265c188823dae79731338a150b6e712ec0580401
   1#include "cache.h"
   2#include "pkt-line.h"
   3#include "exec_cmd.h"
   4#include "run-command.h"
   5#include "strbuf.h"
   6#include "string-list.h"
   7
   8#ifndef HOST_NAME_MAX
   9#define HOST_NAME_MAX 256
  10#endif
  11
  12#ifdef NO_INITGROUPS
  13#define initgroups(x, y) (0) /* nothing */
  14#endif
  15
  16static int log_syslog;
  17static int verbose;
  18static int reuseaddr;
  19static int informative_errors;
  20
  21static const char daemon_usage[] =
  22"git daemon [--verbose] [--syslog] [--export-all]\n"
  23"           [--timeout=<n>] [--init-timeout=<n>] [--max-connections=<n>]\n"
  24"           [--strict-paths] [--base-path=<path>] [--base-path-relaxed]\n"
  25"           [--user-path | --user-path=<path>]\n"
  26"           [--interpolated-path=<path>]\n"
  27"           [--reuseaddr] [--pid-file=<file>]\n"
  28"           [--(enable|disable|allow-override|forbid-override)=<service>]\n"
  29"           [--access-hook=<path>]\n"
  30"           [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
  31"                      [--detach] [--user=<user> [--group=<group>]]\n"
  32"           [<directory>...]";
  33
  34/* List of acceptable pathname prefixes */
  35static char **ok_paths;
  36static int strict_paths;
  37
  38/* If this is set, git-daemon-export-ok is not required */
  39static int export_all_trees;
  40
  41/* Take all paths relative to this one if non-NULL */
  42static const char *base_path;
  43static const char *interpolated_path;
  44static int base_path_relaxed;
  45
  46/* Flag indicating client sent extra args. */
  47static int saw_extended_args;
  48
  49/* If defined, ~user notation is allowed and the string is inserted
  50 * after ~user/.  E.g. a request to git://host/~alice/frotz would
  51 * go to /home/alice/pub_git/frotz with --user-path=pub_git.
  52 */
  53static const char *user_path;
  54
  55/* Timeout, and initial timeout */
  56static unsigned int timeout;
  57static unsigned int init_timeout;
  58
  59static struct strbuf hostname = STRBUF_INIT;
  60static struct strbuf canon_hostname = STRBUF_INIT;
  61static struct strbuf ip_address = STRBUF_INIT;
  62static struct strbuf tcp_port = STRBUF_INIT;
  63
  64static int hostname_lookup_done;
  65
  66static void lookup_hostname(void);
  67
  68static const char *get_canon_hostname(void)
  69{
  70        lookup_hostname();
  71        return canon_hostname.buf;
  72}
  73
  74static const char *get_ip_address(void)
  75{
  76        lookup_hostname();
  77        return ip_address.buf;
  78}
  79
  80static void logreport(int priority, const char *err, va_list params)
  81{
  82        if (log_syslog) {
  83                char buf[1024];
  84                vsnprintf(buf, sizeof(buf), err, params);
  85                syslog(priority, "%s", buf);
  86        } else {
  87                /*
  88                 * Since stderr is set to buffered mode, the
  89                 * logging of different processes will not overlap
  90                 * unless they overflow the (rather big) buffers.
  91                 */
  92                fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
  93                vfprintf(stderr, err, params);
  94                fputc('\n', stderr);
  95                fflush(stderr);
  96        }
  97}
  98
  99__attribute__((format (printf, 1, 2)))
 100static void logerror(const char *err, ...)
 101{
 102        va_list params;
 103        va_start(params, err);
 104        logreport(LOG_ERR, err, params);
 105        va_end(params);
 106}
 107
 108__attribute__((format (printf, 1, 2)))
 109static void loginfo(const char *err, ...)
 110{
 111        va_list params;
 112        if (!verbose)
 113                return;
 114        va_start(params, err);
 115        logreport(LOG_INFO, err, params);
 116        va_end(params);
 117}
 118
 119static void NORETURN daemon_die(const char *err, va_list params)
 120{
 121        logreport(LOG_ERR, err, params);
 122        exit(1);
 123}
 124
 125struct expand_path_context {
 126        const char *directory;
 127};
 128
 129static size_t expand_path(struct strbuf *sb, const char *placeholder, void *ctx)
 130{
 131        struct expand_path_context *context = ctx;
 132
 133        switch (placeholder[0]) {
 134        case 'H':
 135                strbuf_addbuf(sb, &hostname);
 136                return 1;
 137        case 'C':
 138                if (placeholder[1] == 'H') {
 139                        strbuf_addstr(sb, get_canon_hostname());
 140                        return 2;
 141                }
 142                break;
 143        case 'I':
 144                if (placeholder[1] == 'P') {
 145                        strbuf_addstr(sb, get_ip_address());
 146                        return 2;
 147                }
 148                break;
 149        case 'P':
 150                strbuf_addbuf(sb, &tcp_port);
 151                return 1;
 152        case 'D':
 153                strbuf_addstr(sb, context->directory);
 154                return 1;
 155        }
 156        return 0;
 157}
 158
 159static const char *path_ok(const char *directory)
 160{
 161        static char rpath[PATH_MAX];
 162        static char interp_path[PATH_MAX];
 163        const char *path;
 164        const char *dir;
 165
 166        dir = directory;
 167
 168        if (daemon_avoid_alias(dir)) {
 169                logerror("'%s': aliased", dir);
 170                return NULL;
 171        }
 172
 173        if (*dir == '~') {
 174                if (!user_path) {
 175                        logerror("'%s': User-path not allowed", dir);
 176                        return NULL;
 177                }
 178                if (*user_path) {
 179                        /* Got either "~alice" or "~alice/foo";
 180                         * rewrite them to "~alice/%s" or
 181                         * "~alice/%s/foo".
 182                         */
 183                        int namlen, restlen = strlen(dir);
 184                        const char *slash = strchr(dir, '/');
 185                        if (!slash)
 186                                slash = dir + restlen;
 187                        namlen = slash - dir;
 188                        restlen -= namlen;
 189                        loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
 190                        snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
 191                                 namlen, dir, user_path, restlen, slash);
 192                        dir = rpath;
 193                }
 194        }
 195        else if (interpolated_path && saw_extended_args) {
 196                struct strbuf expanded_path = STRBUF_INIT;
 197                struct expand_path_context context;
 198
 199                context.directory = directory;
 200
 201                if (*dir != '/') {
 202                        /* Allow only absolute */
 203                        logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 204                        return NULL;
 205                }
 206
 207                strbuf_expand(&expanded_path, interpolated_path,
 208                              expand_path, &context);
 209                strlcpy(interp_path, expanded_path.buf, PATH_MAX);
 210                strbuf_release(&expanded_path);
 211                loginfo("Interpolated dir '%s'", interp_path);
 212
 213                dir = interp_path;
 214        }
 215        else if (base_path) {
 216                if (*dir != '/') {
 217                        /* Allow only absolute */
 218                        logerror("'%s': Non-absolute path denied (base-path active)", dir);
 219                        return NULL;
 220                }
 221                snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
 222                dir = rpath;
 223        }
 224
 225        path = enter_repo(dir, strict_paths);
 226        if (!path && base_path && base_path_relaxed) {
 227                /*
 228                 * if we fail and base_path_relaxed is enabled, try without
 229                 * prefixing the base path
 230                 */
 231                dir = directory;
 232                path = enter_repo(dir, strict_paths);
 233        }
 234
 235        if (!path) {
 236                logerror("'%s' does not appear to be a git repository", dir);
 237                return NULL;
 238        }
 239
 240        if ( ok_paths && *ok_paths ) {
 241                char **pp;
 242                int pathlen = strlen(path);
 243
 244                /* The validation is done on the paths after enter_repo
 245                 * appends optional {.git,.git/.git} and friends, but
 246                 * it does not use getcwd().  So if your /pub is
 247                 * a symlink to /mnt/pub, you can whitelist /pub and
 248                 * do not have to say /mnt/pub.
 249                 * Do not say /pub/.
 250                 */
 251                for ( pp = ok_paths ; *pp ; pp++ ) {
 252                        int len = strlen(*pp);
 253                        if (len <= pathlen &&
 254                            !memcmp(*pp, path, len) &&
 255                            (path[len] == '\0' ||
 256                             (!strict_paths && path[len] == '/')))
 257                                return path;
 258                }
 259        }
 260        else {
 261                /* be backwards compatible */
 262                if (!strict_paths)
 263                        return path;
 264        }
 265
 266        logerror("'%s': not in whitelist", path);
 267        return NULL;            /* Fallthrough. Deny by default */
 268}
 269
 270typedef int (*daemon_service_fn)(void);
 271struct daemon_service {
 272        const char *name;
 273        const char *config_name;
 274        daemon_service_fn fn;
 275        int enabled;
 276        int overridable;
 277};
 278
 279static int daemon_error(const char *dir, const char *msg)
 280{
 281        if (!informative_errors)
 282                msg = "access denied or repository not exported";
 283        packet_write(1, "ERR %s: %s", msg, dir);
 284        return -1;
 285}
 286
 287static const char *access_hook;
 288
 289static int run_access_hook(struct daemon_service *service, const char *dir, const char *path)
 290{
 291        struct child_process child = CHILD_PROCESS_INIT;
 292        struct strbuf buf = STRBUF_INIT;
 293        const char *argv[8];
 294        const char **arg = argv;
 295        char *eol;
 296        int seen_errors = 0;
 297
 298        *arg++ = access_hook;
 299        *arg++ = service->name;
 300        *arg++ = path;
 301        *arg++ = hostname.buf;
 302        *arg++ = get_canon_hostname();
 303        *arg++ = get_ip_address();
 304        *arg++ = tcp_port.buf;
 305        *arg = NULL;
 306
 307        child.use_shell = 1;
 308        child.argv = argv;
 309        child.no_stdin = 1;
 310        child.no_stderr = 1;
 311        child.out = -1;
 312        if (start_command(&child)) {
 313                logerror("daemon access hook '%s' failed to start",
 314                         access_hook);
 315                goto error_return;
 316        }
 317        if (strbuf_read(&buf, child.out, 0) < 0) {
 318                logerror("failed to read from pipe to daemon access hook '%s'",
 319                         access_hook);
 320                strbuf_reset(&buf);
 321                seen_errors = 1;
 322        }
 323        if (close(child.out) < 0) {
 324                logerror("failed to close pipe to daemon access hook '%s'",
 325                         access_hook);
 326                seen_errors = 1;
 327        }
 328        if (finish_command(&child))
 329                seen_errors = 1;
 330
 331        if (!seen_errors) {
 332                strbuf_release(&buf);
 333                return 0;
 334        }
 335
 336error_return:
 337        strbuf_ltrim(&buf);
 338        if (!buf.len)
 339                strbuf_addstr(&buf, "service rejected");
 340        eol = strchr(buf.buf, '\n');
 341        if (eol)
 342                *eol = '\0';
 343        errno = EACCES;
 344        daemon_error(dir, buf.buf);
 345        strbuf_release(&buf);
 346        return -1;
 347}
 348
 349static int run_service(const char *dir, struct daemon_service *service)
 350{
 351        const char *path;
 352        int enabled = service->enabled;
 353        struct strbuf var = STRBUF_INIT;
 354
 355        loginfo("Request %s for '%s'", service->name, dir);
 356
 357        if (!enabled && !service->overridable) {
 358                logerror("'%s': service not enabled.", service->name);
 359                errno = EACCES;
 360                return daemon_error(dir, "service not enabled");
 361        }
 362
 363        if (!(path = path_ok(dir)))
 364                return daemon_error(dir, "no such repository");
 365
 366        /*
 367         * Security on the cheap.
 368         *
 369         * We want a readable HEAD, usable "objects" directory, and
 370         * a "git-daemon-export-ok" flag that says that the other side
 371         * is ok with us doing this.
 372         *
 373         * path_ok() uses enter_repo() and does whitelist checking.
 374         * We only need to make sure the repository is exported.
 375         */
 376
 377        if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 378                logerror("'%s': repository not exported.", path);
 379                errno = EACCES;
 380                return daemon_error(dir, "repository not exported");
 381        }
 382
 383        if (service->overridable) {
 384                strbuf_addf(&var, "daemon.%s", service->config_name);
 385                git_config_get_bool(var.buf, &enabled);
 386                strbuf_release(&var);
 387        }
 388        if (!enabled) {
 389                logerror("'%s': service not enabled for '%s'",
 390                         service->name, path);
 391                errno = EACCES;
 392                return daemon_error(dir, "service not enabled");
 393        }
 394
 395        /*
 396         * Optionally, a hook can choose to deny access to the
 397         * repository depending on the phase of the moon.
 398         */
 399        if (access_hook && run_access_hook(service, dir, path))
 400                return -1;
 401
 402        /*
 403         * We'll ignore SIGTERM from now on, we have a
 404         * good client.
 405         */
 406        signal(SIGTERM, SIG_IGN);
 407
 408        return service->fn();
 409}
 410
 411static void copy_to_log(int fd)
 412{
 413        struct strbuf line = STRBUF_INIT;
 414        FILE *fp;
 415
 416        fp = fdopen(fd, "r");
 417        if (fp == NULL) {
 418                logerror("fdopen of error channel failed");
 419                close(fd);
 420                return;
 421        }
 422
 423        while (strbuf_getline(&line, fp, '\n') != EOF) {
 424                logerror("%s", line.buf);
 425                strbuf_setlen(&line, 0);
 426        }
 427
 428        strbuf_release(&line);
 429        fclose(fp);
 430}
 431
 432static int run_service_command(const char **argv)
 433{
 434        struct child_process cld = CHILD_PROCESS_INIT;
 435
 436        cld.argv = argv;
 437        cld.git_cmd = 1;
 438        cld.err = -1;
 439        if (start_command(&cld))
 440                return -1;
 441
 442        close(0);
 443        close(1);
 444
 445        copy_to_log(cld.err);
 446
 447        return finish_command(&cld);
 448}
 449
 450static int upload_pack(void)
 451{
 452        /* Timeout as string */
 453        char timeout_buf[64];
 454        const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
 455
 456        argv[2] = timeout_buf;
 457
 458        snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 459        return run_service_command(argv);
 460}
 461
 462static int upload_archive(void)
 463{
 464        static const char *argv[] = { "upload-archive", ".", NULL };
 465        return run_service_command(argv);
 466}
 467
 468static int receive_pack(void)
 469{
 470        static const char *argv[] = { "receive-pack", ".", NULL };
 471        return run_service_command(argv);
 472}
 473
 474static struct daemon_service daemon_service[] = {
 475        { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 476        { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 477        { "receive-pack", "receivepack", receive_pack, 0, 1 },
 478};
 479
 480static void enable_service(const char *name, int ena)
 481{
 482        int i;
 483        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 484                if (!strcmp(daemon_service[i].name, name)) {
 485                        daemon_service[i].enabled = ena;
 486                        return;
 487                }
 488        }
 489        die("No such service %s", name);
 490}
 491
 492static void make_service_overridable(const char *name, int ena)
 493{
 494        int i;
 495        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 496                if (!strcmp(daemon_service[i].name, name)) {
 497                        daemon_service[i].overridable = ena;
 498                        return;
 499                }
 500        }
 501        die("No such service %s", name);
 502}
 503
 504static void parse_host_and_port(char *hostport, char **host,
 505        char **port)
 506{
 507        if (*hostport == '[') {
 508                char *end;
 509
 510                end = strchr(hostport, ']');
 511                if (!end)
 512                        die("Invalid request ('[' without ']')");
 513                *end = '\0';
 514                *host = hostport + 1;
 515                if (!end[1])
 516                        *port = NULL;
 517                else if (end[1] == ':')
 518                        *port = end + 2;
 519                else
 520                        die("Garbage after end of host part");
 521        } else {
 522                *host = hostport;
 523                *port = strrchr(hostport, ':');
 524                if (*port) {
 525                        **port = '\0';
 526                        ++*port;
 527                }
 528        }
 529}
 530
 531/*
 532 * Sanitize a string from the client so that it's OK to be inserted into a
 533 * filesystem path. Specifically, we disallow slashes, runs of "..", and
 534 * trailing and leading dots, which means that the client cannot escape
 535 * our base path via ".." traversal.
 536 */
 537static void sanitize_client(struct strbuf *out, const char *in)
 538{
 539        for (; *in; in++) {
 540                if (*in == '/')
 541                        continue;
 542                if (*in == '.' && (!out->len || out->buf[out->len - 1] == '.'))
 543                        continue;
 544                strbuf_addch(out, *in);
 545        }
 546
 547        while (out->len && out->buf[out->len - 1] == '.')
 548                strbuf_setlen(out, out->len - 1);
 549}
 550
 551/*
 552 * Like sanitize_client, but we also perform any canonicalization
 553 * to make life easier on the admin.
 554 */
 555static void canonicalize_client(struct strbuf *out, const char *in)
 556{
 557        sanitize_client(out, in);
 558        strbuf_tolower(out);
 559}
 560
 561/*
 562 * Read the host as supplied by the client connection.
 563 */
 564static void parse_host_arg(char *extra_args, int buflen)
 565{
 566        char *val;
 567        int vallen;
 568        char *end = extra_args + buflen;
 569
 570        if (extra_args < end && *extra_args) {
 571                saw_extended_args = 1;
 572                if (strncasecmp("host=", extra_args, 5) == 0) {
 573                        val = extra_args + 5;
 574                        vallen = strlen(val) + 1;
 575                        if (*val) {
 576                                /* Split <host>:<port> at colon. */
 577                                char *host;
 578                                char *port;
 579                                parse_host_and_port(val, &host, &port);
 580                                if (port) {
 581                                        strbuf_reset(&tcp_port);
 582                                        sanitize_client(&tcp_port, port);
 583                                }
 584                                strbuf_reset(&hostname);
 585                                canonicalize_client(&hostname, host);
 586                                hostname_lookup_done = 0;
 587                        }
 588
 589                        /* On to the next one */
 590                        extra_args = val + vallen;
 591                }
 592                if (extra_args < end && *extra_args)
 593                        die("Invalid request");
 594        }
 595}
 596
 597/*
 598 * Locate canonical hostname and its IP address.
 599 */
 600static void lookup_hostname(void)
 601{
 602        if (!hostname_lookup_done && hostname.len) {
 603#ifndef NO_IPV6
 604                struct addrinfo hints;
 605                struct addrinfo *ai;
 606                int gai;
 607                static char addrbuf[HOST_NAME_MAX + 1];
 608
 609                memset(&hints, 0, sizeof(hints));
 610                hints.ai_flags = AI_CANONNAME;
 611
 612                gai = getaddrinfo(hostname.buf, NULL, &hints, &ai);
 613                if (!gai) {
 614                        struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 615
 616                        inet_ntop(AF_INET, &sin_addr->sin_addr,
 617                                  addrbuf, sizeof(addrbuf));
 618                        strbuf_reset(&ip_address);
 619                        strbuf_addstr(&ip_address, addrbuf);
 620
 621                        strbuf_reset(&canon_hostname);
 622                        if (ai->ai_canonname)
 623                                sanitize_client(&canon_hostname,
 624                                                ai->ai_canonname);
 625                        else
 626                                strbuf_addbuf(&canon_hostname, &ip_address);
 627
 628                        freeaddrinfo(ai);
 629                }
 630#else
 631                struct hostent *hent;
 632                struct sockaddr_in sa;
 633                char **ap;
 634                static char addrbuf[HOST_NAME_MAX + 1];
 635
 636                hent = gethostbyname(hostname.buf);
 637                if (hent) {
 638                        ap = hent->h_addr_list;
 639                        memset(&sa, 0, sizeof sa);
 640                        sa.sin_family = hent->h_addrtype;
 641                        sa.sin_port = htons(0);
 642                        memcpy(&sa.sin_addr, *ap, hent->h_length);
 643
 644                        inet_ntop(hent->h_addrtype, &sa.sin_addr,
 645                                  addrbuf, sizeof(addrbuf));
 646
 647                        strbuf_reset(&canon_hostname);
 648                        sanitize_client(&canon_hostname, hent->h_name);
 649                        strbuf_reset(&ip_address);
 650                        strbuf_addstr(&ip_address, addrbuf);
 651                }
 652#endif
 653                hostname_lookup_done = 1;
 654        }
 655}
 656
 657
 658static int execute(void)
 659{
 660        char *line = packet_buffer;
 661        int pktlen, len, i;
 662        char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
 663
 664        if (addr)
 665                loginfo("Connection from %s:%s", addr, port);
 666
 667        alarm(init_timeout ? init_timeout : timeout);
 668        pktlen = packet_read(0, NULL, NULL, packet_buffer, sizeof(packet_buffer), 0);
 669        alarm(0);
 670
 671        len = strlen(line);
 672        if (pktlen != len)
 673                loginfo("Extended attributes (%d bytes) exist <%.*s>",
 674                        (int) pktlen - len,
 675                        (int) pktlen - len, line + len + 1);
 676        if (len && line[len-1] == '\n') {
 677                line[--len] = 0;
 678                pktlen--;
 679        }
 680
 681        strbuf_release(&hostname);
 682        strbuf_release(&canon_hostname);
 683        strbuf_release(&ip_address);
 684        strbuf_release(&tcp_port);
 685
 686        if (len != pktlen)
 687                parse_host_arg(line + len + 1, pktlen - len - 1);
 688
 689        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 690                struct daemon_service *s = &(daemon_service[i]);
 691                const char *arg;
 692
 693                if (skip_prefix(line, "git-", &arg) &&
 694                    skip_prefix(arg, s->name, &arg) &&
 695                    *arg++ == ' ') {
 696                        /*
 697                         * Note: The directory here is probably context sensitive,
 698                         * and might depend on the actual service being performed.
 699                         */
 700                        return run_service(arg, s);
 701                }
 702        }
 703
 704        logerror("Protocol error: '%s'", line);
 705        return -1;
 706}
 707
 708static int addrcmp(const struct sockaddr_storage *s1,
 709    const struct sockaddr_storage *s2)
 710{
 711        const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 712        const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 713
 714        if (sa1->sa_family != sa2->sa_family)
 715                return sa1->sa_family - sa2->sa_family;
 716        if (sa1->sa_family == AF_INET)
 717                return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 718                    &((struct sockaddr_in *)s2)->sin_addr,
 719                    sizeof(struct in_addr));
 720#ifndef NO_IPV6
 721        if (sa1->sa_family == AF_INET6)
 722                return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 723                    &((struct sockaddr_in6 *)s2)->sin6_addr,
 724                    sizeof(struct in6_addr));
 725#endif
 726        return 0;
 727}
 728
 729static int max_connections = 32;
 730
 731static unsigned int live_children;
 732
 733static struct child {
 734        struct child *next;
 735        struct child_process cld;
 736        struct sockaddr_storage address;
 737} *firstborn;
 738
 739static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
 740{
 741        struct child *newborn, **cradle;
 742
 743        newborn = xcalloc(1, sizeof(*newborn));
 744        live_children++;
 745        memcpy(&newborn->cld, cld, sizeof(*cld));
 746        memcpy(&newborn->address, addr, addrlen);
 747        for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 748                if (!addrcmp(&(*cradle)->address, &newborn->address))
 749                        break;
 750        newborn->next = *cradle;
 751        *cradle = newborn;
 752}
 753
 754/*
 755 * This gets called if the number of connections grows
 756 * past "max_connections".
 757 *
 758 * We kill the newest connection from a duplicate IP.
 759 */
 760static void kill_some_child(void)
 761{
 762        const struct child *blanket, *next;
 763
 764        if (!(blanket = firstborn))
 765                return;
 766
 767        for (; (next = blanket->next); blanket = next)
 768                if (!addrcmp(&blanket->address, &next->address)) {
 769                        kill(blanket->cld.pid, SIGTERM);
 770                        break;
 771                }
 772}
 773
 774static void check_dead_children(void)
 775{
 776        int status;
 777        pid_t pid;
 778
 779        struct child **cradle, *blanket;
 780        for (cradle = &firstborn; (blanket = *cradle);)
 781                if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
 782                        const char *dead = "";
 783                        if (status)
 784                                dead = " (with error)";
 785                        loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 786
 787                        /* remove the child */
 788                        *cradle = blanket->next;
 789                        live_children--;
 790                        free(blanket);
 791                } else
 792                        cradle = &blanket->next;
 793}
 794
 795static char **cld_argv;
 796static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 797{
 798        struct child_process cld = CHILD_PROCESS_INIT;
 799        char addrbuf[300] = "REMOTE_ADDR=", portbuf[300];
 800        char *env[] = { addrbuf, portbuf, NULL };
 801
 802        if (max_connections && live_children >= max_connections) {
 803                kill_some_child();
 804                sleep(1);  /* give it some time to die */
 805                check_dead_children();
 806                if (live_children >= max_connections) {
 807                        close(incoming);
 808                        logerror("Too many children, dropping connection");
 809                        return;
 810                }
 811        }
 812
 813        if (addr->sa_family == AF_INET) {
 814                struct sockaddr_in *sin_addr = (void *) addr;
 815                inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf + 12,
 816                    sizeof(addrbuf) - 12);
 817                snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 818                    ntohs(sin_addr->sin_port));
 819#ifndef NO_IPV6
 820        } else if (addr->sa_family == AF_INET6) {
 821                struct sockaddr_in6 *sin6_addr = (void *) addr;
 822
 823                char *buf = addrbuf + 12;
 824                *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 825                inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf,
 826                    sizeof(addrbuf) - 13);
 827                strcat(buf, "]");
 828
 829                snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 830                    ntohs(sin6_addr->sin6_port));
 831#endif
 832        }
 833
 834        cld.env = (const char **)env;
 835        cld.argv = (const char **)cld_argv;
 836        cld.in = incoming;
 837        cld.out = dup(incoming);
 838
 839        if (start_command(&cld))
 840                logerror("unable to fork");
 841        else
 842                add_child(&cld, addr, addrlen);
 843}
 844
 845static void child_handler(int signo)
 846{
 847        /*
 848         * Otherwise empty handler because systemcalls will get interrupted
 849         * upon signal receipt
 850         * SysV needs the handler to be rearmed
 851         */
 852        signal(SIGCHLD, child_handler);
 853}
 854
 855static int set_reuse_addr(int sockfd)
 856{
 857        int on = 1;
 858
 859        if (!reuseaddr)
 860                return 0;
 861        return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 862                          &on, sizeof(on));
 863}
 864
 865struct socketlist {
 866        int *list;
 867        size_t nr;
 868        size_t alloc;
 869};
 870
 871static const char *ip2str(int family, struct sockaddr *sin, socklen_t len)
 872{
 873#ifdef NO_IPV6
 874        static char ip[INET_ADDRSTRLEN];
 875#else
 876        static char ip[INET6_ADDRSTRLEN];
 877#endif
 878
 879        switch (family) {
 880#ifndef NO_IPV6
 881        case AF_INET6:
 882                inet_ntop(family, &((struct sockaddr_in6*)sin)->sin6_addr, ip, len);
 883                break;
 884#endif
 885        case AF_INET:
 886                inet_ntop(family, &((struct sockaddr_in*)sin)->sin_addr, ip, len);
 887                break;
 888        default:
 889                strcpy(ip, "<unknown>");
 890        }
 891        return ip;
 892}
 893
 894#ifndef NO_IPV6
 895
 896static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 897{
 898        int socknum = 0;
 899        char pbuf[NI_MAXSERV];
 900        struct addrinfo hints, *ai0, *ai;
 901        int gai;
 902        long flags;
 903
 904        sprintf(pbuf, "%d", listen_port);
 905        memset(&hints, 0, sizeof(hints));
 906        hints.ai_family = AF_UNSPEC;
 907        hints.ai_socktype = SOCK_STREAM;
 908        hints.ai_protocol = IPPROTO_TCP;
 909        hints.ai_flags = AI_PASSIVE;
 910
 911        gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 912        if (gai) {
 913                logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
 914                return 0;
 915        }
 916
 917        for (ai = ai0; ai; ai = ai->ai_next) {
 918                int sockfd;
 919
 920                sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 921                if (sockfd < 0)
 922                        continue;
 923                if (sockfd >= FD_SETSIZE) {
 924                        logerror("Socket descriptor too large");
 925                        close(sockfd);
 926                        continue;
 927                }
 928
 929#ifdef IPV6_V6ONLY
 930                if (ai->ai_family == AF_INET6) {
 931                        int on = 1;
 932                        setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 933                                   &on, sizeof(on));
 934                        /* Note: error is not fatal */
 935                }
 936#endif
 937
 938                if (set_reuse_addr(sockfd)) {
 939                        logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 940                        close(sockfd);
 941                        continue;
 942                }
 943
 944                if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 945                        logerror("Could not bind to %s: %s",
 946                                 ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 947                                 strerror(errno));
 948                        close(sockfd);
 949                        continue;       /* not fatal */
 950                }
 951                if (listen(sockfd, 5) < 0) {
 952                        logerror("Could not listen to %s: %s",
 953                                 ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 954                                 strerror(errno));
 955                        close(sockfd);
 956                        continue;       /* not fatal */
 957                }
 958
 959                flags = fcntl(sockfd, F_GETFD, 0);
 960                if (flags >= 0)
 961                        fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 962
 963                ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 964                socklist->list[socklist->nr++] = sockfd;
 965                socknum++;
 966        }
 967
 968        freeaddrinfo(ai0);
 969
 970        return socknum;
 971}
 972
 973#else /* NO_IPV6 */
 974
 975static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 976{
 977        struct sockaddr_in sin;
 978        int sockfd;
 979        long flags;
 980
 981        memset(&sin, 0, sizeof sin);
 982        sin.sin_family = AF_INET;
 983        sin.sin_port = htons(listen_port);
 984
 985        if (listen_addr) {
 986                /* Well, host better be an IP address here. */
 987                if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 988                        return 0;
 989        } else {
 990                sin.sin_addr.s_addr = htonl(INADDR_ANY);
 991        }
 992
 993        sockfd = socket(AF_INET, SOCK_STREAM, 0);
 994        if (sockfd < 0)
 995                return 0;
 996
 997        if (set_reuse_addr(sockfd)) {
 998                logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 999                close(sockfd);
1000                return 0;
1001        }
1002
1003        if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
1004                logerror("Could not bind to %s: %s",
1005                         ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
1006                         strerror(errno));
1007                close(sockfd);
1008                return 0;
1009        }
1010
1011        if (listen(sockfd, 5) < 0) {
1012                logerror("Could not listen to %s: %s",
1013                         ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
1014                         strerror(errno));
1015                close(sockfd);
1016                return 0;
1017        }
1018
1019        flags = fcntl(sockfd, F_GETFD, 0);
1020        if (flags >= 0)
1021                fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
1022
1023        ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
1024        socklist->list[socklist->nr++] = sockfd;
1025        return 1;
1026}
1027
1028#endif
1029
1030static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
1031{
1032        if (!listen_addr->nr)
1033                setup_named_sock(NULL, listen_port, socklist);
1034        else {
1035                int i, socknum;
1036                for (i = 0; i < listen_addr->nr; i++) {
1037                        socknum = setup_named_sock(listen_addr->items[i].string,
1038                                                   listen_port, socklist);
1039
1040                        if (socknum == 0)
1041                                logerror("unable to allocate any listen sockets for host %s on port %u",
1042                                         listen_addr->items[i].string, listen_port);
1043                }
1044        }
1045}
1046
1047static int service_loop(struct socketlist *socklist)
1048{
1049        struct pollfd *pfd;
1050        int i;
1051
1052        pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
1053
1054        for (i = 0; i < socklist->nr; i++) {
1055                pfd[i].fd = socklist->list[i];
1056                pfd[i].events = POLLIN;
1057        }
1058
1059        signal(SIGCHLD, child_handler);
1060
1061        for (;;) {
1062                int i;
1063
1064                check_dead_children();
1065
1066                if (poll(pfd, socklist->nr, -1) < 0) {
1067                        if (errno != EINTR) {
1068                                logerror("Poll failed, resuming: %s",
1069                                      strerror(errno));
1070                                sleep(1);
1071                        }
1072                        continue;
1073                }
1074
1075                for (i = 0; i < socklist->nr; i++) {
1076                        if (pfd[i].revents & POLLIN) {
1077                                union {
1078                                        struct sockaddr sa;
1079                                        struct sockaddr_in sai;
1080#ifndef NO_IPV6
1081                                        struct sockaddr_in6 sai6;
1082#endif
1083                                } ss;
1084                                socklen_t sslen = sizeof(ss);
1085                                int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
1086                                if (incoming < 0) {
1087                                        switch (errno) {
1088                                        case EAGAIN:
1089                                        case EINTR:
1090                                        case ECONNABORTED:
1091                                                continue;
1092                                        default:
1093                                                die_errno("accept returned");
1094                                        }
1095                                }
1096                                handle(incoming, &ss.sa, sslen);
1097                        }
1098                }
1099        }
1100}
1101
1102#ifdef NO_POSIX_GOODIES
1103
1104struct credentials;
1105
1106static void drop_privileges(struct credentials *cred)
1107{
1108        /* nothing */
1109}
1110
1111static struct credentials *prepare_credentials(const char *user_name,
1112    const char *group_name)
1113{
1114        die("--user not supported on this platform");
1115}
1116
1117#else
1118
1119struct credentials {
1120        struct passwd *pass;
1121        gid_t gid;
1122};
1123
1124static void drop_privileges(struct credentials *cred)
1125{
1126        if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
1127            setgid (cred->gid) || setuid(cred->pass->pw_uid)))
1128                die("cannot drop privileges");
1129}
1130
1131static struct credentials *prepare_credentials(const char *user_name,
1132    const char *group_name)
1133{
1134        static struct credentials c;
1135
1136        c.pass = getpwnam(user_name);
1137        if (!c.pass)
1138                die("user not found - %s", user_name);
1139
1140        if (!group_name)
1141                c.gid = c.pass->pw_gid;
1142        else {
1143                struct group *group = getgrnam(group_name);
1144                if (!group)
1145                        die("group not found - %s", group_name);
1146
1147                c.gid = group->gr_gid;
1148        }
1149
1150        return &c;
1151}
1152#endif
1153
1154static void store_pid(const char *path)
1155{
1156        FILE *f = fopen(path, "w");
1157        if (!f)
1158                die_errno("cannot open pid file '%s'", path);
1159        if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
1160                die_errno("failed to write pid file '%s'", path);
1161}
1162
1163static int serve(struct string_list *listen_addr, int listen_port,
1164    struct credentials *cred)
1165{
1166        struct socketlist socklist = { NULL, 0, 0 };
1167
1168        socksetup(listen_addr, listen_port, &socklist);
1169        if (socklist.nr == 0)
1170                die("unable to allocate any listen sockets on port %u",
1171                    listen_port);
1172
1173        drop_privileges(cred);
1174
1175        loginfo("Ready to rumble");
1176
1177        return service_loop(&socklist);
1178}
1179
1180int main(int argc, char **argv)
1181{
1182        int listen_port = 0;
1183        struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1184        int serve_mode = 0, inetd_mode = 0;
1185        const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1186        int detach = 0;
1187        struct credentials *cred = NULL;
1188        int i;
1189
1190        git_setup_gettext();
1191
1192        git_extract_argv0_path(argv[0]);
1193
1194        for (i = 1; i < argc; i++) {
1195                char *arg = argv[i];
1196                const char *v;
1197
1198                if (skip_prefix(arg, "--listen=", &v)) {
1199                        string_list_append(&listen_addr, xstrdup_tolower(v));
1200                        continue;
1201                }
1202                if (skip_prefix(arg, "--port=", &v)) {
1203                        char *end;
1204                        unsigned long n;
1205                        n = strtoul(v, &end, 0);
1206                        if (*v && !*end) {
1207                                listen_port = n;
1208                                continue;
1209                        }
1210                }
1211                if (!strcmp(arg, "--serve")) {
1212                        serve_mode = 1;
1213                        continue;
1214                }
1215                if (!strcmp(arg, "--inetd")) {
1216                        inetd_mode = 1;
1217                        log_syslog = 1;
1218                        continue;
1219                }
1220                if (!strcmp(arg, "--verbose")) {
1221                        verbose = 1;
1222                        continue;
1223                }
1224                if (!strcmp(arg, "--syslog")) {
1225                        log_syslog = 1;
1226                        continue;
1227                }
1228                if (!strcmp(arg, "--export-all")) {
1229                        export_all_trees = 1;
1230                        continue;
1231                }
1232                if (skip_prefix(arg, "--access-hook=", &v)) {
1233                        access_hook = v;
1234                        continue;
1235                }
1236                if (skip_prefix(arg, "--timeout=", &v)) {
1237                        timeout = atoi(v);
1238                        continue;
1239                }
1240                if (skip_prefix(arg, "--init-timeout=", &v)) {
1241                        init_timeout = atoi(v);
1242                        continue;
1243                }
1244                if (skip_prefix(arg, "--max-connections=", &v)) {
1245                        max_connections = atoi(v);
1246                        if (max_connections < 0)
1247                                max_connections = 0;            /* unlimited */
1248                        continue;
1249                }
1250                if (!strcmp(arg, "--strict-paths")) {
1251                        strict_paths = 1;
1252                        continue;
1253                }
1254                if (skip_prefix(arg, "--base-path=", &v)) {
1255                        base_path = v;
1256                        continue;
1257                }
1258                if (!strcmp(arg, "--base-path-relaxed")) {
1259                        base_path_relaxed = 1;
1260                        continue;
1261                }
1262                if (skip_prefix(arg, "--interpolated-path=", &v)) {
1263                        interpolated_path = v;
1264                        continue;
1265                }
1266                if (!strcmp(arg, "--reuseaddr")) {
1267                        reuseaddr = 1;
1268                        continue;
1269                }
1270                if (!strcmp(arg, "--user-path")) {
1271                        user_path = "";
1272                        continue;
1273                }
1274                if (skip_prefix(arg, "--user-path=", &v)) {
1275                        user_path = v;
1276                        continue;
1277                }
1278                if (skip_prefix(arg, "--pid-file=", &v)) {
1279                        pid_file = v;
1280                        continue;
1281                }
1282                if (!strcmp(arg, "--detach")) {
1283                        detach = 1;
1284                        log_syslog = 1;
1285                        continue;
1286                }
1287                if (skip_prefix(arg, "--user=", &v)) {
1288                        user_name = v;
1289                        continue;
1290                }
1291                if (skip_prefix(arg, "--group=", &v)) {
1292                        group_name = v;
1293                        continue;
1294                }
1295                if (skip_prefix(arg, "--enable=", &v)) {
1296                        enable_service(v, 1);
1297                        continue;
1298                }
1299                if (skip_prefix(arg, "--disable=", &v)) {
1300                        enable_service(v, 0);
1301                        continue;
1302                }
1303                if (skip_prefix(arg, "--allow-override=", &v)) {
1304                        make_service_overridable(v, 1);
1305                        continue;
1306                }
1307                if (skip_prefix(arg, "--forbid-override=", &v)) {
1308                        make_service_overridable(v, 0);
1309                        continue;
1310                }
1311                if (!strcmp(arg, "--informative-errors")) {
1312                        informative_errors = 1;
1313                        continue;
1314                }
1315                if (!strcmp(arg, "--no-informative-errors")) {
1316                        informative_errors = 0;
1317                        continue;
1318                }
1319                if (!strcmp(arg, "--")) {
1320                        ok_paths = &argv[i+1];
1321                        break;
1322                } else if (arg[0] != '-') {
1323                        ok_paths = &argv[i];
1324                        break;
1325                }
1326
1327                usage(daemon_usage);
1328        }
1329
1330        if (log_syslog) {
1331                openlog("git-daemon", LOG_PID, LOG_DAEMON);
1332                set_die_routine(daemon_die);
1333        } else
1334                /* avoid splitting a message in the middle */
1335                setvbuf(stderr, NULL, _IOFBF, 4096);
1336
1337        if (inetd_mode && (detach || group_name || user_name))
1338                die("--detach, --user and --group are incompatible with --inetd");
1339
1340        if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1341                die("--listen= and --port= are incompatible with --inetd");
1342        else if (listen_port == 0)
1343                listen_port = DEFAULT_GIT_PORT;
1344
1345        if (group_name && !user_name)
1346                die("--group supplied without --user");
1347
1348        if (user_name)
1349                cred = prepare_credentials(user_name, group_name);
1350
1351        if (strict_paths && (!ok_paths || !*ok_paths))
1352                die("option --strict-paths requires a whitelist");
1353
1354        if (base_path && !is_directory(base_path))
1355                die("base-path '%s' does not exist or is not a directory",
1356                    base_path);
1357
1358        if (inetd_mode) {
1359                if (!freopen("/dev/null", "w", stderr))
1360                        die_errno("failed to redirect stderr to /dev/null");
1361        }
1362
1363        if (inetd_mode || serve_mode)
1364                return execute();
1365
1366        if (detach) {
1367                if (daemonize())
1368                        die("--detach not supported on this platform");
1369        } else
1370                sanitize_stdfds();
1371
1372        if (pid_file)
1373                store_pid(pid_file);
1374
1375        /* prepare argv for serving-processes */
1376        cld_argv = xmalloc(sizeof (char *) * (argc + 2));
1377        cld_argv[0] = argv[0];  /* git-daemon */
1378        cld_argv[1] = "--serve";
1379        for (i = 1; i < argc; ++i)
1380                cld_argv[i+1] = argv[i];
1381        cld_argv[argc+1] = NULL;
1382
1383        return serve(&listen_addr, listen_port, cred);
1384}