From: Pan Bian <bianpan2016@163.com>
To: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: linux-nilfs@vger.kernel.org, linux-kernel@vger.kernel.org,
Pan Bian <bianpan2016@163.com>
Subject: [PATCH] nilfs2: fix potential use after free
Date: Mon, 26 Nov 2018 11:08:29 +0800 [thread overview]
Message-ID: <1543201709-53191-1-git-send-email-bianpan2016@163.com> (raw)
brelse(bh) is called to drop the reference count of bh when the call
to nilfs_dat_translate fails. If the reference count hits 0, bh may be
freed. However, bh->b_page is unlocked and put after that, which may
result in a use-after-free bug. This patch moves the release operation
after unlocking and putting the page.
Signed-off-by: Pan Bian <bianpan2016@163.com>
---
fs/nilfs2/gcinode.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/nilfs2/gcinode.c b/fs/nilfs2/gcinode.c
index aa3c328..a24bb29 100644
--- a/fs/nilfs2/gcinode.c
+++ b/fs/nilfs2/gcinode.c
@@ -73,10 +73,8 @@ int nilfs_gccache_submit_read_data(struct inode *inode, sector_t blkoff,
struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
err = nilfs_dat_translate(nilfs->ns_dat, vbn, &pbn);
- if (unlikely(err)) { /* -EIO, -ENOMEM, -ENOENT */
- brelse(bh);
+ if (unlikely(err)) /* -EIO, -ENOMEM, -ENOENT */
goto failed;
- }
}
lock_buffer(bh);
@@ -102,6 +100,8 @@ int nilfs_gccache_submit_read_data(struct inode *inode, sector_t blkoff,
failed:
unlock_page(bh->b_page);
put_page(bh->b_page);
+ if (unlikely(err))
+ brelse(bh);
return err;
}
--
2.7.4
next reply other threads:[~2018-11-26 3:08 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-26 3:08 Pan Bian [this message]
2018-12-03 9:10 ` [PATCH] nilfs2: fix potential use after free Ryusuke Konishi
2018-12-03 9:14 ` PanBian
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