FreeBSD Manual Pages
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 <rwatson@FreeBSD.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
NAME | DESCRIPTION | SEE ALSO | AUTHORS | HISTORY | BUGS
Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=audit.log&sektion=5&manpath=FreeBSD+6.2-RELEASE>