ACK: [SRU Bionic/Focal/Hirsute/Impish/hwe-5.8/oem-5.10/oem-5.13 0/1] CVE-2021-3759

[Stefan Bader]

On 28.09.21 20:56, Thadeu Lima de Souza Cascardo wrote:
> [Impact]
> IPC objects are unaccounted as memcg limits, breaking them and leading
> to DoS (OOM outside the memory cgroup).
> 
> [Backports]
> The allocation calls have changed from kvmalloc from kmalloc or kmalloc to
> kzalloc. I kept them as they were, just changing the GPF_KERNEL to
> GPF_KERNEL_ACCOUNT as from the original commit.
> 
> [Test case]
> I did a large semget loop. When the process was on a memcg, without the fix,
> processes from outside the cgroup would be killed, whereas, with the fix,
> only processes whithin the cgroup would be OOM-killed.
> 
> [Potential regression]
> IPC requests may be refused when processes are restricted to memory cgroups.
> 
> Vasily Averin (1):
>    memcg: enable accounting of ipc resources
> 
>   ipc/msg.c | 2 +-
>   ipc/sem.c | 9 +++++----
>   ipc/shm.c | 2 +-
>   3 files changed, 7 insertions(+), 6 deletions(-)
> 
Acked-by: Stefan Bader <stefan.bader at canonical.com>

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