[PATCH] AUDIT: kerneldoc for kernel/audit*.c

- add kerneldoc for non-static functions;
- don't init static data to 0;
- limit lines to < 80 columns;
- fix long-format style;
- delete whitespace at end of some lines;

(chrisw: resend and update to current audit-2.6 tree)

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Chris Wright <chrisw@osdl.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

2 files changed, 238 insertions, 46 deletions

diff --git a/kernel/audit.c b/kernel/audit.c
index 0a813d2..973ca5a 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -72,7 +72,7 @@ static int	audit_failure = AUDIT_FAIL_PRINTK;
  * contains the (non-zero) pid. */
 int		audit_pid;
 
-/* If audit_limit is non-zero, limit the rate of sending audit records
+/* If audit_rate_limit is non-zero, limit the rate of sending audit records
  * to that number per second.  This prevents DoS attacks, but results in
  * audit records being dropped. */
 static int	audit_rate_limit;
@@ -102,7 +102,7 @@ static struct sock *audit_sock;
  * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
  * being placed on the freelist). */
 static DEFINE_SPINLOCK(audit_freelist_lock);
-static int	   audit_freelist_count = 0;
+static int	   audit_freelist_count;
 static LIST_HEAD(audit_freelist);
 
 static struct sk_buff_head audit_skb_queue;
@@ -186,8 +186,14 @@ static inline int audit_rate_check(void)
 	return retval;
 }
 
-/* Emit at least 1 message per second, even if audit_rate_check is
- * throttling. */
+/**
+ * audit_log_lost - conditionally log lost audit message event
+ * @message: the message stating reason for lost audit message
+ *
+ * Emit at least 1 message per second, even if audit_rate_check is
+ * throttling.
+ * Always increment the lost messages counter.
+*/
 void audit_log_lost(const char *message)
 {
 	static unsigned long	last_msg = 0;
@@ -218,7 +224,6 @@ void audit_log_lost(const char *message)
 		       audit_backlog_limit);
 		audit_panic(message);
 	}
-
 }
 
 static int audit_set_rate_limit(int limit, uid_t loginuid)
@@ -302,6 +307,19 @@ static int kauditd_thread(void *dummy)
 	}
 }
 
+/**
+ * audit_send_reply - send an audit reply message via netlink
+ * @pid: process id to send reply to
+ * @seq: sequence number
+ * @type: audit message type
+ * @done: done (last) flag
+ * @multi: multi-part message flag
+ * @payload: payload data
+ * @size: payload size
+ *
+ * Allocates an skb, builds the netlink message, and sends it to the pid.
+ * No failure notifications.
+ */
 void audit_send_reply(int pid, int seq, int type, int done, int multi,
 		      void *payload, int size)
 {
@@ -376,7 +394,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 	if (err)
 		return err;
 
-	/* As soon as there's any sign of userspace auditd, start kauditd to talk to it */
+	/* As soon as there's any sign of userspace auditd,
+	 * start kauditd to talk to it */
 	if (!kauditd_task)
 		kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
 	if (IS_ERR(kauditd_task)) {
@@ -469,9 +488,11 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 	return err < 0 ? err : 0;
 }
 
-/* Get message from skb (based on rtnetlink_rcv_skb).  Each message is
+/*
+ * Get message from skb (based on rtnetlink_rcv_skb).  Each message is
  * processed by audit_receive_msg.  Malformed skbs with wrong length are
- * discarded silently.  */
+ * discarded silently.
+ */
 static void audit_receive_skb(struct sk_buff *skb)
 {
 	int		err;
@@ -600,7 +621,10 @@ err:
 	return NULL;
 }
 
-/* Compute a serial number for the audit record.  Audit records are
+/**
+ * audit_serial - compute a serial number for the audit record
+ *
+ * Compute a serial number for the audit record.  Audit records are
  * written to user-space as soon as they are generated, so a complete
  * audit record may be written in several pieces.  The timestamp of the
  * record and this serial number are used by the user-space tools to
@@ -612,8 +636,8 @@ err:
  * audit context (for those records that have a context), and emit them
  * all at syscall exit.  However, this could delay the reporting of
  * significant errors until syscall exit (or never, if the system
- * halts). */
-
+ * halts).
+ */
 unsigned int audit_serial(void)
 {
 	static spinlock_t serial_lock = SPIN_LOCK_UNLOCKED;
@@ -649,6 +673,21 @@ static inline void audit_get_stamp(struct audit_context *ctx,
  * will be written at syscall exit.  If there is no associated task, tsk
  * should be NULL. */
 
+/**
+ * audit_log_start - obtain an audit buffer
+ * @ctx: audit_context (may be NULL)
+ * @gfp_mask: type of allocation
+ * @type: audit message type
+ *
+ * Returns audit_buffer pointer on success or NULL on error.
+ *
+ * Obtain an audit buffer.  This routine does locking to obtain the
+ * audit buffer, but then no locking is required for calls to
+ * audit_log_*format.  If the task (ctx) is a task that is currently in a
+ * syscall, then the syscall is marked as auditable and an audit record
+ * will be written at syscall exit.  If there is no associated task, then
+ * task context (ctx) should be NULL.
+ */
 struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
 				     int type)
 {
@@ -713,6 +752,7 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
 /**
  * audit_expand - expand skb in the audit buffer
  * @ab: audit_buffer
+ * @extra: space to add at tail of the skb
  *
  * Returns 0 (no space) on failed expansion, or available space if
  * successful.
@@ -729,10 +769,12 @@ static inline int audit_expand(struct audit_buffer *ab, int extra)
 	return skb_tailroom(skb);
 }
 
-/* Format an audit message into the audit buffer.  If there isn't enough
+/*
+ * Format an audit message into the audit buffer.  If there isn't enough
  * room in the audit buffer, more room will be allocated and vsnprint
  * will be called a second time.  Currently, we assume that a printk
- * can't format message larger than 1024 bytes, so we don't either. */
+ * can't format message larger than 1024 bytes, so we don't either.
+ */
 static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
 			      va_list args)
 {
@@ -757,7 +799,8 @@ static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
 		/* The printk buffer is 1024 bytes long, so if we get
 		 * here and AUDIT_BUFSIZ is at least 1024, then we can
 		 * log everything that printk could have logged. */
-		avail = audit_expand(ab, max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
+		avail = audit_expand(ab,
+			max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
 		if (!avail)
 			goto out;
 		len = vsnprintf(skb->tail, avail, fmt, args2);
@@ -768,8 +811,14 @@ out:
 	return;
 }
 
-/* Format a message into the audit buffer.  All the work is done in
- * audit_log_vformat. */
+/**
+ * audit_log_format - format a message into the audit buffer.
+ * @ab: audit_buffer
+ * @fmt: format string
+ * @...: optional parameters matching @fmt string
+ *
+ * All the work is done in audit_log_vformat.
+ */
 void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
 {
 	va_list args;
@@ -781,9 +830,18 @@ void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
 	va_end(args);
 }
 
-/* This function will take the passed buf and convert it into a string of
- * ascii hex digits. The new string is placed onto the skb. */
-void audit_log_hex(struct audit_buffer *ab, const unsigned char *buf, 
+/**
+ * audit_log_hex - convert a buffer to hex and append it to the audit skb
+ * @ab: the audit_buffer
+ * @buf: buffer to convert to hex
+ * @len: length of @buf to be converted
+ *
+ * No return value; failure to expand is silently ignored.
+ *
+ * This function will take the passed buf and convert it into a string of
+ * ascii hex digits. The new string is placed onto the skb.
+ */
+void audit_log_hex(struct audit_buffer *ab, const unsigned char *buf,
 		size_t len)
 {
 	int i, avail, new_len;
@@ -812,10 +870,16 @@ void audit_log_hex(struct audit_buffer *ab, const unsigned char *buf,
 	skb_put(skb, len << 1); /* new string is twice the old string */
 }
 
-/* This code will escape a string that is passed to it if the string
- * contains a control character, unprintable character, double quote mark, 
+/**
+ * audit_log_unstrustedstring - log a string that may contain random characters
+ * @ab: audit_buffer
+ * @string: string to be logged
+ *
+ * This code will escape a string that is passed to it if the string
+ * contains a control character, unprintable character, double quote mark,
  * or a space. Unescaped strings will start and end with a double quote mark.
- * Strings that are escaped are printed in hex (2 digits per char). */
+ * Strings that are escaped are printed in hex (2 digits per char).
+ */
 void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
 {
 	const unsigned char *p = string;
@@ -854,10 +918,15 @@ void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
 	kfree(path);
 }
 
-/* The netlink_* functions cannot be called inside an irq context, so
- * the audit buffer is places on a queue and a tasklet is scheduled to
+/**
+ * audit_log_end - end one audit record
+ * @ab: the audit_buffer
+ *
+ * The netlink_* functions cannot be called inside an irq context, so
+ * the audit buffer is placed on a queue and a tasklet is scheduled to
  * remove them from the queue outside the irq context.  May be called in
- * any context. */
+ * any context.
+ */
 void audit_log_end(struct audit_buffer *ab)
 {
 	if (!ab)
@@ -878,9 +947,18 @@ void audit_log_end(struct audit_buffer *ab)
 	audit_buffer_free(ab);
 }
 
-/* Log an audit record.  This is a convenience function that calls
- * audit_log_start, audit_log_vformat, and audit_log_end.  It may be
- * called in any context. */
+/**
+ * audit_log - Log an audit record
+ * @ctx: audit context
+ * @gfp_mask: type of allocation
+ * @type: audit message type
+ * @fmt: format string to use
+ * @...: variable parameters matching the format string
+ *
+ * This is a convenience function that calls audit_log_start,
+ * audit_log_vformat, and audit_log_end.  It may be called
+ * in any context.
+ */
 void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type, 
 	       const char *fmt, ...)
 {
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index cfaa4a2..51a4f58a 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -330,6 +330,15 @@ static int audit_list_rules(void *_dest)
 	return 0;
 }
 
+/**
+ * audit_receive_filter - apply all rules to the specified message type
+ * @type: audit message type
+ * @pid: target pid for netlink audit messages
+ * @uid: target uid for netlink audit messages
+ * @seq: netlink audit message sequence (serial) number
+ * @data: payload data
+ * @loginuid: loginuid of sender
+ */
 int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
 							uid_t loginuid)
 {
@@ -527,7 +536,7 @@ static enum audit_state audit_filter_task(struct task_struct *tsk)
 /* At syscall entry and exit time, this filter is called if the
  * audit_state is not low enough that auditing cannot take place, but is
  * also not high enough that we already know we have to write an audit
- * record (i.e., the state is AUDIT_SETUP_CONTEXT or  AUDIT_BUILD_CONTEXT).
+ * record (i.e., the state is AUDIT_SETUP_CONTEXT or AUDIT_BUILD_CONTEXT).
  */
 static enum audit_state audit_filter_syscall(struct task_struct *tsk,
 					     struct audit_context *ctx,
@@ -721,10 +730,15 @@ static inline struct audit_context *audit_alloc_context(enum audit_state state)
 	return context;
 }
 
-/* Filter on the task information and allocate a per-task audit context
+/**
+ * audit_alloc - allocate an audit context block for a task
+ * @tsk: task
+ *
+ * Filter on the task information and allocate a per-task audit context
  * if necessary.  Doing so turns on system call auditing for the
  * specified task.  This is called from copy_process, so no lock is
- * needed. */
+ * needed.
+ */
 int audit_alloc(struct task_struct *tsk)
 {
 	struct audit_context *context;
@@ -911,8 +925,12 @@ static void audit_log_exit(struct audit_context *context, gfp_t gfp_mask)
 	}
 }
 
-/* Free a per-task audit context.  Called from copy_process and
- * __put_task_struct. */
+/**
+ * audit_free - free a per-task audit context
+ * @tsk: task whose audit context block to free
+ *
+ * Called from copy_process and __put_task_struct.
+ */
 void audit_free(struct task_struct *tsk)
 {
 	struct audit_context *context;
@@ -934,13 +952,24 @@ void audit_free(struct task_struct *tsk)
 	audit_free_context(context);
 }
 
-/* Fill in audit context at syscall entry.  This only happens if the
+/**
+ * audit_syscall_entry - fill in an audit record at syscall entry
+ * @tsk: task being audited
+ * @arch: architecture type
+ * @major: major syscall type (function)
+ * @a1: additional syscall register 1
+ * @a2: additional syscall register 2
+ * @a3: additional syscall register 3
+ * @a4: additional syscall register 4
+ *
+ * Fill in audit context at syscall entry.  This only happens if the
  * audit context was created when the task was created and the state or
  * filters demand the audit context be built.  If the state from the
  * per-task filter or from the per-syscall filter is AUDIT_RECORD_CONTEXT,
  * then the record will be written at syscall exit time (otherwise, it
  * will only be written if another part of the kernel requests that it
- * be written). */
+ * be written).
+ */
 void audit_syscall_entry(struct task_struct *tsk, int arch, int major,
 			 unsigned long a1, unsigned long a2,
 			 unsigned long a3, unsigned long a4)
@@ -950,7 +979,8 @@ void audit_syscall_entry(struct task_struct *tsk, int arch, int major,
 
 	BUG_ON(!context);
 
-	/* This happens only on certain architectures that make system
+	/*
+	 * This happens only on certain architectures that make system
 	 * calls in kernel_thread via the entry.S interface, instead of
 	 * with direct calls.  (If you are porting to a new
 	 * architecture, hitting this condition can indicate that you
@@ -1009,11 +1039,18 @@ void audit_syscall_entry(struct task_struct *tsk, int arch, int major,
 	context->auditable  = !!(state == AUDIT_RECORD_CONTEXT);
 }
 
-/* Tear down after system call.  If the audit context has been marked as
+/**
+ * audit_syscall_exit - deallocate audit context after a system call
+ * @tsk: task being audited
+ * @valid: success/failure flag
+ * @return_code: syscall return value
+ *
+ * Tear down after system call.  If the audit context has been marked as
  * auditable (either because of the AUDIT_RECORD_CONTEXT state from
  * filtering, or because some other part of the kernel write an audit
  * message), then write out the syscall information.  In call cases,
- * free the names stored from getname(). */
+ * free the names stored from getname().
+ */
 void audit_syscall_exit(struct task_struct *tsk, int valid, long return_code)
 {
 	struct audit_context *context;
@@ -1048,7 +1085,13 @@ void audit_syscall_exit(struct task_struct *tsk, int valid, long return_code)
 	put_task_struct(tsk);
 }
 
-/* Add a name to the list.  Called from fs/namei.c:getname(). */
+/**
+ * audit_getname - add a name to the list
+ * @name: name to add
+ *
+ * Add a name to the list of audit names for this context.
+ * Called from fs/namei.c:getname().
+ */
 void audit_getname(const char *name)
 {
 	struct audit_context *context = current->audit_context;
@@ -1077,10 +1120,13 @@ void audit_getname(const char *name)
 		
 }
 
-/* Intercept a putname request.  Called from
- * include/linux/fs.h:putname().  If we have stored the name from
- * getname in the audit context, then we delay the putname until syscall
- * exit. */
+/* audit_putname - intercept a putname request
+ * @name: name to intercept and delay for putname
+ *
+ * If we have stored the name from getname in the audit context,
+ * then we delay the putname until syscall exit.
+ * Called from include/linux/fs.h:putname().
+ */
 void audit_putname(const char *name)
 {
 	struct audit_context *context = current->audit_context;
@@ -1117,8 +1163,14 @@ void audit_putname(const char *name)
 #endif
 }
 
-/* Store the inode and device from a lookup.  Called from
- * fs/namei.c:path_lookup(). */
+/**
+ * audit_inode - store the inode and device from a lookup
+ * @name: name being audited
+ * @inode: inode being audited
+ * @flags: lookup flags (as used in path_lookup())
+ *
+ * Called from fs/namei.c:path_lookup().
+ */
 void audit_inode(const char *name, const struct inode *inode, unsigned flags)
 {
 	int idx;
@@ -1154,6 +1206,14 @@ void audit_inode(const char *name, const struct inode *inode, unsigned flags)
 	context->names[idx].rdev  = inode->i_rdev;
 }
 
+/**
+ * auditsc_get_stamp - get local copies of audit_context values
+ * @ctx: audit_context for the task
+ * @t: timespec to store time recorded in the audit_context
+ * @serial: serial value that is recorded in the audit_context
+ *
+ * Also sets the context as auditable.
+ */
 void auditsc_get_stamp(struct audit_context *ctx,
 		       struct timespec *t, unsigned int *serial)
 {
@@ -1165,6 +1225,15 @@ void auditsc_get_stamp(struct audit_context *ctx,
 	ctx->auditable = 1;
 }
 
+/**
+ * audit_set_loginuid - set a task's audit_context loginuid
+ * @task: task whose audit context is being modified
+ * @loginuid: loginuid value
+ *
+ * Returns 0.
+ *
+ * Called (set) from fs/proc/base.c::proc_loginuid_write().
+ */
 int audit_set_loginuid(struct task_struct *task, uid_t loginuid)
 {
 	if (task->audit_context) {
@@ -1183,11 +1252,26 @@ int audit_set_loginuid(struct task_struct *task, uid_t loginuid)
 	return 0;
 }
 
+/**
+ * audit_get_loginuid - get the loginuid for an audit_context
+ * @ctx: the audit_context
+ *
+ * Returns the context's loginuid or -1 if @ctx is NULL.
+ */
 uid_t audit_get_loginuid(struct audit_context *ctx)
 {
 	return ctx ? ctx->loginuid : -1;
 }
 
+/**
+ * audit_ipc_perms - record audit data for ipc
+ * @qbytes: msgq bytes
+ * @uid: msgq user id
+ * @gid: msgq group id
+ * @mode: msgq mode (permissions)
+ *
+ * Returns 0 for success or NULL context or < 0 on error.
+ */
 int audit_ipc_perms(unsigned long qbytes, uid_t uid, gid_t gid, mode_t mode)
 {
 	struct audit_aux_data_ipcctl *ax;
@@ -1211,6 +1295,13 @@ int audit_ipc_perms(unsigned long qbytes, uid_t uid, gid_t gid, mode_t mode)
 	return 0;
 }
 
+/**
+ * audit_socketcall - record audit data for sys_socketcall
+ * @nargs: number of args
+ * @args: args array
+ *
+ * Returns 0 for success or NULL context or < 0 on error.
+ */
 int audit_socketcall(int nargs, unsigned long *args)
 {
 	struct audit_aux_data_socketcall *ax;
@@ -1232,6 +1323,13 @@ int audit_socketcall(int nargs, unsigned long *args)
 	return 0;
 }
 
+/**
+ * audit_sockaddr - record audit data for sys_bind, sys_connect, sys_sendto
+ * @len: data length in user space
+ * @a: data address in kernel space
+ *
+ * Returns 0 for success or NULL context or < 0 on error.
+ */
 int audit_sockaddr(int len, void *a)
 {
 	struct audit_aux_data_sockaddr *ax;
@@ -1253,6 +1351,15 @@ int audit_sockaddr(int len, void *a)
 	return 0;
 }
 
+/**
+ * audit_avc_path - record the granting or denial of permissions
+ * @dentry: dentry to record
+ * @mnt: mnt to record
+ *
+ * Returns 0 for success or NULL context or < 0 on error.
+ *
+ * Called from security/selinux/avc.c::avc_audit()
+ */
 int audit_avc_path(struct dentry *dentry, struct vfsmount *mnt)
 {
 	struct audit_aux_data_path *ax;
@@ -1274,6 +1381,14 @@ int audit_avc_path(struct dentry *dentry, struct vfsmount *mnt)
 	return 0;
 }
 
+/**
+ * audit_signal_info - record signal info for shutting down audit subsystem
+ * @sig: signal value
+ * @t: task being signaled
+ *
+ * If the audit subsystem is being terminated, record the task (pid)
+ * and uid that is doing that.
+ */
 void audit_signal_info(int sig, struct task_struct *t)
 {
 	extern pid_t audit_sig_pid;
@@ -1290,4 +1405,3 @@ void audit_signal_info(int sig, struct task_struct *t)
 		}
 	}
 }
-