diff options
| author | Prasad J Pandit <pjp@fedoraproject.org> | 2016-08-31 12:19:29 +0530 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2016-09-13 19:08:46 +0200 |
| commit | 7f61f4690dd153be98900a2a508b88989e692753 (patch) | |
| tree | 22d6c3e4fd3a9aa96fddc028633690fd5f196e9b /hw | |
| parent | 48b6206305b8d56524ac2ee347b68e6e0a528559 (diff) | |
vmw_pvscsi: check page count while initialising descriptor rings
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 <vv474172261@gmail.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Message-Id: <1472626169-12989-1-git-send-email-ppandit@redhat.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'hw')
| -rw-r--r-- | hw/scsi/vmw_pvscsi.c | 19 |
1 files changed, 9 insertions, 10 deletions
diff --git a/hw/scsi/vmw_pvscsi.c b/hw/scsi/vmw_pvscsi.c index 5116f4ad68..4245c15101 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; } |