ACK/Cmnt: [SRU B/D/E/F/focal:linux-oem-5.6 0/2] cgroup refcount is bogus when cgroup_sk_alloc is disabled

[Stefan Bader]

On 27.07.20 15:28, Thadeu Lima de Souza Cascardo wrote:
> BugLink: https://bugs.launchpad.net/bugs/1886860
> 
> This is a followup from LP: #1886668.
> 
> [Impact]
> When net_prio and net_cls cgroups are used, cgroup refcount is bogus, as it's
> not incremented anymore, but decremented when sockets are closed.
> 
> This might lead to crashes possibly because of use-after-free when packets are
> received as shown in LP #1886668.
> 
> [Test case]
> Ran reproducer from comment #2.
> 
> [Regression potential]
> We could break the use of cgroup bpf. The use of cgroup bpf looks to still be
> working from the reproducer.
> 
> Cong Wang (2):
>   cgroup: fix cgroup_sk_alloc() for sk_clone_lock()
>   cgroup: Fix sock_cgroup_data on big-endian.
> 
>  include/linux/cgroup-defs.h |  8 ++++++--
>  include/linux/cgroup.h      |  4 +++-
>  kernel/cgroup/cgroup.c      | 29 ++++++++++++++++++-----------
>  net/core/sock.c             |  2 +-
>  4 files changed, 28 insertions(+), 15 deletions(-)
> 
When applying, since Eoan is end of life, eoan/linux -> bionic/linux-hwe.

Acked-by: Stefan Bader <stefan.bader at canonical.com>

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