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audit.log

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AUDIT.LOG(5) FreeBSD File Formats Manual AUDIT.LOG(5)

NAME
audit -- Basic Security Module (BSM) File Format

DESCRIPTION
The audit file format is based on Sun's Basic Security Module (BSM) file
format, a token-based record stream to represent system audit data. This
file format is both flexible and extensible, able to describe a broad
range of data types, and easily extended to describe new data types in a
moderately backward and forward compatible way.

BSM token streams typically begin and end with a file token, which pro-
vides time stamp and file name information for the stream; when process-
ing a BSM token stream from a stream as opposed to a single file source,
file tokens may be seen at any point between ordinary records identifying
when particular parts of the stream begin and end. All other tokens will
appear in the context of a complete BSM audit record, which begins with a
header token, and ends with a trailer token, which describe the audit
record. Between these two tokens will appear a variety of data tokens,
such as process information, file path names, IPC object information, MAC
labels, socket information, and so on.

The BSM file format defines specific token orders for each record event
type; however, some variation may occur depending on the operating system
in use, what system options, such as mandatory access control, are
present.

This manual page documents the common token types and their binary for-
mat, and is intended for reference purposes only. It is recommended that
application programmers use the libbsm(3) interface to read and write
tokens, rather than parsing or constructing records by hand.

File Token
The file token is used at the beginning and end of an audit log file to
indicate when the audit log begins and ends. It includes a pathname so
that, if concatenated together, original file boundaries are still
observable, and gaps in the audit log can be identified. A file token
can be created using au_to_file(3).

Field Bytes Description
Token ID 1 byte Token ID
Seconds 4 bytes File time stamp
Microseconds 4 bytes File time stamp
File name lengh 2 bytes File name of audit trail
File pathname N bytes + 1 nul File name of audit trail

Header Token
The header token is used to mark the beginning of a complete audit
record, and includes the length of the total record in bytes, a version
number for the record layout, the event type and subtype, and the time at
which the event occurred. A 32-bit header token can be created using
au_to_header32(3); a 64-bit header token can be created using
au_to_header64(3).

Field Bytes Description
Token ID 1 byte Token ID
Record Byte Count 4 bytes Number of bytes in record
Version Number 2 bytes Record version number
Event Type 2 bytes Event type
Event Modifier 2 bytes Event sub-type
Seconds 4/8 bytes Record time stamp (32/64-bits)
Nanoseconds 4/8 byets Record time stamp (32/64-bits)

Expanded Header Token
The expanded header token is an expanded version of the header token,
with the addition of a machine IPv4 or IPv6 address. A 32-bit extended
header token can be created using au_to_header32_ex(3); a 64-bit extended
header token can be created using au_to_header64_ex(3).

Field Bytes Description
Token ID 1 byte Token ID
Record Byte Count 4 bytes Number of bytes in record
Version Number 2 bytes Record version number
Event Type 2 bytes Event type
Event Modifier 2 bytes Event sub-type
Address Type/Length 1 byte Host address type and length
Machine Address 4/16 bytes IPv4 or IPv6 address
Seconds 4/8 bytes Record time stamp (32/64-bits)
Nanoseconds 4/8 byets Record time stamp (32/64-bits)

Trailer Token
The trailer terminates a BSM audit record, and contains a magic number,
TRAILER_PAD_MAGIC and length that can be used to validate that the record
was read properly. A trailer token can be created using
au_to_trailer(3).

Field Bytes Description
Token ID 1 byte Token ID
Trailer Magic 2 bytes Trailer magic number
Record Byte Count 4 bytes Number of bytes in record

Arbitrary Data Token
The arbitrary data token contains a byte stream of opaque (untyped) data.
The size of the data is calculated as the size of each unit of data mul-
tipled by the number of units of data. A How to print field is present
to specify how to print the data, but interpretation of that field is not
currently defined. An arbitrary data token can be created using
au_to_data(3).

Field Bytes Description
Token ID 1 byte Token ID
How to Print 1 byte User-defined printing
information
Basic Unit 1 byte Size of a unit in bytes
Unit Count 1 byte Number of units of data
present
Data Items Variable User data

in_addr Token
The in_addr token holds a network byte order IPv4 or IPv6 address. An
in_addr token can be created using au_to_in_addr(3) for an IPv4 address,
or au_to_in_addr_ex(3) for an IPv6 address.

See the BUGS section for information on the storage of this token.

Field Bytes Description
Token ID 1 byte Token ID
IP Address Type 1 byte Type of address
IP Address 4/16 bytes IPv4 or IPv6 address

Expanded in_addr Token
The expanded in_addr token ...

See the BUGS section for information on the storage of this token.

Field Bytes Description
Token ID 1 byte Token ID
XXXX

ip Token
The ip token contains an IP packet header in network byte order. An ip
token can be created using au_to_ip(3).

Field Bytes Description
Token ID 1 byte Token ID
Version and IHL 1 byte Version and IP header length
Type of Service 1 byte IP TOS field
Length 2 bytes IP packet length in network
byte order
ID 2 bytes IP header ID for reassembly
Offset 2 bytes IP fragment offset and flags,
network byte
order
TTL 1 byte IP Time-to-Live
Protocol 1 byte IP protocol number
Checksum 2 bytes IP header checksum, network
byte order
Source Address 4 bytes IPv4 source address
Destination Address 4 bytes IPv4 destination address

Expanded ip Token
The expanded ip token ...

Field Bytes Description
Token ID 1 byte Token ID
XXXX

iport Token
The iport token stores an IP port number in network byte order. An iport
token can be created using au_to_iport(3).

Field Bytes Description
Token ID 1 byte Token ID
Port Number 2 bytes Port number in network byte
order

Path Token
The path token contains a pathname. A path token can be created using
au_to_path(3).

Field Bytes Description
Token ID 1 byte Token ID
Path Length 2 bytes Length of path in bytes
Path N bytes + 1 nul Path name

path_attr Token
The path_attr token contains a set of nul-terminated path names. The
libbsm(3) API cannot currently create a path_attr token.

Field Bytes Description
Token ID 1 byte Token ID
Count 2 bytes Number of nul-terminated
string(s) in
token
Path Variable count nul-terminated string(s)

Process Token
The process token contains a description of the security properties of a
process involved as the target of an auditable event, such as the desti-
nation for signal delivery. It should not be confused with the subject
token, which describes the subject performing an auditable event. This
includes both the traditional UNIX security properties, such as user IDs
and group IDs, but also audit information such as the audit user ID and
session. A process token can be created using au_to_process32(3) or
au_to_process64(3).

Field Bytes Description
Token ID 1 byte Token ID
Audit ID 4 bytes Audit user ID
Effective User ID 4 bytes Effective user ID
Effective Group ID 4 bytes Effective group ID
Real User ID 4 bytes Real user ID
Real Group ID 4 bytes Real group ID
Process ID 4 bytes Process ID
Session ID 4 bytes Audit session ID
Terminal Port ID 4/8 bytes Terminal port ID (32/64-bits)
Terminal Machine Address 4 bytes IP address of
machine

Expanded Process Token
The expanded process token contains the contents of the process token,
with the addition of a machine address type and variable length address
storage capable of containing IPv6 addresses. An expanded process token
can be created using au_to_process32_ex(3) or au_to_process64_ex(3).

Field Bytes Description
Token ID 1 byte Token ID
Audit ID 4 bytes Audit user ID
Effective User ID 4 bytes Effective user ID
Effective Group ID 4 bytes Effective group ID
Real User ID 4 bytes Real user ID
Real Group ID 4 bytes Real group ID
Process ID 4 bytes Process ID
Session ID 4 bytes Audit session ID
Terminal Port ID 4/8 bytes Terminal port ID (32/64-bits)
Terminal Address Type/Length 1 byte Length of machine
address
Terminal Machine Address 4 bytes IPv4 or IPv6
address of
machine

Return Token
The return token contains a system call or library function return condi-
tion, including return value and error number associated with the global
variable errno. A return token can be created using au_to_return32(3) or
au_to_return64(3).

Field Bytes Description
Token ID 1 byte Token ID
Error Number 1 byte Errno value, or 0 if undefined
Return Value 4/8 bytes Return value (32/64-bits)

Subject Token
The subject token contains information on the subject performing the
operation described by an audit record, and includes similar information
to that found in the process and expanded process tokens. However, those
tokens are used where the process being described is the target of the
operation, not the authorizing party. A subject token can be created
using au_to_subject32(3) and au_to_subject64(3).

Field Bytes Description
Token ID 1 byte Token ID
Audit ID 4 bytes Audit user ID
Effective User ID 4 bytes Effective user ID
Effective Group ID 4 bytes Effective group ID
Real User ID 4 bytes Real user ID
Real Group ID 4 bytes Real group ID
Process ID 4 bytes Process ID
Session ID 4 bytes Audit session ID
Terminal Port ID 4/8 bytes Terminal port ID (32/64-bits)
Terminal Machine Address 4 bytes IP address of
machine

Expanded Subject Token
The expanded subject token consists of the same elements as the subject
token, with the addition of type/length and variable size machine address
information in the terminal ID. An expanded subject token can be created
using au_to_subject32_ex(3) or au_to_subject64_ex(3).

Field Bytes Description
Token ID 1 byte Token ID
Audit ID 4 bytes Audit user ID
Effective User ID 4 bytes Effective user ID
Effective Group ID 4 bytes Effective group ID
Real User ID 4 bytes Real user ID
Real Group ID 4 bytes Real group ID
Process ID 4 bytes Process ID
Session ID 4 bytes Audit session ID
Terminal Port ID 4/8 bytes Terminal port ID (32/64-bits)
Terminal Address Type/Length 1 byte Length of machine
address
Terminal Machine Address 4 bytes IPv4 or IPv6
address of
machine

System V IPC Token
The System V IPC token ...

Field Bytes Description
Token ID 1 byte Token ID
Object ID type 1 byte Object ID
Object ID 4 bytes Object ID

Text Token
The text token contains a single nul-terminated text string. A text
token may be created using au_to_text(3).

Field Bytes Description
Token ID 1 byte Token ID
Text Length 2 bytes Length of text string
including nul
Text N bytes + 1 nul Text string including nul

Attribute Token
The attribute token describes the attributes of a file associated with
the audit event. As files may be identified by 0, 1, or many path names,
a path name is not included with the attribute block for a file; optional
path tokens may also be present in an audit record indicating which path,
if any, was used to reach the object. An attribute token can be created
using au_to_attr32(3) or au_to_attr64(3).

Field Bytes Description
Token ID 1 byte Token ID
File Access Mode 1 byte mode_t associated with file
Owner User ID 4 bytes uid_t associated with file
Owner Group ID 4 bytes gid_t associated with file
File System ID 4 bytes fsid_t associated with file
File System Node ID 8 bytes ino_t associated with file
Device 4/8 bytes Device major/minor number
(32/64-bit)

Groups Token
The groups token contains a list of group IDs associated with the audit
event. A groups token can be created using au_to_groups(3).

Field Bytes Description
Token ID 1 byte Token ID
Number of Groups 2 bytes Number of groups in token
Group List N * 4 bytes List of N group IDs

System V IPC Permission Token
The System V IPC permission token ...

Field Bytes Description
Token ID 1 byte Token ID
XXXXX

Arg Token
The arg token ...

Field Bytes Description
Token ID 1 byte Token ID
XXXXX

exec_args Token
The exec_args token ...

Field Bytes Description
Token ID 1 byte Token ID
XXXXX

exec_env Token
The exec_env token ...

Field Bytes Description
Token ID 1 byte Token ID
XXXXX

Exit Token
The exit token contains process exit/return code information. An exit
token can be created using au_to_exit(3).

Field Bytes Description
Token ID 1 byte Token ID
Status 4 bytes Process status on exit
Return Value ta 4 bytes Process return value on exit

Socket Token
The socket token ...

Field Bytes Description
Token ID 1 byte Token ID
XXXXX

Expanded Socket Token
The expanded socket token ...

Field Bytes Description
Token ID 1 byte Token ID
XXXXX

Seq Token
The seq token contains a unique and monotonically increasing audit event
sequence ID. Due to the limited range of 32 bits, serial number arith-
metic and caution should be used when comparing sequence numbers.

Field Bytes Description
Token ID 1 byte Token ID
Sequence Number 4 bytes Audit event sequence number

privilege Token
The privilege token ...

Field Bytes Description
Token ID 1 byte Token ID
XXXXX

Use-of-auth Token
The use-of-auth token ...

Field Bytes Description
Token ID 1 byte Token ID
XXXXX

Command Token
The command token ...

Field Bytes Description
Token ID 1 byte Token ID
XXXXX

ACL Token
The ACL token ...

Field Bytes Description
Token ID 1 byte Token ID
XXXXX

Zonename Token
The zonename token ...

Field Bytes Description
Token ID 1 byte Token ID
XXXXX

SEE ALSO
libbsm(3), audit(8)

AUTHORS
The Basic Security Module (BSM) interface to audit records and audit
event stream format were defined by Sun Microsystems.

This manual page was written by Robert Watson <rwatsonATFreeBSD.org>.

HISTORY
The OpenBSM implementation was created by McAfee Research, the security
division of McAfee Inc., under contract to Apple Computer Inc. in 2004.
It was subsequently adopted by the TrustedBSD Project as the foundation
for the OpenBSM distribution.

BUGS
The How to print field in the arbitrary data token has undefined values.

The in_addr and in_addr_ex token layout documented here appears to be in
conflict with the libbsm(3) implementations of au_to_in_addr(3) and
au_to_in_addr_ex(3).

FreeBSD 6.2 May 1, 2005 FreeBSD 6.2

Copyright ©2006 TheBestISP.com

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