kernel-packages team mailing list archive

[Philipp Kern <pkern@xxxxxxxxxx>]

The following commit landed upstream that at least intends to fix the
bug outlined here, even though it does not enable proper auditing for
x32.

commit a3c54931199565930d6d84f4c3456f6440aefd41
Author: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Date:   Wed May 28 23:09:58 2014 -0400

    auditsc: audit_krule mask accesses need bounds checking
    
    Fixes an easy DoS and possible information disclosure.
    
    This does nothing about the broken state of x32 auditing.
    
    eparis: If the admin has enabled auditd and has specifically loaded
    audit rules.  This bug has been around since before git.  Wow...
    
    Cc: stable@xxxxxxxxxxxxxxx
    Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
    Signed-off-by: Eric Paris <eparis@xxxxxxxxxx>
    Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>

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https://bugs.launchpad.net/bugs/1302605

Title:
  Calls to /libx32/ld-linux-x32.so.2 hang when using auditd

Status in “linux” package in Ubuntu:
  Confirmed
Status in “linux” source package in Trusty:
  New

Bug description:
  I'm running trusty on a bunch of machines, doing frequent dist-
  upgrades.  My hosts have gcc-multilib installed.

  Yesterday, I noticed that initramfs generation was hanging.  Today I
  investigated further and found out that what was hanging were the
  calls to /libx32/ld-linux-x32.so.2.

  This is triggered in initramfs generation because there are at some
  hooks that incorrectly use copy_exec to copy shell scripts into the
  initramfs image.  In a working machine, when ldd encounters a shell
  script, it will first call the 64bit linker and since it fails, it
  will then call the 32bit linker which will also fail.

  However, in a machine affected by this bug, the second call will hang
  forever, preventing new image generation, and package updates in
  general, when this happens as a trigger for update-initramfs.

  Originally I thought this was related to the kernel version, since I
  was unable to reproduce in a freshly installed machine running -22 and
  was reproducing it in a machine running -20, but now I'm also
  reproducing it in a machine running -22, so it must be something else.

  I'm sorry I can't provide the exact cause right now, but I think it's
  worth noting that in some situation there might be a problem, and try
  to find out which those situations are.

  I now have one host running 3.13.0-22-generic, with
  libc6-x32=2.19-0ubuntu3, where doing ldd /usr/bin/ldd hangs, and
  another host, with the exact same kernel and libc6-x32 version where
  doing ldd /usr/bin/ldd produces the expected error message (not a
  dynamic executable).  The main difference is that the first one was
  installed yesterday and the second one was installed today.  Both are
  dist-upgraded to the latest version of everything.

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