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auditctl

NAME

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

SYNOPSIS

auditctl [options]

DESCRIPTION

The auditctl program is used to control the behavior, get status, and add or delete rules into the 2.6 kernel's audit system.

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.

-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 flag 0=silent 1=printk 2=panic. This option lets you determine how you want the kernel to handle critical errors. Example conditions where this flag is consulted 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

-l

List all rules 1 per line.

-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 the watch.

-m text

Send a user space message into the audit system. This can only be done by the root user.

-p [r|w|x|a]

Set permissions filter for a file system watch. 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.

-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 preceeded by auditctl (since auditctl is the one executing the file).

-s

Report status

-t

Trim the subtrees after a mount command.

-a list,action

Append rule to the end of list with action. Please note the comma separating the two values. Omitting it will cause errors. 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.

entry

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

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, and pid. All other fields will be treated as non-matching.

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.

-d list,action

Delete rule from list with action. The rule is deleted only if it exactly matches syscall name and field names.

-D

Delete all rules and watches.

-S [Syscall name or number|all]

Any syscall name or number may be used. The word 'all' may also be used. If this 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. Doing so improves performance since fewer rules need to be evaluated.

-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 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

auid

The original ID the user logged in with. Its an abbreviation of audit uid.

b32

for the arch. The same applies to the 64 bit syscall table, you can use

b64.

devmajor

Device Major Number

devminor

Device Minor Number

dir

Full Path of Directory to watch. See "-w". Should only be used on exit list.

egid

Effective Group ID

euid

Effective User ID

exit

Exit value from a syscall

fsgid

Filesystem Group ID

fsuid

Filesystem User ID

gid

Group ID

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 message type number. It should only be used on the exclude filter list.

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. See "-w". Should only be used on exit list.

perm

Permission filter for file operations. See "-p". Should only be used on exit list.

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

Set Group ID

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

Set User ID

uid

User ID

-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. This means that if you put a watch on a directory, you will see what appears to be file events, but it is really just the updating of meta data. You might miss a few events by doing this. If you need to watch all files in a directory, its recommended to place an individual watch on each file. Unlike syscall auditing rules, watches do not impact performance based on the number of rules sent to the kernel.

-W path

Remove a watch for the file system object at path.

EXAMPLES

To see all syscalls made by a specific program:

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

To see files opened by a specific user:

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

To see unsuccessful open call's:

auditctl -a exit,always -S open -F success!=0

FILES

/etc/audit/audit.rules

SEE ALSO

auditd(8).

AUTHOR

Steve Grubb