linux-kernel - [PATCH v2] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list

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-next>] [day] [month] [year] [list]

Message-Id: <1343218390-24310-1-git-send-email-senwang@linux.vnet.ibm.com>
Date:	Wed, 25 Jul 2012 20:13:10 +0800
From:	Wang Sen <senwang@...ux.vnet.ibm.com>
To:	linux-scsi@...r.kernel.org
Cc:	JBottomley@...allels.com, pbonzini@...hat.com,
	stefanha@...ux.vnet.ibm.com, mc@...ux.vnet.ibm.com,
	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	Wang Sen <senwang@...ux.vnet.ibm.com>
Subject: [PATCH v2] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list

When using the commands below to write some data to a virtio-scsi LUN of the
QEMU guest(32-bit) with 1G physical memory(qemu -m 1024), the qemu will crash.

        # sudo mkfs.ext4 /dev/sdb  (/dev/sdb is the virtio-scsi LUN.)
        # sudo mount /dev/sdb /mnt
        # dd if=/dev/zero of=/mnt/file bs=1M count=1024

In current implementation, sg_set_buf is called to add buffers to sg list which
is put into the virtqueue eventually. But if there are some HighMem pages in
table->sgl you can not get virtual address by sg_virt. So, sg_virt(sg_elem) may
return NULL value. This will cause QEMU exit when virtqueue_map_sg is called
in QEMU because an invalid GPA is passed by virtqueue.

I take Paolo's solution mentioned in last thread to avoid failure on handling 
flag bits.

I have tested the patch on my workstation. QEMU would not crash any more.

Signed-off-by: Wang Sen <senwang@...ux.vnet.ibm.com>
---
 drivers/scsi/virtio_scsi.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index 1b38431..6661610 100644
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -198,7 +198,7 @@ static void virtscsi_map_sgl(struct scatterlist *sg, unsigned int *p_idx,
 	int i;

 	for_each_sg(table->sgl, sg_elem, table->nents, i)
-		sg_set_buf(&sg[idx++], sg_virt(sg_elem), sg_elem->length);
+		sg[idx++] = *sg_elem;

 	*p_idx = idx;
 }
-- 
1.7.9.5

--
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/