group.of.nepali.translators team mailing list archive

[Thadeu Lima de Souza Cascardo <1881339@xxxxxxxxxxxxxxxxxx>]

Public bug reported:

The following fixes were backported to bionic and xenial to prevent a
potential security issue:

    - Make filldir[64]() verify the directory entry filename is valid
    - filldir[64]: remove WARN_ON_ONCE() for bad directory entries

In that process, they introduced a potential performace impact on
readdir. How much is yet to be measured.

9f79b78ef74436c7507bac6bfb7b8b989263bccb Convert filldir[64]() from __put_user() to unsafe_put_user()
c512c69187197fe08026cb5bbe7b9709f4f89b73 uaccess: implement a proper unsafe_copy_to_user() and switch filldir over to it

The two commits above try to mitigate that performance impact. At least
on x86 with SMAP, that should have some effect. At any other platforms,
at least on bionic and xenial, any improvements should be measured.
Though that is true for x86 with SMAP too.

This bug is opened in order to keep track of that possible performance
improvement we might add in the future as followup for those two
commits.

Cascardo.

** Affects: linux (Ubuntu)
     Importance: Undecided
         Status: Fix Released

** Affects: linux (Ubuntu Xenial)
     Importance: Low
         Status: Triaged

** Affects: linux (Ubuntu Bionic)
     Importance: Low
     Assignee: Thadeu Lima de Souza Cascardo (cascardo)
         Status: In Progress

** Also affects: linux (Ubuntu)
   Importance: Undecided
       Status: New

** No longer affects: kernel-sru-workflow

** Also affects: linux (Ubuntu Bionic)
   Importance: Undecided
       Status: New

** Also affects: linux (Ubuntu Xenial)
   Importance: Undecided
       Status: New

** Changed in: linux (Ubuntu Xenial)
       Status: New => In Progress

** Changed in: linux (Ubuntu Bionic)
       Status: New => In Progress

** Changed in: linux (Ubuntu Xenial)
       Status: In Progress => Triaged

** Changed in: linux (Ubuntu Bionic)
     Assignee: (unassigned) => Thadeu Lima de Souza Cascardo (cascardo)

** Changed in: linux (Ubuntu Bionic)
   Importance: Undecided => Low

** Changed in: linux (Ubuntu Xenial)
   Importance: Undecided => Low

** Changed in: linux (Ubuntu)
       Status: New => Fix Released

-- 
You received this bug notification because you are a member of नेपाली
भाषा समायोजकहरुको समूह, which is subscribed to Xenial.
Matching subscriptions: Ubuntu 16.04 Bugs
https://bugs.launchpad.net/bugs/1881339

Title:
  readdir performance when copying to userspace

Status in linux package in Ubuntu:
  Fix Released
Status in linux source package in Xenial:
  Triaged
Status in linux source package in Bionic:
  In Progress

Bug description:
  The following fixes were backported to bionic and xenial to prevent a
  potential security issue:

      - Make filldir[64]() verify the directory entry filename is valid
      - filldir[64]: remove WARN_ON_ONCE() for bad directory entries

  In that process, they introduced a potential performace impact on
  readdir. How much is yet to be measured.

  9f79b78ef74436c7507bac6bfb7b8b989263bccb Convert filldir[64]() from __put_user() to unsafe_put_user()
  c512c69187197fe08026cb5bbe7b9709f4f89b73 uaccess: implement a proper unsafe_copy_to_user() and switch filldir over to it

  The two commits above try to mitigate that performance impact. At
  least on x86 with SMAP, that should have some effect. At any other
  platforms, at least on bionic and xenial, any improvements should be
  measured. Though that is true for x86 with SMAP too.

  This bug is opened in order to keep track of that possible performance
  improvement we might add in the future as followup for those two
  commits.

  Cascardo.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1881339/+subscriptions