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