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| author | Stefan Hajnoczi <stefanha@redhat.com> | 2020-09-17 10:44:54 +0100 |
|---|---|---|
| committer | Stefan Hajnoczi <stefanha@redhat.com> | 2020-09-23 13:41:58 +0100 |
| commit | 7bd04a041addcdef6a03e6498aafaea55ca6e88b (patch) | |
| tree | be7bbcdcab48a8a9b94a1af4be03ca8b33265c9d /include | |
| parent | 9dd6f7c28eaa7d001a526d51c74bbf89d5402b8c (diff) | |
| download | qemu-7bd04a041addcdef6a03e6498aafaea55ca6e88b.zip qemu-7bd04a041addcdef6a03e6498aafaea55ca6e88b.tar.gz qemu-7bd04a041addcdef6a03e6498aafaea55ca6e88b.tar.bz2 | |
virtio-blk: undo destructive iov_discard_*() operations
Fuzzing discovered that virtqueue_unmap_sg() is being called on modified
req->in/out_sg iovecs. This means dma_memory_map() and
dma_memory_unmap() calls do not have matching memory addresses.
Fuzzing discovered that non-RAM addresses trigger a bug:
void address_space_unmap(AddressSpace *as, void *buffer, hwaddr len,
bool is_write, hwaddr access_len)
{
if (buffer != bounce.buffer) {
^^^^^^^^^^^^^^^^^^^^^^^
A modified iov->iov_base is no longer recognized as a bounce buffer and
the wrong branch is taken.
There are more potential bugs: dirty memory is not tracked correctly and
MemoryRegion refcounts can be leaked.
Use the new iov_discard_undo() API to restore elem->in/out_sg before
virtqueue_push() is called.
Fixes: 827805a2492c1bbf1c0712ed18ee069b4ebf3dd6 ("virtio-blk: Convert VirtIOBlockReq.out to structrue")
Reported-by: Alexander Bulekov <alxndr@bu.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Li Qiang <liq3ea@gmail.com>
Buglink: https://bugs.launchpad.net/qemu/+bug/1890360
Message-Id: <20200917094455.822379-3-stefanha@redhat.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/hw/virtio/virtio-blk.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h index 5953cf8..214ab74 100644 --- a/include/hw/virtio/virtio-blk.h +++ b/include/hw/virtio/virtio-blk.h @@ -70,6 +70,8 @@ typedef struct VirtIOBlockReq { int64_t sector_num; VirtIOBlock *dev; VirtQueue *vq; + IOVDiscardUndo inhdr_undo; + IOVDiscardUndo outhdr_undo; struct virtio_blk_inhdr *in; struct virtio_blk_outhdr out; QEMUIOVector qiov; |