diff options
Diffstat (limited to 'third_party/git/daemon.c')
| -rw-r--r-- | third_party/git/daemon.c | 1485 |
1 files changed, 1485 insertions, 0 deletions
diff --git a/third_party/git/daemon.c b/third_party/git/daemon.c new file mode 100644 index 000000000000..9d2e0d20ef30 --- /dev/null +++ b/third_party/git/daemon.c @@ -0,0 +1,1485 @@ +#include "cache.h" +#include "config.h" +#include "pkt-line.h" +#include "run-command.h" +#include "strbuf.h" +#include "string-list.h" + +#ifdef NO_INITGROUPS +#define initgroups(x, y) (0) /* nothing */ +#endif + +static enum log_destination { + LOG_DESTINATION_UNSET = -1, + LOG_DESTINATION_NONE = 0, + LOG_DESTINATION_STDERR = 1, + LOG_DESTINATION_SYSLOG = 2, +} log_destination = LOG_DESTINATION_UNSET; +static int verbose; +static int reuseaddr; +static int informative_errors; + +static const char daemon_usage[] = +"git daemon [--verbose] [--syslog] [--export-all]\n" +" [--timeout=<n>] [--init-timeout=<n>] [--max-connections=<n>]\n" +" [--strict-paths] [--base-path=<path>] [--base-path-relaxed]\n" +" [--user-path | --user-path=<path>]\n" +" [--interpolated-path=<path>]\n" +" [--reuseaddr] [--pid-file=<file>]\n" +" [--(enable|disable|allow-override|forbid-override)=<service>]\n" +" [--access-hook=<path>]\n" +" [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n" +" [--detach] [--user=<user> [--group=<group>]]\n" +" [--log-destination=(stderr|syslog|none)]\n" +" [<directory>...]"; + +/* List of acceptable pathname prefixes */ +static const char **ok_paths; +static int strict_paths; + +/* If this is set, git-daemon-export-ok is not required */ +static int export_all_trees; + +/* Take all paths relative to this one if non-NULL */ +static const char *base_path; +static const char *interpolated_path; +static int base_path_relaxed; + +/* If defined, ~user notation is allowed and the string is inserted + * after ~user/. E.g. a request to git://host/~alice/frotz would + * go to /home/alice/pub_git/frotz with --user-path=pub_git. + */ +static const char *user_path; + +/* Timeout, and initial timeout */ +static unsigned int timeout; +static unsigned int init_timeout; + +struct hostinfo { + struct strbuf hostname; + struct strbuf canon_hostname; + struct strbuf ip_address; + struct strbuf tcp_port; + unsigned int hostname_lookup_done:1; + unsigned int saw_extended_args:1; +}; + +static void lookup_hostname(struct hostinfo *hi); + +static const char *get_canon_hostname(struct hostinfo *hi) +{ + lookup_hostname(hi); + return hi->canon_hostname.buf; +} + +static const char *get_ip_address(struct hostinfo *hi) +{ + lookup_hostname(hi); + return hi->ip_address.buf; +} + +static void logreport(int priority, const char *err, va_list params) +{ + switch (log_destination) { + case LOG_DESTINATION_SYSLOG: { + char buf[1024]; + vsnprintf(buf, sizeof(buf), err, params); + syslog(priority, "%s", buf); + break; + } + case LOG_DESTINATION_STDERR: + /* + * Since stderr is set to buffered mode, the + * logging of different processes will not overlap + * unless they overflow the (rather big) buffers. + */ + fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid()); + vfprintf(stderr, err, params); + fputc('\n', stderr); + fflush(stderr); + break; + case LOG_DESTINATION_NONE: + break; + case LOG_DESTINATION_UNSET: + BUG("log destination not initialized correctly"); + } +} + +__attribute__((format (printf, 1, 2))) +static void logerror(const char *err, ...) +{ + va_list params; + va_start(params, err); + logreport(LOG_ERR, err, params); + va_end(params); +} + +__attribute__((format (printf, 1, 2))) +static void loginfo(const char *err, ...) +{ + va_list params; + if (!verbose) + return; + va_start(params, err); + logreport(LOG_INFO, err, params); + va_end(params); +} + +static void NORETURN daemon_die(const char *err, va_list params) +{ + logreport(LOG_ERR, err, params); + exit(1); +} + +struct expand_path_context { + const char *directory; + struct hostinfo *hostinfo; +}; + +static size_t expand_path(struct strbuf *sb, const char *placeholder, void *ctx) +{ + struct expand_path_context *context = ctx; + struct hostinfo *hi = context->hostinfo; + + switch (placeholder[0]) { + case 'H': + strbuf_addbuf(sb, &hi->hostname); + return 1; + case 'C': + if (placeholder[1] == 'H') { + strbuf_addstr(sb, get_canon_hostname(hi)); + return 2; + } + break; + case 'I': + if (placeholder[1] == 'P') { + strbuf_addstr(sb, get_ip_address(hi)); + return 2; + } + break; + case 'P': + strbuf_addbuf(sb, &hi->tcp_port); + return 1; + case 'D': + strbuf_addstr(sb, context->directory); + return 1; + } + return 0; +} + +static const char *path_ok(const char *directory, struct hostinfo *hi) +{ + static char rpath[PATH_MAX]; + static char interp_path[PATH_MAX]; + size_t rlen; + const char *path; + const char *dir; + + dir = directory; + + if (daemon_avoid_alias(dir)) { + logerror("'%s': aliased", dir); + return NULL; + } + + if (*dir == '~') { + if (!user_path) { + logerror("'%s': User-path not allowed", dir); + return NULL; + } + if (*user_path) { + /* Got either "~alice" or "~alice/foo"; + * rewrite them to "~alice/%s" or + * "~alice/%s/foo". + */ + int namlen, restlen = strlen(dir); + const char *slash = strchr(dir, '/'); + if (!slash) + slash = dir + restlen; + namlen = slash - dir; + restlen -= namlen; + loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash); + rlen = snprintf(rpath, sizeof(rpath), "%.*s/%s%.*s", + namlen, dir, user_path, restlen, slash); + if (rlen >= sizeof(rpath)) { + logerror("user-path too large: %s", rpath); + return NULL; + } + dir = rpath; + } + } + else if (interpolated_path && hi->saw_extended_args) { + struct strbuf expanded_path = STRBUF_INIT; + struct expand_path_context context; + + context.directory = directory; + context.hostinfo = hi; + + if (*dir != '/') { + /* Allow only absolute */ + logerror("'%s': Non-absolute path denied (interpolated-path active)", dir); + return NULL; + } + + strbuf_expand(&expanded_path, interpolated_path, + expand_path, &context); + + rlen = strlcpy(interp_path, expanded_path.buf, + sizeof(interp_path)); + if (rlen >= sizeof(interp_path)) { + logerror("interpolated path too large: %s", + interp_path); + return NULL; + } + + strbuf_release(&expanded_path); + loginfo("Interpolated dir '%s'", interp_path); + + dir = interp_path; + } + else if (base_path) { + if (*dir != '/') { + /* Allow only absolute */ + logerror("'%s': Non-absolute path denied (base-path active)", dir); + return NULL; + } + rlen = snprintf(rpath, sizeof(rpath), "%s%s", base_path, dir); + if (rlen >= sizeof(rpath)) { + logerror("base-path too large: %s", rpath); + return NULL; + } + dir = rpath; + } + + path = enter_repo(dir, strict_paths); + if (!path && base_path && base_path_relaxed) { + /* + * if we fail and base_path_relaxed is enabled, try without + * prefixing the base path + */ + dir = directory; + path = enter_repo(dir, strict_paths); + } + + if (!path) { + logerror("'%s' does not appear to be a git repository", dir); + return NULL; + } + + if ( ok_paths && *ok_paths ) { + const char **pp; + int pathlen = strlen(path); + + /* The validation is done on the paths after enter_repo + * appends optional {.git,.git/.git} and friends, but + * it does not use getcwd(). So if your /pub is + * a symlink to /mnt/pub, you can whitelist /pub and + * do not have to say /mnt/pub. + * Do not say /pub/. + */ + for ( pp = ok_paths ; *pp ; pp++ ) { + int len = strlen(*pp); + if (len <= pathlen && + !memcmp(*pp, path, len) && + (path[len] == '\0' || + (!strict_paths && path[len] == '/'))) + return path; + } + } + else { + /* be backwards compatible */ + if (!strict_paths) + return path; + } + + logerror("'%s': not in whitelist", path); + return NULL; /* Fallthrough. Deny by default */ +} + +typedef int (*daemon_service_fn)(const struct argv_array *env); +struct daemon_service { + const char *name; + const char *config_name; + daemon_service_fn fn; + int enabled; + int overridable; +}; + +static int daemon_error(const char *dir, const char *msg) +{ + if (!informative_errors) + msg = "access denied or repository not exported"; + packet_write_fmt(1, "ERR %s: %s", msg, dir); + return -1; +} + +static const char *access_hook; + +static int run_access_hook(struct daemon_service *service, const char *dir, + const char *path, struct hostinfo *hi) +{ + struct child_process child = CHILD_PROCESS_INIT; + struct strbuf buf = STRBUF_INIT; + const char *argv[8]; + const char **arg = argv; + char *eol; + int seen_errors = 0; + + *arg++ = access_hook; + *arg++ = service->name; + *arg++ = path; + *arg++ = hi->hostname.buf; + *arg++ = get_canon_hostname(hi); + *arg++ = get_ip_address(hi); + *arg++ = hi->tcp_port.buf; + *arg = NULL; + + child.use_shell = 1; + child.argv = argv; + child.no_stdin = 1; + child.no_stderr = 1; + child.out = -1; + if (start_command(&child)) { + logerror("daemon access hook '%s' failed to start", + access_hook); + goto error_return; + } + if (strbuf_read(&buf, child.out, 0) < 0) { + logerror("failed to read from pipe to daemon access hook '%s'", + access_hook); + strbuf_reset(&buf); + seen_errors = 1; + } + if (close(child.out) < 0) { + logerror("failed to close pipe to daemon access hook '%s'", + access_hook); + seen_errors = 1; + } + if (finish_command(&child)) + seen_errors = 1; + + if (!seen_errors) { + strbuf_release(&buf); + return 0; + } + +error_return: + strbuf_ltrim(&buf); + if (!buf.len) + strbuf_addstr(&buf, "service rejected"); + eol = strchr(buf.buf, '\n'); + if (eol) + *eol = '\0'; + errno = EACCES; + daemon_error(dir, buf.buf); + strbuf_release(&buf); + return -1; +} + +static int run_service(const char *dir, struct daemon_service *service, + struct hostinfo *hi, const struct argv_array *env) +{ + const char *path; + int enabled = service->enabled; + struct strbuf var = STRBUF_INIT; + + loginfo("Request %s for '%s'", service->name, dir); + + if (!enabled && !service->overridable) { + logerror("'%s': service not enabled.", service->name); + errno = EACCES; + return daemon_error(dir, "service not enabled"); + } + + if (!(path = path_ok(dir, hi))) + return daemon_error(dir, "no such repository"); + + /* + * Security on the cheap. + * + * We want a readable HEAD, usable "objects" directory, and + * a "git-daemon-export-ok" flag that says that the other side + * is ok with us doing this. + * + * path_ok() uses enter_repo() and does whitelist checking. + * We only need to make sure the repository is exported. + */ + + if (!export_all_trees && access("git-daemon-export-ok", F_OK)) { + logerror("'%s': repository not exported.", path); + errno = EACCES; + return daemon_error(dir, "repository not exported"); + } + + if (service->overridable) { + strbuf_addf(&var, "daemon.%s", service->config_name); + git_config_get_bool(var.buf, &enabled); + strbuf_release(&var); + } + if (!enabled) { + logerror("'%s': service not enabled for '%s'", + service->name, path); + errno = EACCES; + return daemon_error(dir, "service not enabled"); + } + + /* + * Optionally, a hook can choose to deny access to the + * repository depending on the phase of the moon. + */ + if (access_hook && run_access_hook(service, dir, path, hi)) + return -1; + + /* + * We'll ignore SIGTERM from now on, we have a + * good client. + */ + signal(SIGTERM, SIG_IGN); + + return service->fn(env); +} + +static void copy_to_log(int fd) +{ + struct strbuf line = STRBUF_INIT; + FILE *fp; + + fp = fdopen(fd, "r"); + if (fp == NULL) { + logerror("fdopen of error channel failed"); + close(fd); + return; + } + + while (strbuf_getline_lf(&line, fp) != EOF) { + logerror("%s", line.buf); + strbuf_setlen(&line, 0); + } + + strbuf_release(&line); + fclose(fp); +} + +static int run_service_command(struct child_process *cld) +{ + argv_array_push(&cld->args, "."); + cld->git_cmd = 1; + cld->err = -1; + if (start_command(cld)) + return -1; + + close(0); + close(1); + + copy_to_log(cld->err); + + return finish_command(cld); +} + +static int upload_pack(const struct argv_array *env) +{ + struct child_process cld = CHILD_PROCESS_INIT; + argv_array_pushl(&cld.args, "upload-pack", "--strict", NULL); + argv_array_pushf(&cld.args, "--timeout=%u", timeout); + + argv_array_pushv(&cld.env_array, env->argv); + + return run_service_command(&cld); +} + +static int upload_archive(const struct argv_array *env) +{ + struct child_process cld = CHILD_PROCESS_INIT; + argv_array_push(&cld.args, "upload-archive"); + + argv_array_pushv(&cld.env_array, env->argv); + + return run_service_command(&cld); +} + +static int receive_pack(const struct argv_array *env) +{ + struct child_process cld = CHILD_PROCESS_INIT; + argv_array_push(&cld.args, "receive-pack"); + + argv_array_pushv(&cld.env_array, env->argv); + + return run_service_command(&cld); +} + +static struct daemon_service daemon_service[] = { + { "upload-archive", "uploadarch", upload_archive, 0, 1 }, + { "upload-pack", "uploadpack", upload_pack, 1, 1 }, + { "receive-pack", "receivepack", receive_pack, 0, 1 }, +}; + +static void enable_service(const char *name, int ena) +{ + int i; + for (i = 0; i < ARRAY_SIZE(daemon_service); i++) { + if (!strcmp(daemon_service[i].name, name)) { + daemon_service[i].enabled = ena; + return; + } + } + die("No such service %s", name); +} + +static void make_service_overridable(const char *name, int ena) +{ + int i; + for (i = 0; i < ARRAY_SIZE(daemon_service); i++) { + if (!strcmp(daemon_service[i].name, name)) { + daemon_service[i].overridable = ena; + return; + } + } + die("No such service %s", name); +} + +static void parse_host_and_port(char *hostport, char **host, + char **port) +{ + if (*hostport == '[') { + char *end; + + end = strchr(hostport, ']'); + if (!end) + die("Invalid request ('[' without ']')"); + *end = '\0'; + *host = hostport + 1; + if (!end[1]) + *port = NULL; + else if (end[1] == ':') + *port = end + 2; + else + die("Garbage after end of host part"); + } else { + *host = hostport; + *port = strrchr(hostport, ':'); + if (*port) { + **port = '\0'; + ++*port; + } + } +} + +/* + * Sanitize a string from the client so that it's OK to be inserted into a + * filesystem path. Specifically, we disallow slashes, runs of "..", and + * trailing and leading dots, which means that the client cannot escape + * our base path via ".." traversal. + */ +static void sanitize_client(struct strbuf *out, const char *in) +{ + for (; *in; in++) { + if (*in == '/') + continue; + if (*in == '.' && (!out->len || out->buf[out->len - 1] == '.')) + continue; + strbuf_addch(out, *in); + } + + while (out->len && out->buf[out->len - 1] == '.') + strbuf_setlen(out, out->len - 1); +} + +/* + * Like sanitize_client, but we also perform any canonicalization + * to make life easier on the admin. + */ +static void canonicalize_client(struct strbuf *out, const char *in) +{ + sanitize_client(out, in); + strbuf_tolower(out); +} + +/* + * Read the host as supplied by the client connection. + * + * Returns a pointer to the character after the NUL byte terminating the host + * arguemnt, or 'extra_args' if there is no host arguemnt. + */ +static char *parse_host_arg(struct hostinfo *hi, char *extra_args, int buflen) +{ + char *val; + int vallen; + char *end = extra_args + buflen; + + if (extra_args < end && *extra_args) { + hi->saw_extended_args = 1; + if (strncasecmp("host=", extra_args, 5) == 0) { + val = extra_args + 5; + vallen = strlen(val) + 1; + loginfo("Extended attribute \"host\": %s", val); + if (*val) { + /* Split <host>:<port> at colon. */ + char *host; + char *port; + parse_host_and_port(val, &host, &port); + if (port) + sanitize_client(&hi->tcp_port, port); + canonicalize_client(&hi->hostname, host); + hi->hostname_lookup_done = 0; + } + + /* On to the next one */ + extra_args = val + vallen; + } + if (extra_args < end && *extra_args) + die("Invalid request"); + } + + return extra_args; +} + +static void parse_extra_args(struct hostinfo *hi, struct argv_array *env, + char *extra_args, int buflen) +{ + const char *end = extra_args + buflen; + struct strbuf git_protocol = STRBUF_INIT; + + /* First look for the host argument */ + extra_args = parse_host_arg(hi, extra_args, buflen); + + /* Look for additional arguments places after a second NUL byte */ + for (; extra_args < end; extra_args += strlen(extra_args) + 1) { + const char *arg = extra_args; + + /* + * Parse the extra arguments, adding most to 'git_protocol' + * which will be used to set the 'GIT_PROTOCOL' envvar in the + * service that will be run. + * + * If there ends up being a particular arg in the future that + * git-daemon needs to parse specificly (like the 'host' arg) + * then it can be parsed here and not added to 'git_protocol'. + */ + if (*arg) { + if (git_protocol.len > 0) + strbuf_addch(&git_protocol, ':'); + strbuf_addstr(&git_protocol, arg); + } + } + + if (git_protocol.len > 0) { + loginfo("Extended attribute \"protocol\": %s", git_protocol.buf); + argv_array_pushf(env, GIT_PROTOCOL_ENVIRONMENT "=%s", + git_protocol.buf); + } + strbuf_release(&git_protocol); +} + +/* + * Locate canonical hostname and its IP address. + */ +static void lookup_hostname(struct hostinfo *hi) +{ + if (!hi->hostname_lookup_done && hi->hostname.len) { +#ifndef NO_IPV6 + struct addrinfo hints; + struct addrinfo *ai; + int gai; + static char addrbuf[HOST_NAME_MAX + 1]; + + memset(&hints, 0, sizeof(hints)); + hints.ai_flags = AI_CANONNAME; + + gai = getaddrinfo(hi->hostname.buf, NULL, &hints, &ai); + if (!gai) { + struct sockaddr_in *sin_addr = (void *)ai->ai_addr; + + inet_ntop(AF_INET, &sin_addr->sin_addr, + addrbuf, sizeof(addrbuf)); + strbuf_addstr(&hi->ip_address, addrbuf); + + if (ai->ai_canonname) + sanitize_client(&hi->canon_hostname, + ai->ai_canonname); + else + strbuf_addbuf(&hi->canon_hostname, + &hi->ip_address); + + freeaddrinfo(ai); + } +#else + struct hostent *hent; + struct sockaddr_in sa; + char **ap; + static char addrbuf[HOST_NAME_MAX + 1]; + + hent = gethostbyname(hi->hostname.buf); + if (hent) { + ap = hent->h_addr_list; + memset(&sa, 0, sizeof sa); + sa.sin_family = hent->h_addrtype; + sa.sin_port = htons(0); + memcpy(&sa.sin_addr, *ap, hent->h_length); + + inet_ntop(hent->h_addrtype, &sa.sin_addr, + addrbuf, sizeof(addrbuf)); + + sanitize_client(&hi->canon_hostname, hent->h_name); + strbuf_addstr(&hi->ip_address, addrbuf); + } +#endif + hi->hostname_lookup_done = 1; + } +} + +static void hostinfo_init(struct hostinfo *hi) +{ + memset(hi, 0, sizeof(*hi)); + strbuf_init(&hi->hostname, 0); + strbuf_init(&hi->canon_hostname, 0); + strbuf_init(&hi->ip_address, 0); + strbuf_init(&hi->tcp_port, 0); +} + +static void hostinfo_clear(struct hostinfo *hi) +{ + strbuf_release(&hi->hostname); + strbuf_release(&hi->canon_hostname); + strbuf_release(&hi->ip_address); + strbuf_release(&hi->tcp_port); +} + +static void set_keep_alive(int sockfd) +{ + int ka = 1; + + if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0) { + if (errno != ENOTSOCK) + logerror("unable to set SO_KEEPALIVE on socket: %s", + strerror(errno)); + } +} + +static int execute(void) +{ + char *line = packet_buffer; + int pktlen, len, i; + char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT"); + struct hostinfo hi; + struct argv_array env = ARGV_ARRAY_INIT; + + hostinfo_init(&hi); + + if (addr) + loginfo("Connection from %s:%s", addr, port); + + set_keep_alive(0); + alarm(init_timeout ? init_timeout : timeout); + pktlen = packet_read(0, NULL, NULL, packet_buffer, sizeof(packet_buffer), 0); + alarm(0); + + len = strlen(line); + if (len && line[len-1] == '\n') + line[len-1] = 0; + + /* parse additional args hidden behind a NUL byte */ + if (len != pktlen) + parse_extra_args(&hi, &env, line + len + 1, pktlen - len - 1); + + for (i = 0; i < ARRAY_SIZE(daemon_service); i++) { + struct daemon_service *s = &(daemon_service[i]); + const char *arg; + + if (skip_prefix(line, "git-", &arg) && + skip_prefix(arg, s->name, &arg) && + *arg++ == ' ') { + /* + * Note: The directory here is probably context sensitive, + * and might depend on the actual service being performed. + */ + int rc = run_service(arg, s, &hi, &env); + hostinfo_clear(&hi); + argv_array_clear(&env); + return rc; + } + } + + hostinfo_clear(&hi); + argv_array_clear(&env); + logerror("Protocol error: '%s'", line); + return -1; +} + +static int addrcmp(const struct sockaddr_storage *s1, + const struct sockaddr_storage *s2) +{ + const struct sockaddr *sa1 = (const struct sockaddr*) s1; + const struct sockaddr *sa2 = (const struct sockaddr*) s2; + + if (sa1->sa_family != sa2->sa_family) + return sa1->sa_family - sa2->sa_family; + if (sa1->sa_family == AF_INET) + return memcmp(&((struct sockaddr_in *)s1)->sin_addr, + &((struct sockaddr_in *)s2)->sin_addr, + sizeof(struct in_addr)); +#ifndef NO_IPV6 + if (sa1->sa_family == AF_INET6) + return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr, + &((struct sockaddr_in6 *)s2)->sin6_addr, + sizeof(struct in6_addr)); +#endif + return 0; +} + +static int max_connections = 32; + +static unsigned int live_children; + +static struct child { + struct child *next; + struct child_process cld; + struct sockaddr_storage address; +} *firstborn; + +static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen) +{ + struct child *newborn, **cradle; + + newborn = xcalloc(1, sizeof(*newborn)); + live_children++; + memcpy(&newborn->cld, cld, sizeof(*cld)); + memcpy(&newborn->address, addr, addrlen); + for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next) + if (!addrcmp(&(*cradle)->address, &newborn->address)) + break; + newborn->next = *cradle; + *cradle = newborn; +} + +/* + * This gets called if the number of connections grows + * past "max_connections". + * + * We kill the newest connection from a duplicate IP. + */ +static void kill_some_child(void) +{ + const struct child *blanket, *next; + + if (!(blanket = firstborn)) + return; + + for (; (next = blanket->next); blanket = next) + if (!addrcmp(&blanket->address, &next->address)) { + kill(blanket->cld.pid, SIGTERM); + break; + } +} + +static void check_dead_children(void) +{ + int status; + pid_t pid; + + struct child **cradle, *blanket; + for (cradle = &firstborn; (blanket = *cradle);) + if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) { + const char *dead = ""; + if (status) + dead = " (with error)"; + loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead); + + /* remove the child */ + *cradle = blanket->next; + live_children--; + child_process_clear(&blanket->cld); + free(blanket); + } else + cradle = &blanket->next; +} + +static struct argv_array cld_argv = ARGV_ARRAY_INIT; +static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen) +{ + struct child_process cld = CHILD_PROCESS_INIT; + + if (max_connections && live_children >= max_connections) { + kill_some_child(); + sleep(1); /* give it some time to die */ + check_dead_children(); + if (live_children >= max_connections) { + close(incoming); + logerror("Too many children, dropping connection"); + return; + } + } + + if (addr->sa_family == AF_INET) { + char buf[128] = ""; + struct sockaddr_in *sin_addr = (void *) addr; + inet_ntop(addr->sa_family, &sin_addr->sin_addr, buf, sizeof(buf)); + argv_array_pushf(&cld.env_array, "REMOTE_ADDR=%s", buf); + argv_array_pushf(&cld.env_array, "REMOTE_PORT=%d", + ntohs(sin_addr->sin_port)); +#ifndef NO_IPV6 + } else if (addr->sa_family == AF_INET6) { + char buf[128] = ""; + struct sockaddr_in6 *sin6_addr = (void *) addr; + inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(buf)); + argv_array_pushf(&cld.env_array, "REMOTE_ADDR=[%s]", buf); + argv_array_pushf(&cld.env_array, "REMOTE_PORT=%d", + ntohs(sin6_addr->sin6_port)); +#endif + } + + cld.argv = cld_argv.argv; + cld.in = incoming; + cld.out = dup(incoming); + + if (start_command(&cld)) + logerror("unable to fork"); + else + add_child(&cld, addr, addrlen); +} + +static void child_handler(int signo) +{ + /* + * Otherwise empty handler because systemcalls will get interrupted + * upon signal receipt + * SysV needs the handler to be rearmed + */ + signal(SIGCHLD, child_handler); +} + +static int set_reuse_addr(int sockfd) +{ + int on = 1; + + if (!reuseaddr) + return 0; + return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, + &on, sizeof(on)); +} + +struct socketlist { + int *list; + size_t nr; + size_t alloc; +}; + +static const char *ip2str(int family, struct sockaddr *sin, socklen_t len) +{ +#ifdef NO_IPV6 + static char ip[INET_ADDRSTRLEN]; +#else + static char ip[INET6_ADDRSTRLEN]; +#endif + + switch (family) { +#ifndef NO_IPV6 + case AF_INET6: + inet_ntop(family, &((struct sockaddr_in6*)sin)->sin6_addr, ip, len); + break; +#endif + case AF_INET: + inet_ntop(family, &((struct sockaddr_in*)sin)->sin_addr, ip, len); + break; + default: + xsnprintf(ip, sizeof(ip), "<unknown>"); + } + return ip; +} + +#ifndef NO_IPV6 + +static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist) +{ + int socknum = 0; + char pbuf[NI_MAXSERV]; + struct addrinfo hints, *ai0, *ai; + int gai; + long flags; + + xsnprintf(pbuf, sizeof(pbuf), "%d", listen_port); + memset(&hints, 0, sizeof(hints)); + hints.ai_family = AF_UNSPEC; + hints.ai_socktype = SOCK_STREAM; + hints.ai_protocol = IPPROTO_TCP; + hints.ai_flags = AI_PASSIVE; + + gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0); + if (gai) { + logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai)); + return 0; + } + + for (ai = ai0; ai; ai = ai->ai_next) { + int sockfd; + + sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); + if (sockfd < 0) + continue; + if (sockfd >= FD_SETSIZE) { + logerror("Socket descriptor too large"); + close(sockfd); + continue; + } + +#ifdef IPV6_V6ONLY + if (ai->ai_family == AF_INET6) { + int on = 1; + setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY, + &on, sizeof(on)); + /* Note: error is not fatal */ + } +#endif + + if (set_reuse_addr(sockfd)) { + logerror("Could not set SO_REUSEADDR: %s", strerror(errno)); + close(sockfd); + continue; + } + + set_keep_alive(sockfd); + + if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) { + logerror("Could not bind to %s: %s", + ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen), + strerror(errno)); + close(sockfd); + continue; /* not fatal */ + } + if (listen(sockfd, 5) < 0) { + logerror("Could not listen to %s: %s", + ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen), + strerror(errno)); + close(sockfd); + continue; /* not fatal */ + } + + flags = fcntl(sockfd, F_GETFD, 0); + if (flags >= 0) + fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC); + + ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc); + socklist->list[socklist->nr++] = sockfd; + socknum++; + } + + freeaddrinfo(ai0); + + return socknum; +} + +#else /* NO_IPV6 */ + +static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist) +{ + struct sockaddr_in sin; + int sockfd; + long flags; + + memset(&sin, 0, sizeof sin); + sin.sin_family = AF_INET; + sin.sin_port = htons(listen_port); + + if (listen_addr) { + /* Well, host better be an IP address here. */ + if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0) + return 0; + } else { + sin.sin_addr.s_addr = htonl(INADDR_ANY); + } + + sockfd = socket(AF_INET, SOCK_STREAM, 0); + if (sockfd < 0) + return 0; + + if (set_reuse_addr(sockfd)) { + logerror("Could not set SO_REUSEADDR: %s", strerror(errno)); + close(sockfd); + return 0; + } + + set_keep_alive(sockfd); + + if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) { + logerror("Could not bind to %s: %s", + ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)), + strerror(errno)); + close(sockfd); + return 0; + } + + if (listen(sockfd, 5) < 0) { + logerror("Could not listen to %s: %s", + ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)), + strerror(errno)); + close(sockfd); + return 0; + } + + flags = fcntl(sockfd, F_GETFD, 0); + if (flags >= 0) + fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC); + + ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc); + socklist->list[socklist->nr++] = sockfd; + return 1; +} + +#endif + +static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist) +{ + if (!listen_addr->nr) + setup_named_sock(NULL, listen_port, socklist); + else { + int i, socknum; + for (i = 0; i < listen_addr->nr; i++) { + socknum = setup_named_sock(listen_addr->items[i].string, + listen_port, socklist); + + if (socknum == 0) + logerror("unable to allocate any listen sockets for host %s on port %u", + listen_addr->items[i].string, listen_port); + } + } +} + +static int service_loop(struct socketlist *socklist) +{ + struct pollfd *pfd; + int i; + + pfd = xcalloc(socklist->nr, sizeof(struct pollfd)); + + for (i = 0; i < socklist->nr; i++) { + pfd[i].fd = socklist->list[i]; + pfd[i].events = POLLIN; + } + + signal(SIGCHLD, child_handler); + + for (;;) { + int i; + + check_dead_children(); + + if (poll(pfd, socklist->nr, -1) < 0) { + if (errno != EINTR) { + logerror("Poll failed, resuming: %s", + strerror(errno)); + sleep(1); + } + continue; + } + + for (i = 0; i < socklist->nr; i++) { + if (pfd[i].revents & POLLIN) { + union { + struct sockaddr sa; + struct sockaddr_in sai; +#ifndef NO_IPV6 + struct sockaddr_in6 sai6; +#endif + } ss; + socklen_t sslen = sizeof(ss); + int incoming = accept(pfd[i].fd, &ss.sa, &sslen); + if (incoming < 0) { + switch (errno) { + case EAGAIN: + case EINTR: + case ECONNABORTED: + continue; + default: + die_errno("accept returned"); + } + } + handle(incoming, &ss.sa, sslen); + } + } + } +} + +#ifdef NO_POSIX_GOODIES + +struct credentials; + +static void drop_privileges(struct credentials *cred) +{ + /* nothing */ +} + +static struct credentials *prepare_credentials(const char *user_name, + const char *group_name) +{ + die("--user not supported on this platform"); +} + +#else + +struct credentials { + struct passwd *pass; + gid_t gid; +}; + +static void drop_privileges(struct credentials *cred) +{ + if (cred && (initgroups(cred->pass->pw_name, cred->gid) || + setgid (cred->gid) || setuid(cred->pass->pw_uid))) + die("cannot drop privileges"); +} + +static struct credentials *prepare_credentials(const char *user_name, + const char *group_name) +{ + static struct credentials c; + + c.pass = getpwnam(user_name); + if (!c.pass) + die("user not found - %s", user_name); + + if (!group_name) + c.gid = c.pass->pw_gid; + else { + struct group *group = getgrnam(group_name); + if (!group) + die("group not found - %s", group_name); + + c.gid = group->gr_gid; + } + + return &c; +} +#endif + +static int serve(struct string_list *listen_addr, int listen_port, + struct credentials *cred) +{ + struct socketlist socklist = { NULL, 0, 0 }; + + socksetup(listen_addr, listen_port, &socklist); + if (socklist.nr == 0) + die("unable to allocate any listen sockets on port %u", + listen_port); + + drop_privileges(cred); + + loginfo("Ready to rumble"); + + return service_loop(&socklist); +} + +int cmd_main(int argc, const char **argv) +{ + int listen_port = 0; + struct string_list listen_addr = STRING_LIST_INIT_NODUP; + int serve_mode = 0, inetd_mode = 0; + const char *pid_file = NULL, *user_name = NULL, *group_name = NULL; + int detach = 0; + struct credentials *cred = NULL; + int i; + + for (i = 1; i < argc; i++) { + const char *arg = argv[i]; + const char *v; + + if (skip_prefix(arg, "--listen=", &v)) { + string_list_append(&listen_addr, xstrdup_tolower(v)); + continue; + } + if (skip_prefix(arg, "--port=", &v)) { + char *end; + unsigned long n; + n = strtoul(v, &end, 0); + if (*v && !*end) { + listen_port = n; + continue; + } + } + if (!strcmp(arg, "--serve")) { + serve_mode = 1; + continue; + } + if (!strcmp(arg, "--inetd")) { + inetd_mode = 1; + continue; + } + if (!strcmp(arg, "--verbose")) { + verbose = 1; + continue; + } + if (!strcmp(arg, "--syslog")) { + log_destination = LOG_DESTINATION_SYSLOG; + continue; + } + if (skip_prefix(arg, "--log-destination=", &v)) { + if (!strcmp(v, "syslog")) { + log_destination = LOG_DESTINATION_SYSLOG; + continue; + } else if (!strcmp(v, "stderr")) { + log_destination = LOG_DESTINATION_STDERR; + continue; + } else if (!strcmp(v, "none")) { + log_destination = LOG_DESTINATION_NONE; + continue; + } else + die("unknown log destination '%s'", v); + } + if (!strcmp(arg, "--export-all")) { + export_all_trees = 1; + continue; + } + if (skip_prefix(arg, "--access-hook=", &v)) { + access_hook = v; + continue; + } + if (skip_prefix(arg, "--timeout=", &v)) { + timeout = atoi(v); + continue; + } + if (skip_prefix(arg, "--init-timeout=", &v)) { + init_timeout = atoi(v); + continue; + } + if (skip_prefix(arg, "--max-connections=", &v)) { + max_connections = atoi(v); + if (max_connections < 0) + max_connections = 0; /* unlimited */ + continue; + } + if (!strcmp(arg, "--strict-paths")) { + strict_paths = 1; + continue; + } + if (skip_prefix(arg, "--base-path=", &v)) { + base_path = v; + continue; + } + if (!strcmp(arg, "--base-path-relaxed")) { + base_path_relaxed = 1; + continue; + } + if (skip_prefix(arg, "--interpolated-path=", &v)) { + interpolated_path = v; + continue; + } + if (!strcmp(arg, "--reuseaddr")) { + reuseaddr = 1; + continue; + } + if (!strcmp(arg, "--user-path")) { + user_path = ""; + continue; + } + if (skip_prefix(arg, "--user-path=", &v)) { + user_path = v; + continue; + } + if (skip_prefix(arg, "--pid-file=", &v)) { + pid_file = v; + continue; + } + if (!strcmp(arg, "--detach")) { + detach = 1; + continue; + } + if (skip_prefix(arg, "--user=", &v)) { + user_name = v; + continue; + } + if (skip_prefix(arg, "--group=", &v)) { + group_name = v; + continue; + } + if (skip_prefix(arg, "--enable=", &v)) { + enable_service(v, 1); + continue; + } + if (skip_prefix(arg, "--disable=", &v)) { + enable_service(v, 0); + continue; + } + if (skip_prefix(arg, "--allow-override=", &v)) { + make_service_overridable(v, 1); + continue; + } + if (skip_prefix(arg, "--forbid-override=", &v)) { + make_service_overridable(v, 0); + continue; + } + if (!strcmp(arg, "--informative-errors")) { + informative_errors = 1; + continue; + } + if (!strcmp(arg, "--no-informative-errors")) { + informative_errors = 0; + continue; + } + if (!strcmp(arg, "--")) { + ok_paths = &argv[i+1]; + break; + } else if (arg[0] != '-') { + ok_paths = &argv[i]; + break; + } + + usage(daemon_usage); + } + + if (log_destination == LOG_DESTINATION_UNSET) { + if (inetd_mode || detach) + log_destination = LOG_DESTINATION_SYSLOG; + else + log_destination = LOG_DESTINATION_STDERR; + } + + if (log_destination == LOG_DESTINATION_SYSLOG) { + openlog("git-daemon", LOG_PID, LOG_DAEMON); + set_die_routine(daemon_die); + } else + /* avoid splitting a message in the middle */ + setvbuf(stderr, NULL, _IOFBF, 4096); + + if (inetd_mode && (detach || group_name || user_name)) + die("--detach, --user and --group are incompatible with --inetd"); + + if (inetd_mode && (listen_port || (listen_addr.nr > 0))) + die("--listen= and --port= are incompatible with --inetd"); + else if (listen_port == 0) + listen_port = DEFAULT_GIT_PORT; + + if (group_name && !user_name) + die("--group supplied without --user"); + + if (user_name) + cred = prepare_credentials(user_name, group_name); + + if (strict_paths && (!ok_paths || !*ok_paths)) + die("option --strict-paths requires a whitelist"); + + if (base_path && !is_directory(base_path)) + die("base-path '%s' does not exist or is not a directory", + base_path); + + if (log_destination != LOG_DESTINATION_STDERR) { + if (!freopen("/dev/null", "w", stderr)) + die_errno("failed to redirect stderr to /dev/null"); + } + + if (inetd_mode || serve_mode) + return execute(); + + if (detach) { + if (daemonize()) + die("--detach not supported on this platform"); + } + + if (pid_file) + write_file(pid_file, "%"PRIuMAX, (uintmax_t) getpid()); + + /* prepare argv for serving-processes */ + argv_array_push(&cld_argv, argv[0]); /* git-daemon */ + argv_array_push(&cld_argv, "--serve"); + for (i = 1; i < argc; ++i) + argv_array_push(&cld_argv, argv[i]); + + return serve(&listen_addr, listen_port, cred); +} |