netdev - Re: [PATCH net-next] ipv6: add debug checks in fib6_info

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date: Thu, 7 Dec 2023 10:40:12 -0800
From: Kui-Feng Lee <sinquersw@...il.com>
To: David Ahern <dsahern@...nel.org>, Eric Dumazet <edumazet@...gle.com>
Cc: patchwork-bot+netdevbpf@...nel.org, Kui-Feng Lee <thinker.li@...il.com>,
 davem@...emloft.net, kuba@...nel.org, pabeni@...hat.com,
 netdev@...r.kernel.org, eric.dumazet@...il.com
Subject: Re: [PATCH net-next] ipv6: add debug checks in fib6_info_release()



On 12/7/23 10:36, Kui-Feng Lee wrote:
> 
> 
> On 12/7/23 10:25, David Ahern wrote:
>> On 12/7/23 11:22 AM, Eric Dumazet wrote:
>>> Feel free to amend the patch, but the issue is that we insert a fib
>>> gc_link to a list, then free the fi6 object without removing it first
>>> from the external list.
>>
>> yes, move the insert down:
>>
>> diff --git a/net/ipv6/route.c b/net/ipv6/route.c
>> index b132feae3393..7257ba0e72b7 100644
>> --- a/net/ipv6/route.c
>> +++ b/net/ipv6/route.c
>> @@ -3762,12 +3762,6 @@ static struct fib6_info
>> *ip6_route_info_create(struct fib6_config *cfg,
>>          if (cfg->fc_flags & RTF_ADDRCONF)
>>                  rt->dst_nocount = true;
>>
>> -       if (cfg->fc_flags & RTF_EXPIRES)
>> -               fib6_set_expires_locked(rt, jiffies +
>> -
>> clock_t_to_jiffies(cfg->fc_expires));
>> -       else
>> -               fib6_clean_expires_locked(rt);
>> -
> 
> fib6_set_expires_locked() here actually doesn't insert a fib gc_link
> since rt->fib6_table is not assigned yet.  The gc_link will
> be inserted by fib6_add() being called later.
> 
> 
>>          if (cfg->fc_protocol == RTPROT_UNSPEC)
>>                  cfg->fc_protocol = RTPROT_BOOT;
>>          rt->fib6_protocol = cfg->fc_protocol;
>> @@ -3824,6 +3818,12 @@ static struct fib6_info
>> *ip6_route_info_create(struct fib6_config *cfg,
>>          } else
>>                  rt->fib6_prefsrc.plen = 0;
>>
>> +
>> +       if (cfg->fc_flags & RTF_EXPIRES)
>> +               fib6_set_expires_locked(rt, jiffies +
>> +
>> clock_t_to_jiffies(cfg->fc_expires));
>> +       else
>> +               fib6_clean_expires_locked(rt);
>>          return rt;
>>   out:
>>          fib6_info_release(rt);
> 
> However, this should fix the warning messages.
Just realize this cause inserting the gc_link twice.  fib6_add()
will try to add it again!