From: Florian Westphal <fw@strlen.de>
To: Paolo Abeni <pabeni@redhat.com>
Cc: netdev@vger.kernel.org, Pablo Neira Ayuso <pablo@netfilter.org>,
Florian Westphal <fw@strlen.de>,
Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>,
Stephen Hemminger <stephen@networkplumber.org>,
netfilter-devel@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: Re: [PATCH net] netfilter: check for out-of-bounds while copying compat entries
Date: Mon, 5 Mar 2018 15:32:35 +0100 [thread overview]
Message-ID: <20180305143235.GK11889@breakpoint.cc> (raw)
In-Reply-To: <334d4b64cf1adb8fe65ae4581d01b9698d5e23b1.1520258376.git.pabeni@redhat.com>
Paolo Abeni <pabeni@redhat.com> wrote:
> Currently, when coping ebt compat entries, no checks are in place
> for the offsets provided by user space, so that syzbot was able to
> trigger the following splat:
> ---
> net/bridge/netfilter/ebtables.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
> index 02c4b409d317..54ceaff701fb 100644
> --- a/net/bridge/netfilter/ebtables.c
> +++ b/net/bridge/netfilter/ebtables.c
> @@ -2114,7 +2114,7 @@ static int size_entry_mwt(struct ebt_entry *entry, const unsigned char *base,
> unsigned int size;
> char *buf = buf_start + offsets[i];
>
> - if (offsets[i] > offsets[j])
> + if (offsets[i] > offsets[j] || offsets[j] > *total)
> return -EINVAL;
I thought i fixed this via b71812168571fa55e44cdd0254471331b9c4c4c6,
and, after looking at it again I still don't see why that doesn't cover
this :-(
next prev parent reply other threads:[~2018-03-05 14:32 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-05 14:07 [PATCH net] netfilter: check for out-of-bounds while copying compat entries Paolo Abeni
2018-03-05 14:32 ` Florian Westphal [this message]
2018-03-05 15:17 ` Paolo Abeni
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