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, "wwwauth[]")) {
 243                         strvec_push(&c->wwwauth_headers, value);
 244                 } else if (!strcmp(key, "password_expiry_utc")) {
 245                         errno = 0;
 246                         c->password_expiry_utc = parse_timestamp(value, NULL, 10);
 247                         if (c->password_expiry_utc == 0 || errno == ERANGE)
 248                                 c->password_expiry_utc = TIME_MAX;
 249                 } else if (!strcmp(key, "url")) {
 250                         credential_from_url(c, value);
 251                 } else if (!strcmp(key, "quit")) {
 252                         c->quit = !!git_config_bool("quit", value);
 253                 }
 254                 /*
 255                  * Ignore other lines; we don't know what they mean, but
 256                  * this future-proofs us when later versions of git do
 257                  * learn new lines, and the helpers are updated to match.
 258                  */
 259         }
 260
 261         strbuf_release(&line);
 262         return 0;
 263 }
 264
 265 static void credential_write_item(FILE *fp, const char *key, const char *value,
 266                                   int required)
 267 {
 268         if (!value && required)
 269                 BUG("credential value for %s is missing", key);
 270         if (!value)
 271                 return;
 272         if (strchr(value, '\n'))
 273                 die("credential value for %s contains newline", key);
 274         fprintf(fp, "%s=%s\n", key, value);
 275 }
 276
 277 void credential_write(const struct credential *c, FILE *fp)
 278 {
 279         credential_write_item(fp, "protocol", c->protocol, 1);
 280         credential_write_item(fp, "host", c->host, 1);
 281         credential_write_item(fp, "path", c->path, 0);
 282         credential_write_item(fp, "username", c->username, 0);
 283         credential_write_item(fp, "password", c->password, 0);
 284         if (c->password_expiry_utc != TIME_MAX) {
 285                 char *s = xstrfmt("%"PRItime, c->password_expiry_utc);
 286                 credential_write_item(fp, "password_expiry_utc", s, 0);
 287                 free(s);
 288         }
 289         for (size_t i = 0; i < c->wwwauth_headers.nr; i++)
 290                 credential_write_item(fp, "wwwauth[]", c->wwwauth_headers.v[i], 0);
 291 }
 292
 293 static int run_credential_helper(struct credential *c,
 294                                  const char *cmd,
 295                                  int want_output)
 296 {
 297         struct child_process helper = CHILD_PROCESS_INIT;
 298         FILE *fp;
 299
 300         strvec_push(&helper.args, cmd);
 301         helper.use_shell = 1;
 302         helper.in = -1;
 303         if (want_output)
 304                 helper.out = -1;
 305         else
 306                 helper.no_stdout = 1;
 307
 308         if (start_command(&helper) < 0)
 309                 return -1;
 310
 311         fp = xfdopen(helper.in, "w");
 312         sigchain_push(SIGPIPE, SIG_IGN);
 313         credential_write(c, fp);
 314         fclose(fp);
 315         sigchain_pop(SIGPIPE);
 316
 317         if (want_output) {
 318                 int r;
 319                 fp = xfdopen(helper.out, "r");
 320                 r = credential_read(c, fp);
 321                 fclose(fp);
 322                 if (r < 0) {
 323                         finish_command(&helper);
 324                         return -1;
 325                 }
 326         }
 327
 328         if (finish_command(&helper))
 329                 return -1;
 330         return 0;
 331 }
 332
 333 static int credential_do(struct credential *c, const char *helper,
 334                          const char *operation)
 335 {
 336         struct strbuf cmd = STRBUF_INIT;
 337         int r;
 338
 339         if (helper[0] == '!')
 340                 strbuf_addstr(&cmd, helper + 1);
 341         else if (is_absolute_path(helper))
 342                 strbuf_addstr(&cmd, helper);
 343         else
 344                 strbuf_addf(&cmd, "git credential-%s", helper);
 345
 346         strbuf_addf(&cmd, " %s", operation);
 347         r = run_credential_helper(c, cmd.buf, !strcmp(operation, "get"));
 348
 349         strbuf_release(&cmd);
 350         return r;
 351 }
 352
 353 void credential_fill(struct credential *c)
 354 {
 355         int i;
 356
 357         if (c->username && c->password)
 358                 return;
 359
 360         credential_apply_config(c);
 361
 362         for (i = 0; i < c->helpers.nr; i++) {
 363                 credential_do(c, c->helpers.items[i].string, "get");
 364                 if (c->password_expiry_utc < time(NULL)) {
 365                         /* Discard expired password */
 366                         FREE_AND_NULL(c->password);
 367                         /* Reset expiry to maintain consistency */
 368                         c->password_expiry_utc = TIME_MAX;
 369                 }
 370                 if (c->username && c->password)
 371                         return;
 372                 if (c->quit)
 373                         die("credential helper '%s' told us to quit",
 374                             c->helpers.items[i].string);
 375         }
 376
 377         credential_getpass(c);
 378         if (!c->username && !c->password)
 379                 die("unable to get password from user");
 380 }
 381
 382 void credential_approve(struct credential *c)
 383 {
 384         int i;
 385
 386         if (c->approved)
 387                 return;
 388         if (!c->username || !c->password || c->password_expiry_utc < time(NULL))
 389                 return;
 390
 391         credential_apply_config(c);
 392
 393         for (i = 0; i < c->helpers.nr; i++)
 394                 credential_do(c, c->helpers.items[i].string, "store");
 395         c->approved = 1;
 396 }
 397
 398 void credential_reject(struct credential *c)
 399 {
 400         int i;
 401
 402         credential_apply_config(c);
 403
 404         for (i = 0; i < c->helpers.nr; i++)
 405                 credential_do(c, c->helpers.items[i].string, "erase");
 406
 407         FREE_AND_NULL(c->username);
 408         FREE_AND_NULL(c->password);
 409         c->password_expiry_utc = TIME_MAX;
 410         c->approved = 0;
 411 }
 412
 413 static int check_url_component(const char *url, int quiet,
 414                                const char *name, const char *value)
 415 {
 416         if (!value)
 417                 return 0;
 418         if (!strchr(value, '\n'))
 419                 return 0;
 420
 421         if (!quiet)
 422                 warning(_("url contains a newline in its %s component: %s"),
 423                         name, url);
 424         return -1;
 425 }
 426
 427 /*
 428  * Potentially-partial URLs can, but do not have to, contain
 429  *
 430  * - a protocol (or scheme) of the form "<protocol>://"
 431  *
 432  * - a host name (the part after the protocol and before the first slash after
 433  *   that, if any)
 434  *
 435  * - a user name and potentially a password (as "<user>[:<password>]@" part of
 436  *   the host name)
 437  *
 438  * - a path (the part after the host name, if any, starting with the slash)
 439  *
 440  * Missing parts will be left unset in `struct credential`. Thus, `https://`
 441  * will have only the `protocol` set, `example.com` only the host name, and
 442  * `/git` only the path.
 443  *
 444  * Note that an empty host name in an otherwise fully-qualified URL (e.g.
 445  * `cert:///path/to/cert.pem`) will be treated as unset if we expect the URL to
 446  * be potentially partial, and only then (otherwise, the empty string is used).
 447  *
 448  * The credential_from_url() function does not allow partial URLs.
 449  */
 450 static int credential_from_url_1(struct credential *c, const char *url,
 451                                  int allow_partial_url, int quiet)
 452 {
 453         const char *at, *colon, *cp, *slash, *host, *proto_end;
 454
 455         credential_clear(c);
 456
 457         /*
 458          * Match one of:
 459          *   (1) proto://<host>/...
 460          *   (2) proto://<user>@<host>/...
 461          *   (3) proto://<user>:<pass>@<host>/...
 462          */
 463         proto_end = strstr(url, "://");
 464         if (!allow_partial_url && (!proto_end || proto_end == url)) {
 465                 if (!quiet)
 466                         warning(_("url has no scheme: %s"), url);
 467                 return -1;
 468         }
 469         cp = proto_end ? proto_end + 3 : url;
 470         at = strchr(cp, '@');
 471         colon = strchr(cp, ':');
 472
 473         /*
 474          * A query or fragment marker before the slash ends the host portion.
 475          * We'll just continue to call this "slash" for simplicity. Notably our
 476          * "trim leading slashes" part won't skip over this part of the path,
 477          * but that's what we'd want.
 478          */
 479         slash = cp + strcspn(cp, "/?#");
 480
 481         if (!at || slash <= at) {
 482                 /* Case (1) */
 483                 host = cp;
 484         }
 485         else if (!colon || at <= colon) {
 486                 /* Case (2) */
 487                 c->username = url_decode_mem(cp, at - cp);
 488                 if (c->username && *c->username)
 489                         c->username_from_proto = 1;
 490                 host = at + 1;
 491         } else {
 492                 /* Case (3) */
 493                 c->username = url_decode_mem(cp, colon - cp);
 494                 if (c->username && *c->username)
 495                         c->username_from_proto = 1;
 496                 c->password = url_decode_mem(colon + 1, at - (colon + 1));
 497                 host = at + 1;
 498         }
 499
 500         if (proto_end && proto_end - url > 0)
 501                 c->protocol = xmemdupz(url, proto_end - url);
 502         if (!allow_partial_url || slash - host > 0)
 503                 c->host = url_decode_mem(host, slash - host);
 504         /* Trim leading and trailing slashes from path */
 505         while (*slash == '/')
 506                 slash++;
 507         if (*slash) {
 508                 char *p;
 509                 c->path = url_decode(slash);
 510                 p = c->path + strlen(c->path) - 1;
 511                 while (p > c->path && *p == '/')
 512                         *p-- = '\0';
 513         }
 514
 515         if (check_url_component(url, quiet, "username", c->username) < 0 ||
 516             check_url_component(url, quiet, "password", c->password) < 0 ||
 517             check_url_component(url, quiet, "protocol", c->protocol) < 0 ||
 518             check_url_component(url, quiet, "host", c->host) < 0 ||
 519             check_url_component(url, quiet, "path", c->path) < 0)
 520                 return -1;
 521
 522         return 0;
 523 }
 524
 525 static int credential_from_potentially_partial_url(struct credential *c,
 526                                                    const char *url)
 527 {
 528         return credential_from_url_1(c, url, 1, 0);
 529 }
 530
 531 int credential_from_url_gently(struct credential *c, const char *url, int quiet)
 532 {
 533         return credential_from_url_1(c, url, 0, quiet);
 534 }
 535
 536 void credential_from_url(struct credential *c, const char *url)
 537 {
 538         if (credential_from_url_gently(c, url, 0) < 0)
 539                 die(_("credential url cannot be parsed: %s"), url);
 540 }