Re: [Qemu-devel] [PATCH v4 27/30] vmxnet3: validate interrupt indices coming from guest

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Dmitry Fleytman (dmitry@daynix.com) wrote:
> 
> On Mar 31, 2014, at 18:45 PM, Dr. David Alan Gilbert <dgilbert@redhat.com> wrote:
> 
> > * Michael S. Tsirkin (mst@redhat.com) wrote:
> >> From: Dmitry Fleytman <dmitry@daynix.com>
> >> 
> >> 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>
> >> ---
> >> hw/net/vmxnet3.c | 36 ++++++++++++++++++++++++++++++++++--
> >> 1 file changed, 34 insertions(+), 2 deletions(-)
> >> 
> >> diff --git a/hw/net/vmxnet3.c b/hw/net/vmxnet3.c
> >> index 5be807c..a4b5c11 100644
> >> --- a/hw/net/vmxnet3.c
> >> +++ b/hw/net/vmxnet3.c
> >> @@ -52,6 +52,9 @@
> >> #define VMXNET3_DEVICE_VERSION    0x1
> >> #define VMXNET3_DEVICE_REVISION   0x1
> >> 
> >> +/* Number of interrupt vectors for INTx/MSI */
> >> +#define VMXNET3_MAX_NMSIX_INTRS   (1)
> >> +
> >> /* Macros for rings descriptors access */
> >> #define VMXNET3_READ_TX_QUEUE_DESCR8(dpa, field) \
> >>     (vmw_shmem_ld8(dpa + offsetof(struct Vmxnet3_TxQueueDesc, field)))
> >> @@ -1305,6 +1308,34 @@ static bool vmxnet3_verify_intx(VMXNET3State *s, int intx)
> >>            (pci_get_byte(s->parent_obj.config + PCI_INTERRUPT_PIN) - 1));
> >> }
> >> 
> >> +static void vmxnet3_validate_interrupt_idx(bool is_msix, int idx)
> >> +{
> >> +    int max_ints = is_msix ? VMXNET3_MAX_INTRS : VMXNET3_MAX_NMSIX_INTRS;
> > 
> > Is that ?: the right way around?
> 
> Yes, this is the right way around.
> VMXNET3_MAX_NMSIX_INTRS - NMSIX is for Non-MSIx

Ah, thank you - makes more sense now :-)

Dave
> 
> > 
> >> +    if (idx >= max_ints) {
> >> +        hw_error("Bad interrupt index: %d\n", idx);
> >> +    }
> >> +}
> >> +
> >> +static void vmxnet3_validate_interrupts(VMXNET3State *s)
> >> +{
> >> +    int i;
> >> +
> >> +    VMW_CFPRN("Verifying event interrupt index (%d)", s->event_int_idx);
> >> +    vmxnet3_validate_interrupt_idx(s->msix_used, s->event_int_idx);
> >> +
> >> +    for (i = 0; i < s->txq_num; i++) {
> >> +        int idx = s->txq_descr[i].intr_idx;
> >> +        VMW_CFPRN("Verifying TX queue %d interrupt index (%d)", i, idx);
> >> +        vmxnet3_validate_interrupt_idx(s->msix_used, idx);
> >> +    }
> >> +
> >> +    for (i = 0; i < s->rxq_num; i++) {
> >> +        int idx = s->rxq_descr[i].intr_idx;
> >> +        VMW_CFPRN("Verifying RX queue %d interrupt index (%d)", i, idx);
> >> +        vmxnet3_validate_interrupt_idx(s->msix_used, idx);
> >> +    }
> >> +}
> >> +
> >> static void vmxnet3_activate_device(VMXNET3State *s)
> >> {
> >>     int i;
> >> @@ -1447,6 +1478,8 @@ static void vmxnet3_activate_device(VMXNET3State *s)
> >>                sizeof(s->rxq_descr[i].rxq_stats));
> >>     }
> >> 
> >> +    vmxnet3_validate_interrupts(s);
> >> +
> >>     /* Make sure everything is in place before device activation */
> >>     smp_wmb();
> >> 
> >> @@ -2005,7 +2038,6 @@ vmxnet3_cleanup_msix(VMXNET3State *s)
> >>     }
> >> }
> >> 
> >> -#define VMXNET3_MSI_NUM_VECTORS   (1)
> >> #define VMXNET3_MSI_OFFSET        (0x50)
> >> #define VMXNET3_USE_64BIT         (true)
> >> #define VMXNET3_PER_VECTOR_MASK   (false)
> >> @@ -2016,7 +2048,7 @@ vmxnet3_init_msi(VMXNET3State *s)
> >>     PCIDevice *d = PCI_DEVICE(s);
> >>     int res;
> >> 
> >> -    res = msi_init(d, VMXNET3_MSI_OFFSET, VMXNET3_MSI_NUM_VECTORS,
> >> +    res = msi_init(d, VMXNET3_MSI_OFFSET, VMXNET3_MAX_NMSIX_INTRS,
> >>                    VMXNET3_USE_64BIT, VMXNET3_PER_VECTOR_MASK);
> >>     if (0 > res) {
> >>         VMW_WRPRN("Failed to initialize MSI, error %d", res);
> >> -- 
> >> MST
> >> 
> > --
> > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK