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There are multiple reports showing we have a use-after-free in the timer prb_retire_rx_blk_timer_expired(), where we use struct tpacket_kbdq_core::pkbdq, a pg_vec, after it gets freed by free_pg_vec(). The interesting part is it is not freed via packet_release() but via packet_setsockopt(), which means we are not closing the socket. Looking into the big and fat function packet_set_ring(), this could happen if we satisfy the following conditions: 1. closing == 0, not on packet_release() path 2. req->tp_block_nr == 0, we don't allocate a new pg_vec 3. rx_ring->pg_vec is already set as V3, which means we already called packet_set_ring() wtih req->tp_block_nr > 0 previously 4. req->tp_frame_nr == 0, pass sanity check 5. po->mapped == 0, never called mmap() In this scenario we are clearing the old rx_ring->pg_vec, so we need to free this pg_vec, but we don't stop the timer on this path because of closing==0. The timer has to be stopped as long as we need to free pg_vec, therefore the check on closing!=0 is wrong, we should check pg_vec!=NULL instead. Thanks to liujian for testing different fixes. Reported-by: alexander.levin@verizon.com Reported-by: Dave Jones <davej@codemonkey.org.uk> Reported-by: liujian (CE) <liujian56@huawei.com> Tested-by: liujian (CE) <liujian56@huawei.com> Cc: Ding Tianhong <dingtianhong@huawei.com> Cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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| .. | ||
| af_packet.c | ||
| diag.c | ||
| internal.h | ||
| Kconfig | ||
| Makefile | ||