Commit message: vmxnet3: validate queues configuration coming from guest

CVE-2013-4544

Signed-off-by: Dmitry Fleytman <dmitry@daynix.com>
Reported-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-id: 1396604722-11902-3-git-send-email-dmitry@daynix.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
CVE: CVE-2013-4544
CWE: CWE-20
Vulnerability description: hw/net/vmxnet3.c in QEMU 2.0.0-rc0, 1.7.1, and earlier allows local guest users to cause a denial of service or possibly execute arbitrary code via vectors related to (1) RX or (2) TX queue numbers or (3) interrupt indices.  NOTE: some of these details are obtained from third party information.

Project: qemu

 static void vmxnet3_activate_device(VMXNET3State *s)
 {
     int i;
    VMW_CFPRN("MTU is %u", s->mtu);

    s->max_rx_frags =
        VMXNET3_READ_DRV_SHARED16(s->drv_shmem, devRead.misc.maxNumRxSG);

    if (s->max_rx_frags == 0) {
        s->max_rx_frags = 1;
    }

    VMW_CFPRN("Max RX fragments is %u", s->max_rx_frags);

    s->event_int_idx =
        VMXNET3_READ_DRV_SHARED8(s->drv_shmem, devRead.intrConf.eventIntrIdx);
    assert(vmxnet3_verify_intx(s, s->event_int_idx));
    VMW_CFPRN("Events interrupt line is %u", s->event_int_idx);

    s->auto_int_masking =
        VMXNET3_READ_DRV_SHARED8(s->drv_shmem, devRead.intrConf.autoMask);
    VMW_CFPRN("Automatic interrupt masking is %d", (int)s->auto_int_masking);

    s->txq_num =
        VMXNET3_READ_DRV_SHARED8(s->drv_shmem, devRead.misc.numTxQueues);
    s->rxq_num =
        VMXNET3_READ_DRV_SHARED8(s->drv_shmem, devRead.misc.numRxQueues);

    VMW_CFPRN("Number of TX/RX queues %u/%u", s->txq_num, s->rxq_num);
    assert(s->txq_num <= VMXNET3_DEVICE_MAX_TX_QUEUES);

    qdescr_table_pa =
        VMXNET3_READ_DRV_SHARED64(s->drv_shmem, devRead.misc.queueDescPA);
    VMW_CFPRN("TX queues descriptors table is at 0x%" PRIx64, qdescr_table_pa);

    /*
     * Worst-case scenario is a packet that holds all TX rings space so
     * we calculate total size of all TX rings for max TX fragments number
     */
    s->max_tx_frags = 0;

    /* TX queues */
    for (i = 0; i < s->txq_num; i++) {
         VMXNET3_READ_DRV_SHARED8(s->drv_shmem, devRead.misc.numRxQueues);
 
     VMW_CFPRN("Number of TX/RX queues %u/%u", s->txq_num, s->rxq_num);
    vmxnet3_validate_queues(s);
 
     qdescr_table_pa =
         VMXNET3_READ_DRV_SHARED64(s->drv_shmem, devRead.misc.queueDescPA);

        VMW_CFPRN("TX Queue %d interrupt: %d", i, s->txq_descr[i].intr_idx);

        /* Read rings memory locations for TX queues */
        pa = VMXNET3_READ_TX_QUEUE_DESCR64(qdescr_pa, conf.txRingBasePA);
        size = VMXNET3_READ_TX_QUEUE_DESCR32(qdescr_pa, conf.txRingSize);

        vmxnet3_ring_init(&s->txq_descr[i].tx_ring, pa, size,
                          sizeof(struct Vmxnet3_TxDesc), false);
        VMXNET3_RING_DUMP(VMW_CFPRN, "TX", i, &s->txq_descr[i].tx_ring);

        s->max_tx_frags += size;

        /* TXC ring */
        pa = VMXNET3_READ_TX_QUEUE_DESCR64(qdescr_pa, conf.compRingBasePA);
        size = VMXNET3_READ_TX_QUEUE_DESCR32(qdescr_pa, conf.compRingSize);
        vmxnet3_ring_init(&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);

        s->txq_descr[i].tx_stats_pa =
            qdescr_pa + offsetof(struct Vmxnet3_TxQueueDesc, stats);

        memset(&s->txq_descr[i].txq_stats, 0,
               sizeof(s->txq_descr[i].txq_stats));

        /* Fill device-managed parameters for queues */
        VMXNET3_WRITE_TX_QUEUE_DESCR32(qdescr_pa,
                                       ctrl.txThreshold,
                                       VMXNET3_DEF_TX_THRESHOLD);
    }

    /* Preallocate TX packet wrapper */
    VMW_CFPRN("Max TX fragments is %u", s->max_tx_frags);
    vmxnet_tx_pkt_init(&s->tx_pkt, s->max_tx_frags, s->peer_has_vhdr);
    vmxnet_rx_pkt_init(&s->rx_pkt, s->peer_has_vhdr);

    /* Read rings memory locations for RX queues */
    for (i = 0; i < s->rxq_num; i++) {
        int j;
        hwaddr qd_pa =
            qdescr_table_pa + s->txq_num * sizeof(struct Vmxnet3_TxQueueDesc) +
            i * sizeof(struct Vmxnet3_RxQueueDesc);

        /* Read interrupt number for this RX queue */
        s->rxq_descr[i].intr_idx =
            VMXNET3_READ_TX_QUEUE_DESCR8(qd_pa, conf.intrIdx);
        assert(vmxnet3_verify_intx(s, s->rxq_descr[i].intr_idx));

        VMW_CFPRN("RX Queue %d interrupt: %d", i, s->rxq_descr[i].intr_idx);

        /* Read rings memory locations */
        for (j = 0; j < VMXNET3_RX_RINGS_PER_QUEUE; j++) {
            /* RX rings */
            pa = VMXNET3_READ_RX_QUEUE_DESCR64(qd_pa, conf.rxRingBasePA[j]);
            size = VMXNET3_READ_RX_QUEUE_DESCR32(qd_pa, conf.rxRingSize[j]);
            vmxnet3_ring_init(&s->rxq_descr[i].rx_ring[j], pa, size,
                              sizeof(struct Vmxnet3_RxDesc), false);
            VMW_CFPRN("RX queue %d:%d: Base: %" PRIx64 ", Size: %d",
                      i, j, pa, size);
        }

        /* RXC ring */
        pa = VMXNET3_READ_RX_QUEUE_DESCR64(qd_pa, conf.compRingBasePA);
        size = VMXNET3_READ_RX_QUEUE_DESCR32(qd_pa, conf.compRingSize);
        vmxnet3_ring_init(&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);

        s->rxq_descr[i].rx_stats_pa =
            qd_pa + offsetof(struct Vmxnet3_RxQueueDesc, stats);
        memset(&s->rxq_descr[i].rxq_stats, 0,
               sizeof(s->rxq_descr[i].rxq_stats));
    }

    vmxnet3_validate_interrupts(s);

    /* Make sure everything is in place before device activation */
    smp_wmb();

    vmxnet3_reset_mac(s);

    s->device_active = true;
}