automount: check for recursive automount

automount_mount calls run_command which may trigger an automount
again. This results in an endless loop. A simple way to trigger
this is:

mkdir /x; automount /x false; cd /x; something

Use a static variable to detect if we are currently in automount_mount()
and bail out if we are.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 9 insertions, 1 deletions

diff --git a/fs/fs.c b/fs/fs.c
index b0ac918acc..dd410b731a 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -409,6 +409,12 @@ static void automount_mount(const char *path, int instat)
 {
 	struct automount *am;
 	int ret;
+	static int in_automount;
+
+	if (in_automount)
+		return;
+
+	in_automount++;
 
 	list_for_each_entry(am, &automount_list, list) {
 		int len_path = strlen(path);
@@ -444,8 +450,10 @@ static void automount_mount(const char *path, int instat)
 		else
 			automount_remove(am->path);
 
-		return;
+		break;
 	}
+
+	in_automount--;
 }
 
 BAREBOX_MAGICVAR(automount_path, "mountpath passed to automount scripts");