[PATCH AUTOSEL 5.7 189/388] f2fs: fix potential use-after-free issue

Sasha Levin
2020-06-18T02:39:02Z

From: Chao Yu <yuchao0@huawei.com>

[ Upstream commit f3494345ce9999624b36109252a4bf5f00e51a46 ]

In error path of f2fs_read_multi_pages(), it should let last referrer
release decompress io context memory, otherwise, other referrer will
cause use-after-free issue.

Fixes: 4c8ff7095bef ("f2fs: support data compression")
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/f2fs/data.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index cdf2f626bea7..10491ae1cb85 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2130,16 +2130,16 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,
page->index, for_write);
if (IS_ERR(bio)) {
ret = PTR_ERR(bio);
- bio = NULL;
dic->failed = true;
if (refcount_sub_and_test(dic->nr_cpages - i,
- &dic->ref))
+ &dic->ref)) {
f2fs_decompress_end_io(dic->rpages,
cc->cluster_size, true,
false);
- f2fs_free_dic(dic);
+ f2fs_free_dic(dic);
+ }
f2fs_put_dnode(&dn);
- *bio_ret = bio;
+ *bio_ret = NULL;
return ret;
}
}
--
2.25.1