From 6e5a79de658cb1c8012c86e0837379aa6eabd024 Mon Sep 17 00:00:00 2001
From: Paul Emge <paulemge@forallsecure.com>
Date: Mon, 8 Jul 2019 16:37:04 -0700
Subject: [PATCH] CVE-2019-13105: ext4: fix double-free in ext4_cache_read

ext_cache_read doesn't null cache->buf, after freeing, which results
in a later function double-freeing it. This patch fixes
ext_cache_read to call ext_cache_fini instead of free.

Signed-off-by: Paul Emge <paulemge@forallsecure.com>
---
 fs/ext4/ext4fs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ext4/ext4fs.c b/fs/ext4/ext4fs.c
index 26db677a1f17..85dc122f3003 100644
--- a/fs/ext4/ext4fs.c
+++ b/fs/ext4/ext4fs.c
@@ -286,7 +286,7 @@ int ext_cache_read(struct ext_block_cache *cache, lbaint_t block, int size)
 	if (!cache->buf)
 		return 0;
 	if (!ext4fs_devread(block, 0, size, cache->buf)) {
-		free(cache->buf);
+		ext_cache_fini(cache);
 		return 0;
 	}
 	cache->block = block;