ACK: [SRU][B][PULL] btrfs: fixes for multiple CVEs

[Thadeu Lima de Souza Cascardo]

On Thu, Jun 11, 2020 at 07:11:25PM +0200, Andrea Righi wrote:
> [Impact/Description]
> 
> This pull request contains fixes for the following CVEs:
> 
>  CVE-2019-19036
>  CVE-2019-19816
>  CVE-2019-19039
>  CVE-2019-19318
>  CVE-2019-19813
>  CVE-2019-19377
> 
> I am sending a single pull request, because it is important to apply the
> fixes in a precise order: some fixes are relying on the fact that other
> fixes are also applied.
> 
> [Test case]
> 
> Each CVE has its own PoC, usually a btrfs image and a small C program.
> These PoC's have been used to verify the correctness of the fixes.
> 
> [Fixes]
> 
> The biggest chunk of changes is represented by the tree-checker fixes
> that are addressing CVE-2019-19318 specifically, but they are also
> required to apply the other fixes for CVE-2019-19318, CVE-2019-19036,
> CVE-2019-19377 and CVE-2019-19039.
> 
> All fixes are clean cherry picks or backports of upstream commits.
> 
> Backport activity was minimal, mostly small context adjustments. Only
> the following commit required some extra work to include few changes
> from other commits (that seemed to be a better solution rather than
> including too many other dependent commits with lots of conflicts to
> resolve):
> 
>  17632ac6d932f btrfs: extent_io: Move the BUG_ON() in flush_write_bio() one level up
> 
> [Regression potential]
> 
> This change is pretty big and it also includes backported commits, so
> there is a risk of regression.
> 
> However, all the CVE PoC's have been tested with positive results. I
> also stress tested a mounted btrfs filesystem both using fio and iozone
> and I could not break it (even if doing additional stress testing
> activity would not be bad).

[...]

Tested against the known PoCs and stressed. Thanks a lot, Andrea.

Acked-by: Thadeu Lima de Souza Cascardo <cascardo at canonical.com>

Cascardo.