git/daemon.c
Derrick Stolee dee8a1455c daemon: clarify directory arguments
The undecorated arguments to the 'git-daemon' command provide a list of
directories. When at least one directory is specified, then 'git-daemon'
only serves requests that are within that directory list. The boolean
'--strict-paths' option makes the list more explicit in that
subdirectories are no longer included.

The existing documentation and error messages around this directory list
refer to it and its behavior as a "whitelist". The word "whitelist" has
cultural implications that are not inclusive.  Thankfully, it is not
difficult to reword and avoid its use. In the process, we can define the
purpose of this directory list directly.

In Documentation/git-daemon.txt, rewrite the OPTIONS section around the
'<directory>' option. Add additional clarity to the other options that
refer to these directories.

Some error messages can also be improved in daemon.c. The
'--strict-paths' option requires '<directory>' arguments, so refer to
that section of the documentation directly. A logerror() call points out
that a requested directory is not in the specified directory list. We
can use "list" here without any loss of information.

Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-07-19 12:45:31 -07:00

1477 lines
34 KiB
C

#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;
};
#define HOSTINFO_INIT { \
.hostname = STRBUF_INIT, \
.canon_hostname = STRBUF_INIT, \
.ip_address = STRBUF_INIT, \
.tcp_port = STRBUF_INIT, \
}
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));
strbuf_release(&expanded_path);
if (rlen >= sizeof(interp_path)) {
logerror("interpolated path too large: %s",
interp_path);
return NULL;
}
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 include /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 directory list", path);
return NULL; /* Fallthrough. Deny by default */
}
typedef int (*daemon_service_fn)(const struct strvec *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;
char *eol;
int seen_errors = 0;
strvec_push(&child.args, access_hook);
strvec_push(&child.args, service->name);
strvec_push(&child.args, path);
strvec_push(&child.args, hi->hostname.buf);
strvec_push(&child.args, get_canon_hostname(hi));
strvec_push(&child.args, get_ip_address(hi));
strvec_push(&child.args, hi->tcp_port.buf);
child.use_shell = 1;
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 strvec *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 checks for included directories.
* 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) {
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)
{
strvec_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 strvec *env)
{
struct child_process cld = CHILD_PROCESS_INIT;
strvec_pushl(&cld.args, "upload-pack", "--strict", NULL);
strvec_pushf(&cld.args, "--timeout=%u", timeout);
strvec_pushv(&cld.env, env->v);
return run_service_command(&cld);
}
static int upload_archive(const struct strvec *env)
{
struct child_process cld = CHILD_PROCESS_INIT;
strvec_push(&cld.args, "upload-archive");
strvec_pushv(&cld.env, env->v);
return run_service_command(&cld);
}
static int receive_pack(const struct strvec *env)
{
struct child_process cld = CHILD_PROCESS_INIT;
strvec_push(&cld.args, "receive-pack");
strvec_pushv(&cld.env, env->v);
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 directory separators, 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 (is_dir_sep(*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
* argument, or 'extra_args' if there is no host argument.
*/
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 strvec *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 specifically (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);
strvec_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_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 = HOSTINFO_INIT;
struct strvec env = STRVEC_INIT;
if (addr)
loginfo("Connection from %s:%s", addr, port);
set_keep_alive(0);
alarm(init_timeout ? init_timeout : timeout);
pktlen = packet_read(0, 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);
strvec_clear(&env);
return rc;
}
}
hostinfo_clear(&hi);
strvec_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;
CALLOC_ARRAY(newborn, 1);
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 strvec cld_argv = STRVEC_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));
strvec_pushf(&cld.env, "REMOTE_ADDR=%s", buf);
strvec_pushf(&cld.env, "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));
strvec_pushf(&cld.env, "REMOTE_ADDR=[%s]", buf);
strvec_pushf(&cld.env, "REMOTE_PORT=%d",
ntohs(sin6_addr->sin6_port));
#endif
}
strvec_pushv(&cld.args, cld_argv.v);
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;
CALLOC_ARRAY(pfd, socklist->nr);
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 '<directory>' arguments");
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 */
strvec_push(&cld_argv, argv[0]); /* git-daemon */
strvec_push(&cld_argv, "--serve");
for (i = 1; i < argc; ++i)
strvec_push(&cld_argv, argv[i]);
return serve(&listen_addr, listen_port, cred);
}