-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, msgtype, and executable name. 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. Events can be excluded by process ID,
user ID, group ID, login user ID, message type,
subject context, or executable name. The action is
ignored and uses its default of "never".
filesystem
Add a rule that will be applied to a whole
filesystem. The filesystem must be identified with
a fstype field. Normally this filter is used to
exclude any events for a whole filesystem such as
tracefs or debugfs.
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.
exe
Absolute path to application that while executing
this rule will apply to. It supports = and !=
operators. Note that you can only use this once for
each rule.
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
saddr_fam
Address family number as found in
/usr/include/bits/socket.h. For example, IPv4 would
be 2 and IPv6 would be 10.
sessionid
User's login session 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 auditd 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 do 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.