commit 7cdfa44227b0d8842d46a775cebe4311150cb8f2
author David Howells <dhowells@redhat.com> Mon Mar 25 16:38:22 2019 +0000
committer Al Viro <viro@zeniv.linux.org.uk> Sat May 25 18:00:02 2019 -0400
tree a6e3cfd0e07a2a7e355fe80a2ec0719f38b71852
parent c3aabf0780a506225b53bfe2b5177dd5dfec093d

vfs: Fix refcounting of filenames in fs_parser

Fix an overput in which filename_lookup() unconditionally drops a ref to
the filename it was given, but this isn't taken account of in the caller,
fs_lookup_param().

Addresses-Coverity-ID: 1443811 ("Use after free")
Signed-off-by: David Howells <dhowells@redhat.com>

fs/fs_parser.c

diff --git a/fs/fs_parser.c b/fs/fs_parser.c
index 570d710..3a1697c 100644
--- a/fs/fs_parser.c
+++ b/fs/fs_parser.c
@@ -268,6 +268,7 @@
 		return invalf(fc, "%s: not usable as path", param->key);
 	}
 
+	f->refcnt++; /* filename_lookup() drops our ref. */
 	ret = filename_lookup(param->dirfd, f, flags, _path, NULL);
 	if (ret < 0) {
 		errorf(fc, "%s: Lookup failure for '%s'", param->key, f->name);