Andrew's git / gitweb.git / daemon.c
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daemon.con commit Merge branch 'jk/daemon-path-ok-check-truncation' into maint (aa22ef8)
   1#include "cache.h"
   2#include "pkt-line.h"
   3#include "run-command.h"
   4#include "strbuf.h"
   5#include "string-list.h"
   6
   7#ifndef HOST_NAME_MAX
   8#define HOST_NAME_MAX 256
   9#endif
  10
  11#ifdef NO_INITGROUPS
  12#define initgroups(x, y) (0) /* nothing */
  13#endif
  14
  15static int log_syslog;
  16static int verbose;
  17static int reuseaddr;
  18static int informative_errors;
  19
  20static const char daemon_usage[] =
  21"git daemon [--verbose] [--syslog] [--export-all]\n"
  22"           [--timeout=<n>] [--init-timeout=<n>] [--max-connections=<n>]\n"
  23"           [--strict-paths] [--base-path=<path>] [--base-path-relaxed]\n"
  24"           [--user-path | --user-path=<path>]\n"
  25"           [--interpolated-path=<path>]\n"
  26"           [--reuseaddr] [--pid-file=<file>]\n"
  27"           [--(enable|disable|allow-override|forbid-override)=<service>]\n"
  28"           [--access-hook=<path>]\n"
  29"           [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
  30"                      [--detach] [--user=<user> [--group=<group>]]\n"
  31"           [<directory>...]";
  32
  33/* List of acceptable pathname prefixes */
  34static const char **ok_paths;
  35static int strict_paths;
  36
  37/* If this is set, git-daemon-export-ok is not required */
  38static int export_all_trees;
  39
  40/* Take all paths relative to this one if non-NULL */
  41static const char *base_path;
  42static const char *interpolated_path;
  43static int base_path_relaxed;
  44
  45/* If defined, ~user notation is allowed and the string is inserted
  46 * after ~user/.  E.g. a request to git://host/~alice/frotz would
  47 * go to /home/alice/pub_git/frotz with --user-path=pub_git.
  48 */
  49static const char *user_path;
  50
  51/* Timeout, and initial timeout */
  52static unsigned int timeout;
  53static unsigned int init_timeout;
  54
  55struct hostinfo {
  56        struct strbuf hostname;
  57        struct strbuf canon_hostname;
  58        struct strbuf ip_address;
  59        struct strbuf tcp_port;
  60        unsigned int hostname_lookup_done:1;
  61        unsigned int saw_extended_args:1;
  62};
  63
  64static void lookup_hostname(struct hostinfo *hi);
  65
  66static const char *get_canon_hostname(struct hostinfo *hi)
  67{
  68        lookup_hostname(hi);
  69        return hi->canon_hostname.buf;
  70}
  71
  72static const char *get_ip_address(struct hostinfo *hi)
  73{
  74        lookup_hostname(hi);
  75        return hi->ip_address.buf;
  76}
  77
  78static void logreport(int priority, const char *err, va_list params)
  79{
  80        if (log_syslog) {
  81                char buf[1024];
  82                vsnprintf(buf, sizeof(buf), err, params);
  83                syslog(priority, "%s", buf);
  84        } else {
  85                /*
  86                 * Since stderr is set to buffered mode, the
  87                 * logging of different processes will not overlap
  88                 * unless they overflow the (rather big) buffers.
  89                 */
  90                fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
  91                vfprintf(stderr, err, params);
  92                fputc('\n', stderr);
  93                fflush(stderr);
  94        }
  95}
  96
  97__attribute__((format (printf, 1, 2)))
  98static void logerror(const char *err, ...)
  99{
 100        va_list params;
 101        va_start(params, err);
 102        logreport(LOG_ERR, err, params);
 103        va_end(params);
 104}
 105
 106__attribute__((format (printf, 1, 2)))
 107static void loginfo(const char *err, ...)
 108{
 109        va_list params;
 110        if (!verbose)
 111                return;
 112        va_start(params, err);
 113        logreport(LOG_INFO, err, params);
 114        va_end(params);
 115}
 116
 117static void NORETURN daemon_die(const char *err, va_list params)
 118{
 119        logreport(LOG_ERR, err, params);
 120        exit(1);
 121}
 122
 123struct expand_path_context {
 124        const char *directory;
 125        struct hostinfo *hostinfo;
 126};
 127
 128static size_t expand_path(struct strbuf *sb, const char *placeholder, void *ctx)
 129{
 130        struct expand_path_context *context = ctx;
 131        struct hostinfo *hi = context->hostinfo;
 132
 133        switch (placeholder[0]) {
 134        case 'H':
 135                strbuf_addbuf(sb, &hi->hostname);
 136                return 1;
 137        case 'C':
 138                if (placeholder[1] == 'H') {
 139                        strbuf_addstr(sb, get_canon_hostname(hi));
 140                        return 2;
 141                }
 142                break;
 143        case 'I':
 144                if (placeholder[1] == 'P') {
 145                        strbuf_addstr(sb, get_ip_address(hi));
 146                        return 2;
 147                }
 148                break;
 149        case 'P':
 150                strbuf_addbuf(sb, &hi->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, struct hostinfo *hi)
 160{
 161        static char rpath[PATH_MAX];
 162        static char interp_path[PATH_MAX];
 163        size_t rlen;
 164        const char *path;
 165        const char *dir;
 166
 167        dir = directory;
 168
 169        if (daemon_avoid_alias(dir)) {
 170                logerror("'%s': aliased", dir);
 171                return NULL;
 172        }
 173
 174        if (*dir == '~') {
 175                if (!user_path) {
 176                        logerror("'%s': User-path not allowed", dir);
 177                        return NULL;
 178                }
 179                if (*user_path) {
 180                        /* Got either "~alice" or "~alice/foo";
 181                         * rewrite them to "~alice/%s" or
 182                         * "~alice/%s/foo".
 183                         */
 184                        int namlen, restlen = strlen(dir);
 185                        const char *slash = strchr(dir, '/');
 186                        if (!slash)
 187                                slash = dir + restlen;
 188                        namlen = slash - dir;
 189                        restlen -= namlen;
 190                        loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
 191                        rlen = snprintf(rpath, sizeof(rpath), "%.*s/%s%.*s",
 192                                        namlen, dir, user_path, restlen, slash);
 193                        if (rlen >= sizeof(rpath)) {
 194                                logerror("user-path too large: %s", rpath);
 195                                return NULL;
 196                        }
 197                        dir = rpath;
 198                }
 199        }
 200        else if (interpolated_path && hi->saw_extended_args) {
 201                struct strbuf expanded_path = STRBUF_INIT;
 202                struct expand_path_context context;
 203
 204                context.directory = directory;
 205                context.hostinfo = hi;
 206
 207                if (*dir != '/') {
 208                        /* Allow only absolute */
 209                        logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 210                        return NULL;
 211                }
 212
 213                strbuf_expand(&expanded_path, interpolated_path,
 214                              expand_path, &context);
 215
 216                rlen = strlcpy(interp_path, expanded_path.buf,
 217                               sizeof(interp_path));
 218                if (rlen >= sizeof(interp_path)) {
 219                        logerror("interpolated path too large: %s",
 220                                 interp_path);
 221                        return NULL;
 222                }
 223
 224                strbuf_release(&expanded_path);
 225                loginfo("Interpolated dir '%s'", interp_path);
 226
 227                dir = interp_path;
 228        }
 229        else if (base_path) {
 230                if (*dir != '/') {
 231                        /* Allow only absolute */
 232                        logerror("'%s': Non-absolute path denied (base-path active)", dir);
 233                        return NULL;
 234                }
 235                rlen = snprintf(rpath, sizeof(rpath), "%s%s", base_path, dir);
 236                if (rlen >= sizeof(rpath)) {
 237                        logerror("base-path too large: %s", rpath);
 238                        return NULL;
 239                }
 240                dir = rpath;
 241        }
 242
 243        path = enter_repo(dir, strict_paths);
 244        if (!path && base_path && base_path_relaxed) {
 245                /*
 246                 * if we fail and base_path_relaxed is enabled, try without
 247                 * prefixing the base path
 248                 */
 249                dir = directory;
 250                path = enter_repo(dir, strict_paths);
 251        }
 252
 253        if (!path) {
 254                logerror("'%s' does not appear to be a git repository", dir);
 255                return NULL;
 256        }
 257
 258        if ( ok_paths && *ok_paths ) {
 259                const char **pp;
 260                int pathlen = strlen(path);
 261
 262                /* The validation is done on the paths after enter_repo
 263                 * appends optional {.git,.git/.git} and friends, but
 264                 * it does not use getcwd().  So if your /pub is
 265                 * a symlink to /mnt/pub, you can whitelist /pub and
 266                 * do not have to say /mnt/pub.
 267                 * Do not say /pub/.
 268                 */
 269                for ( pp = ok_paths ; *pp ; pp++ ) {
 270                        int len = strlen(*pp);
 271                        if (len <= pathlen &&
 272                            !memcmp(*pp, path, len) &&
 273                            (path[len] == '\0' ||
 274                             (!strict_paths && path[len] == '/')))
 275                                return path;
 276                }
 277        }
 278        else {
 279                /* be backwards compatible */
 280                if (!strict_paths)
 281                        return path;
 282        }
 283
 284        logerror("'%s': not in whitelist", path);
 285        return NULL;            /* Fallthrough. Deny by default */
 286}
 287
 288typedef int (*daemon_service_fn)(void);
 289struct daemon_service {
 290        const char *name;
 291        const char *config_name;
 292        daemon_service_fn fn;
 293        int enabled;
 294        int overridable;
 295};
 296
 297static int daemon_error(const char *dir, const char *msg)
 298{
 299        if (!informative_errors)
 300                msg = "access denied or repository not exported";
 301        packet_write(1, "ERR %s: %s", msg, dir);
 302        return -1;
 303}
 304
 305static const char *access_hook;
 306
 307static int run_access_hook(struct daemon_service *service, const char *dir,
 308                           const char *path, struct hostinfo *hi)
 309{
 310        struct child_process child = CHILD_PROCESS_INIT;
 311        struct strbuf buf = STRBUF_INIT;
 312        const char *argv[8];
 313        const char **arg = argv;
 314        char *eol;
 315        int seen_errors = 0;
 316
 317        *arg++ = access_hook;
 318        *arg++ = service->name;
 319        *arg++ = path;
 320        *arg++ = hi->hostname.buf;
 321        *arg++ = get_canon_hostname(hi);
 322        *arg++ = get_ip_address(hi);
 323        *arg++ = hi->tcp_port.buf;
 324        *arg = NULL;
 325
 326        child.use_shell = 1;
 327        child.argv = argv;
 328        child.no_stdin = 1;
 329        child.no_stderr = 1;
 330        child.out = -1;
 331        if (start_command(&child)) {
 332                logerror("daemon access hook '%s' failed to start",
 333                         access_hook);
 334                goto error_return;
 335        }
 336        if (strbuf_read(&buf, child.out, 0) < 0) {
 337                logerror("failed to read from pipe to daemon access hook '%s'",
 338                         access_hook);
 339                strbuf_reset(&buf);
 340                seen_errors = 1;
 341        }
 342        if (close(child.out) < 0) {
 343                logerror("failed to close pipe to daemon access hook '%s'",
 344                         access_hook);
 345                seen_errors = 1;
 346        }
 347        if (finish_command(&child))
 348                seen_errors = 1;
 349
 350        if (!seen_errors) {
 351                strbuf_release(&buf);
 352                return 0;
 353        }
 354
 355error_return:
 356        strbuf_ltrim(&buf);
 357        if (!buf.len)
 358                strbuf_addstr(&buf, "service rejected");
 359        eol = strchr(buf.buf, '\n');
 360        if (eol)
 361                *eol = '\0';
 362        errno = EACCES;
 363        daemon_error(dir, buf.buf);
 364        strbuf_release(&buf);
 365        return -1;
 366}
 367
 368static int run_service(const char *dir, struct daemon_service *service,
 369                       struct hostinfo *hi)
 370{
 371        const char *path;
 372        int enabled = service->enabled;
 373        struct strbuf var = STRBUF_INIT;
 374
 375        loginfo("Request %s for '%s'", service->name, dir);
 376
 377        if (!enabled && !service->overridable) {
 378                logerror("'%s': service not enabled.", service->name);
 379                errno = EACCES;
 380                return daemon_error(dir, "service not enabled");
 381        }
 382
 383        if (!(path = path_ok(dir, hi)))
 384                return daemon_error(dir, "no such repository");
 385
 386        /*
 387         * Security on the cheap.
 388         *
 389         * We want a readable HEAD, usable "objects" directory, and
 390         * a "git-daemon-export-ok" flag that says that the other side
 391         * is ok with us doing this.
 392         *
 393         * path_ok() uses enter_repo() and does whitelist checking.
 394         * We only need to make sure the repository is exported.
 395         */
 396
 397        if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 398                logerror("'%s': repository not exported.", path);
 399                errno = EACCES;
 400                return daemon_error(dir, "repository not exported");
 401        }
 402
 403        if (service->overridable) {
 404                strbuf_addf(&var, "daemon.%s", service->config_name);
 405                git_config_get_bool(var.buf, &enabled);
 406                strbuf_release(&var);
 407        }
 408        if (!enabled) {
 409                logerror("'%s': service not enabled for '%s'",
 410                         service->name, path);
 411                errno = EACCES;
 412                return daemon_error(dir, "service not enabled");
 413        }
 414
 415        /*
 416         * Optionally, a hook can choose to deny access to the
 417         * repository depending on the phase of the moon.
 418         */
 419        if (access_hook && run_access_hook(service, dir, path, hi))
 420                return -1;
 421
 422        /*
 423         * We'll ignore SIGTERM from now on, we have a
 424         * good client.
 425         */
 426        signal(SIGTERM, SIG_IGN);
 427
 428        return service->fn();
 429}
 430
 431static void copy_to_log(int fd)
 432{
 433        struct strbuf line = STRBUF_INIT;
 434        FILE *fp;
 435
 436        fp = fdopen(fd, "r");
 437        if (fp == NULL) {
 438                logerror("fdopen of error channel failed");
 439                close(fd);
 440                return;
 441        }
 442
 443        while (strbuf_getline_lf(&line, fp) != EOF) {
 444                logerror("%s", line.buf);
 445                strbuf_setlen(&line, 0);
 446        }
 447
 448        strbuf_release(&line);
 449        fclose(fp);
 450}
 451
 452static int run_service_command(const char **argv)
 453{
 454        struct child_process cld = CHILD_PROCESS_INIT;
 455
 456        cld.argv = argv;
 457        cld.git_cmd = 1;
 458        cld.err = -1;
 459        if (start_command(&cld))
 460                return -1;
 461
 462        close(0);
 463        close(1);
 464
 465        copy_to_log(cld.err);
 466
 467        return finish_command(&cld);
 468}
 469
 470static int upload_pack(void)
 471{
 472        /* Timeout as string */
 473        char timeout_buf[64];
 474        const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
 475
 476        argv[2] = timeout_buf;
 477
 478        snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 479        return run_service_command(argv);
 480}
 481
 482static int upload_archive(void)
 483{
 484        static const char *argv[] = { "upload-archive", ".", NULL };
 485        return run_service_command(argv);
 486}
 487
 488static int receive_pack(void)
 489{
 490        static const char *argv[] = { "receive-pack", ".", NULL };
 491        return run_service_command(argv);
 492}
 493
 494static struct daemon_service daemon_service[] = {
 495        { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 496        { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 497        { "receive-pack", "receivepack", receive_pack, 0, 1 },
 498};
 499
 500static void enable_service(const char *name, int ena)
 501{
 502        int i;
 503        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 504                if (!strcmp(daemon_service[i].name, name)) {
 505                        daemon_service[i].enabled = ena;
 506                        return;
 507                }
 508        }
 509        die("No such service %s", name);
 510}
 511
 512static void make_service_overridable(const char *name, int ena)
 513{
 514        int i;
 515        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 516                if (!strcmp(daemon_service[i].name, name)) {
 517                        daemon_service[i].overridable = ena;
 518                        return;
 519                }
 520        }
 521        die("No such service %s", name);
 522}
 523
 524static void parse_host_and_port(char *hostport, char **host,
 525        char **port)
 526{
 527        if (*hostport == '[') {
 528                char *end;
 529
 530                end = strchr(hostport, ']');
 531                if (!end)
 532                        die("Invalid request ('[' without ']')");
 533                *end = '\0';
 534                *host = hostport + 1;
 535                if (!end[1])
 536                        *port = NULL;
 537                else if (end[1] == ':')
 538                        *port = end + 2;
 539                else
 540                        die("Garbage after end of host part");
 541        } else {
 542                *host = hostport;
 543                *port = strrchr(hostport, ':');
 544                if (*port) {
 545                        **port = '\0';
 546                        ++*port;
 547                }
 548        }
 549}
 550
 551/*
 552 * Sanitize a string from the client so that it's OK to be inserted into a
 553 * filesystem path. Specifically, we disallow slashes, runs of "..", and
 554 * trailing and leading dots, which means that the client cannot escape
 555 * our base path via ".." traversal.
 556 */
 557static void sanitize_client(struct strbuf *out, const char *in)
 558{
 559        for (; *in; in++) {
 560                if (*in == '/')
 561                        continue;
 562                if (*in == '.' && (!out->len || out->buf[out->len - 1] == '.'))
 563                        continue;
 564                strbuf_addch(out, *in);
 565        }
 566
 567        while (out->len && out->buf[out->len - 1] == '.')
 568                strbuf_setlen(out, out->len - 1);
 569}
 570
 571/*
 572 * Like sanitize_client, but we also perform any canonicalization
 573 * to make life easier on the admin.
 574 */
 575static void canonicalize_client(struct strbuf *out, const char *in)
 576{
 577        sanitize_client(out, in);
 578        strbuf_tolower(out);
 579}
 580
 581/*
 582 * Read the host as supplied by the client connection.
 583 */
 584static void parse_host_arg(struct hostinfo *hi, char *extra_args, int buflen)
 585{
 586        char *val;
 587        int vallen;
 588        char *end = extra_args + buflen;
 589
 590        if (extra_args < end && *extra_args) {
 591                hi->saw_extended_args = 1;
 592                if (strncasecmp("host=", extra_args, 5) == 0) {
 593                        val = extra_args + 5;
 594                        vallen = strlen(val) + 1;
 595                        if (*val) {
 596                                /* Split <host>:<port> at colon. */
 597                                char *host;
 598                                char *port;
 599                                parse_host_and_port(val, &host, &port);
 600                                if (port)
 601                                        sanitize_client(&hi->tcp_port, port);
 602                                canonicalize_client(&hi->hostname, host);
 603                                hi->hostname_lookup_done = 0;
 604                        }
 605
 606                        /* On to the next one */
 607                        extra_args = val + vallen;
 608                }
 609                if (extra_args < end && *extra_args)
 610                        die("Invalid request");
 611        }
 612}
 613
 614/*
 615 * Locate canonical hostname and its IP address.
 616 */
 617static void lookup_hostname(struct hostinfo *hi)
 618{
 619        if (!hi->hostname_lookup_done && hi->hostname.len) {
 620#ifndef NO_IPV6
 621                struct addrinfo hints;
 622                struct addrinfo *ai;
 623                int gai;
 624                static char addrbuf[HOST_NAME_MAX + 1];
 625
 626                memset(&hints, 0, sizeof(hints));
 627                hints.ai_flags = AI_CANONNAME;
 628
 629                gai = getaddrinfo(hi->hostname.buf, NULL, &hints, &ai);
 630                if (!gai) {
 631                        struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 632
 633                        inet_ntop(AF_INET, &sin_addr->sin_addr,
 634                                  addrbuf, sizeof(addrbuf));
 635                        strbuf_addstr(&hi->ip_address, addrbuf);
 636
 637                        if (ai->ai_canonname)
 638                                sanitize_client(&hi->canon_hostname,
 639                                                ai->ai_canonname);
 640                        else
 641                                strbuf_addbuf(&hi->canon_hostname,
 642                                              &hi->ip_address);
 643
 644                        freeaddrinfo(ai);
 645                }
 646#else
 647                struct hostent *hent;
 648                struct sockaddr_in sa;
 649                char **ap;
 650                static char addrbuf[HOST_NAME_MAX + 1];
 651
 652                hent = gethostbyname(hi->hostname.buf);
 653                if (hent) {
 654                        ap = hent->h_addr_list;
 655                        memset(&sa, 0, sizeof sa);
 656                        sa.sin_family = hent->h_addrtype;
 657                        sa.sin_port = htons(0);
 658                        memcpy(&sa.sin_addr, *ap, hent->h_length);
 659
 660                        inet_ntop(hent->h_addrtype, &sa.sin_addr,
 661                                  addrbuf, sizeof(addrbuf));
 662
 663                        sanitize_client(&hi->canon_hostname, hent->h_name);
 664                        strbuf_addstr(&hi->ip_address, addrbuf);
 665                }
 666#endif
 667                hi->hostname_lookup_done = 1;
 668        }
 669}
 670
 671static void hostinfo_init(struct hostinfo *hi)
 672{
 673        memset(hi, 0, sizeof(*hi));
 674        strbuf_init(&hi->hostname, 0);
 675        strbuf_init(&hi->canon_hostname, 0);
 676        strbuf_init(&hi->ip_address, 0);
 677        strbuf_init(&hi->tcp_port, 0);
 678}
 679
 680static void hostinfo_clear(struct hostinfo *hi)
 681{
 682        strbuf_release(&hi->hostname);
 683        strbuf_release(&hi->canon_hostname);
 684        strbuf_release(&hi->ip_address);
 685        strbuf_release(&hi->tcp_port);
 686}
 687
 688static void set_keep_alive(int sockfd)
 689{
 690        int ka = 1;
 691
 692        if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0) {
 693                if (errno != ENOTSOCK)
 694                        logerror("unable to set SO_KEEPALIVE on socket: %s",
 695                                strerror(errno));
 696        }
 697}
 698
 699static int execute(void)
 700{
 701        char *line = packet_buffer;
 702        int pktlen, len, i;
 703        char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
 704        struct hostinfo hi;
 705
 706        hostinfo_init(&hi);
 707
 708        if (addr)
 709                loginfo("Connection from %s:%s", addr, port);
 710
 711        set_keep_alive(0);
 712        alarm(init_timeout ? init_timeout : timeout);
 713        pktlen = packet_read(0, NULL, NULL, packet_buffer, sizeof(packet_buffer), 0);
 714        alarm(0);
 715
 716        len = strlen(line);
 717        if (pktlen != len)
 718                loginfo("Extended attributes (%d bytes) exist <%.*s>",
 719                        (int) pktlen - len,
 720                        (int) pktlen - len, line + len + 1);
 721        if (len && line[len-1] == '\n') {
 722                line[--len] = 0;
 723                pktlen--;
 724        }
 725
 726        if (len != pktlen)
 727                parse_host_arg(&hi, line + len + 1, pktlen - len - 1);
 728
 729        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 730                struct daemon_service *s = &(daemon_service[i]);
 731                const char *arg;
 732
 733                if (skip_prefix(line, "git-", &arg) &&
 734                    skip_prefix(arg, s->name, &arg) &&
 735                    *arg++ == ' ') {
 736                        /*
 737                         * Note: The directory here is probably context sensitive,
 738                         * and might depend on the actual service being performed.
 739                         */
 740                        int rc = run_service(arg, s, &hi);
 741                        hostinfo_clear(&hi);
 742                        return rc;
 743                }
 744        }
 745
 746        hostinfo_clear(&hi);
 747        logerror("Protocol error: '%s'", line);
 748        return -1;
 749}
 750
 751static int addrcmp(const struct sockaddr_storage *s1,
 752    const struct sockaddr_storage *s2)
 753{
 754        const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 755        const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 756
 757        if (sa1->sa_family != sa2->sa_family)
 758                return sa1->sa_family - sa2->sa_family;
 759        if (sa1->sa_family == AF_INET)
 760                return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 761                    &((struct sockaddr_in *)s2)->sin_addr,
 762                    sizeof(struct in_addr));
 763#ifndef NO_IPV6
 764        if (sa1->sa_family == AF_INET6)
 765                return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 766                    &((struct sockaddr_in6 *)s2)->sin6_addr,
 767                    sizeof(struct in6_addr));
 768#endif
 769        return 0;
 770}
 771
 772static int max_connections = 32;
 773
 774static unsigned int live_children;
 775
 776static struct child {
 777        struct child *next;
 778        struct child_process cld;
 779        struct sockaddr_storage address;
 780} *firstborn;
 781
 782static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
 783{
 784        struct child *newborn, **cradle;
 785
 786        newborn = xcalloc(1, sizeof(*newborn));
 787        live_children++;
 788        memcpy(&newborn->cld, cld, sizeof(*cld));
 789        memcpy(&newborn->address, addr, addrlen);
 790        for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 791                if (!addrcmp(&(*cradle)->address, &newborn->address))
 792                        break;
 793        newborn->next = *cradle;
 794        *cradle = newborn;
 795}
 796
 797/*
 798 * This gets called if the number of connections grows
 799 * past "max_connections".
 800 *
 801 * We kill the newest connection from a duplicate IP.
 802 */
 803static void kill_some_child(void)
 804{
 805        const struct child *blanket, *next;
 806
 807        if (!(blanket = firstborn))
 808                return;
 809
 810        for (; (next = blanket->next); blanket = next)
 811                if (!addrcmp(&blanket->address, &next->address)) {
 812                        kill(blanket->cld.pid, SIGTERM);
 813                        break;
 814                }
 815}
 816
 817static void check_dead_children(void)
 818{
 819        int status;
 820        pid_t pid;
 821
 822        struct child **cradle, *blanket;
 823        for (cradle = &firstborn; (blanket = *cradle);)
 824                if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
 825                        const char *dead = "";
 826                        if (status)
 827                                dead = " (with error)";
 828                        loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 829
 830                        /* remove the child */
 831                        *cradle = blanket->next;
 832                        live_children--;
 833                        child_process_clear(&blanket->cld);
 834                        free(blanket);
 835                } else
 836                        cradle = &blanket->next;
 837}
 838
 839static struct argv_array cld_argv = ARGV_ARRAY_INIT;
 840static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 841{
 842        struct child_process cld = CHILD_PROCESS_INIT;
 843
 844        if (max_connections && live_children >= max_connections) {
 845                kill_some_child();
 846                sleep(1);  /* give it some time to die */
 847                check_dead_children();
 848                if (live_children >= max_connections) {
 849                        close(incoming);
 850                        logerror("Too many children, dropping connection");
 851                        return;
 852                }
 853        }
 854
 855        if (addr->sa_family == AF_INET) {
 856                char buf[128] = "";
 857                struct sockaddr_in *sin_addr = (void *) addr;
 858                inet_ntop(addr->sa_family, &sin_addr->sin_addr, buf, sizeof(buf));
 859                argv_array_pushf(&cld.env_array, "REMOTE_ADDR=%s", buf);
 860                argv_array_pushf(&cld.env_array, "REMOTE_PORT=%d",
 861                                 ntohs(sin_addr->sin_port));
 862#ifndef NO_IPV6
 863        } else if (addr->sa_family == AF_INET6) {
 864                char buf[128] = "";
 865                struct sockaddr_in6 *sin6_addr = (void *) addr;
 866                inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(buf));
 867                argv_array_pushf(&cld.env_array, "REMOTE_ADDR=[%s]", buf);
 868                argv_array_pushf(&cld.env_array, "REMOTE_PORT=%d",
 869                                 ntohs(sin6_addr->sin6_port));
 870#endif
 871        }
 872
 873        cld.argv = cld_argv.argv;
 874        cld.in = incoming;
 875        cld.out = dup(incoming);
 876
 877        if (start_command(&cld))
 878                logerror("unable to fork");
 879        else
 880                add_child(&cld, addr, addrlen);
 881}
 882
 883static void child_handler(int signo)
 884{
 885        /*
 886         * Otherwise empty handler because systemcalls will get interrupted
 887         * upon signal receipt
 888         * SysV needs the handler to be rearmed
 889         */
 890        signal(SIGCHLD, child_handler);
 891}
 892
 893static int set_reuse_addr(int sockfd)
 894{
 895        int on = 1;
 896
 897        if (!reuseaddr)
 898                return 0;
 899        return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 900                          &on, sizeof(on));
 901}
 902
 903struct socketlist {
 904        int *list;
 905        size_t nr;
 906        size_t alloc;
 907};
 908
 909static const char *ip2str(int family, struct sockaddr *sin, socklen_t len)
 910{
 911#ifdef NO_IPV6
 912        static char ip[INET_ADDRSTRLEN];
 913#else
 914        static char ip[INET6_ADDRSTRLEN];
 915#endif
 916
 917        switch (family) {
 918#ifndef NO_IPV6
 919        case AF_INET6:
 920                inet_ntop(family, &((struct sockaddr_in6*)sin)->sin6_addr, ip, len);
 921                break;
 922#endif
 923        case AF_INET:
 924                inet_ntop(family, &((struct sockaddr_in*)sin)->sin_addr, ip, len);
 925                break;
 926        default:
 927                xsnprintf(ip, sizeof(ip), "<unknown>");
 928        }
 929        return ip;
 930}
 931
 932#ifndef NO_IPV6
 933
 934static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 935{
 936        int socknum = 0;
 937        char pbuf[NI_MAXSERV];
 938        struct addrinfo hints, *ai0, *ai;
 939        int gai;
 940        long flags;
 941
 942        xsnprintf(pbuf, sizeof(pbuf), "%d", listen_port);
 943        memset(&hints, 0, sizeof(hints));
 944        hints.ai_family = AF_UNSPEC;
 945        hints.ai_socktype = SOCK_STREAM;
 946        hints.ai_protocol = IPPROTO_TCP;
 947        hints.ai_flags = AI_PASSIVE;
 948
 949        gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 950        if (gai) {
 951                logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
 952                return 0;
 953        }
 954
 955        for (ai = ai0; ai; ai = ai->ai_next) {
 956                int sockfd;
 957
 958                sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 959                if (sockfd < 0)
 960                        continue;
 961                if (sockfd >= FD_SETSIZE) {
 962                        logerror("Socket descriptor too large");
 963                        close(sockfd);
 964                        continue;
 965                }
 966
 967#ifdef IPV6_V6ONLY
 968                if (ai->ai_family == AF_INET6) {
 969                        int on = 1;
 970                        setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 971                                   &on, sizeof(on));
 972                        /* Note: error is not fatal */
 973                }
 974#endif
 975
 976                if (set_reuse_addr(sockfd)) {
 977                        logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 978                        close(sockfd);
 979                        continue;
 980                }
 981
 982                set_keep_alive(sockfd);
 983
 984                if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 985                        logerror("Could not bind to %s: %s",
 986                                 ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 987                                 strerror(errno));
 988                        close(sockfd);
 989                        continue;       /* not fatal */
 990                }
 991                if (listen(sockfd, 5) < 0) {
 992                        logerror("Could not listen to %s: %s",
 993                                 ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 994                                 strerror(errno));
 995                        close(sockfd);
 996                        continue;       /* not fatal */
 997                }
 998
 999                flags = fcntl(sockfd, F_GETFD, 0);
1000                if (flags >= 0)
1001                        fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
1002
1003                ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
1004                socklist->list[socklist->nr++] = sockfd;
1005                socknum++;
1006        }
1007
1008        freeaddrinfo(ai0);
1009
1010        return socknum;
1011}
1012
1013#else /* NO_IPV6 */
1014
1015static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
1016{
1017        struct sockaddr_in sin;
1018        int sockfd;
1019        long flags;
1020
1021        memset(&sin, 0, sizeof sin);
1022        sin.sin_family = AF_INET;
1023        sin.sin_port = htons(listen_port);
1024
1025        if (listen_addr) {
1026                /* Well, host better be an IP address here. */
1027                if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
1028                        return 0;
1029        } else {
1030                sin.sin_addr.s_addr = htonl(INADDR_ANY);
1031        }
1032
1033        sockfd = socket(AF_INET, SOCK_STREAM, 0);
1034        if (sockfd < 0)
1035                return 0;
1036
1037        if (set_reuse_addr(sockfd)) {
1038                logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
1039                close(sockfd);
1040                return 0;
1041        }
1042
1043        set_keep_alive(sockfd);
1044
1045        if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
1046                logerror("Could not bind to %s: %s",
1047                         ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
1048                         strerror(errno));
1049                close(sockfd);
1050                return 0;
1051        }
1052
1053        if (listen(sockfd, 5) < 0) {
1054                logerror("Could not listen to %s: %s",
1055                         ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
1056                         strerror(errno));
1057                close(sockfd);
1058                return 0;
1059        }
1060
1061        flags = fcntl(sockfd, F_GETFD, 0);
1062        if (flags >= 0)
1063                fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
1064
1065        ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
1066        socklist->list[socklist->nr++] = sockfd;
1067        return 1;
1068}
1069
1070#endif
1071
1072static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
1073{
1074        if (!listen_addr->nr)
1075                setup_named_sock(NULL, listen_port, socklist);
1076        else {
1077                int i, socknum;
1078                for (i = 0; i < listen_addr->nr; i++) {
1079                        socknum = setup_named_sock(listen_addr->items[i].string,
1080                                                   listen_port, socklist);
1081
1082                        if (socknum == 0)
1083                                logerror("unable to allocate any listen sockets for host %s on port %u",
1084                                         listen_addr->items[i].string, listen_port);
1085                }
1086        }
1087}
1088
1089static int service_loop(struct socketlist *socklist)
1090{
1091        struct pollfd *pfd;
1092        int i;
1093
1094        pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
1095
1096        for (i = 0; i < socklist->nr; i++) {
1097                pfd[i].fd = socklist->list[i];
1098                pfd[i].events = POLLIN;
1099        }
1100
1101        signal(SIGCHLD, child_handler);
1102
1103        for (;;) {
1104                int i;
1105
1106                check_dead_children();
1107
1108                if (poll(pfd, socklist->nr, -1) < 0) {
1109                        if (errno != EINTR) {
1110                                logerror("Poll failed, resuming: %s",
1111                                      strerror(errno));
1112                                sleep(1);
1113                        }
1114                        continue;
1115                }
1116
1117                for (i = 0; i < socklist->nr; i++) {
1118                        if (pfd[i].revents & POLLIN) {
1119                                union {
1120                                        struct sockaddr sa;
1121                                        struct sockaddr_in sai;
1122#ifndef NO_IPV6
1123                                        struct sockaddr_in6 sai6;
1124#endif
1125                                } ss;
1126                                socklen_t sslen = sizeof(ss);
1127                                int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
1128                                if (incoming < 0) {
1129                                        switch (errno) {
1130                                        case EAGAIN:
1131                                        case EINTR:
1132                                        case ECONNABORTED:
1133                                                continue;
1134                                        default:
1135                                                die_errno("accept returned");
1136                                        }
1137                                }
1138                                handle(incoming, &ss.sa, sslen);
1139                        }
1140                }
1141        }
1142}
1143
1144#ifdef NO_POSIX_GOODIES
1145
1146struct credentials;
1147
1148static void drop_privileges(struct credentials *cred)
1149{
1150        /* nothing */
1151}
1152
1153static struct credentials *prepare_credentials(const char *user_name,
1154    const char *group_name)
1155{
1156        die("--user not supported on this platform");
1157}
1158
1159#else
1160
1161struct credentials {
1162        struct passwd *pass;
1163        gid_t gid;
1164};
1165
1166static void drop_privileges(struct credentials *cred)
1167{
1168        if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
1169            setgid (cred->gid) || setuid(cred->pass->pw_uid)))
1170                die("cannot drop privileges");
1171}
1172
1173static struct credentials *prepare_credentials(const char *user_name,
1174    const char *group_name)
1175{
1176        static struct credentials c;
1177
1178        c.pass = getpwnam(user_name);
1179        if (!c.pass)
1180                die("user not found - %s", user_name);
1181
1182        if (!group_name)
1183                c.gid = c.pass->pw_gid;
1184        else {
1185                struct group *group = getgrnam(group_name);
1186                if (!group)
1187                        die("group not found - %s", group_name);
1188
1189                c.gid = group->gr_gid;
1190        }
1191
1192        return &c;
1193}
1194#endif
1195
1196static int serve(struct string_list *listen_addr, int listen_port,
1197    struct credentials *cred)
1198{
1199        struct socketlist socklist = { NULL, 0, 0 };
1200
1201        socksetup(listen_addr, listen_port, &socklist);
1202        if (socklist.nr == 0)
1203                die("unable to allocate any listen sockets on port %u",
1204                    listen_port);
1205
1206        drop_privileges(cred);
1207
1208        loginfo("Ready to rumble");
1209
1210        return service_loop(&socklist);
1211}
1212
1213int cmd_main(int argc, const char **argv)
1214{
1215        int listen_port = 0;
1216        struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1217        int serve_mode = 0, inetd_mode = 0;
1218        const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1219        int detach = 0;
1220        struct credentials *cred = NULL;
1221        int i;
1222
1223        for (i = 1; i < argc; i++) {
1224                const char *arg = argv[i];
1225                const char *v;
1226
1227                if (skip_prefix(arg, "--listen=", &v)) {
1228                        string_list_append(&listen_addr, xstrdup_tolower(v));
1229                        continue;
1230                }
1231                if (skip_prefix(arg, "--port=", &v)) {
1232                        char *end;
1233                        unsigned long n;
1234                        n = strtoul(v, &end, 0);
1235                        if (*v && !*end) {
1236                                listen_port = n;
1237                                continue;
1238                        }
1239                }
1240                if (!strcmp(arg, "--serve")) {
1241                        serve_mode = 1;
1242                        continue;
1243                }
1244                if (!strcmp(arg, "--inetd")) {
1245                        inetd_mode = 1;
1246                        log_syslog = 1;
1247                        continue;
1248                }
1249                if (!strcmp(arg, "--verbose")) {
1250                        verbose = 1;
1251                        continue;
1252                }
1253                if (!strcmp(arg, "--syslog")) {
1254                        log_syslog = 1;
1255                        continue;
1256                }
1257                if (!strcmp(arg, "--export-all")) {
1258                        export_all_trees = 1;
1259                        continue;
1260                }
1261                if (skip_prefix(arg, "--access-hook=", &v)) {
1262                        access_hook = v;
1263                        continue;
1264                }
1265                if (skip_prefix(arg, "--timeout=", &v)) {
1266                        timeout = atoi(v);
1267                        continue;
1268                }
1269                if (skip_prefix(arg, "--init-timeout=", &v)) {
1270                        init_timeout = atoi(v);
1271                        continue;
1272                }
1273                if (skip_prefix(arg, "--max-connections=", &v)) {
1274                        max_connections = atoi(v);
1275                        if (max_connections < 0)
1276                                max_connections = 0;            /* unlimited */
1277                        continue;
1278                }
1279                if (!strcmp(arg, "--strict-paths")) {
1280                        strict_paths = 1;
1281                        continue;
1282                }
1283                if (skip_prefix(arg, "--base-path=", &v)) {
1284                        base_path = v;
1285                        continue;
1286                }
1287                if (!strcmp(arg, "--base-path-relaxed")) {
1288                        base_path_relaxed = 1;
1289                        continue;
1290                }
1291                if (skip_prefix(arg, "--interpolated-path=", &v)) {
1292                        interpolated_path = v;
1293                        continue;
1294                }
1295                if (!strcmp(arg, "--reuseaddr")) {
1296                        reuseaddr = 1;
1297                        continue;
1298                }
1299                if (!strcmp(arg, "--user-path")) {
1300                        user_path = "";
1301                        continue;
1302                }
1303                if (skip_prefix(arg, "--user-path=", &v)) {
1304                        user_path = v;
1305                        continue;
1306                }
1307                if (skip_prefix(arg, "--pid-file=", &v)) {
1308                        pid_file = v;
1309                        continue;
1310                }
1311                if (!strcmp(arg, "--detach")) {
1312                        detach = 1;
1313                        log_syslog = 1;
1314                        continue;
1315                }
1316                if (skip_prefix(arg, "--user=", &v)) {
1317                        user_name = v;
1318                        continue;
1319                }
1320                if (skip_prefix(arg, "--group=", &v)) {
1321                        group_name = v;
1322                        continue;
1323                }
1324                if (skip_prefix(arg, "--enable=", &v)) {
1325                        enable_service(v, 1);
1326                        continue;
1327                }
1328                if (skip_prefix(arg, "--disable=", &v)) {
1329                        enable_service(v, 0);
1330                        continue;
1331                }
1332                if (skip_prefix(arg, "--allow-override=", &v)) {
1333                        make_service_overridable(v, 1);
1334                        continue;
1335                }
1336                if (skip_prefix(arg, "--forbid-override=", &v)) {
1337                        make_service_overridable(v, 0);
1338                        continue;
1339                }
1340                if (!strcmp(arg, "--informative-errors")) {
1341                        informative_errors = 1;
1342                        continue;
1343                }
1344                if (!strcmp(arg, "--no-informative-errors")) {
1345                        informative_errors = 0;
1346                        continue;
1347                }
1348                if (!strcmp(arg, "--")) {
1349                        ok_paths = &argv[i+1];
1350                        break;
1351                } else if (arg[0] != '-') {
1352                        ok_paths = &argv[i];
1353                        break;
1354                }
1355
1356                usage(daemon_usage);
1357        }
1358
1359        if (log_syslog) {
1360                openlog("git-daemon", LOG_PID, LOG_DAEMON);
1361                set_die_routine(daemon_die);
1362        } else
1363                /* avoid splitting a message in the middle */
1364                setvbuf(stderr, NULL, _IOFBF, 4096);
1365
1366        if (inetd_mode && (detach || group_name || user_name))
1367                die("--detach, --user and --group are incompatible with --inetd");
1368
1369        if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1370                die("--listen= and --port= are incompatible with --inetd");
1371        else if (listen_port == 0)
1372                listen_port = DEFAULT_GIT_PORT;
1373
1374        if (group_name && !user_name)
1375                die("--group supplied without --user");
1376
1377        if (user_name)
1378                cred = prepare_credentials(user_name, group_name);
1379
1380        if (strict_paths && (!ok_paths || !*ok_paths))
1381                die("option --strict-paths requires a whitelist");
1382
1383        if (base_path && !is_directory(base_path))
1384                die("base-path '%s' does not exist or is not a directory",
1385                    base_path);
1386
1387        if (inetd_mode) {
1388                if (!freopen("/dev/null", "w", stderr))
1389                        die_errno("failed to redirect stderr to /dev/null");
1390        }
1391
1392        if (inetd_mode || serve_mode)
1393                return execute();
1394
1395        if (detach) {
1396                if (daemonize())
1397                        die("--detach not supported on this platform");
1398        }
1399
1400        if (pid_file)
1401                write_file(pid_file, "%"PRIuMAX, (uintmax_t) getpid());
1402
1403        /* prepare argv for serving-processes */
1404        argv_array_push(&cld_argv, argv[0]); /* git-daemon */
1405        argv_array_push(&cld_argv, "--serve");
1406        for (i = 1; i < argc; ++i)
1407                argv_array_push(&cld_argv, argv[i]);
1408
1409        return serve(&listen_addr, listen_port, cred);
1410}