From: David Miller <davem@davemloft.net>
To: daniel@iogearbox.net
Cc: alexei.starovoitov@gmail.com, elena.reshetova@intel.com,
eric.dumazet@gmail.com, netdev@vger.kernel.org
Subject: Re: [PATCH net] bpf: fix branch offset adjustment on backjumps after patching ctx expansion
Date: Wed, 10 Feb 2016 17:02:12 -0500 (EST) [thread overview]
Message-ID: <20160210.170212.1863380328830638787.davem@davemloft.net> (raw)
In-Reply-To: <f0e3ee64ddd8d92894d87b10f2f6e83f9a6cd33e.1454792171.git.daniel@iogearbox.net>
From: Daniel Borkmann <daniel@iogearbox.net>
Date: Wed, 10 Feb 2016 16:47:11 +0100
> When ctx access is used, the kernel often needs to expand/rewrite
> instructions, so after that patching, branch offsets have to be
> adjusted for both forward and backward jumps in the new eBPF program,
> but for backward jumps it fails to account the delta. Meaning, for
> example, if the expansion happens exactly on the insn that sits at
> the jump target, it doesn't fix up the back jump offset.
...
> Fixes: 9bac3d6d548e ("bpf: allow extended BPF programs access skb fields")
> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Applied and queued up for -stable, thanks Daniel.
prev parent reply other threads:[~2016-02-10 22:14 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-10 15:47 [PATCH net] bpf: fix branch offset adjustment on backjumps after patching ctx expansion Daniel Borkmann
2016-02-10 22:02 ` David Miller [this message]
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