From: Florian Westphal <fw@strlen.de>
To: john.p.donnelly@oracle.com
Cc: Florian Westphal <fw@strlen.de>,
netfilter-devel@vger.kernel.org, syzkaller@googlegroups.com,
george.kennedy@oracle.com, vegard.nossum@oracle.com,
bridge@lists.linux-foundation.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org,
Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Subject: Re: [PATCH nf] netfilter: ebtables: reject blobs that don't provide all entry points
Date: Mon, 29 Aug 2022 16:03:20 +0200 [thread overview]
Message-ID: <20220829140320.GB27814@breakpoint.cc> (raw)
In-Reply-To: <93eca5ab-46ee-241a-b01c-a6131b28ba29@oracle.com>
john.p.donnelly@oracle.com <john.p.donnelly@oracle.com> wrote:
> On 8/20/22 12:35 PM, Florian Westphal wrote:
> > For some reason ebtables reject blobs that provide entry points that are
> > not supported by the table.
> >
> > What it should instead reject is the opposite, i.e. rulesets that
> > DO NOT provide an entry point that is supported by the table.
> >
> > t->valid_hooks is the bitmask of hooks (input, forward ...) that will
> > see packets. So, providing an entry point that is not support is
> > harmless (never called/used), but the reverse is NOT, this will cause
> > crash because the ebtables traverser doesn't expect a NULL blob for
> > a location its receiving packets for.
> >
> > Instead of fixing all the individual checks, do what iptables is doing and
> > reject all blobs that doesn't provide the expected hooks.
> >
> > Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> > Reported-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
> > Signed-off-by: Florian Westphal <fw@strlen.de>
>
> Hi,
>
> Could you please add the panic stack mentioned above and syzkaller
> reproducer ID to the commit text ?
I did not see a reproducer ID. What ended up in the tree is this:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7997eff82828304b780dc0a39707e1946d6f1ebf
WARNING: multiple messages have this Message-ID (diff)
From: Florian Westphal <fw@strlen.de>
To: john.p.donnelly@oracle.com
Cc: vegard.nossum@oracle.com, netdev@vger.kernel.org,
bridge@lists.linux-foundation.org,
Florian Westphal <fw@strlen.de>,
linux-kernel@vger.kernel.org, george.kennedy@oracle.com,
syzkaller@googlegroups.com, netfilter-devel@vger.kernel.org,
Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Subject: Re: [Bridge] [PATCH nf] netfilter: ebtables: reject blobs that don't provide all entry points
Date: Mon, 29 Aug 2022 16:03:20 +0200 [thread overview]
Message-ID: <20220829140320.GB27814@breakpoint.cc> (raw)
In-Reply-To: <93eca5ab-46ee-241a-b01c-a6131b28ba29@oracle.com>
john.p.donnelly@oracle.com <john.p.donnelly@oracle.com> wrote:
> On 8/20/22 12:35 PM, Florian Westphal wrote:
> > For some reason ebtables reject blobs that provide entry points that are
> > not supported by the table.
> >
> > What it should instead reject is the opposite, i.e. rulesets that
> > DO NOT provide an entry point that is supported by the table.
> >
> > t->valid_hooks is the bitmask of hooks (input, forward ...) that will
> > see packets. So, providing an entry point that is not support is
> > harmless (never called/used), but the reverse is NOT, this will cause
> > crash because the ebtables traverser doesn't expect a NULL blob for
> > a location its receiving packets for.
> >
> > Instead of fixing all the individual checks, do what iptables is doing and
> > reject all blobs that doesn't provide the expected hooks.
> >
> > Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> > Reported-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
> > Signed-off-by: Florian Westphal <fw@strlen.de>
>
> Hi,
>
> Could you please add the panic stack mentioned above and syzkaller
> reproducer ID to the commit text ?
I did not see a reproducer ID. What ended up in the tree is this:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7997eff82828304b780dc0a39707e1946d6f1ebf
next prev parent reply other threads:[~2022-08-29 14:03 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-20 7:03 [PATCH] netfilter: ebtables: fix a NULL pointer dereference in ebt_do_table() Harshit Mogalapalli
2022-08-20 7:03 ` [Bridge] " Harshit Mogalapalli
2022-08-20 16:26 ` Florian Westphal
2022-08-20 16:26 ` [Bridge] " Florian Westphal
2022-08-20 19:18 ` [External] : " Harshit Mogalapalli
2022-08-20 19:18 ` [Bridge] " Harshit Mogalapalli
2022-08-20 17:35 ` [PATCH nf] netfilter: ebtables: reject blobs that don't provide all entry points Florian Westphal
2022-08-20 17:35 ` [Bridge] " Florian Westphal
2022-08-20 19:20 ` [External] : " Harshit Mogalapalli
2022-08-20 19:20 ` [Bridge] " Harshit Mogalapalli
2022-08-22 10:55 ` John Donnelly
2022-08-29 13:57 ` john.p.donnelly
2022-08-29 13:57 ` [Bridge] " john.p.donnelly
2022-08-29 14:03 ` Florian Westphal [this message]
2022-08-29 14:03 ` Florian Westphal
2022-08-29 14:10 ` john.p.donnelly
2022-08-29 14:10 ` [Bridge] " john.p.donnelly
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