netdev - Re: [PATCH rdma-next v1 2/3] RDMA/mlx5: Handling dct common resource destruction upon firmware failure

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:   Mon, 20 Mar 2023 16:18:14 -0300
From:   Jason Gunthorpe <jgg@...dia.com>
To:     Leon Romanovsky <leon@...nel.org>
Cc:     Patrisious Haddad <phaddad@...dia.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>, linux-rdma@...r.kernel.org,
        netdev@...r.kernel.org, Paolo Abeni <pabeni@...hat.com>,
        Saeed Mahameed <saeedm@...dia.com>
Subject: Re: [PATCH rdma-next v1 2/3] RDMA/mlx5: Handling dct common resource
 destruction upon firmware failure

On Thu, Mar 16, 2023 at 03:39:27PM +0200, Leon Romanovsky wrote:
> From: Patrisious Haddad <phaddad@...dia.com>
> 
> Previously when destroying a DCT, if the firmware function for the
> destruction failed, the common resource would have been destroyed
> either way, since it was destroyed before the firmware object.
> Which leads to kernel warning "refcount_t: underflow" which indicates
> possible use-after-free.
> Which is triggered when we try to destroy the common resource for the
> second time and execute refcount_dec_and_test(&common->refcount).
> 
> So, currently before destroying the common resource we check its
> refcount and continue with the destruction only if it isn't zero.

This seems super sketchy

If the destruction fails why not set the refcount back to 1?

Jason