From: Pan Bian <bianpan2016@163.com>
To: Jan Kara <jack@suse.com>
Cc: linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org,
Pan Bian <bianpan2016@163.com>
Subject: [PATCH] ext2: fix potential use after free
Date: Sun, 25 Nov 2018 08:58:02 +0800 [thread overview]
Message-ID: <1543107482-97334-1-git-send-email-bianpan2016@163.com> (raw)
The function ext2_xattr_set calls brelse(bh) to drop the reference count
of bh. After that, bh may be freed. However, following brelse(bh),
it reads bh->b_data via macro HDR(bh). This may result in a
use-after-free bug. This patch moves brelse(bh) after reading field.
Signed-off-by: Pan Bian <bianpan2016@163.com>
---
fs/ext2/xattr.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/ext2/xattr.c b/fs/ext2/xattr.c
index 62d9a659a..dd8f10d 100644
--- a/fs/ext2/xattr.c
+++ b/fs/ext2/xattr.c
@@ -612,9 +612,9 @@ bad_block: ext2_error(sb, "ext2_xattr_set",
}
cleanup:
- brelse(bh);
if (!(bh && header == HDR(bh)))
kfree(header);
+ brelse(bh);
up_write(&EXT2_I(inode)->xattr_sem);
return error;
--
2.7.4
next reply other threads:[~2018-11-25 0:58 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-25 0:58 Pan Bian [this message]
2018-11-27 9:19 ` [PATCH] ext2: fix potential use after free Jan Kara
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1543107482-97334-1-git-send-email-bianpan2016@163.com \
--to=bianpan2016@163.com \
--cc=jack@suse.com \
--cc=linux-ext4@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.