From: Ilya Leoshkevich <iii@linux.ibm.com>
To: Colin King <colin.king@canonical.com>,
Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@kernel.org>,
Michael Holzheu <holzheu@linux.vnet.ibm.com>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
netdev@vger.kernel.org, bpf@vger.kernel.org,
linux-s390@vger.kernel.org
Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] s390/bpf: perform r1 range checking before accessing jit->seen_reg[r1]
Date: Thu, 15 Jul 2021 19:02:01 +0200 [thread overview]
Message-ID: <2fbdf14a9e87d240411a420550cf8f797eac3f8c.camel@linux.ibm.com> (raw)
In-Reply-To: <20210715125712.24690-1-colin.king@canonical.com>
On Thu, 2021-07-15 at 13:57 +0100, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> Currently array jit->seen_reg[r1] is being accessed before the range
> checking of index r1. The range changing on r1 should be performed
> first since it will avoid any potential out-of-range accesses on the
> array seen_reg[] and also it is more optimal to perform checks on
> r1 before fetching data from the array. Fix this by swapping the
> order of the checks before the array access.
>
> Fixes: 054623105728 ("s390/bpf: Add s390x eBPF JIT compiler backend")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
> arch/s390/net/bpf_jit_comp.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/s390/net/bpf_jit_comp.c
> b/arch/s390/net/bpf_jit_comp.c
> index 63cae0476bb4..2ae419f5115a 100644
> --- a/arch/s390/net/bpf_jit_comp.c
> +++ b/arch/s390/net/bpf_jit_comp.c
> @@ -112,7 +112,7 @@ static inline void reg_set_seen(struct bpf_jit
> *jit, u32 b1)
> {
> u32 r1 = reg2hex[b1];
>
> - if (!jit->seen_reg[r1] && r1 >= 6 && r1 <= 15)
> + if (r1 >= 6 && r1 <= 15 && !jit->seen_reg[r1])
> jit->seen_reg[r1] = 1;
> }
>
Looks good to me, thanks!
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>
next prev parent reply other threads:[~2021-07-15 17:02 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-15 12:57 [PATCH] s390/bpf: perform r1 range checking before accessing jit->seen_reg[r1] Colin King
2021-07-15 17:02 ` Ilya Leoshkevich [this message]
2021-07-15 17:50 ` patchwork-bot+netdevbpf
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