Re: [PATCH 4.4 00/24] 4.4.137-stable review

Naresh Kamboju
2018-06-14T08:54:33Z

On 14 June 2018 at 12:04, Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:
> On Wed, Jun 13, 2018 at 10:48:50PM -0300, Rafael Tinoco wrote:
>> On 13 June 2018 at 18:08, Rafael David Tinoco
>> <rafaeldtinoco@kernelpath.com> wrote:
>> > On Wed, Jun 13, 2018 at 6:00 PM, Greg Kroah-Hartman
>> > <gregkh@linuxfoundation.org> wrote:
>> >> On Wed, Jun 13, 2018 at 05:47:49PM -0300, Rafael Tinoco wrote:
>> >>> Results from Linaro’s test farm.
>> >>> Regressions detected.
>> >>>
>> >>> NOTE:
>> >>>
>> >>> 1) LTP vma03 test (cve-2011-2496) broken on v4.4-137-rc1 because of:
>> >>>
>> >>> 6ea1dc96a03a mmap: relax file size limit for regular files
>> >>> bd2f9ce5bacb mmap: introduce sane default mmap limits
>> >>>
>> >>> discussion:
>> >>>
>> >>> https://github.com/linux-test-project/ltp/issues/341
>> >>>
>> >>> mainline commit (v4.13-rc7):
>> >>>
>> >>> 0cc3b0ec23ce Clarify (and fix) MAX_LFS_FILESIZE macros
>> >>>
>> >>> should be backported to 4.4.138-rc2 and fixes the issue.
>> >>
>> >> Really? That commit says it fixes c2a9737f45e2 ("vfs,mm: fix a dead
>> >> loop in truncate_inode_pages_range()") which is not in 4.4.y at all.
>> >>
>> >> Did you test this out?
>> >
>> > Yes, the LTP contains the tests (last comment is the final test for
>> > arm32, right before Jan tests i686).
>> >
>> > Fixing MAX_LFS_FILESIZE fixes the new limit for mmap() brought by
>> > those 2 commits (file_mmap_size_max()).
>> > offset tested by the LTP test is 0xfffffffe000.
>> > file_mmap_size_max gives: 0xFFFFFFFF000 as max value, but only after
>> > the mentioned patch.
>> >
>> > Original intent for this fix was other though.
>>
>> To clarify this a bit further.
>>
>> The LTP CVE test is breaking in the first call to mmap(), even before
>> trying to remap and test the security issue. That start happening in
>> this round because of those mmap() changes and the offset used in the
>> LTP test. Linus changed limit checks and made them to be related to
>> MAX_LFS_FILESIZE. Unfortunately, in 4.4 stable, we were missing the
>> fix for MAX_LFS_FILESIZE (which before commit 0cc3b0ec23ce was less
>> than the REAL 32 bit limit).
>>
>> Commit 0cc3b0ec23ce was made because an user noticed the FS limit not
>> being what it should be. In our case, the 4.4 stable kernel, we are
>> facing this 32 bit lower limit (than the real 32 bit real limit),
>> because of the LTP CVE test, so we need this fix to have the real 32
>> bit limit set for that macro (mmap limits did not use that macro
>> before).
>>
>> I have tested in arm32 and Jan Stancek, who first responded to LTP
>> issue, has tested this in i686 and both worked after that patch was
>> included to v4.4-137-rc1 (my last test was even with 4.4.138-rc1).
>>
>> Hope that helps a bit.
>
> Ok, thanks, it didn't apply cleanly but I've fixed it up now.

On the latest 4.4.138-rc1,
LTP "cve-2011-2496" test still fails on arm32 beagleboard x15 and qemu_arm.

Summary
------------------------------------------------------------------------
kernel: 4.4.138-rc1
git repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git
git branch: linux-4.4.y
git commit: 7d690c56754ef7be647fbcf7bcdceebd59926b3f
git describe: v4.4.137-15-g7d690c56754e
Test details: https://qa-reports.linaro.org/lkft/linux-stable-rc-4.4-oe/build/v4.4.137-15-g7d690c56754e

On the side note,
Kernel selftests version upgrade to 4.17.

- Naresh