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Date: Sat, 9 Mar 2024 10:40:54 -0800
From: Jakub Kicinski <kuba@kernel.org>
To: Eric Dumazet <edumazet@google.com>
Cc: syzbot <syzbot+65bb09a7208ce3d4a633@syzkaller.appspotmail.com>, Petr
 Machata <petrm@nvidia.com>, davem@davemloft.net, dsahern@kernel.org,
 linux-kernel@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com,
 syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [net?] kernel BUG in __nla_validate_parse
Message-ID: <20240309104054.5f058be3@kernel.org>
In-Reply-To: <CANn89iKLAOJ+HG_y7M27-tx+9HSLUyDaf_NtrJMjs2bZ52KZbA@mail.gmail.com>
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	<CANn89iKLAOJ+HG_y7M27-tx+9HSLUyDaf_NtrJMjs2bZ52KZbA@mail.gmail.com>
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On Sat, 9 Mar 2024 16:25:18 +0100 Eric Dumazet wrote:
> On Sat, Mar 9, 2024 at 4:13=E2=80=AFPM syzbot
> > ..
> Petr, can you take a look ?
>=20
> Thanks !
>=20
>=20
> commit 2118f9390d83cf942de8b34faf3d35b54f9f4eee
> Author: Petr Machata <petrm@nvidia.com>
> Date:   Wed Mar 6 13:49:15 2024 +0100
>=20
>     net: nexthop: Adjust netlink policy parsing for a new attribute

Yeah

+static const struct nla_policy rtm_nh_policy_del[] =3D {
+       [NHA_ID]                =3D { .type =3D NLA_U32 },
+};

+       err =3D nlmsg_parse(nlh, sizeof(struct nhmsg), tb, NHA_MAX,
+                         rtm_nh_policy_del, extack);

The policy size must be >=3D max_attr (NHA_MAX).