Provided by: auditd_2.4.5-1ubuntu2_amd64 bug

NAME

       auditctl - a utility to assist controlling the kernel's audit system

SYNOPSIS

       auditctl [options]

DESCRIPTION

       The  auditctl  program  is  used  to  configure kernel options related to auditing, to see
       status of the configuration, and to load discretionary audit rules.

CONFIGURATION OPTIONS

       -b backlog
              Set max number of outstanding audit buffers  allowed  (Kernel  Default=64)  If  all
              buffers are full, the failure flag is consulted by the kernel for action.

       --backlog_wait_time wait_time
              Set  the  time for the kernel to wait (Kernel Default 60*HZ) when the backlog_limit
              is reached before queuing more audit events to be transferred to auditd. The number
              must be greater than or equal to zero and less that 10 times the default value.

       -c     Continue loading rules in spite of an error. This summarizes the results of loading
              the rules. The exit code will not be success if any rule fails to load.

       -D     Delete all rules and watches. This can take a key option (-k), too.

       -e [0..2]
              Set enabled flag. When 0 is  passed,  this  can  be  used  to  temporarily  disable
              auditing.  When  1  is  passed as an argument, it will enable auditing. To lock the
              audit configuration so that it can't be changed, pass a 2 as the argument.  Locking
              the  configuration  is  intended  to  be the last command in audit.rules for anyone
              wishing this feature to be active. Any attempt to change the configuration in  this
              mode will be audited and denied. The configuration can only be changed by rebooting
              the machine.

       -f [0..2]
              Set failure mode 0=silent 1=printk 2=panic. This option lets you determine how  you
              want  the  kernel to handle critical errors. Example conditions where this mode may
              have an effect includes: transmission errors to  userspace  audit  daemon,  backlog
              limit exceeded, out of kernel memory, and rate limit exceeded. The default value is
              1. Secure environments will probably want to set this to 2.

       -h     Help

       -i     Ignore errors when reading rules from a file. This causes auditctl to always return
              a success exit code.

       --loginuid-immutable
              This  option  tells  the  kernel  to make loginuids unchangeable once they are set.
              Changing loginuids requires CAP_AUDIT_CONTROL. So, its not something  that  can  be
              done by unprivileged users. Setting this makes loginuid tamper-proof, but can cause
              some problems in certain kinds of containers.

       -q mount-point,subtree
              If you have an existing directory watch and bind or move mount another  subtree  in
              the  watched subtree, you need to tell the kernel to make the subtree being mounted
              equivalent to the directory being watched. If the subtree is already mounted at the
              time  the  directory  watch  is  issued,  the  subtree  is automatically tagged for
              watching. Please note the comma separating the two values. Omitting it  will  cause
              errors.

       -r rate
              Set  limit  in messages/sec (0=none). If this rate is non-zero and is exceeded, the
              failure flag is consulted by the kernel for action. The default value is 0.

       -R file
              Read rules from a file. The rules must be 1 per line and in the order that they are
              to  be  executed  in. The rule file must be owned by root and not readable by other
              users or it will be rejected. The rule file may have comments embedded by  starting
              the  line  with  a  '#' character. Rules that are read from a file are identical to
              what you would type on a command line except they  are  not  preceded  by  auditctl
              (since auditctl is the one executing the file) and you would not use shell escaping
              since auditctl is reading the file instead of bash.

       -t     Trim the subtrees after a mount command.

STATUS OPTIONS

       -l     List all rules 1 per line. Two more options may be given to this command.  You  can
              give  either  a key option (-k) to list rules that match a key or a (-i) to have a0
              through a3 interpretted to help determine the syscall argument values are correct .

       -m text
              Send a user space message into the audit system. This can only be done if you  have
              CAP_AUDIT_WRITE  capability  (normally the root user has this). The resulting event
              will be the USER type.

       -s     Report the kernel's audit subsystem status. It will tell you the  in-kernel  values
              that  can be set by -e, -f, -r, and -b options. The pid value is the process number
              of the audit daemon. Note that a pid of 0 indicates that the audit  daemon  is  not
              running.  The  lost  entry  will  tell  you  how  many event records that have been
              discarded due to the kernel audit queue overflowing. The backlog  field  tells  how
              many  event  records  are  currently  queued  waiting for auditd to read them. This
              option can be followed by the -i to get a couple fields interpreted.

       -v     Print the version of auditctl.

RULE OPTIONS

       -a [list,action|action,list]
              Append rule to the end of list with action. Please note the  comma  separating  the
              two  values.  Omitting  it will cause errors. The fields may be in either order. It
              could be list,action or action,list. The following describes the valid list names:

              task        Add a rule to the per task list. This rule list is  used  only  at  the
                          time  a  task  is  created  -- when fork() or clone() are called by the
                          parent task. When using this list, you should only use fields that  are
                          known at task creation time, such as the uid, gid, etc.

              exit        Add a rule to the syscall exit list. This list is used upon exit from a
                          system call to determine if an audit event should be created.

              user        Add a rule to the user message filter list. This list is  used  by  the
                          kernel  to filter events originating in user space before relaying them
                          to the audit daemon. It should be noted that the only fields  that  are
                          valid  are:  uid,  auid,  gid,  pid,  subj_user,  subj_role, subj_type,
                          subj_sen, subj_clr, and msgtype. All other fields will  be  treated  as
                          non-matching.  It  should be understood that any event originating from
                          user space from a process that has  CAP_AUDIT_WRITE  will  be  recorded
                          into  the  audit  trail.  This  means that the most likely use for this
                          filter is with rules that have an action of never since nothing has  to
                          be done to allow events to be recorded.

              exclude     Add  a  rule to the event type exclusion filter list. This list is used
                          to filter events that you do not want to see. For example,  if  you  do
                          not  want  to see any avc messages, you would using this list to record
                          that. The message type that you do not wish to see is  given  with  the
                          msgtype field.

       The following describes the valid actions for the rule:

              never       No  audit records will be generated. This can be used to suppress event
                          generation. In general, you want suppressions at the top  of  the  list
                          instead  of the bottom. This is because the event triggers on the first
                          matching rule.

              always      Allocate an audit context, always fill it in at syscall entry time, and
                          always write out a record at syscall exit time.

       -A list,action
              Add rule to the beginning list with action.

       -C [f=f | f!=f]
              Build  an  inter-field  comparison  rule:  field,  operation,  field.  You may pass
              multiple comparisons on a single command line. Each one must start  with  -C.  Each
              inter-field equation is anded with each other as well as equations starting with -F
              to trigger an audit record. There are 2 operators supported - equal, and not equal.
              Valid fields are:

              auid, uid, euid, suid, fsuid, obj_uid; and gid, egid, sgid, fsgid, obj_gid

              The  two groups of uid and gid cannot be mixed. But any comparison within the group
              can be made. The obj_uid/gid fields are collected from the object of the event such
              as a file or directory.

       -d list,action
              Delete  rule  from list with action. The rule is deleted only if it exactly matches
              syscall name(s) and every field name and value.

       -F [n=v | n!=v | n<v | n>v | n<=v | n>=v | n&v | n&=v]
              Build a rule field: name, operation, value. You may have up to 64 fields passed  on
              a  single  command  line. Each one must start with -F. Each field equation is anded
              with each other (as well as equations starting with -C) to trigger an audit record.
              There  are  8 operators supported - equal, not equal, less than, greater than, less
              than or equal, and greater than or equal, bit mask, and bit test respectively.  Bit
              test  will "and" the values and check that they are equal, bit mask just "ands" the
              values. Fields that take a user ID may instead have the user's  name;  the  program
              will  convert  the  name  to user ID. The same is true of group names. Valid fields
              are:

              a0, a1, a2, a3
                          Respectively, the first 4 arguments to  a  syscall.  Note  that  string
                          arguments  are  not  supported.  This is because the kernel is passed a
                          pointer to the string. Triggering on a pointer  address  value  is  not
                          likely  to  work.  So,  when using this, you should only use on numeric
                          values. This is most likely to be  used  on  platforms  that  multiplex
                          socket or IPC operations.

              arch        The CPU architecture of the syscall. The arch can be found doing 'uname
                          -m'. If you do not know the arch of your machine but you  want  to  use
                          the 32 bit syscall table and your machine supports 32 bit, you can also
                          use b32 for the arch. The same applies to the 64 bit syscall table, you
                          can  use  b64.  In this way, you can write rules that are somewhat arch
                          independent because the family type will  be  auto  detected.  However,
                          syscalls  can be arch specific and what is available on x86_64, may not
                          be available on ppc. The arch directive should precede the -S option so
                          that  auditctl knows which internal table to use to look up the syscall
                          numbers.

              auid        The original ID the user logged in with. Its an abbreviation  of  audit
                          uid.  Sometimes  its  referred  to as loginuid. Either the user account
                          text or number may be used.

              devmajor    Device Major Number

              devminor    Device Minor Number

              dir         Full Path of Directory to watch. This will place a recursive  watch  on
                          the  directory and its whole subtree. It can only be used on exit list.
                          See "-w".

              egid        Effective Group ID. May be numeric or the groups name.

              euid        Effective User ID. May be numeric or the user account name.

              exit        Exit value from a syscall. If the exit code is an errno,  you  may  use
                          the text representation, too.

              fsgid       Filesystem Group ID. May be numeric or the groups name.

              fsuid       Filesystem User ID. May be numeric or the user account name.

              filetype    The  target  file's  type.  Can  be  either  file,  dir,  socket, link,
                          character, block, or fifo.

              gid         Group ID. May be numeric or the groups name.

              inode       Inode Number

              key         This is another way of setting a filter key. See discussion  above  for
                          -k option.

              msgtype     This  is  used to match the event's record type. It should only be used
                          on the exclude or user filter lists.

              obj_uid     Object's UID

              obj_gid     Object's GID

              obj_user    Resource's SE Linux User

              obj_role    Resource's SE Linux Role

              obj_type    Resource's SE Linux Type

              obj_lev_low Resource's SE Linux Low Level

              obj_lev_high
                          Resource's SE Linux High Level

              path        Full Path of File to watch. It can only be used on exit list.

              perm        Permission filter for file operations. See "-p". It can only be used on
                          exit list. You can use this without specifying a syscall and the kernel
                          will select the syscalls that satisfy the permissions being requested.

              pers        OS Personality Number

              pid         Process ID

              ppid        Parent's Process ID

              subj_user   Program's SE Linux User

              subj_role   Program's SE Linux Role

              subj_type   Program's SE Linux Type

              subj_sen    Program's SE Linux Sensitivity

              subj_clr    Program's SE Linux Clearance

              sgid        Saved Group ID. See getresgid(2) man page.

              success     If the exit value is >= 0 this is true/yes otherwise its false/no. When
                          writing a rule, use a 1 for true/yes and a 0 for false/no

              suid        Saved User ID. See getresuid(2) man page.

              uid         User ID. May be numeric or the user account name.

       -k key Set  a  filter  key on an audit rule. The filter key is an arbitrary string of text
              that can be up to 31 bytes  long.  It  can  uniquely  identify  the  audit  records
              produced  by  a  rule. Typical use is for when you have several rules that together
              satisfy a security requirement. The key value can be searched on with  ausearch  so
              that  no  matter  which rule triggered the event, you can find its results. The key
              can also be used on delete all (-D) and list rules (-l)  to  select  rules  with  a
              specific  key.  You  may have more than one key on a rule if you want to be able to
              search logged events in multiple ways or if you have an audispd plugin that uses  a
              key to aid its analysis.

       -p [r|w|x|a]
              Describe  the  permission  access  type  that  a file system watch will trigger on.
              r=read, w=write, x=execute, a=attribute  change.  These  permissions  are  not  the
              standard  file  permissions, but rather the kind of syscall that would do this kind
              of thing. The read & write syscalls are omitted from  this  set  since  they  would
              overwhelm the logs. But rather for reads or writes, the open flags are looked at to
              see what permission was requested.

       -S [Syscall name or number|all]
              Any syscall name or number may be used. The word 'all' may also be  used.   If  the
              given  syscall is made by a program, then start an audit record. If a field rule is
              given and no syscall is specified, it will default to all syscalls.  You  may  also
              specify multiple syscalls in the same rule by using multiple -S options in the same
              rule. Doing so improves  performance  since  fewer  rules  need  to  be  evaluated.
              Alternatively,  you may pass a comma separated list of syscall names. If you are on
              a bi-arch system, like x86_64, you should be aware that auditctl simply  takes  the
              text, looks it up for the native arch (in this case b64) and sends that rule to the
              kernel. If there are no additional arch directives, IT WILL APPLY TO BOTH 32  &  64
              BIT  SYSCALLS.  This  can have undesirable effects since there is no guarantee that
              any syscall has the same number on both 32 and 64 bit interfaces. You  will  likely
              want to control this and write 2 rules, one with arch equal to b32 and one with b64
              to make sure the kernel finds the events  that  you  intend.  See  the  arch  field
              discussion for more info.

       -w path
              Insert a watch for the file system object at path. You cannot insert a watch to the
              top level directory. This is prohibited by the kernel. Wildcards are not  supported
              either  and  will  generate a warning. The way that watches work is by tracking the
              inode internally. If you place a watch on a file, its the same as using the -F path
              option  on  a  syscall  rule.  If you place a watch on a directory, its the same as
              using the -F dir option on a syscall rule. The -w form of writing  watches  is  for
              backwards  compatibility and the syscall based form is more expressive. Unlike most
              syscall auditing rules, watches do not impact performance based on  the  number  of
              rules  sent to the kernel. The only valid options when using a watch are the -p and
              -k. If you need to anything fancy like audit a specific user accessing a file, then
              use the syscall auditing form with the path or dir fields. See the EXAMPLES section
              for an example of converting one form to another.

       -W path
              Remove a watch for the file system object at path. The rule must match exactly. See
              -d discussion for more info.

PERFORMANCE TIPS

       Syscall  rules  get  evaluated  for each syscall for every program. If you have 10 syscall
       rules, every program on your system will delay during a syscall  while  the  audit  system
       evaluates  each rule. Too many syscall rules will hurt performance. Try to combine as many
       as you can whenever the filter, action, key, and fields are identical. For example:

       auditctl -a always,exit -S openat -F success=0
       auditctl -a always,exit -S truncate -F success=0

       could be re-written as one rule:

       auditctl -a always,exit -S openat -S truncate -F success=0

       Also, try to use file system auditing wherever practical. This improves  performance.  For
       example,  if you were wanting to capture all failed opens & truncates like above, but were
       only concerned about files in /etc and didn't care about /usr or /sbin,  its  possible  to
       use this rule:

       auditctl -a always,exit -S openat -S truncate -F dir=/etc -F success=0

       This  will  be  higher  performance  since  the kernel will not evaluate it each and every
       syscall. It will be handled by the filesystem auditing code and only checked on filesystem
       related syscalls.

EXAMPLES

       To see all syscalls made by a specific program:

       auditctl -a always,exit -S all -F pid=1005

       To see files opened by a specific user:

       auditctl -a always,exit -S openat -F auid=510

       To see unsuccessful openat calls:

       auditctl -a always,exit -S openat -F success=0

       To watch a file for changes (2 ways to express):

       auditctl -w /etc/shadow -p wa
       auditctl -a always,exit -F path=/etc/shadow -F perm=wa

       To recursively watch a directory for changes (2 ways to express):

       auditctl -w /etc/ -p wa
       auditctl -a always,exit -F dir=/etc/ -F perm=wa

       To see if an admin is accessing other user's files:

       auditctl -a always,exit -F dir=/home/ -F uid=0 -C auid!=obj_uid

FILES

       /etc/audit/audit.rules

SEE ALSO

       audit.rules(7), auditd(8).

AUTHOR

       Steve Grubb