SETAUDIT(2)

💅 SETAUDIT(2) — the setaudit / setaudit_addr glow-up

okay bestie, buckle up, we're in section 2 of the manual (System Calls Manual) and this one is literally about setting your audit session state. yes, audits. yes, they're watching. no, you can't opt out. 🎀

---

✨ NAME ✨

setaudit, setaudit_addr — set audit session state, aka "tell the kernel who you are and what you want logged" 🫶

---

🌸 SYNOPSIS 🌸

#include <bsm/audit.h>

int
setaudit(auditinfo_t *auditinfo);

int
setaudit_addr(auditinfo_addr_t *auditinfo_addr, u_int length);

---

🦋 DESCRIPTION 🦋

so the setaudit() system call sets the active audit session state for the current process, using the auditinfo_t that auditinfo points at. iconic behavior. and setaudit_addr() sets the extended state via auditinfo_addr and length — that's the deluxe version, iykyk. ✨

the auditinfo_t data structure is defined like this, no cap:

struct auditinfo {
     au_id_t        ai_auid;         /* Audit user ID */
     au_mask_t      ai_mask;         /* Audit masks */
     au_tid_t       ai_termid;       /* Terminal ID */
     au_asid_t      ai_asid;         /* Audit session ID */
};
typedef struct auditinfo        auditinfo_t;

the ai_auid variable contains the audit identifier which is recorded in the audit log for each event the process caused. so like, every single thing you do? logged with your name on it. main character energy but make it surveillance. 😭

the au_mask_t data structure defines the bit mask for auditing successful and failed events out of the predefined list of event classes. it's giving "choose your own adventure" but for logging:

struct au_mask {
     unsigned int    am_success;     /* success bits */
     unsigned int    am_failure;     /* failure bits */
};
typedef struct au_mask  au_mask_t;

the au_termid_t data structure defines the Terminal ID recorded with every event caused by the process. hi bestie, it's where you were:

struct au_tid {
     dev_t           port;
     u_int32_t       machine;
};
typedef struct au_tid   au_tid_t;

the ai_asid variable contains the audit session ID which is recorded with every event caused by the process. your little audit fingerprint. so demure. 💅

now the setaudit_addr() system call uses the expanded auditinfo_addr_t data structure, which supports Terminal IDs with larger addresses such as those used in IP version 6. yes, IPv6 girlies get their own struct. it is defined as follows:

struct auditinfo_addr {
     au_id_t         ai_auid;        /* Audit user ID. */
     au_mask_t       ai_mask;        /* Audit masks. */
     au_tid_addr_t   ai_termid;      /* Terminal ID. */
     au_asid_t       ai_asid;        /* Audit session ID. */
};
typedef struct auditinfo_addr   auditinfo_addr_t;

and the au_tid_addr_t data structure, which includes a larger address storage field and an additional field with the type of address stored:

struct au_tid_addr {
     dev_t           at_port;
     u_int32_t       at_type;
     u_int32_t       at_addr[4];
};
typedef struct au_tid_addr      au_tid_addr_t;

⚠️ heads up bestie: these system calls require an appropriate privilege to complete. no privilege, no audit state. periodt.

---

🎀 RETURN VALUES 🎀

the setaudit() and setaudit_addr() functions return the value 0 if successful — slay. otherwise the value -1 is returned and the global variable errno is set to indicate the error. it's giving "not me making it worse". 🙈

---

🧚 ERRORS 🧚

• [EFAULT] — A failure occurred while data transferred to or from the kernel failed. the transfer ate itself. 💀
• [EINVAL] — Illegal argument was passed by a system call. you gave it something it literally cannot accept. rude of you.
• [EPERM] — The process does not have sufficient permission to complete the operation. no privilege, no party. ✋

---

🌈 SEE ALSO 🌈

audit(2), auditon(2), getaudit(2), getauid(2), setauid(2), libbsm(3)

go read these next, bestie. the lore is deep.

---

💜 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. 2004!! vintage!! 🍓

---

👑 AUTHORS 👑

This software was created by McAfee Research, the security research division of McAfee, Inc., under contract to Apple Computer Inc. Additional authors include Wayne Salamon, Robert Watson, and SPARTA Inc.

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>.

---

okay that's the whole page, literally every flag and field and caveat, I promise, I would never gatekeep 🌸

and for the cute sign-off: this little beauty comes from Debian, dated April 19, 2005 — so when you see SETAUDIT(2) in the wild, that's the timestamp on the vibe check. old but gold, fr fr 💖