| Message ID | 1396275242-10810-5-git-send-email-mst@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 03/31/14 16:16, Michael S. Tsirkin wrote: > CVE-2013-4148 QEMU 1.0 integer conversion in > virtio_net_load()@hw/net/virtio-net.c > > Deals with loading a corrupted savevm image. > >> n->mac_table.in_use = qemu_get_be32(f); > > in_use is int so it can get negative when assigned 32bit unsigned value. > >> /* MAC_TABLE_ENTRIES may be different from the saved image */ >> if (n->mac_table.in_use <= MAC_TABLE_ENTRIES) { > > passing this check ^^^ > >> qemu_get_buffer(f, n->mac_table.macs, >> n->mac_table.in_use * ETH_ALEN); > > with good in_use value, "n->mac_table.in_use * ETH_ALEN" can get > positive and bigger than mac_table.macs. For example 0x81000000 > satisfies this condition when ETH_ALEN is 6. > > A similar problem exists with is_multi. ("first_multi") > > Fix both by making the value unsigned. > > Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > Edit: "for consistency, change first_multi as well". > > Note: all call sites were audited to confirm that > making them unsigned didn't cause any issues: > it turns out we actually never do math on them, > so it's easy to validate because both values are > always <= MAC_TABLE_ENTRIES. > --- > include/hw/virtio/virtio-net.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/include/hw/virtio/virtio-net.h b/include/hw/virtio/virtio-net.h > index df60f16..4b32440 100644 > --- a/include/hw/virtio/virtio-net.h > +++ b/include/hw/virtio/virtio-net.h > @@ -176,8 +176,8 @@ typedef struct VirtIONet { > uint8_t nobcast; > uint8_t vhost_started; > struct { > - int in_use; > - int first_multi; > + uint32_t in_use; > + uint32_t first_multi; > uint8_t multi_overflow; > uint8_t uni_overflow; > uint8_t *macs; > I ran git grep -EHn '\<(in_use|first_multi)\>' Many hits, hard to audit (esp. because I'm unfamiliar with the code). Several loops with signed int loop variables. I checked cursorily. Reviewed-by: Laszlo Ersek <lersek@redhat.com>
On Mon, Mar 31, 2014 at 07:21:30PM +0200, Laszlo Ersek wrote: > On 03/31/14 16:16, Michael S. Tsirkin wrote: > > CVE-2013-4148 QEMU 1.0 integer conversion in > > virtio_net_load()@hw/net/virtio-net.c > > > > Deals with loading a corrupted savevm image. > > > >> n->mac_table.in_use = qemu_get_be32(f); > > > > in_use is int so it can get negative when assigned 32bit unsigned value. > > > >> /* MAC_TABLE_ENTRIES may be different from the saved image */ > >> if (n->mac_table.in_use <= MAC_TABLE_ENTRIES) { > > > > passing this check ^^^ > > > >> qemu_get_buffer(f, n->mac_table.macs, > >> n->mac_table.in_use * ETH_ALEN); > > > > with good in_use value, "n->mac_table.in_use * ETH_ALEN" can get > > positive and bigger than mac_table.macs. For example 0x81000000 > > satisfies this condition when ETH_ALEN is 6. > > > > A similar problem exists with is_multi. > > ("first_multi") Actually it doesn't even exist: Peter commented on this in v1 and I forgot to fix up the commit log :( I really wanted to fix the commit log to say "make first_multi unsigned for consistency" but forgot. > > > > Fix both by making the value unsigned. > > > > Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com> > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > > Edit: "for consistency, change first_multi as well". > > > > Note: all call sites were audited to confirm that > > making them unsigned didn't cause any issues: > > it turns out we actually never do math on them, > > so it's easy to validate because both values are > > always <= MAC_TABLE_ENTRIES. > > --- > > include/hw/virtio/virtio-net.h | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/include/hw/virtio/virtio-net.h b/include/hw/virtio/virtio-net.h > > index df60f16..4b32440 100644 > > --- a/include/hw/virtio/virtio-net.h > > +++ b/include/hw/virtio/virtio-net.h > > @@ -176,8 +176,8 @@ typedef struct VirtIONet { > > uint8_t nobcast; > > uint8_t vhost_started; > > struct { > > - int in_use; > > - int first_multi; > > + uint32_t in_use; > > + uint32_t first_multi; > > uint8_t multi_overflow; > > uint8_t uni_overflow; > > uint8_t *macs; > > > > I ran > > git grep -EHn '\<(in_use|first_multi)\>' > > Many hits, hard to audit (esp. because I'm unfamiliar with the code). > Several loops with signed int loop variables. I checked cursorily. > > Reviewed-by: Laszlo Ersek <lersek@redhat.com> >
diff --git a/include/hw/virtio/virtio-net.h b/include/hw/virtio/virtio-net.h index df60f16..4b32440 100644 --- a/include/hw/virtio/virtio-net.h +++ b/include/hw/virtio/virtio-net.h @@ -176,8 +176,8 @@ typedef struct VirtIONet { uint8_t nobcast; uint8_t vhost_started; struct { - int in_use; - int first_multi; + uint32_t in_use; + uint32_t first_multi; uint8_t multi_overflow; uint8_t uni_overflow; uint8_t *macs;