper(c, cmd.buf, !strcmp(operation, "get"));
 343
 344         strbuf_release(&cmd);
 345         return r;
 346 }
 347
 348 void credential_fill(struct credential *c)
 349 {
 350         int i;
 351
 352         if (c->username && c->password)
 353                 return;
 354
 355         credential_apply_config(c);
 356
 357         for (i = 0; i < c->helpers.nr; i++) {
 358                 credential_do(c, c->helpers.items[i].string, "get");
 359                 if (c->password_expiry_utc < time(NULL)) {
 360                         /* Discard expired password */
 361                         FREE_AND_NULL(c->password);
 362                         /* Reset expiry to maintain consistency */
 363                         c->password_expiry_utc = TIME_MAX;
 364                 }
 365                 if (c->username && c->password)
 366                         return;
 367                 if (c->quit)
 368                         die("credential helper '%s' told us to quit",
 369                             c->helpers.items[i].string);
 370         }
 371
 372         credential_getpass(c);
 373         if (!c->username && !c->password)
 374                 die("unable to get password from user");
 375 }
 376
 377 void credential_approve(struct credential *c)
 378 {
 379         int i;
 380
 381         if (c->approved)
 382                 return;
 383         if (!c->username || !c->password || c->password_expiry_utc < time(NULL))
 384                 return;
 385
 386         credential_apply_config(c);
 387
 388         for (i = 0; i < c->helpers.nr; i++)
 389                 credential_do(c, c->helpers.items[i].string, "store");
 390         c->approved = 1;
 391 }
 392
 393 void credential_reject(struct credential *c)
 394 {
 395         int i;
 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, "erase");
 401
 402         FREE_AND_NULL(c->username);
 403         FREE_AND_NULL(c->password);
 404         c->password_expiry_utc = TIME_MAX;
 405         c->approved = 0;
 406 }
 407
 408 static int check_url_component(const char *url, int quiet,
 409                                const char *name, const char *value)
 410 {
 411         if (!value)
 412                 return 0;
 413         if (!strchr(value, '\n'))
 414                 return 0;
 415
 416         if (!quiet)
 417                 warning(_("url contains a newline in its %s component: %s"),
 418                         name, url);
 419         return -1;
 420 }
 421
 422 /*
 423  * Potentially-partial URLs can, but do not have to, contain
 424  *
 425  * - a protocol (or scheme) of the form "<protocol>://"
 426  *
 427  * - a host name (the part after the protocol and before the first slash after
 428  *   that, if any)
 429  *
 430  * - a user name and potentially a password (as "<user>[:<password>]@" part of
 431  *   the host name)
 432  *
 433  * - a path (the part after the host name, if any, starting with the slash)
 434  *
 435  * Missing parts will be left unset in `struct credential`. Thus, `https://`
 436  * will have only the `protocol` set, `example.com` only the host name, and
 437  * `/git` only the path.
 438  *
 439  * Note that an empty host name in an otherwise fully-qualified URL (e.g.
 440  * `cert:///path/to/cert.pem`) will be treated as unset if we expect the URL to
 441  * be potentially partial, and only then (otherwise, the empty string is used).
 442  *
 443  * The credential_from_url() function does not allow partial URLs.
 444  */
 445 static int credential_from_url_1(struct credential *c, const char *url,
 446                                  int allow_partial_url, int quiet)
 447 {
 448         const char *at, *colon, *cp, *slash, *host, *proto_end;
 449
 450         credential_clear(c);
 451
 452         /*
 453          * Match one of:
 454          *   (1) proto://<host>/...
 455          *   (2) proto://<user>@<host>/...
 456          *   (3) proto://<user>:<pass>@<host>/...
 457          */
 458         proto_end = strstr(url, "://");
 459         if (!allow_partial_url && (!proto_end || proto_end == url)) {
 460                 if (!quiet)
 461                         warning(_("url has no scheme: %s"), url);
 462                 return -1;
 463         }
 464         cp = proto_end ? proto_end + 3 : url;
 465         at = strchr(cp, '@');
 466         colon = strchr(cp, ':');
 467
 468         /*
 469          * A query or fragment marker before the slash ends the host portion.
 470          * We'll just continue to call this "slash" for simplicity. Notably our
 471          * "trim leading slashes" part won't skip over this part of the path,
 472          * but that's what we'd want.
 473          */
 474         slash = cp + strcspn(cp, "/?#");
 475
 476         if (!at || slash <= at) {
 477                 /* Case (1) */
 478                 host = cp;
 479         }
 480         else if (!colon || at <= colon) {
 481                 /* Case (2) */
 482                 c->username = url_decode_mem(cp, at - cp);
 483                 if (c->username && *c->username)
 484                         c->username_from_proto = 1;
 485                 host = at + 1;
 486         } else {
 487                 /* Case (3) */
 488                 c->username = url_decode_mem(cp, colon - cp);
 489                 if (c->username && *c->username)
 490                         c->username_from_proto = 1;
 491                 c->password = url_decode_mem(colon + 1, at - (colon + 1));
 492                 host = at + 1;
 493         }
 494
 495         if (proto_end && proto_end - url > 0)
 496                 c->protocol = xmemdupz(url, proto_end - url);
 497         if (!allow_partial_url || slash - host > 0)
 498                 c->host = url_decode_mem(host, slash - host);
 499         /* Trim leading and trailing slashes from path */
 500         while (*slash == '/')
 501                 slash++;
 502         if (*slash) {
 503                 char *p;
 504                 c->path = url_decode(slash);
 505                 p = c->path + strlen(c->path) - 1;
 506                 while (p > c->path && *p == '/')
 507                         *p-- = '\0';
 508         }
 509
 510         if (check_url_component(url, quiet, "username", c->username) < 0 ||
 511             check_url_component(url, quiet, "password", c->password) < 0 ||
 512             check_url_component(url, quiet, "protocol", c->protocol) < 0 ||
 513             check_url_component(url, quiet, "host", c->host) < 0 ||
 514             check_url_component(url, quiet, "path", c->path) < 0)
 515                 return -1;
 516
 517         return 0;
 518 }
 519
 520 static int credential_from_potentially_partial_url(struct credential *c,
 521                                                    const char *url)
 522 {
 523         return credential_from_url_1(c, url, 1, 0);
 524 }
 525
 526 int credential_from_url_gently(struct credential *c, const char *url, int quiet)
 527 {
 528         return credential_from_url_1(c, url, 0, quiet);
 529 }
 530
 531 void credential_from_url(struct credential *c, const char *url)
 532 {
 533         if (credential_from_url_gently(c, url, 0) < 0)
 534                 die(_("credential url cannot be parsed: %s"), url);
 535 }