linux-kernel - [PATCH 3.16.y-ckt 073/118] sg_start_req(): make sure that there's not too many elements in iovec

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: <1439369820-27005-74-git-send-email-luis.henriques@canonical.com>
Date:	Wed, 12 Aug 2015 09:56:15 +0100
From:	Luis Henriques <luis.henriques@...onical.com>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	kernel-team@...ts.ubuntu.com
Cc:	Al Viro <viro@...iv.linux.org.uk>,
	Ben Hutchings <ben@...adent.org.uk>,
	Luis Henriques <luis.henriques@...onical.com>
Subject: [PATCH 3.16.y-ckt 073/118] sg_start_req(): make sure that there's not too many elements in iovec

3.16.7-ckt16 -stable review patch.  If anyone has any objections, please let me know.

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

From: Al Viro <viro@...iv.linux.org.uk>

commit 451a2886b6bf90e2fb378f7c46c655450fb96e81 upstream.

unfortunately, allowing an arbitrary 16bit value means a possibility of
overflow in the calculation of total number of pages in bio_map_user_iov() -
we rely on there being no more than PAGE_SIZE members of sum in the
first loop there.  If that sum wraps around, we end up allocating
too small array of pointers to pages and it's easy to overflow it in
the second loop.

X-Coverup: TINC (and there's no lumber cartel either)
Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
[bwh: s/MAX_UIOVEC/UIO_MAXIOV/. This was fixed upstream by commit
 fdc81f45e9f5 ("sg_start_req(): use import_iovec()"), but we don't have
 that function.]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
Signed-off-by: Luis Henriques <luis.henriques@...onical.com>
---
 drivers/scsi/sg.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 791460b798f4..2aa95c89b5bf 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -1693,6 +1693,9 @@ static int sg_start_req(Sg_request *srp, unsigned char *cmd)
 			md->from_user = 0;
 	}
 
+	if (unlikely(iov_count > UIO_MAXIOV))
+		return -EINVAL;
+
 	if (iov_count) {
 		int len, size = sizeof(struct sg_iovec) * iov_count;
 		struct iovec *iov;
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/