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>
Junio C Hamano committed
Aug 14, 2012 at 11:37 UTC
93741e4a915fc33a00e6facff88cd27565d10f82
2 files changed
+93
Documentation/git-daemon.txt
+16
@@ -16,6 +16,7 @@ SYNOPSIS
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[--reuseaddr] [--detach] [--pid-file=<file>]
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[--enable=<service>] [--disable=<service>]
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[--allow-override=<service>] [--forbid-override=<service>]
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+ [--access-hook=<path>]
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[--inetd | [--listen=<host_or_ipaddr>] [--port=<n>] [--user=<user> [--group=<group>]]
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[<directory>...]
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@@ -171,6 +172,21 @@ the facility of inet daemon to achieve the same before spawning
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errors are not enabled, all errors report "access denied" to the
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client. The default is --no-informative-errors.
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+--access-hook=<path>::
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+ Every time a client connects, first run an external command
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+ specified by the <path> with service name (e.g. "upload-pack"),
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+ path to the repository, hostname (%H), canonical hostname
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+ (%CH), ip address (%IP), and tcp port (%P) as its command line
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+ arguments. The external command can decide to decline the
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+ service by exiting with a non-zero status (or to allow it by
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+ exiting with a zero status). It can also look at the $REMOTE_ADDR
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+ and $REMOTE_PORT environment variables to learn about the
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+ requestor when making this decision.
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++
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+The external command can optionally write a single line to its
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+standard output to be sent to the requestor as an error message when
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+it declines the service.
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+
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<directory>::
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A directory to add to the whitelist of allowed directories. Unless
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--strict-paths is specified this will also include subdirectories
daemon.c
+77
@@ -30,6 +30,7 @@ static const char daemon_usage[] =
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" [--interpolated-path=<path>]\n"
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" [--reuseaddr] [--pid-file=<file>]\n"
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" [--(enable|disable|allow-override|forbid-override)=<service>]\n"
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+" [--access-hook=<path>]\n"
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" [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
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" [--detach] [--user=<user> [--group=<group>]]\n"
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" [<directory>...]";
@@ -256,6 +257,71 @@ static int daemon_error(const char *dir, const char *msg)
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return -1;
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}
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+static char *access_hook;
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+
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+static int run_access_hook(struct daemon_service *service, const char *dir, const char *path)
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+{
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+ struct child_process child;
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+ struct strbuf buf = STRBUF_INIT;
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+ const char *argv[8];
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+ const char **arg = argv;
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+ char *eol;
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+ int seen_errors = 0;
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+
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+#define STRARG(x) ((x) ? (x) : "")
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+ *arg++ = access_hook;
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+ *arg++ = service->name;
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+ *arg++ = path;
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+ *arg++ = STRARG(hostname);
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+ *arg++ = STRARG(canon_hostname);
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+ *arg++ = STRARG(ip_address);
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+ *arg++ = STRARG(tcp_port);
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+ *arg = NULL;
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+#undef STRARG
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+
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+ memset(&child, 0, sizeof(child));
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+ child.use_shell = 1;
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+ child.argv = argv;
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+ child.no_stdin = 1;
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+ child.no_stderr = 1;
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+ child.out = -1;
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+ if (start_command(&child)) {
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+ logerror("daemon access hook '%s' failed to start",
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+ access_hook);
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+ goto error_return;
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+ }
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+ if (strbuf_read(&buf, child.out, 0) < 0) {
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+ logerror("failed to read from pipe to daemon access hook '%s'",
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+ access_hook);
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+ strbuf_reset(&buf);
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+ seen_errors = 1;
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+ }
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+ if (close(child.out) < 0) {
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+ logerror("failed to close pipe to daemon access hook '%s'",
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+ access_hook);
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+ seen_errors = 1;
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+ }
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+ if (finish_command(&child))
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+ seen_errors = 1;
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+
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+ if (!seen_errors) {
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+ strbuf_release(&buf);
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+ return 0;
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+ }
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+
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+error_return:
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+ strbuf_ltrim(&buf);
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+ if (!buf.len)
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+ strbuf_addstr(&buf, "service rejected");
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+ eol = strchr(buf.buf, '\n');
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+ if (eol)
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+ *eol = '\0';
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+ errno = EACCES;
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+ daemon_error(dir, buf.buf);
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+ strbuf_release(&buf);
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+ return -1;
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+}
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+
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static int run_service(char *dir, struct daemon_service *service)
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{
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const char *path;
@@ -303,6 +369,13 @@ static int run_service(char *dir, struct daemon_service *service)
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return daemon_error(dir, "service not enabled");
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}
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+ /*
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+ * Optionally, a hook can choose to deny access to the
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+ * repository depending on the phase of the moon.
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+ */
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+ if (access_hook && run_access_hook(service, dir, path))
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+ return -1;
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+
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/*
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* We'll ignore SIGTERM from now on, we have a
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* good client.
@@ -1142,6 +1215,10 @@ int main(int argc, char **argv)
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export_all_trees = 1;
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continue;
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}
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+ if (!prefixcmp(arg, "--access-hook=")) {
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+ access_hook = arg + 14;
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+ continue;
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+ }
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if (!prefixcmp(arg, "--timeout=")) {
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timeout = atoi(arg+10);
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continue;