While fuzzing the virtio-net tx vq, I ran into an assertion failure due to iov_copy offsets larger than the total iov size. Though there is a check to cover this, it does not execute when !n->has_vnet_hdr. This patch tries to fix this. The call stack for the assertion failure:
#8 in __assert_fail (libc.so.6+0x300f1) #9 in iov_copy iov.c:266:5 #10 in virtio_net_flush_tx virtio-net.c:2073:23 #11 in virtio_net_tx_bh virtio-net.c:2197:11 #12 in aio_bh_poll async.c:118:13 #13 in aio_dispatch aio-posix.c:460:5 #14 in aio_ctx_dispatch async.c:261:5 #15 in g_main_context_dispatch (libglib-2.0.so.0+0x4df2d) #16 in glib_pollfds_poll main-loop.c:213:9 #17 in os_host_main_loop_wait main-loop.c:236 #18 in main_loop_wait main-loop.c:512 #19 in virtio_net_tx_fuzz virtio-net-fuzz.c:160:3 v2: add details to comment for the change to qemu_sendv_packet_async Alexander Oleinik (2): net: assert that tx packets have nonzero size virtio-net: check that tx packet has positive size hw/net/virtio-net.c | 15 +++++++++------ net/net.c | 9 +++++++++ 2 files changed, 18 insertions(+), 6 deletions(-) -- 2.20.1
