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scsi: pvscsi: check command descriptor ring buffer size (CVE-2016-4952)

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Vmware Paravirtual SCSI emulation uses command descriptors to
process SCSI commands. These descriptors come with their ring
buffers. A guest could set the ring buffer size to an arbitrary
value leading to OOB access issue. Add check to avoid it.

Reported-by: Li Qiang <liqiang6-s@360.cn>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Cc: qemu-stable@nongnu.org
Message-Id: <1464000485-27041-1-git-send-email-ppandit@redhat.com>
Reviewed-by: Shmulik Ladkani <shmulik.ladkani@ravellosystems.com>
Reviewed-by: Dmitry Fleytman <dmitry@daynix.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Prasad J Pandit 2016-05-23 16:18:05 +05:30 committed by Paolo Bonzini
parent 60b412dd18
commit 3e831b40e0
1 changed files with 20 additions and 4 deletions
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24
hw/scsi/vmw_pvscsi.c
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@ -153,7 +153,7 @@ pvscsi_log2(uint32_t input)
return log; return log;
} }
static void static int
pvscsi_ring_init_data(PVSCSIRingInfo *m, PVSCSICmdDescSetupRings *ri) pvscsi_ring_init_data(PVSCSIRingInfo *m, PVSCSICmdDescSetupRings *ri)
{ {
int i; int i;
@ -161,6 +161,10 @@ pvscsi_ring_init_data(PVSCSIRingInfo *m, PVSCSICmdDescSetupRings *ri)
uint32_t req_ring_size, cmp_ring_size; uint32_t req_ring_size, cmp_ring_size;
m->rs_pa = ri->ringsStatePPN << VMW_PAGE_SHIFT; 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; req_ring_size = ri->reqRingNumPages * PVSCSI_MAX_NUM_REQ_ENTRIES_PER_PAGE;
cmp_ring_size = ri->cmpRingNumPages * PVSCSI_MAX_NUM_CMP_ENTRIES_PER_PAGE; cmp_ring_size = ri->cmpRingNumPages * PVSCSI_MAX_NUM_CMP_ENTRIES_PER_PAGE;
txr_len_log2 = pvscsi_log2(req_ring_size - 1); txr_len_log2 = pvscsi_log2(req_ring_size - 1);
@ -192,15 +196,20 @@ pvscsi_ring_init_data(PVSCSIRingInfo *m, PVSCSICmdDescSetupRings *ri)
/* Flush ring state page changes */ /* Flush ring state page changes */
smp_wmb(); smp_wmb();
return 0;
} }
static void static int
pvscsi_ring_init_msg(PVSCSIRingInfo *m, PVSCSICmdDescSetupMsgRing *ri) pvscsi_ring_init_msg(PVSCSIRingInfo *m, PVSCSICmdDescSetupMsgRing *ri)
{ {
int i; int i;
uint32_t len_log2; uint32_t len_log2;
uint32_t ring_size; uint32_t ring_size;
if (ri->numPages > PVSCSI_SETUP_MSG_RING_MAX_NUM_PAGES) {
return -1;
}
ring_size = ri->numPages * PVSCSI_MAX_NUM_MSG_ENTRIES_PER_PAGE; ring_size = ri->numPages * PVSCSI_MAX_NUM_MSG_ENTRIES_PER_PAGE;
len_log2 = pvscsi_log2(ring_size - 1); len_log2 = pvscsi_log2(ring_size - 1);
@ -220,6 +229,8 @@ pvscsi_ring_init_msg(PVSCSIRingInfo *m, PVSCSICmdDescSetupMsgRing *ri)
/* Flush ring state page changes */ /* Flush ring state page changes */
smp_wmb(); smp_wmb();
return 0;
} }
static void static void
@ -770,7 +781,10 @@ pvscsi_on_cmd_setup_rings(PVSCSIState *s)
trace_pvscsi_on_cmd_arrived("PVSCSI_CMD_SETUP_RINGS"); trace_pvscsi_on_cmd_arrived("PVSCSI_CMD_SETUP_RINGS");
pvscsi_dbg_dump_tx_rings_config(rc); pvscsi_dbg_dump_tx_rings_config(rc);
pvscsi_ring_init_data(&s->rings, rc); if (pvscsi_ring_init_data(&s->rings, rc) < 0) {
return PVSCSI_COMMAND_PROCESSING_FAILED;
}
s->rings_info_valid = TRUE; s->rings_info_valid = TRUE;
return PVSCSI_COMMAND_PROCESSING_SUCCEEDED; return PVSCSI_COMMAND_PROCESSING_SUCCEEDED;
} }
@ -850,7 +864,9 @@ pvscsi_on_cmd_setup_msg_ring(PVSCSIState *s)
} }
if (s->rings_info_valid) { if (s->rings_info_valid) {
pvscsi_ring_init_msg(&s->rings, rc); if (pvscsi_ring_init_msg(&s->rings, rc) < 0) {
return PVSCSI_COMMAND_PROCESSING_FAILED;
}
s->msg_ring_info_valid = TRUE; s->msg_ring_info_valid = TRUE;
} }
return sizeof(PVSCSICmdDescSetupMsgRing) / sizeof(uint32_t); return sizeof(PVSCSICmdDescSetupMsgRing) / sizeof(uint32_t);