diff options
Diffstat (limited to 'daemon.c')
| -rw-r--r-- | daemon.c | 214 |
1 files changed, 155 insertions, 59 deletions
@@ -43,9 +43,6 @@ static const char *base_path; static const char *interpolated_path; static int base_path_relaxed; -/* Flag indicating client sent extra args. */ -static int saw_extended_args; - /* 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. @@ -56,10 +53,28 @@ static const char *user_path; static unsigned int timeout; static unsigned int init_timeout; -static char *hostname; -static char *canon_hostname; -static char *ip_address; -static char *tcp_port; +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) { @@ -106,7 +121,43 @@ static void NORETURN daemon_die(const char *err, va_list params) exit(1); } -static const char *path_ok(const char *directory) +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]; @@ -142,16 +193,13 @@ static const char *path_ok(const char *directory) dir = rpath; } } - else if (interpolated_path && saw_extended_args) { + else if (interpolated_path && hi->saw_extended_args) { struct strbuf expanded_path = STRBUF_INIT; - struct strbuf_expand_dict_entry dict[6]; - - dict[0].placeholder = "H"; dict[0].value = hostname; - dict[1].placeholder = "CH"; dict[1].value = canon_hostname; - dict[2].placeholder = "IP"; dict[2].value = ip_address; - dict[3].placeholder = "P"; dict[3].value = tcp_port; - dict[4].placeholder = "D"; dict[4].value = directory; - dict[5].placeholder = NULL; dict[5].value = NULL; + 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); @@ -159,7 +207,7 @@ static const char *path_ok(const char *directory) } strbuf_expand(&expanded_path, interpolated_path, - strbuf_expand_dict_cb, &dict); + expand_path, &context); strlcpy(interp_path, expanded_path.buf, PATH_MAX); strbuf_release(&expanded_path); loginfo("Interpolated dir '%s'", interp_path); @@ -240,7 +288,8 @@ static int daemon_error(const char *dir, const char *msg) static const char *access_hook; -static int run_access_hook(struct daemon_service *service, const char *dir, const char *path) +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; @@ -249,16 +298,14 @@ static int run_access_hook(struct daemon_service *service, const char *dir, cons char *eol; int seen_errors = 0; -#define STRARG(x) ((x) ? (x) : "") *arg++ = access_hook; *arg++ = service->name; *arg++ = path; - *arg++ = STRARG(hostname); - *arg++ = STRARG(canon_hostname); - *arg++ = STRARG(ip_address); - *arg++ = STRARG(tcp_port); + *arg++ = hi->hostname.buf; + *arg++ = get_canon_hostname(hi); + *arg++ = get_ip_address(hi); + *arg++ = hi->tcp_port.buf; *arg = NULL; -#undef STRARG child.use_shell = 1; child.argv = argv; @@ -302,7 +349,8 @@ error_return: return -1; } -static int run_service(const char *dir, struct daemon_service *service) +static int run_service(const char *dir, struct daemon_service *service, + struct hostinfo *hi) { const char *path; int enabled = service->enabled; @@ -316,7 +364,7 @@ static int run_service(const char *dir, struct daemon_service *service) return daemon_error(dir, "service not enabled"); } - if (!(path = path_ok(dir))) + if (!(path = path_ok(dir, hi))) return daemon_error(dir, "no such repository"); /* @@ -352,7 +400,7 @@ static int run_service(const char *dir, struct daemon_service *service) * 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)) + if (access_hook && run_access_hook(service, dir, path, hi)) return -1; /* @@ -485,16 +533,46 @@ static void parse_host_and_port(char *hostport, char **host, } /* + * 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. */ -static void parse_host_arg(char *extra_args, int buflen) +static void 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) { - saw_extended_args = 1; + hi->saw_extended_args = 1; if (strncasecmp("host=", extra_args, 5) == 0) { val = extra_args + 5; vallen = strlen(val) + 1; @@ -503,12 +581,10 @@ static void parse_host_arg(char *extra_args, int buflen) char *host; char *port; parse_host_and_port(val, &host, &port); - if (port) { - free(tcp_port); - tcp_port = xstrdup(port); - } - free(hostname); - hostname = xstrdup_tolower(host); + if (port) + sanitize_client(&hi->tcp_port, port); + canonicalize_client(&hi->hostname, host); + hi->hostname_lookup_done = 0; } /* On to the next one */ @@ -517,11 +593,14 @@ static void parse_host_arg(char *extra_args, int buflen) if (extra_args < end && *extra_args) die("Invalid request"); } +} - /* - * Locate canonical hostname and its IP address. - */ - if (hostname) { +/* + * 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; @@ -531,18 +610,20 @@ static void parse_host_arg(char *extra_args, int buflen) memset(&hints, 0, sizeof(hints)); hints.ai_flags = AI_CANONNAME; - gai = getaddrinfo(hostname, NULL, &hints, &ai); + 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)); - free(ip_address); - ip_address = xstrdup(addrbuf); + strbuf_addstr(&hi->ip_address, addrbuf); - free(canon_hostname); - canon_hostname = xstrdup(ai->ai_canonname ? - ai->ai_canonname : ip_address); + if (ai->ai_canonname) + sanitize_client(&hi->canon_hostname, + ai->ai_canonname); + else + strbuf_addbuf(&hi->canon_hostname, + &hi->ip_address); freeaddrinfo(ai); } @@ -552,7 +633,7 @@ static void parse_host_arg(char *extra_args, int buflen) char **ap; static char addrbuf[HOST_NAME_MAX + 1]; - hent = gethostbyname(hostname); + hent = gethostbyname(hostname.buf); if (hent) { ap = hent->h_addr_list; memset(&sa, 0, sizeof sa); @@ -563,21 +644,39 @@ static void parse_host_arg(char *extra_args, int buflen) inet_ntop(hent->h_addrtype, &sa.sin_addr, addrbuf, sizeof(addrbuf)); - free(canon_hostname); - canon_hostname = xstrdup(hent->h_name); - free(ip_address); - ip_address = xstrdup(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 int execute(void) { char *line = packet_buffer; int pktlen, len, i; char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT"); + struct hostinfo hi; + + hostinfo_init(&hi); if (addr) loginfo("Connection from %s:%s", addr, port); @@ -596,14 +695,8 @@ static int execute(void) pktlen--; } - free(hostname); - free(canon_hostname); - free(ip_address); - free(tcp_port); - hostname = canon_hostname = ip_address = tcp_port = NULL; - if (len != pktlen) - parse_host_arg(line + len + 1, pktlen - len - 1); + parse_host_arg(&hi, line + len + 1, pktlen - len - 1); for (i = 0; i < ARRAY_SIZE(daemon_service); i++) { struct daemon_service *s = &(daemon_service[i]); @@ -616,10 +709,13 @@ static int execute(void) * Note: The directory here is probably context sensitive, * and might depend on the actual service being performed. */ - return run_service(arg, s); + int rc = run_service(arg, s, &hi); + hostinfo_clear(&hi); + return rc; } } + hostinfo_clear(&hi); logerror("Protocol error: '%s'", line); return -1; } |