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[Qemu-stable] [PULL 24/58] vmw_pvscsi: check page count while initialisi
From: |
Paolo Bonzini |
Subject: |
[Qemu-stable] [PULL 24/58] vmw_pvscsi: check page count while initialising descriptor rings |
Date: |
Tue, 13 Sep 2016 19:15:55 +0200 |
From: Prasad J Pandit <address@hidden>
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
an arbitrary value, leading to infinite loop or OOB access.
Add check to avoid it.
Reported-by: Tom Victor <address@hidden>
Signed-off-by: Prasad J Pandit <address@hidden>
Message-Id: <address@hidden>
Cc: address@hidden
Signed-off-by: Paolo Bonzini <address@hidden>
---
hw/scsi/vmw_pvscsi.c | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)
diff --git a/hw/scsi/vmw_pvscsi.c b/hw/scsi/vmw_pvscsi.c
index 5116f4a..4245c15 100644
--- a/hw/scsi/vmw_pvscsi.c
+++ b/hw/scsi/vmw_pvscsi.c
@@ -152,7 +152,7 @@ pvscsi_log2(uint32_t input)
return log;
}
-static int
+static void
pvscsi_ring_init_data(PVSCSIRingInfo *m, PVSCSICmdDescSetupRings *ri)
{
int i;
@@ -160,10 +160,6 @@ 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)) {
- return -1;
- }
req_ring_size = ri->reqRingNumPages * PVSCSI_MAX_NUM_REQ_ENTRIES_PER_PAGE;
cmp_ring_size = ri->cmpRingNumPages * PVSCSI_MAX_NUM_CMP_ENTRIES_PER_PAGE;
txr_len_log2 = pvscsi_log2(req_ring_size - 1);
@@ -195,8 +191,6 @@ pvscsi_ring_init_data(PVSCSIRingInfo *m,
PVSCSICmdDescSetupRings *ri)
/* Flush ring state page changes */
smp_wmb();
-
- return 0;
}
static int
@@ -746,7 +740,7 @@ pvscsi_dbg_dump_tx_rings_config(PVSCSICmdDescSetupRings *rc)
trace_pvscsi_tx_rings_num_pages("Confirm Ring", rc->cmpRingNumPages);
for (i = 0; i < rc->cmpRingNumPages; i++) {
- trace_pvscsi_tx_rings_ppn("Confirm Ring", rc->reqRingPPNs[i]);
+ trace_pvscsi_tx_rings_ppn("Confirm Ring", rc->cmpRingPPNs[i]);
}
}
@@ -779,11 +773,16 @@ pvscsi_on_cmd_setup_rings(PVSCSIState *s)
trace_pvscsi_on_cmd_arrived("PVSCSI_CMD_SETUP_RINGS");
- pvscsi_dbg_dump_tx_rings_config(rc);
- if (pvscsi_ring_init_data(&s->rings, rc) < 0) {
+ if (!rc->reqRingNumPages
+ || rc->reqRingNumPages > PVSCSI_SETUP_RINGS_MAX_NUM_PAGES
+ || !rc->cmpRingNumPages
+ || rc->cmpRingNumPages > PVSCSI_SETUP_RINGS_MAX_NUM_PAGES) {
return PVSCSI_COMMAND_PROCESSING_FAILED;
}
+ pvscsi_dbg_dump_tx_rings_config(rc);
+ pvscsi_ring_init_data(&s->rings, rc);
+
s->rings_info_valid = TRUE;
return PVSCSI_COMMAND_PROCESSING_SUCCEEDED;
}
--
1.8.3.1
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