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[Qemu-devel] [PATCH v5 21/24] virtio-scsi: fix buffer overrun on invalid
From: |
Michael S. Tsirkin |
Subject: |
[Qemu-devel] [PATCH v5 21/24] virtio-scsi: fix buffer overrun on invalid state load |
Date: |
Thu, 3 Apr 2014 19:52:17 +0300 |
CVE-2013-4542
hw/scsi/scsi-bus.c invokes load_request.
virtio_scsi_load_request does:
qemu_get_buffer(f, (unsigned char *)&req->elem, sizeof(req->elem));
this probably can make elem invalid, for example,
make in_num or out_num huge, then:
virtio_scsi_parse_req(s, vs->cmd_vqs[n], req);
will do:
if (req->elem.out_num > 1) {
qemu_sgl_init_external(req, &req->elem.out_sg[1],
&req->elem.out_addr[1],
req->elem.out_num - 1);
} else {
qemu_sgl_init_external(req, &req->elem.in_sg[1],
&req->elem.in_addr[1],
req->elem.in_num - 1);
}
and this will access out of array bounds.
Note: this adds security checks within assert calls since
SCSIBusInfo's load_request cannot fail.
For now simply disable builds with NDEBUG - there seems
to be little value in supporting these.
Cc: Andreas Färber <address@hidden>
Signed-off-by: Michael S. Tsirkin <address@hidden>
---
hw/scsi/virtio-scsi.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index b0d7517..1752193 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -147,6 +147,15 @@ static void *virtio_scsi_load_request(QEMUFile *f,
SCSIRequest *sreq)
qemu_get_be32s(f, &n);
assert(n < vs->conf.num_queues);
qemu_get_buffer(f, (unsigned char *)&req->elem, sizeof(req->elem));
+ /* TODO: add a way for SCSIBusInfo's load_request to fail,
+ * and fail migration instead of asserting here.
+ * When we do, we might be able to re-enable NDEBUG below.
+ */
+#ifdef NDEBUG
+#error building with NDEBUG is not supported
+#endif
+ assert(req->elem.in_num <= ARRAY_SIZE(req->elem.in_sg));
+ assert(req->elem.out_num <= ARRAY_SIZE(req->elem.out_sg));
virtio_scsi_parse_req(s, vs->cmd_vqs[n], req);
scsi_req_ref(sreq);
--
MST
- Re: [Qemu-devel] [PATCH v5 14/24] openpic: avoid buffer overrun on incoming migration, (continued)
- [Qemu-devel] [PATCH v5 16/24] pxa2xx: avoid buffer overrun on incoming migration, Michael S. Tsirkin, 2014/04/03
- [Qemu-devel] [PATCH v5 15/24] virtio: validate num_sg when mapping, Michael S. Tsirkin, 2014/04/03
- [Qemu-devel] [PATCH v5 17/24] ssi-sd: fix buffer overrun on invalid state load, Michael S. Tsirkin, 2014/04/03
- [Qemu-devel] [PATCH v5 18/24] ssd0323: fix buffer overun on invalid state load, Michael S. Tsirkin, 2014/04/03
- [Qemu-devel] [PATCH v5 19/24] tsc210x: fix buffer overrun on invalid state load, Michael S. Tsirkin, 2014/04/03
- [Qemu-devel] [PATCH v5 21/24] virtio-scsi: fix buffer overrun on invalid state load,
Michael S. Tsirkin <=
- [Qemu-devel] [PATCH v5 20/24] zaurus: fix buffer overrun on invalid state load, Michael S. Tsirkin, 2014/04/03
- [Qemu-devel] [PATCH v5 22/24] vmstate: s/VMSTATE_INT32_LE/VMSTATE_INT32_POSITIVE_LE/, Michael S. Tsirkin, 2014/04/03
- [Qemu-devel] [PATCH v5 06/24] virtio-net: out-of-bounds buffer write on invalid state load, Michael S. Tsirkin, 2014/04/03
- [Qemu-devel] [PATCH v5 23/24] usb: sanity check setup_index+setup_len in post_load, Michael S. Tsirkin, 2014/04/03
- [Qemu-devel] [PATCH v5 24/24] savevm: Ignore minimum_version_id_old if there is no load_state_old, Michael S. Tsirkin, 2014/04/03
- [Qemu-devel] [PATCH v5 07/24] virtio: out-of-bounds buffer write on invalid state load, Michael S. Tsirkin, 2014/04/03
- [Qemu-devel] [PATCH v5 05/24] virtio-net: out-of-bounds buffer write on load, Michael S. Tsirkin, 2014/04/03