cifs: check pointer before freeing
commit 77b6ec01c29aade01701aa30bf1469acc7f2be76 upstream.
clang static analysis reports this problem
dfs_cache.c:591:2: warning: Argument to kfree() is a constant address
(18446744073709551614), which is not memory allocated by malloc()
kfree(vi);
^~~~~~~~~
In dfs_cache_del_vol() the volume info pointer 'vi' being freed
is the return of a call to find_vol(). The large constant address
is find_vol() returning an error.
Add an error check to dfs_cache_del_vol() similar to the one done
in dfs_cache_update_vol().
Fixes: 54be1f6c1c37 ("cifs: Add DFS cache routines")
Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
CC: <stable@vger.kernel.org> # v5.0+
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/fs/cifs/dfs_cache.c b/fs/cifs/dfs_cache.c
index 6ee8496..7b6db27 100644
--- a/fs/cifs/dfs_cache.c
+++ b/fs/cifs/dfs_cache.c
@@ -1317,7 +1317,8 @@ void dfs_cache_del_vol(const char *fullpath)
vi = find_vol(fullpath);
spin_unlock(&vol_list_lock);
- kref_put(&vi->refcnt, vol_release);
+ if (!IS_ERR(vi))
+ kref_put(&vi->refcnt, vol_release);
}
/**