netdev - Re: [PATCH net 2/2] net/rds: Fix MR reference counting problem

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]

Message-ID: <96f17f7d-365c-32ec-2efe-a6a5d9d306b7@oracle.com>
Date:   Tue, 7 Apr 2020 12:30:26 -0700
From:   santosh.shilimkar@...cle.com
To:     Ka-Cheong Poon <ka-cheong.poon@...cle.com>, netdev@...r.kernel.org,
        sironhide0null@...il.com
Cc:     davem@...emloft.net, rds-devel@....oracle.com
Subject: Re: [PATCH net 2/2] net/rds: Fix MR reference counting problem

On 4/7/20 9:08 AM, Ka-Cheong Poon wrote:
> In rds_free_mr(), it calls rds_destroy_mr(mr) directly.  But this
> defeats the purpose of reference counting and makes MR free handling
> impossible.  It means that holding a reference does not guarantee that
> it is safe to access some fields.  For example, In
> rds_cmsg_rdma_dest(), it increases the ref count, unlocks and then
> calls mr->r_trans->sync_mr().  But if rds_free_mr() (and
> rds_destroy_mr()) is called in between (there is no lock preventing
> this to happen), r_trans_private is set to NULL, causing a panic.
> Similar issue is in rds_rdma_unuse().
> 
> Reported-by: zerons <sironhide0null@...il.com>
> Signed-off-by: Ka-Cheong Poon <ka-cheong.poon@...cle.com>
> ---
Thanks for getting this out on the list.

Hi zerons,
Can you please review it and see it addresses your concern ?

Regards,
Santosh