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[Gavin Guo <gavin.guo@xxxxxxxxxxxxx>]

** Tags removed: verification-needed-trusty
** Tags added: verification-done-trusty

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https://bugs.launchpad.net/bugs/1439441

Title:
  Kernel provides incomplete audit information when an existing
  monitored file is modified

Status in linux package in Ubuntu:
  Fix Released
Status in linux source package in Trusty:
  Fix Committed
Status in linux source package in Utopic:
  Fix Committed
Status in linux source package in Vivid:
  Fix Released

Bug description:
  [Impact]
  The audit system cannot identify the correct path of the monitored file.

  The trusty kernel and utopic kernel both suffer the bug.

  root@node-7:~# echo "lalala" >> /etc/testfile 
  "sudo tail -f /var/log/audit/audit.log" results in the following auditd entry: 
  <14>Jan 15 11:38:24 node-7 audispd: node=node-7 type=SYSCALL msg=audit(1421321904.615:60229): arch=c000003e syscall=2 success=yes exit=3 a0=1dcbd88 a1=441 a2=1b6 a3=7ffff3cc0458 items=3 ppid=49217 pid=49233 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 ses=271 tty=pts13 comm="bash" exe="/bin/bash" key="system_configuration_change" 
  <14>Jan 15 11:38:24 node-7 audispd: node=node-7 type=CWD msg=audit(1421321904.615:60229): cwd="/root" 
  <14>Jan 15 11:38:24 node-7 audispd: node=node-7 type=PATH msg=audit(1421321904.615:60229): item=0 name="/etc/" inode=1572865 dev=08:03 mode=040755 ouid=0 ogid=0 rdev=00:00 nametype=PARENT 
  <14>Jan 15 11:38:24 node-7 audispd: node=node-7 type=PATH msg=audit(1421321904.615:60229): item=1 name=(null) inode=1582123 dev=08:03 mode=0100644 ouid=0 ogid=0 rdev=00:00 nametype=NORMAL 
  <14>Jan 15 11:38:24 node-7 audispd: node=node-7 type=PATH msg=audit(1421321904.615:60229): item=2 name=(null) inode=1582123 dev=08:03 mode=0100644 ouid=0 ogid=0 rdev=00:00 nametype=NORMAL 
  <14>Jan 15 11:38:24 node-7 audispd: node=node-7 type=EOE msg=audit(1421321904.615:60229): 
  the file modified is referenced only by inode : 1582123 

  With non-buggy kernel (e.g. 3.2.0-72-generic) the output is: 
  root@atlas:/tmp# echo "lalal" >> /etc/testfile 
  "sudo tail -f /var/log/audit/audit.log" produces the following output: 
  Jan 15 11:40:36 localhost audispd: node=atlas type=SYSCALL msg=audit(1421322036.194:6825): arch=c000003e syscall=2 success=yes exit=3 a0=24ac028 a1=441 a2=1b6 a3=7fff7ddaefe8 items=1 ppid=18562 pid=18570 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts0 ses=410 comm="bash" exe="/bin/bash" key="system_configuration_change" 
  Jan 15 11:40:36 localhost audispd: node=atlas type=CWD msg=audit(1421322036.194:6825): cwd="/tmp" 
  Jan 15 11:40:36 localhost audispd: node=atlas type=PATH msg=audit(1421322036.194:6825): item=0 name="/etc/testfile" inode=159619 dev=fd:03 mode=0100644 ouid=0 ogid=0 rdev=00:00 
  Jan 15 11:40:36 localhost audispd: node=atlas type=EOE msg=audit(1421322036.194:6825):

  [Fix]
  commit 4a92843601ad0f5067f441d2f0dca55bbe18c076
  Author: Paul Moore <pmoore@xxxxxxxxxx>
  Date:   Mon Dec 22 12:27:39 2014 -0500

      audit: correctly record file names with different path name types
      
      There is a problem with the audit system when multiple audit records
      are created for the same path, each with a different path name type.
      The root cause of the problem is in __audit_inode() when an exact
      match (both the path name and path name type) is not found for a
      path name record; the existing code creates a new path name record,
      but it never sets the path name in this record, leaving it NULL.
      This patch corrects this problem by assigning the path name to these
      newly created records.
      
      There are many ways to reproduce this problem, but one of the
      easiest is the following (assuming auditd is running):
      
        # mkdir /root/tmp/test
        # touch /root/tmp/test/567
        # auditctl -a always,exit -F dir=/root/tmp/test
        # touch /root/tmp/test/567
      
      Afterwards, or while the commands above are running, check the audit
      log and pay special attention to the PATH records.  A faulty kernel
      will display something like the following for the file creation:
      
        type=SYSCALL msg=audit(1416957442.025:93): arch=c000003e syscall=2
          success=yes exit=3 ... comm="touch" exe="/usr/bin/touch"
        type=CWD msg=audit(1416957442.025:93):  cwd="/root/tmp"
        type=PATH msg=audit(1416957442.025:93): item=0 name="test/"
          inode=401409 ... nametype=PARENT
        type=PATH msg=audit(1416957442.025:93): item=1 name=(null)
          inode=393804 ... nametype=NORMAL
        type=PATH msg=audit(1416957442.025:93): item=2 name=(null)
          inode=393804 ... nametype=NORMAL
      
      While a patched kernel will show the following:
      
        type=SYSCALL msg=audit(1416955786.566:89): arch=c000003e syscall=2
          success=yes exit=3 ... comm="touch" exe="/usr/bin/touch"
        type=CWD msg=audit(1416955786.566:89):  cwd="/root/tmp"
        type=PATH msg=audit(1416955786.566:89): item=0 name="test/"
          inode=401409 ... nametype=PARENT
        type=PATH msg=audit(1416955786.566:89): item=1 name="test/567"
          inode=393804 ... nametype=NORMAL
      
      This issue was brought up by a number of people, but special credit
      should go to hujianyang@xxxxxxxxxx for reporting the problem along
      with an explanation of the problem and a patch.  While the original
      patch did have some problems (see the archive link below), it did
      demonstrate the problem and helped kickstart the fix presented here.
      
        * https://lkml.org/lkml/2014/9/5/66
      
      Reported-by: hujianyang <hujianyang@xxxxxxxxxx>
      Signed-off-by: Paul Moore <pmoore@xxxxxxxxxx>
      Acked-by: Richard Guy Briggs <rgb@xxxxxxxxxx>

  $ git describe --contains 4a92843601ad0f5067f441d2f0dca55bbe18c076
  v3.19-rc2~7^2~1

  [Test case]
  - Install any one of the kernel from 3.13 ~ 3.19rc2
  - sudo apt-get install -y auditd
  - sudo vim /etc/audit/audit.rules
  -D
  -b 1024
  -w /etc/     -p wa -k system_configuration_change
  -w /usr/bin  -p wa -k system_binary_change
  -w /usr/sbin -p wa -k system_binary_change
  -w /bin/     -p wa -k system_binary_change
  -w /usr/bin/sudo   -F auid!=nova -F uid!=nova -F auid!=neutron -F uid!=neutron -F auid!=cinder -F uid!=cinder -F auid!=zabbix -F uid!=zabbix  -p x -k privilege_escalation
  -w /bin/su           -p x -k privilege_escalation
  -w /bin/mount -p x -k filesystem_modification
  -w /bin/umount -p x -k filesystem_modification
  -w /bin/chown -p x -k filesystem_modification
  -w /bin/chgrp -p x -k filesystem_modification
  -w /bin/chmod -p x -k filesystem_modification
  -w /var/log -p wra -F auid>10000 -F auid!=4294967295 -k system_logs_access
  -a always,exit -F auid>10000 -F auid!=4294967295 -F arch=b64 -S clock_settime -k time-change_syscall
  -a always,exit -F auid>10000 -F auid!=4294967295 -F arch=b32 -S clock_settime -k time-change_syscall
  -a always,exit -F auid>10000 -F auid!=4294967295 -F arch=b64 -S chroot -S mount -S umount2 -k filesystem_modification_syscall
  -a always,exit -F auid>10000 -F auid!=4294967295 -F arch=b32 -S chroot -S mount -S umount2 -k filesystem_modification_syscall
  -a always,exit -F auid>10000 -F auid!=4294967295 -F arch=b64 -S kill -S tkill -S tgkill -k process_termination_syscall
  -a always,exit -F auid>10000 -F auid!=4294967295 -F arch=b32 -S kill -S tkill -S tgkill -k process_termination_syscall
  -a always,exit -F auid>10000 -F auid!=4294967295 -F arch=b64 -S sethostname -S setdomainname -k system-locale
  -a always,exit -F auid>10000 -F auid!=4294967295 -F arch=b32 -S sethostname -S setdomainname -k system-locale
  -a exit,always -F auid>10000 -F auid!=4294967295 -F arch=b64 -S execve -k audit_trail
  -a exit,always -F auid>10000 -F auid!=4294967295 -F arch=b32 -S execve -k audit_trail

  - sudo vim /etc/audit/auditd.conf
  log_format = RAW
  priority_boost = 3
  disp_qos = lossless
  dispatcher = /sbin/audispd
  name_format = hostname
  space_left = 75
  space_left_action = SYSLOG
  action_mail_acct = root
  admin_space_left = 50
  admin_space_left_action = SYSLOG
  disk_full_action = SYSLOG
  disk_error_action = SYSLOG

  - sudo su
  - # echo "lalala" >>  /etc/testfile
  - Open another console: $ sudo tail -f /var/log/audit/audit.log

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