Messages in this thread | | | From | Song Liu <> | Date | Fri, 3 Jan 2020 09:47:01 -0800 | Subject | Re: [PATCH bpf] bpf: cgroup: prevent out-of-order release of cgroup bpf |
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On Fri, Dec 27, 2019 at 1:50 PM Roman Gushchin <guro@fb.com> 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 <josef@toxicpanda.com> > Signed-off-by: Roman Gushchin <guro@fb.com> > Cc: Alexei Starovoitov <ast@kernel.org> > Cc: stable@vger.kernel.org
LGTM. Thanks for the fix!
Acked-by: Song Liu <songliubraving@fb.com>
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