daemon: --access-hook option

The --access-hook option to "git daemon" specifies an external
command to be run every time a client connects, with

 - service name (e.g. "upload-pack", etc.),
 - path to the repository,
 - hostname (%H),
 - canonical hostname (%CH),
 - ip address (%IP),
 - tcp port (%P)

as its command line arguments.  The external command can decide to
decline the service by exiting with a non-zero status (or to allow it
by exiting with a zero status).  It can also look at the $REMOTE_ADDR
and $REMOTE_PORT environment variables to learn about the requestor
when making this decision.

The external command can optionally write a single line to its
standard output to be sent to the requestor as an error message when
it declines the service.

Acked-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Junio C Hamano
2012-08-14 11:37:51 -07:00
parent 86faaf90b3
commit 93741e4a91
2 changed files with 93 additions and 0 deletions

View File

@ -30,6 +30,7 @@ static const char daemon_usage[] =
" [--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"
" [<directory>...]";
@ -256,6 +257,71 @@ static int daemon_error(const char *dir, const char *msg)
return -1;
}
static char *access_hook;
static int run_access_hook(struct daemon_service *service, const char *dir, const char *path)
{
struct child_process child;
struct strbuf buf = STRBUF_INIT;
const char *argv[8];
const char **arg = argv;
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 = NULL;
#undef STRARG
memset(&child, 0, sizeof(child));
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(char *dir, struct daemon_service *service)
{
const char *path;
@ -303,6 +369,13 @@ static int run_service(char *dir, struct daemon_service *service)
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))
return -1;
/*
* We'll ignore SIGTERM from now on, we have a
* good client.
@ -1142,6 +1215,10 @@ int main(int argc, char **argv)
export_all_trees = 1;
continue;
}
if (!prefixcmp(arg, "--access-hook=")) {
access_hook = arg + 14;
continue;
}
if (!prefixcmp(arg, "--timeout=")) {
timeout = atoi(arg+10);
continue;