fs: fail gracefully in get_mounted_path/get_cdev_by_mountpath

get_fsdevice_by_path will return NULL if no file system was mounted at
location. Returned pointer was dereferenced unconditionally, potentially
leading to null pointer dereference. Fix this.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Link: https://lore.barebox.org/20230508074612.3313870-1-a.fatoum@pengutronix.de
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 4 insertions, 0 deletions

diff --git a/fs/fs.c b/fs/fs.c
index 65e4c661b9..368458cc54 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -240,6 +240,8 @@ struct cdev *get_cdev_by_mountpath(const char *path)
 	struct fs_device *fsdev;
 
 	fsdev = get_fsdevice_by_path(path);
+	if (!fsdev)
+		return NULL;
 
 	return fsdev->cdev;
 }
@@ -249,6 +251,8 @@ char *get_mounted_path(const char *path)
 	struct fs_device *fdev;
 
 	fdev = get_fsdevice_by_path(path);
+	if (!fdev)
+		return NULL;
 
 	return fdev->path;
 }