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