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Message-ID: <0b17a2f1-76aa-488f-a94a-b9d07f0459f9@kernel.org>
Date: Sat, 9 Mar 2024 13:56:09 -0700
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Subject: Re: [syzbot] [net?] kernel BUG in __nla_validate_parse
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To: Jakub Kicinski <kuba@kernel.org>, Eric Dumazet <edumazet@google.com>
Cc: syzbot <syzbot+65bb09a7208ce3d4a633@syzkaller.appspotmail.com>,
 Petr Machata <petrm@nvidia.com>, davem@davemloft.net,
 linux-kernel@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com,
 syzkaller-bugs@googlegroups.com
References: <00000000000088981b06133bc07b@google.com>
 <CANn89iKLAOJ+HG_y7M27-tx+9HSLUyDaf_NtrJMjs2bZ52KZbA@mail.gmail.com>
 <20240309104054.5f058be3@kernel.org>
From: David Ahern <dsahern@kernel.org>
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On 3/9/24 11:40 AM, Jakub Kicinski wrote:
> On Sat, 9 Mar 2024 16:25:18 +0100 Eric Dumazet wrote:
>> On Sat, Mar 9, 2024 at 4:13 PM syzbot
>>> ..
>> Petr, can you take a look ?
>>
>> Thanks !
>>
>>
>> commit 2118f9390d83cf942de8b34faf3d35b54f9f4eee
>> Author: Petr Machata <petrm@nvidia.com>
>> Date:   Wed Mar 6 13:49:15 2024 +0100
>>
>>     net: nexthop: Adjust netlink policy parsing for a new attribute
> 
> Yeah
> 
> +static const struct nla_policy rtm_nh_policy_del[] = {
> +       [NHA_ID]                = { .type = NLA_U32 },
> +};
> 
> +       err = nlmsg_parse(nlh, sizeof(struct nhmsg), tb, NHA_MAX,
> +                         rtm_nh_policy_del, extack);
> 
> The policy size must be >= max_attr (NHA_MAX).

ARRAY_SIZE is sufficient for both tb and parse. That is what the rest of
the file uses.