All autopkgtests for the newly accepted linux-aws-5.3 (5.3.0-1032.34~18.04.1) 
for bionic have finished running.
The following regressions have been reported in tests triggered by the package:

zfs-linux/0.7.5-1ubuntu16.9 (arm64, amd64)


Please visit the excuses page listed below and investigate the failures, 
proceeding afterwards as per the StableReleaseUpdates policy regarding 
autopkgtest regressions [1].

https://people.canonical.com/~ubuntu-archive/proposed-
migration/bionic/update_excuses.html#linux-aws-5.3

[1] https://wiki.ubuntu.com/StableReleaseUpdates#Autopkgtest_Regressions

Thank you!

-- 
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux in Ubuntu.
https://bugs.launchpad.net/bugs/1883962

Title:
  apparmor reference leak causes refcount_t overflow with
  af_alg_accept()

Status in linux package in Ubuntu:
  Fix Committed
Status in linux source package in Bionic:
  Fix Committed
Status in linux source package in Eoan:
  Fix Committed
Status in linux source package in Focal:
  Fix Committed
Status in linux source package in Groovy:
  Invalid

Bug description:
  [Impact]

   * Users of the Crypto (user-space) API (i.e., AF_ALG)
     can trigger refcount errors in AppArmor under high
     load (might lead to memory leak or use after free.)

   * There is a reference leak in AppArmor when af_alg_accept()
     calls security_sock_graft() and then security_sk_clone().

   * Both acquire a reference to a label, to assign it to the
     same pointer, but the latter does not release the former's
     acquired reference (before overwriting the pointer value.)

   * This reference leak builds up over time, and under high
     load can eventually overflow/underflow/saturate refcount,
     depending on which value it has when a program hits that.

   * The fix just checks if the pointer has an assigned label,
     then releases its acquired reference.

  [Test Case]

   * See comment #1 for the test-case 'aa-refcnt-af_alg.c'.

   * Exercise that code path indefinitely until it hits
     the refcount_t overflow/underflow/saturate message
     (or not, with the patch.) (see comment #4)

   * It's possible to monitor refcount values with kprobes,
     to confirm whether or not the problem is happening.
     (see comments #2 and #3)

  [Other Info]

   * Patch applied upstream on v5.8-rc1 [1]
   * Applied on Unstable (tag Ubuntu-5.8-5.8.0-0.1)
   * Not required on Groovy (still 5.4; should sync from Unstable)
   * Not required on Eoan (EOL date before SRU cycle release date)
   * Required on Bionic and Focal.

  [1]
  
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=3b646abc5bc6c0df649daea4c2c976bd4d47e4c8

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1883962/+subscriptions

-- 
Mailing list: https://launchpad.net/~kernel-packages
Post to     : kernel-packages@lists.launchpad.net
Unsubscribe : https://launchpad.net/~kernel-packages
More help   : https://help.launchpad.net/ListHelp

Reply via email to