From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Daniel Borkmann <daniel@iogearbox.net>
Cc: ast@fb.com, netdev@vger.kernel.org
Subject: Re: [PATCH bpf] bpf: arsh is not supported in 32 bit alu thus reject it
Date: Wed, 10 Jan 2018 14:57:06 -0800 [thread overview]
Message-ID: <20180110225704.qquylvq7igzqhxb4@ast-mbp> (raw)
In-Reply-To: <20180110190437.2774-1-daniel@iogearbox.net>
On Wed, Jan 10, 2018 at 08:04:37PM +0100, Daniel Borkmann wrote:
> The following snippet was throwing an 'unknown opcode cc' warning
> in BPF interpreter:
>
> 0: (18) r0 = 0x0
> 2: (7b) *(u64 *)(r10 -16) = r0
> 3: (cc) (u32) r0 s>>= (u32) r0
> 4: (95) exit
>
> Although a number of JITs do support BPF_ALU | BPF_ARSH | BPF_{K,X}
> generation, not all of them do and interpreter does neither. We can
> leave existing ones and implement it later in bpf-next for the
> remaining ones, but reject this properly in verifier for the time
> being.
>
> Fixes: 17a5267067f3 ("bpf: verifier (add verifier core)")
> Reported-by: syzbot+93c4904c5c70348a6890@syzkaller.appspotmail.com
> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
ouch. it's been there forever.
Applied, Thank you Daniel.
prev parent reply other threads:[~2018-01-10 22:57 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-10 19:04 [PATCH bpf] bpf: arsh is not supported in 32 bit alu thus reject it Daniel Borkmann
2018-01-10 22:57 ` Alexei Starovoitov [this message]
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