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         struct credential blank = CREDENTIAL_INIT;
  14         memcpy(c, &blank, sizeof(*c));
  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         string_list_clear(&config.vars, 1);
 132         free(normalized_url);
 133         strbuf_release(&url);
 134
 135         c->configured = 1;
 136
 137         if (!c->use_http_path && proto_is_http(c->protocol)) {
 138                 FREE_AND_NULL(c->path);
 139         }
 140 }
 141
 142 static void credential_describe(struct credential *c, struct strbuf *out)
 143 {
 144         if (!c->protocol)
 145                 return;
 146         strbuf_addf(out, "%s://", c->protocol);
 147         if (c->username && *c->username)
 148                 strbuf_addf(out, "%s@", c->username);
 149         if (c->host)
 150                 strbuf_addstr(out, c->host);
 151         if (c->path)
 152                 strbuf_addf(out, "/%s", c->path);
 153 }
 154
 155 static void credential_format(struct credential *c, struct strbuf *out)
 156 {
 157         if (!c->protocol)
 158                 return;
 159         strbuf_addf(out, "%s://", c->protocol);
 160         if (c->username && *c->username) {
 161                 strbuf_add_percentencode(out, c->username, STRBUF_ENCODE_SLASH);
 162                 strbuf_addch(out, '@');
 163         }
 164         if (c->host)
 165                 strbuf_addstr(out, c->host);
 166         if (c->path) {
 167                 strbuf_addch(out, '/');
 168                 strbuf_add_percentencode(out, c->path, 0);
 169         }
 170 }
 171
 172 static char *credential_ask_one(const char *what, struct credential *c,
 173                                 int flags)
 174 {
 175         struct strbuf desc = STRBUF_INIT;
 176         struct strbuf prompt = STRBUF_INIT;
 177         char *r;
 178
 179         credential_describe(c, &desc);
 180         if (desc.len)
 181                 strbuf_addf(&prompt, "%s for '%s': ", what, desc.buf);
 182         else
 183                 strbuf_addf(&prompt, "%s: ", what);
 184
 185         r = git_prompt(prompt.buf, flags);
 186
 187         strbuf_release(&desc);
 188         strbuf_release(&prompt);
 189         return xstrdup(r);
 190 }
 191
 192 static void credential_getpass(struct credential *c)
 193 {
 194         if (!c->username)
 195                 c->username = credential_ask_one("Username", c,
 196                                                  PROMPT_ASKPASS|PROMPT_ECHO);
 197         if (!c->password)
 198                 c->password = credential_ask_one("Password", c,
 199                                                  PROMPT_ASKPASS);
 200 }
 201
 202 int credential_read(struct credential *c, FILE *fp)
 203 {
 204         struct strbuf line = STRBUF_INIT;
 205
 206         while (strbuf_getline(&line, fp) != EOF) {
 207                 char *key = line.buf;
 208                 char *value = strchr(key, '=');
 209
 210                 if (!line.len)
 211                         break;
 212
 213                 if (!value) {
 214                         warning("invalid credential line: %s", key);
 215                         strbuf_release(&line);
 216                         return -1;
 217                 }
 218                 *value++ = '\0';
 219
 220                 if (!strcmp(key, "username")) {
 221                         free(c->username);
 222                         c->username = xstrdup(value);
 223                         c->username_from_proto = 1;
 224                 } else if (!strcmp(key, "password")) {
 225                         free(c->password);
 226                         c->password = xstrdup(value);
 227                 } else if (!strcmp(key, "protocol")) {
 228                         free(c->protocol);
 229                         c->protocol = xstrdup(value);
 230                 } else if (!strcmp(key, "host")) {
 231                         free(c->host);
 232                         c->host = xstrdup(value);
 233                 } else if (!strcmp(key, "path")) {
 234                         free(c->path);
 235                         c->path = xstrdup(value);
 236                 } else if (!strcmp(key, "url")) {
 237                         credential_from_url(c, value);
 238                 } else if (!strcmp(key, "quit")) {
 239                         c->quit = !!git_config_bool("quit", value);
 240                 }
 241                 /*
 242                  * Ignore other lines; we don't know what they mean, but
 243                  * this future-proofs us when later versions of git do
 244                  * learn new lines, and the helpers are updated to match.
 245                  */
 246         }
 247
 248         strbuf_release(&line);
 249         return 0;
 250 }
 251
 252 static void credential_write_item(FILE *fp, const char *key, const char *value,
 253                                   int required)
 254 {
 255         if (!value && required)
 256                 BUG("credential value for %s is missing", key);
 257         if (!value)
 258                 return;
 259         if (strchr(value, '\n'))
 260                 die("credential value for %s contains newline", key);
 261         fprintf(fp, "%s=%s\n", key, value);
 262 }
 263
 264 void credential_write(const struct credential *c, FILE *fp)
 265 {
 266         credential_write_item(fp, "protocol", c->protocol, 1);
 267         credential_write_item(fp, "host", c->host, 1);
 268         credential_write_item(fp, "path", c->path, 0);
 269         credential_write_item(fp, "username", c->username, 0);
 270         credential_write_item(fp, "password", c->password, 0);
 271 }
 272
 273 static int run_credential_helper(struct credential *c,
 274                                  const char *cmd,
 275                                  int want_output)
 276 {
 277         struct child_process helper = CHILD_PROCESS_INIT;
 278         FILE *fp;
 279
 280         strvec_push(&helper.args, cmd);
 281         helper.use_shell = 1;
 282         helper.in = -1;
 283         if (want_output)
 284                 helper.out = -1;
 285         else
 286                 helper.no_stdout = 1;
 287
 288         if (start_command(&helper) < 0)
 289                 return -1;
 290
 291         fp = xfdopen(helper.in, "w");
 292         sigchain_push(SIGPIPE, SIG_IGN);
 293         credential_write(c, fp);
 294         fclose(fp);
 295         sigchain_pop(SIGPIPE);
 296
 297         if (want_output) {
 298                 int r;
 299                 fp = xfdopen(helper.out, "r");
 300                 r = credential_read(c, fp);
 301                 fclose(fp);
 302                 if (r < 0) {
 303                         finish_command(&helper);
 304                         return -1;
 305                 }
 306         }
 307
 308         if (finish_command(&helper))
 309                 return -1;
 310         return 0;
 311 }
 312
 313 static int credential_do(struct credential *c, const char *helper,
 314                          const char *operation)
 315 {
 316         struct strbuf cmd = STRBUF_INIT;
 317         int r;
 318
 319         if (helper[0] == '!')
 320                 strbuf_addstr(&cmd, helper + 1);
 321         else if (is_absolute_path(helper))
 322                 strbuf_addstr(&cmd, helper);
 323         else
 324                 strbuf_addf(&cmd, "git credential-%s", helper);
 325
 326         strbuf_addf(&cmd, " %s", operation);
 327         r = run_credential_helper(c, cmd.buf, !strcmp(operation, "get"));
 328
 329         strbuf_release(&cmd);
 330         return r;
 331 }
 332
 333 void credential_fill(struct credential *c)
 334 {
 335         int i;
 336
 337         if (c->username && c->password)
 338                 return;
 339
 340         credential_apply_config(c);
 341
 342         for (i = 0; i < c->helpers.nr; i++) {
 343                 credential_do(c, c->helpers.items[i].string, "get");
 344                 if (c->username && c->password)
 345                         return;
 346                 if (c->quit)
 347                         die("credential helper '%s' told us to quit",
 348                             c->helpers.items[i].string);
 349         }
 350
 351         credential_getpass(c);
 352         if (!c->username && !c->password)
 353                 die("unable to get password from user");
 354 }
 355
 356 void credential_approve(struct credential *c)
 357 {
 358         int i;
 359
 360         if (c->approved)
 361                 return;
 362         if (!c->username || !c->password)
 363                 return;
 364
 365         credential_apply_config(c);
 366
 367         for (i = 0; i < c->helpers.nr; i++)
 368                 credential_do(c, c->helpers.items[i].string, "store");
 369         c->approved = 1;
 370 }
 371
 372 void credential_reject(struct credential *c)
 373 {
 374         int i;
 375
 376         credential_apply_config(c);
 377
 378         for (i = 0; i < c->helpers.nr; i++)
 379                 credential_do(c, c->helpers.items[i].string, "erase");
 380
 381         FREE_AND_NULL(c->username);
 382         FREE_AND_NULL(c->password);
 383         c->approved = 0;
 384 }
 385
 386 static int check_url_component(const char *url, int quiet,
 387                                const char *name, const char *value)
 388 {
 389         if (!value)
 390                 return 0;
 391         if (!strchr(value, '\n'))
 392                 return 0;
 393
 394         if (!quiet)
 395                 warning(_("url contains a newline in its %s component: %s"),
 396                         name, url);
 397         return -1;
 398 }
 399
 400 /*
 401  * Potentially-partial URLs can, but do not have to, contain
 402  *
 403  * - a protocol (or scheme) of the form "<protocol>://"
 404  *
 405  * - a host name (the part after the protocol and before the first slash after
 406  *   that, if any)
 407  *
 408  * - a user name and potentially a password (as "<user>[:<password>]@" part of
 409  *   the host name)
 410  *
 411  * - a path (the part after the host name, if any, starting with the slash)
 412  *
 413  * Missing parts will be left unset in `struct credential`. Thus, `https://`
 414  * will have only the `protocol` set, `example.com` only the host name, and
 415  * `/git` only the path.
 416  *
 417  * Note that an empty host name in an otherwise fully-qualified URL (e.g.
 418  * `cert:///path/to/cert.pem`) will be treated as unset if we expect the URL to
 419  * be potentially partial, and only then (otherwise, the empty string is used).
 420  *
 421  * The credential_from_url() function does not allow partial URLs.
 422  */
 423 static int credential_from_url_1(struct credential *c, const char *url,
 424                                  int allow_partial_url, int quiet)
 425 {
 426         const char *at, *colon, *cp, *slash, *host, *proto_end;
 427
 428         credential_clear(c);
 429
 430         /*
 431          * Match one of:
 432          *   (1) proto://<host>/...
 433          *   (2) proto://<user>@<host>/...
 434          *   (3) proto://<user>:<pass>@<host>/...
 435          */
 436         proto_end = strstr(url, "://");
 437         if (!allow_partial_url && (!proto_end || proto_end == url)) {
 438                 if (!quiet)
 439                         warning(_("url has no scheme: %s"), url);
 440                 return -1;
 441         }
 442         cp = proto_end ? proto_end + 3 : url;
 443         at = strchr(cp, '@');
 444         colon = strchr(cp, ':');
 445
 446         /*
 447          * A query or fragment marker before the slash ends the host portion.
 448          * We'll just continue to call this "slash" for simplicity. Notably our
 449          * "trim leading slashes" part won't skip over this part of the path,
 450          * but that's what we'd want.
 451          */
 452         slash = cp + strcspn(cp, "/?#");
 453
 454         if (!at || slash <= at) {
 455                 /* Case (1) */
 456                 host = cp;
 457         }
 458         else if (!colon || at <= colon) {
 459                 /* Case (2) */
 460                 c->username = url_decode_mem(cp, at - cp);
 461                 if (c->username && *c->username)
 462                         c->username_from_proto = 1;
 463                 host = at + 1;
 464         } else {
 465                 /* Case (3) */
 466                 c->username = url_decode_mem(cp, colon - cp);
 467                 if (c->username && *c->username)
 468                         c->username_from_proto = 1;
 469                 c->password = url_decode_mem(colon + 1, at - (colon + 1));
 470                 host = at + 1;
 471         }
 472
 473         if (proto_end && proto_end - url > 0)
 474                 c->protocol = xmemdupz(url, proto_end - url);
 475         if (!allow_partial_url || slash - host > 0)
 476                 c->host = url_decode_mem(host, slash - host);
 477         /* Trim leading and trailing slashes from path */
 478         while (*slash == '/')
 479                 slash++;
 480         if (*slash) {
 481                 char *p;
 482                 c->path = url_decode(slash);
 483                 p = c->path + strlen(c->path) - 1;
 484                 while (p > c->path && *p == '/')
 485                         *p-- = '\0';
 486         }
 487
 488         if (check_url_component(url, quiet, "username", c->username) < 0 ||
 489             check_url_component(url, quiet, "password", c->password) < 0 ||
 490             check_url_component(url, quiet, "protocol", c->protocol) < 0 ||
 491             check_url_component(url, quiet, "host", c->host) < 0 ||
 492             check_url_component(url, quiet, "path", c->path) < 0)
 493                 return -1;
 494
 495         return 0;
 496 }
 497
 498 static int credential_from_potentially_partial_url(struct credential *c,
 499                                                    const char *url)
 500 {
 501         return credential_from_url_1(c, url, 1, 0);
 502 }
 503
 504 int credential_from_url_gently(struct credential *c, const char *url, int quiet)
 505 {
 506         return credential_from_url_1(c, url, 0, quiet);
 507 }
 508
 509 void credential_from_url(struct credential *c, const char *url)
 510 {
 511         if (credential_from_url_gently(c, url, 0) < 0)
 512                 die(_("credential url cannot be parsed: %s"), url);
 513 }