From f47af0af0db5933664c621b8af8067ebbcbe66cd Mon Sep 17 00:00:00 2001 From: Xuan Zhuo Date: Thu, 10 Nov 2022 17:57:39 +0800 Subject: virtio-net: fix for heap-buffer-overflow Run shell script: cat << EOF | valgrind qemu-system-i386 -display none -machine accel=qtest, -m \ 512M -M q35 -nodefaults -device virtio-net,netdev=net0 -netdev \ user,id=net0 -qtest stdio outl 0xcf8 0x80000810 outl 0xcfc 0xc000 outl 0xcf8 0x80000804 outl 0xcfc 0x01 outl 0xc00d 0x0200 outl 0xcf8 0x80000890 outb 0xcfc 0x4 outl 0xcf8 0x80000889 outl 0xcfc 0x1c000000 outl 0xcf8 0x80000893 outw 0xcfc 0x100 EOF Got: ==68666== Invalid read of size 8 ==68666== at 0x688536: virtio_net_queue_enable (virtio-net.c:575) ==68666== by 0x6E31AE: memory_region_write_accessor (memory.c:492) ==68666== by 0x6E098D: access_with_adjusted_size (memory.c:554) ==68666== by 0x6E4DB3: memory_region_dispatch_write (memory.c:1521) ==68666== by 0x6E31AE: memory_region_write_accessor (memory.c:492) ==68666== by 0x6E098D: access_with_adjusted_size (memory.c:554) ==68666== by 0x6E4DB3: memory_region_dispatch_write (memory.c:1521) ==68666== by 0x6EBCD3: flatview_write_continue (physmem.c:2820) ==68666== by 0x6EBFBF: flatview_write (physmem.c:2862) ==68666== by 0x6EF5E7: address_space_write (physmem.c:2958) ==68666== by 0x6DFDEC: cpu_outw (ioport.c:70) ==68666== by 0x6F6DF0: qtest_process_command (qtest.c:480) ==68666== Address 0x29087fe8 is 24 bytes after a block of size 416 in arena "client" That is reported by Alexander Bulekov. https://gitlab.com/qemu-project/qemu/-/issues/1309 Here, the queue_index is the index of the cvq, but in some cases cvq does not have the corresponding NetClientState, so overflow appears. I add a check here, ignore illegal queue_index and cvq queue_index. Note the queue_index is below the VIRTIO_QUEUE_MAX but greater or equal than cvq index could hit this. Other devices are similar. Fixes: 7f863302 ("virtio-net: support queue_enable") Fixes: https://gitlab.com/qemu-project/qemu/-/issues/1309 Reported-by: Alexander Bulekov Signed-off-by: Xuan Zhuo Message-Id: <20221110095739.130393-1-xuanzhuo@linux.alibaba.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/net/virtio-net.c | 18 ++++++++++++++++-- include/hw/virtio/virtio.h | 2 ++ 2 files changed, 18 insertions(+), 2 deletions(-) diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c index 8b32339b76..aba12759d5 100644 --- a/hw/net/virtio-net.c +++ b/hw/net/virtio-net.c @@ -549,7 +549,14 @@ static RxFilterInfo *virtio_net_query_rxfilter(NetClientState *nc) static void virtio_net_queue_reset(VirtIODevice *vdev, uint32_t queue_index) { VirtIONet *n = VIRTIO_NET(vdev); - NetClientState *nc = qemu_get_subqueue(n->nic, vq2q(queue_index)); + NetClientState *nc; + + /* validate queue_index and skip for cvq */ + if (queue_index >= n->max_queue_pairs * 2) { + return; + } + + nc = qemu_get_subqueue(n->nic, vq2q(queue_index)); if (!nc->peer) { return; @@ -566,9 +573,16 @@ static void virtio_net_queue_reset(VirtIODevice *vdev, uint32_t queue_index) static void virtio_net_queue_enable(VirtIODevice *vdev, uint32_t queue_index) { VirtIONet *n = VIRTIO_NET(vdev); - NetClientState *nc = qemu_get_subqueue(n->nic, vq2q(queue_index)); + NetClientState *nc; int r; + /* validate queue_index and skip for cvq */ + if (queue_index >= n->max_queue_pairs * 2) { + return; + } + + nc = qemu_get_subqueue(n->nic, vq2q(queue_index)); + if (!nc->peer || !vdev->vhost_started) { return; } diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h index 141a253a2c..a973811cbf 100644 --- a/include/hw/virtio/virtio.h +++ b/include/hw/virtio/virtio.h @@ -148,7 +148,9 @@ struct VirtioDeviceClass { void (*set_config)(VirtIODevice *vdev, const uint8_t *config); void (*reset)(VirtIODevice *vdev); void (*set_status)(VirtIODevice *vdev, uint8_t val); + /* Device must validate queue_index. */ void (*queue_reset)(VirtIODevice *vdev, uint32_t queue_index); + /* Device must validate queue_index. */ void (*queue_enable)(VirtIODevice *vdev, uint32_t queue_index); /* For transitional devices, this is a bitmap of features * that are only exposed on the legacy interface but not -- cgit v1.2.3