Re: [PATCH FINAL] SCTP: fix race between sctp_bind_addr_free() and sctp_bind_addr_conflict()

[David Miller <davem@davemloft.net>]

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 19 May 2011 21:58:21 +0200

> Le jeudi 19 mai 2011 à 21:55 +0200, Jacek Luczak a écrit :
>> During the sctp_close() call, we do not use rcu primitives to
>> destroy the address list attached to the endpoint.  At the same
>> time, we do the removal of addresses from this list before
>> attempting to remove the socket from the port hash
>> 
>> As a result, it is possible for another process to find the socket
>> in the port hash that is in the process of being closed.  It then
>> proceeds to traverse the address list to find the conflict, only
>> to have that address list suddenly disappear without rcu() critical
>> section.
>> 
>> Fix issue by closing address list removal inside RCU critical
>> section.
>> 
>> Race can result in a kernel crash with general protection fault or
>> kernel NULL pointer dereference:
>> 
> 
>> Signed-off-by: Jacek Luczak <luczak.jacek@gmail.com>
>> Acked-by: Vlad Yasevich <vladislav.yasevich@hp.com>
>> CC: Eric Dumazet <eric.dumazet@gmail.com>
>> 
>> ---
>>  net/sctp/bind_addr.c |   10 ++++------
>>  1 files changed, 4 insertions(+), 6 deletions(-)
>> 
> 
> Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com>
> 

Applied and queued up for -stable.