From: Heiko Carstens <heiko.carstens@de.ibm.com>
To: Alexei Starovoitov <ast@plumgrid.com>
Cc: "David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Daniel Borkmann <dborkman@redhat.com>,
netdev@vger.kernel.org
Subject: Re: [PATCH net] net: filter: x86: fix JIT address randomization
Date: Wed, 14 May 2014 09:36:56 +0200 [thread overview]
Message-ID: <20140514073656.GA9848@osiris> (raw)
In-Reply-To: <1400007214-3236-1-git-send-email-ast@plumgrid.com>
On Tue, May 13, 2014 at 11:53:34AM -0700, Alexei Starovoitov wrote:
> bpf_alloc_binary() adds 128 bytes of room to JITed program image
> and rounds it up to the nearest page size. If image size is close
> to page size (like 4000), it is rounded to two pages:
> round_up(4000 + 4 + 128) == 8192
> then 'hole' is computed as 8192 - (4000 + 4) = 4188
> If prandom_u32() % hole selects a number >= 4096, then kernel will crash
> during bpf_jit_free():
[...]
> Fixes: 314beb9bcabfd ("x86: bpf_jit_comp: secure bpf jit against spraying attacks")
> Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
> ---
>
> s390 commit aa2d2c73c21f ("s390/bpf,jit: address randomize and write protect jit code")
> seems to have the same problem
Yes, that's the same bug on s390. Would you mind fixing s390 as well, since I
assume you're going to send a new patch for x86?
Would be good to keep the code quite identical so these issues can be easily
seen across architectures.
prev parent reply other threads:[~2014-05-14 7:37 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-13 18:53 [PATCH net] net: filter: x86: fix JIT address randomization Alexei Starovoitov
2014-05-13 20:23 ` Eric Dumazet
2014-05-13 20:34 ` Alexei Starovoitov
2014-05-13 21:28 ` H. Peter Anvin
2014-05-13 21:38 ` David Miller
2014-05-14 7:36 ` Heiko Carstens [this message]
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