Re: [PATCH] unix: avoid use-after-free in ep_remove_wait_queue (w/ Fixes:)

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From	Rainer Weikusat <rweikusat@mobileactivedefense.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH] unix: avoid use-after-free in ep_remove_wait_queue (w/ Fixes:)
Date	Fri, 20 Nov 2015 17:30:02 +0100
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Jason Baron <jbaron@akamai.com> writes:
> On 11/19/2015 06:52 PM, Rainer Weikusat wrote:
>
> [...]
>
>> @@ -1590,21 +1718,35 @@ restart:
>>  			goto out_unlock;
>>  	}
>>  
>> -	if (unix_peer(other) != sk && unix_recvq_full(other)) {
>> -		if (!timeo) {
>> +	if (unlikely(unix_peer(other) != sk && unix_recvq_full(other))) {
>> +		if (timeo) {
>> +			timeo = unix_wait_for_peer(other, timeo);
>> +
>> +			err = sock_intr_errno(timeo);
>> +			if (signal_pending(current))
>> +				goto out_free;
>> +
>> +			goto restart;
>> +		}
>> +
>> +		if (unix_peer(sk) != other ||
>> +		    unix_dgram_peer_wake_me(sk, other)) {
>>  			err = -EAGAIN;
>>  			goto out_unlock;
>>  		}
>
> Hi,
>
> So here we are calling unix_dgram_peer_wake_me() without the sk lock the first time
> through - right?

Yes. And this is obviously wrong. I spend most of the 'evening time'
(some people would call that 'night time') with testing this and didn't
get to read through it again yet. Thank you for pointing this out. I'll
send an updated patch shortly.
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Thread

Re: [PATCH] unix: avoid use-after-free in ep_remove_wait_queue Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2015-11-16 23:20 +0100
  Re: [PATCH] unix: avoid use-after-free in ep_remove_wait_queue (w/ Fixes:) Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2015-11-16 23:30 +0100
    Re: [PATCH] unix: avoid use-after-free in ep_remove_wait_queue (w/  Fixes:) Jason Baron <jbaron@akamai.com> - 2015-11-17 17:20 +0100
    Re: [PATCH] unix: avoid use-after-free in ep_remove_wait_queue (w/  Fixes:) David Miller <davem@davemloft.net> - 2015-11-17 21:20 +0100
      Re: [PATCH] unix: avoid use-after-free in ep_remove_wait_queue (w/ Fixes:) Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2015-11-17 22:40 +0100
        Re: [PATCH] unix: avoid use-after-free in ep_remove_wait_queue (w/ Fixes:) Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2015-11-17 23:20 +0100
          Re: [PATCH] unix: avoid use-after-free in ep_remove_wait_queue (w/ Fixes:) Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2015-11-20 00:50 +0100
        Re: [PATCH] unix: avoid use-after-free in ep_remove_wait_queue (w/ Fixes:) Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2015-11-17 23:50 +0100
      Re: [PATCH] unix: avoid use-after-free in ep_remove_wait_queue (w/ Fixes:) Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2015-11-18 19:20 +0100
        more statistics (was: [PATCH] unix: avoid use-after-free in ep_remove_wait_queue (w/ Fixes:)) Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2015-11-19 00:50 +0100
    Re: [PATCH] unix: avoid use-after-free in ep_remove_wait_queue (w/ Fixes:) Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2015-11-20 01:00 +0100
      Re: [PATCH] unix: avoid use-after-free in ep_remove_wait_queue (w/  Fixes:) Jason Baron <jbaron@akamai.com> - 2015-11-20 17:10 +0100
        Re: [PATCH] unix: avoid use-after-free in ep_remove_wait_queue (w/ Fixes:) Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2015-11-20 17:30 +0100
      Re: [PATCH] unix: avoid use-after-free in ep_remove_wait_queue Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2015-11-20 23:10 +0100
        Re: [PATCH] unix: avoid use-after-free in ep_remove_wait_queue Jason Baron <jbaron@akamai.com> - 2015-11-23 17:30 +0100
        Re: [PATCH] unix: avoid use-after-free in ep_remove_wait_queue David Miller <davem@davemloft.net> - 2015-11-23 18:40 +0100
          Re: [PATCH] unix: avoid use-after-free in ep_remove_wait_queue Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2015-11-23 22:40 +0100
            Re: [PATCH] unix: avoid use-after-free in ep_remove_wait_queue Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2015-11-24 00:10 +0100

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