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  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:   Fri, 3 Jan 2020 09:47:01 -0800
From:   Song Liu <>
To:     Roman Gushchin <>
Cc:     bpf <>, Alexei Starovoitov <>,
        Daniel Borkmann <>,
        open list <>,
        Kernel Team <>,
        Networking <>,
Subject: Re: [PATCH bpf] bpf: cgroup: prevent out-of-order release of cgroup bpf

On Fri, Dec 27, 2019 at 1:50 PM Roman Gushchin <> wrote:
> Before commit 4bfc0bb2c60e ("bpf: decouple the lifetime of cgroup_bpf
> from cgroup itself") cgroup bpf structures were released with
> corresponding cgroup structures. It guaranteed the hierarchical order
> of destruction: children were always first. It preserved attached
> programs from being released before their propagated copies.
> But with cgroup auto-detachment there are no such guarantees anymore:
> cgroup bpf is released as soon as the cgroup is offline and there are
> no live associated sockets. It means that an attached program can be
> detached and released, while its propagated copy is still living
> in the cgroup subtree. This will obviously lead to an use-after-free
> bug.
> Thanks to Josef Bacik for the debugging and the initial analysis of
> the problem.
> Fixes: 4bfc0bb2c60e ("bpf: decouple the lifetime of cgroup_bpf from cgroup itself")
> Reported-by: Josef Bacik <>
> Signed-off-by: Roman Gushchin <>
> Cc: Alexei Starovoitov <>
> Cc:

LGTM. Thanks for the fix!

Acked-by: Song Liu <>

Powered by blists - more mailing lists