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[Bug 1717714] Re: @{pid} variable broken on systems with pid_max more than 6 digits

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** Description changed:

  [Impact]
  
  If PID is larger than 6 digits.
  
  apparmor denies process.
  
  this fix is committed, but not released. so all supporting version are
  affected.
  
  [Test Case]
  
  1. making pid over 6 digits
- - i used touch command to do it
- 2. snap install canonical-livepatch ( just picked this pkg )
+ #!/bin/bash
  
- you can see denied msg as original description
+ for i in {1..1000000}
+ do
+   touch t
+ done
+ 
+ 2. snap install --dangerous core_16-2.29.4.2_amd64.snap ( snap core
+ 16-2.30 avoids using /proc/PID/cmdline, so need to use older version
+ 
+ 3. you can see DENIED msgs in syslog
+ 
+ 4. change /etc/apparmor.d/tunables/kernelvars
+ 5. service apparmor restart
+ 6. service snapd restart
+ 7. DENIED is gone
+ 
+ This is one way, can't reproduce this issue again even if you change
+ back to original kernelvars, and restart snapd
  
  [Regression]
  this fix changes regex only, i don't think there is severe regression. also if there is regression, we can revert manually temporarily.
  denied services need to be restarted after fixing this.
  
  [Others]
  
  * Upstream commit:
   https://gitlab.com/apparmor/apparmor/commit/630cb2a981cdc731847e8fdaafc45bcd337fe747
  
  * commit 630cb2a981cdc731847e8fdaafc45bcd337fe747
  Author: Vincas Dargis <vindrg@xxxxxxxxx>
  Date:   Sat Sep 30 15:28:15 2017 +0300
  
      Allow seven digit pid
  
  * Affecting releases : TXZAB
  --------------------------------------------------------------------------
  $ git describe --contains 630cb2a9
  v2.11.95~5^2
  
  $ rmadison apparmor
   apparmor | 2.8.95~2430-0ubuntu5       | trusty
   apparmor | 2.10.95-0ubuntu2.6~14.04.1 | trusty-security
   apparmor | 2.10.95-0ubuntu2.6~14.04.1 | trusty-updates
   apparmor | 2.10.95-0ubuntu2           | xenial
   apparmor | 2.10.95-0ubuntu2.6         | xenial-security
   apparmor | 2.10.95-0ubuntu2.7         | xenial-updates
   apparmor | 2.11.0-2ubuntu4            | zesty
   apparmor | 2.11.0-2ubuntu17           | artful
   apparmor | 2.11.0-2ubuntu18           | bionic
  
  $ rmadison -u debian apparmor
   apparmor   | 2.11.1-4         | unstable
  --------------------------------------------------------------------------
  
  * Revision :
  http://bazaar.launchpad.net/~apparmor-dev/apparmor/master/revision/3722
  
  [Original Description]
  
  If your kernel.pid_max sysctl is set higher than the default, say at 7
  digits, the @{pid} variable no longer matches all pids, causing some
  breakage in any profile using it.
  
  @{pid} is defined in /etc/apparmor.d/tunables:
  @{pid}={[1-9],[1-9][0-9],[1-9][0-9][0-9],[1-9][0-9][0-9][0-9],[1-9][0-9][0-9][0-9][0-9],[1-9][0-9][0-9][0-9][0-9][0-9]}
  
  It only covers up to 6 digits.
  
  This Ubuntu 17.04 system has:
  kernel.pid_max = 4194303
  
  And is showing
  type=1400 audit(1505588857.828:792): apparmor="DENIED" operation="open" profile="libvirt-55e9e12c-e6dc-4f56-a547-8514cf7d9bf3" name="/proc/2168180/task/2769256/comm" pid=2168180 comm="qemu-system-x86" requested_mask="wr" denied_mask="wr" fsuid=111 ouid=111
  
  Which should be matched by
  @{PROC}/sys/vm/overcommit_memory r,
  in /etc/apparmor.d/abstractions/libvirt-qemu
  
  I'm seeing similar failures on 16.04 (2.10.95-0ubuntu2.7), 17.04
  (2.11.0-2ubuntu4) and 17.10 (2.11.0-2ubuntu17)
  
  I am aware this is a non-default configuration, but I think this should
  work.

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https://bugs.launchpad.net/bugs/1717714

Title:
  @{pid} variable broken on systems with pid_max more than 6 digits

Status in AppArmor:
  Fix Committed
Status in AppArmor 2.11 series:
  Fix Committed
Status in apparmor package in Ubuntu:
  Confirmed
Status in apparmor source package in Trusty:
  New
Status in apparmor source package in Xenial:
  New
Status in apparmor source package in Zesty:
  New
Status in apparmor source package in Artful:
  New
Status in apparmor source package in Bionic:
  Confirmed

Bug description:
  [Impact]

  If PID is larger than 6 digits.

  apparmor denies process.

  this fix is committed, but not released. so all supporting version are
  affected.

  [Test Case]

  1. making pid over 6 digits
  #!/bin/bash

  for i in {1..1000000}
  do
    touch t
  done

  2. snap install --dangerous core_16-2.29.4.2_amd64.snap ( snap core
  16-2.30 avoids using /proc/PID/cmdline, so need to use older version

  3. you can see DENIED msgs in syslog

  4. change /etc/apparmor.d/tunables/kernelvars
  5. service apparmor restart
  6. service snapd restart
  7. DENIED is gone

  This is one way, can't reproduce this issue again even if you change
  back to original kernelvars, and restart snapd

  [Regression]
  this fix changes regex only, i don't think there is severe regression. also if there is regression, we can revert manually temporarily.
  denied services need to be restarted after fixing this.

  [Others]

  * Upstream commit:
   https://gitlab.com/apparmor/apparmor/commit/630cb2a981cdc731847e8fdaafc45bcd337fe747

  * commit 630cb2a981cdc731847e8fdaafc45bcd337fe747
  Author: Vincas Dargis <vindrg@xxxxxxxxx>
  Date:   Sat Sep 30 15:28:15 2017 +0300

      Allow seven digit pid

  * Affecting releases : TXZAB
  --------------------------------------------------------------------------
  $ git describe --contains 630cb2a9
  v2.11.95~5^2

  $ rmadison apparmor
   apparmor | 2.8.95~2430-0ubuntu5       | trusty
   apparmor | 2.10.95-0ubuntu2.6~14.04.1 | trusty-security
   apparmor | 2.10.95-0ubuntu2.6~14.04.1 | trusty-updates
   apparmor | 2.10.95-0ubuntu2           | xenial
   apparmor | 2.10.95-0ubuntu2.6         | xenial-security
   apparmor | 2.10.95-0ubuntu2.7         | xenial-updates
   apparmor | 2.11.0-2ubuntu4            | zesty
   apparmor | 2.11.0-2ubuntu17           | artful
   apparmor | 2.11.0-2ubuntu18           | bionic

  $ rmadison -u debian apparmor
   apparmor   | 2.11.1-4         | unstable
  --------------------------------------------------------------------------

  * Revision :
  http://bazaar.launchpad.net/~apparmor-dev/apparmor/master/revision/3722

  [Original Description]

  If your kernel.pid_max sysctl is set higher than the default, say at 7
  digits, the @{pid} variable no longer matches all pids, causing some
  breakage in any profile using it.

  @{pid} is defined in /etc/apparmor.d/tunables:
  @{pid}={[1-9],[1-9][0-9],[1-9][0-9][0-9],[1-9][0-9][0-9][0-9],[1-9][0-9][0-9][0-9][0-9],[1-9][0-9][0-9][0-9][0-9][0-9]}

  It only covers up to 6 digits.

  This Ubuntu 17.04 system has:
  kernel.pid_max = 4194303

  And is showing
  type=1400 audit(1505588857.828:792): apparmor="DENIED" operation="open" profile="libvirt-55e9e12c-e6dc-4f56-a547-8514cf7d9bf3" name="/proc/2168180/task/2769256/comm" pid=2168180 comm="qemu-system-x86" requested_mask="wr" denied_mask="wr" fsuid=111 ouid=111

  Which should be matched by
  @{PROC}/sys/vm/overcommit_memory r,
  in /etc/apparmor.d/abstractions/libvirt-qemu

  I'm seeing similar failures on 16.04 (2.10.95-0ubuntu2.7), 17.04
  (2.11.0-2ubuntu4) and 17.10 (2.11.0-2ubuntu17)

  I am aware this is a non-default configuration, but I think this
  should work.

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