From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38088) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bepQ5-00044U-BC for qemu-devel@nongnu.org; Tue, 30 Aug 2016 16:14:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bepPz-0003RZ-CZ for qemu-devel@nongnu.org; Tue, 30 Aug 2016 16:14:04 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37282) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bepPz-0003RE-7l for qemu-devel@nongnu.org; Tue, 30 Aug 2016 16:13:59 -0400 From: P J P Date: Wed, 31 Aug 2016 01:43:51 +0530 Message-Id: <1472588031-6179-1-git-send-email-ppandit@redhat.com> Subject: [Qemu-devel] [PATCH] scsi: check page count while initialising descriptor rings List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Qemu Developers Cc: Paolo Bonzini , Dmitry Fleytman , Tom Victor , Prasad J Pandit From: Prasad J Pandit Vmware Paravirtual SCSI emulation uses command descriptors to process SCSI commands. These descriptors come with their ring buffers. A guest could set the page count for these rings to be zero, leading to an infinite loop. Add check to avoid it. Reported-by: Tom Victor Signed-off-by: Prasad J Pandit --- hw/scsi/vmw_pvscsi.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/hw/scsi/vmw_pvscsi.c b/hw/scsi/vmw_pvscsi.c index 5116f4a..68c1a00 100644 --- a/hw/scsi/vmw_pvscsi.c +++ b/hw/scsi/vmw_pvscsi.c @@ -160,8 +160,10 @@ pvscsi_ring_init_data(PVSCSIRingInfo *m, PVSCSICmdDescSetupRings *ri) uint32_t req_ring_size, cmp_ring_size; m->rs_pa = ri->ringsStatePPN << VMW_PAGE_SHIFT; - if ((ri->reqRingNumPages > PVSCSI_SETUP_RINGS_MAX_NUM_PAGES) - || (ri->cmpRingNumPages > PVSCSI_SETUP_RINGS_MAX_NUM_PAGES)) { + if (!ri->reqRingNumPages + || ri->reqRingNumPages > PVSCSI_SETUP_RINGS_MAX_NUM_PAGES + || !ri->cmpRingNumPages + || ri->cmpRingNumPages > PVSCSI_SETUP_RINGS_MAX_NUM_PAGES) { return -1; } req_ring_size = ri->reqRingNumPages * PVSCSI_MAX_NUM_REQ_ENTRIES_PER_PAGE; -- 2.5.5