From: Prasad J Pandit <p...@fedoraproject.org> While activating device in vmxnet3_acticate_device(), it does not validate guest supplied configuration values against predefined minimum - maximum limits. This may lead to integer overflow or OOB access issues. Add checks to avoid it.
Fixes: CVE-2021-20203 Buglink: https://bugs.launchpad.net/qemu/+bug/1913873 Reported-by: Gaoning Pan <p...@zju.edu.cn> Signed-off-by: Prasad J Pandit <p...@fedoraproject.org> --- hw/net/vmxnet3.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/hw/net/vmxnet3.c b/hw/net/vmxnet3.c index eff299f629..4a910ca971 100644 --- a/hw/net/vmxnet3.c +++ b/hw/net/vmxnet3.c @@ -1420,6 +1420,7 @@ static void vmxnet3_activate_device(VMXNET3State *s) vmxnet3_setup_rx_filtering(s); /* Cache fields from shared memory */ s->mtu = VMXNET3_READ_DRV_SHARED32(d, s->drv_shmem, devRead.misc.mtu); + assert(VMXNET3_MIN_MTU <= s->mtu && s->mtu < VMXNET3_MAX_MTU); VMW_CFPRN("MTU is %u", s->mtu); s->max_rx_frags = @@ -1473,6 +1474,9 @@ static void vmxnet3_activate_device(VMXNET3State *s) /* Read rings memory locations for TX queues */ pa = VMXNET3_READ_TX_QUEUE_DESCR64(d, qdescr_pa, conf.txRingBasePA); size = VMXNET3_READ_TX_QUEUE_DESCR32(d, qdescr_pa, conf.txRingSize); + if (size > VMXNET3_TX_RING_MAX_SIZE) { + size = VMXNET3_TX_RING_MAX_SIZE; + } vmxnet3_ring_init(d, &s->txq_descr[i].tx_ring, pa, size, sizeof(struct Vmxnet3_TxDesc), false); @@ -1483,6 +1487,9 @@ static void vmxnet3_activate_device(VMXNET3State *s) /* TXC ring */ pa = VMXNET3_READ_TX_QUEUE_DESCR64(d, qdescr_pa, conf.compRingBasePA); size = VMXNET3_READ_TX_QUEUE_DESCR32(d, qdescr_pa, conf.compRingSize); + if (size > VMXNET3_TC_RING_MAX_SIZE) { + size = VMXNET3_TC_RING_MAX_SIZE; + } vmxnet3_ring_init(d, &s->txq_descr[i].comp_ring, pa, size, sizeof(struct Vmxnet3_TxCompDesc), true); VMXNET3_RING_DUMP(VMW_CFPRN, "TXC", i, &s->txq_descr[i].comp_ring); @@ -1524,6 +1531,9 @@ static void vmxnet3_activate_device(VMXNET3State *s) /* RX rings */ pa = VMXNET3_READ_RX_QUEUE_DESCR64(d, qd_pa, conf.rxRingBasePA[j]); size = VMXNET3_READ_RX_QUEUE_DESCR32(d, qd_pa, conf.rxRingSize[j]); + if (size > VMXNET3_RX_RING_MAX_SIZE) { + size = VMXNET3_RX_RING_MAX_SIZE; + } vmxnet3_ring_init(d, &s->rxq_descr[i].rx_ring[j], pa, size, sizeof(struct Vmxnet3_RxDesc), false); VMW_CFPRN("RX queue %d:%d: Base: %" PRIx64 ", Size: %d", @@ -1533,6 +1543,9 @@ static void vmxnet3_activate_device(VMXNET3State *s) /* RXC ring */ pa = VMXNET3_READ_RX_QUEUE_DESCR64(d, qd_pa, conf.compRingBasePA); size = VMXNET3_READ_RX_QUEUE_DESCR32(d, qd_pa, conf.compRingSize); + if (size > VMXNET3_RC_RING_MAX_SIZE) { + size = VMXNET3_RC_RING_MAX_SIZE; + } vmxnet3_ring_init(d, &s->rxq_descr[i].comp_ring, pa, size, sizeof(struct Vmxnet3_RxCompDesc), true); VMW_CFPRN("RXC queue %d: Base: %" PRIx64 ", Size: %d", i, pa, size); -- 2.29.2
