[Qemu-devel] [PATCH 2/5] virtiofsd: prevent lo_lookup() NULL pointer dereference

[Stefan Hajnoczi <stefanha@redhat.com>]

Most lo_do_lookup() have already checked that the parent inode exists.
lo_lookup() hasn't and can therefore hit a NULL pointer dereference when
lo_inode(req, parent) returns NULL.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 contrib/virtiofsd/passthrough_ll.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/contrib/virtiofsd/passthrough_ll.c b/contrib/virtiofsd/passthrough_ll.c
index 9ae1381618..277a17fc03 100644
--- a/contrib/virtiofsd/passthrough_ll.c
+++ b/contrib/virtiofsd/passthrough_ll.c
@@ -766,6 +766,10 @@ static int lo_do_lookup(fuse_req_t req, fuse_ino_t parent, const char *name,
 	struct lo_data *lo = lo_data(req);
 	struct lo_inode *inode, *dir = lo_inode(req, parent);
 
+	if (!dir) {
+		return EBADF;
+	}
+
 	memset(e, 0, sizeof(*e));
 	e->attr_timeout = lo->timeout;
 	e->entry_timeout = lo->timeout;
-- 
2.21.0