APPLIED: [X/B/D][SRU] Fix for CVE-2019-18885

[Kleber Souza]

On 2019-12-10 01:48, Connor Kuehl wrote:
> https://people.canonical.com/~ubuntu-security/cve/2019/CVE-2019-18885.html
> 
> From the link above:
> 
>     "fs/btrfs/volumes.c in the Linux kernel before 5.1 allows a
>     btrfs_verify_dev_extents NULL pointer dereference via a crafted btrfs image
>     because fs_devices->devices is mishandled within find_device, aka
>     CID-09ba3bc9dd15."
> 
> The additional commit, "btrfs: refactor btrfs_find_device() take fs_devices as
> argument" was taken to ease the placement of the commit that is specified by the
> CVE as a fix. This enabled a clean cherry-pick into Disco.
> 
> Cherry picks straight into Disco.
> 
> Minor context adjustments for Bionic.
> 
> Xenial required some hand-holding as certain hunks wouldn't apply to a function
> that perhaps has not been added yet, certain function arguments have not been
> refactored but are accessible by accessing members of the enclosing structure
> that *is* passed.
> 

Applied to xenial/linux, bionic/linux and disco/linux.

Thanks,
Kleber