linux-kernel - [PATCH 4.13 36/53] direct-io: Prevent NULL pointer access in submit_page

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20171016161443.773634261@linuxfoundation.org>
Date:   Mon, 16 Oct 2017 18:16:33 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Andreas Gruenbacher <agruenba@...hat.com>,
        Jan Kara <jack@...e.cz>, Al Viro <viro@...iv.linux.org.uk>
Subject: [PATCH 4.13 36/53] direct-io: Prevent NULL pointer access in submit_page_section

4.13-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Andreas Gruenbacher <agruenba@...hat.com>

commit 899f0429c7d3eed886406cd72182bee3b96aa1f9 upstream.

In the code added to function submit_page_section by commit b1058b981,
sdio->bio can currently be NULL when calling dio_bio_submit.  This then
leads to a NULL pointer access in dio_bio_submit, so check for a NULL
bio in submit_page_section before trying to submit it instead.

Fixes xfstest generic/250 on gfs2.

Signed-off-by: Andreas Gruenbacher <agruenba@...hat.com>
Reviewed-by: Jan Kara <jack@...e.cz>
Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 fs/direct-io.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -838,7 +838,8 @@ out:
 	 */
 	if (sdio->boundary) {
 		ret = dio_send_cur_page(dio, sdio, map_bh);
-		dio_bio_submit(dio, sdio);
+		if (sdio->bio)
+			dio_bio_submit(dio, sdio);
 		put_page(sdio->cur_page);
 		sdio->cur_page = NULL;
 	}