Daniel Borkmann 8da3056c04 packet: tpacket_v3: do not trigger bug() on wrong header status ... Jakub reported that it is fairly easy to trigger the BUG() macro from user space with TPACKET_V3's RX_RING by just giving a wrong header status flag. We already had a similar situation in commit 7f5c3e3a80 (``af_packet: remove BUG statement in tpacket_destruct_skb'') where this was the case in the TX_RING side that could be triggered from user space. So really, don't use BUG() or BUG_ON() unless there's really no way out, and i.e. don't use it for consistency checking when there's user space involved, no excuses, especially not if you're slapping the user with WARN + dump_stack + BUG all at once. The two functions are of concern: prb_retire_current_block() [when block status != TP_STATUS_KERNEL] prb_open_block() [when block_status != TP_STATUS_KERNEL] Calls to prb_open_block() are guarded by ealier checks if block_status is really TP_STATUS_KERNEL (racy!), but the first one BUG() is easily triggable from user space. System behaves still stable after they are removed. Also remove that yoda condition entirely, since it's already guarded. Reported-by: Jakub Zawadzki <darkjames-ws@darkjames.pl> Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2013-05-03 16:10:33 -04:00
..
af_packet.c	packet: tpacket_v3: do not trigger bug() on wrong header status	2013-05-03 16:10:33 -04:00
diag.c	sock_diag: allow to dump bpf filters	2013-04-29 13:21:30 -04:00
internal.h	packet: account statistics only in tpacket_stats_u	2013-04-25 01:29:43 -04:00
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