ACK: [SRU Impish,Hirsute,HWE-5.11,OEM-5.10,Focal,Bionic] CVE-2021-4155

[Tim Gardner]

Acked-by: Tim Gardner <tim.gardner at canonical.com>

On 1/20/22 7:31 AM, Thadeu Lima de Souza Cascardo wrote:
> [Impact]
> Unprivileged users may leak filesystem data.
> 
> [Fix]
> Always use XFS_BMAPI_PREALLOC when calling xfs_alloc_file_space.
> Focal and Bionic backports simply did that as xfs_ioc_space has changed since
> then.
> 
> [Test case]
> Doing allocations with XFS_IOC_ALLOCSP ioctl and checking for a leak.
> It was reproduced with unpatched kernels.
> 
> [Potential regression]
> XFS users may regress, specially when using XFS specific ioctls/tools.
> 

-- 
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Tim Gardner
Canonical, Inc