auditsc.c

linux 2.6.19 kernel source code before patching

		if (!ab)
			continue; /* audit_panic has been called */

		audit_log_format(ab, "item=%d", i);

		if (n->name) {
			switch(n->name_len) {
			case AUDIT_NAME_FULL:
				/* log the full path */
				audit_log_format(ab, " name=");
				audit_log_untrustedstring(ab, n->name);
				break;
			case 0:
				/* name was specified as a relative path and the
				 * directory component is the cwd */
				audit_log_d_path(ab, " name=", context->pwd,
						 context->pwdmnt);
				break;
			default:
				/* log the name's directory component */
				audit_log_format(ab, " name=");
				audit_log_n_untrustedstring(ab, n->name_len,
							    n->name);
			}
		} else
			audit_log_format(ab, " name=(null)");

		if (n->ino != (unsigned long)-1) {
			audit_log_format(ab, " inode=%lu"
					 " dev=%02x:%02x mode=%#o"
					 " ouid=%u ogid=%u rdev=%02x:%02x",
					 n->ino,
					 MAJOR(n->dev),
					 MINOR(n->dev),
					 n->mode,
					 n->uid,
					 n->gid,
					 MAJOR(n->rdev),
					 MINOR(n->rdev));
		}
		if (n->osid != 0) {
			char *ctx = NULL;
			u32 len;
			if (selinux_sid_to_string(
				n->osid, &ctx, &len)) {
				audit_log_format(ab, " osid=%u", n->osid);
				call_panic = 2;
			} else
				audit_log_format(ab, " obj=%s", ctx);
			kfree(ctx);
		}

		audit_log_end(ab);
	}
	if (call_panic)
		audit_panic("error converting sid to string");
}

/**
 * audit_free - free a per-task audit context
 * @tsk: task whose audit context block to free
 *
 * Called from copy_process and do_exit
 */
void audit_free(struct task_struct *tsk)
{
	struct audit_context *context;

	context = audit_get_context(tsk, 0, 0);
	if (likely(!context))
		return;

	/* Check for system calls that do not go through the exit
	 * function (e.g., exit_group), then free context block. 
	 * We use GFP_ATOMIC here because we might be doing this 
	 * in the context of the idle thread */
	/* that can happen only if we are called from do_exit() */
	if (context->in_syscall && context->auditable)
		audit_log_exit(context, tsk);

	audit_free_context(context);
}

/**
 * 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).
 */
void audit_syscall_entry(int arch, int major,
			 unsigned long a1, unsigned long a2,
			 unsigned long a3, unsigned long a4)
{
	struct task_struct *tsk = current;
	struct audit_context *context = tsk->audit_context;
	enum audit_state     state;

	BUG_ON(!context);

	/*
	 * 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
	 * got the _exit/_leave calls backward in entry.S.)
	 *
	 * i386     no
	 * x86_64   no
	 * ppc64    yes (see arch/powerpc/platforms/iseries/misc.S)
	 *
	 * This also happens with vm86 emulation in a non-nested manner
	 * (entries without exits), so this case must be caught.
	 */
	if (context->in_syscall) {
		struct audit_context *newctx;

#if AUDIT_DEBUG
		printk(KERN_ERR
		       "audit(:%d) pid=%d in syscall=%d;"
		       " entering syscall=%d\n",
		       context->serial, tsk->pid, context->major, major);
#endif
		newctx = audit_alloc_context(context->state);
		if (newctx) {
			newctx->previous   = context;
			context		   = newctx;
			tsk->audit_context = newctx;
		} else	{
			/* If we can't alloc a new context, the best we
			 * can do is to leak memory (any pending putname
			 * will be lost).  The only other alternative is
			 * to abandon auditing. */
			audit_zero_context(context, context->state);
		}
	}
	BUG_ON(context->in_syscall || context->name_count);

	if (!audit_enabled)
		return;

	context->arch	    = arch;
	context->major      = major;
	context->argv[0]    = a1;
	context->argv[1]    = a2;
	context->argv[2]    = a3;
	context->argv[3]    = a4;

	state = context->state;
	context->dummy = !audit_n_rules;
	if (!context->dummy && (state == AUDIT_SETUP_CONTEXT || state == AUDIT_BUILD_CONTEXT))
		state = audit_filter_syscall(tsk, context, &audit_filter_list[AUDIT_FILTER_ENTRY]);
	if (likely(state == AUDIT_DISABLED))
		return;

	context->serial     = 0;
	context->ctime      = CURRENT_TIME;
	context->in_syscall = 1;
	context->auditable  = !!(state == AUDIT_RECORD_CONTEXT);
	context->ppid       = 0;
}

/**
 * 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().
 */
void audit_syscall_exit(int valid, long return_code)
{
	struct task_struct *tsk = current;
	struct audit_context *context;

	context = audit_get_context(tsk, valid, return_code);

	if (likely(!context))
		return;

	if (context->in_syscall && context->auditable)
		audit_log_exit(context, tsk);

	context->in_syscall = 0;
	context->auditable  = 0;

	if (context->previous) {
		struct audit_context *new_context = context->previous;
		context->previous  = NULL;
		audit_free_context(context);
		tsk->audit_context = new_context;
	} else {
		audit_free_names(context);
		audit_free_aux(context);
		context->aux = NULL;
		context->aux_pids = NULL;
		context->target_pid = 0;
		context->target_sid = 0;
		kfree(context->filterkey);
		context->filterkey = NULL;
		tsk->audit_context = context;
	}
}

/**
 * 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;

	if (IS_ERR(name) || !name)
		return;

	if (!context->in_syscall) {
#if AUDIT_DEBUG == 2
		printk(KERN_ERR "%s:%d(:%d): ignoring getname(%p)\n",
		       __FILE__, __LINE__, context->serial, name);
		dump_stack();
#endif
		return;
	}
	BUG_ON(context->name_count >= AUDIT_NAMES);
	context->names[context->name_count].name = name;
	context->names[context->name_count].name_len = AUDIT_NAME_FULL;
	context->names[context->name_count].name_put = 1;
	context->names[context->name_count].ino  = (unsigned long)-1;
	context->names[context->name_count].osid = 0;
	++context->name_count;
	if (!context->pwd) {
		read_lock(&current->fs->lock);
		context->pwd = dget(current->fs->pwd);
		context->pwdmnt = mntget(current->fs->pwdmnt);
		read_unlock(&current->fs->lock);
	}
		
}

/* 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;

	BUG_ON(!context);
	if (!context->in_syscall) {
#if AUDIT_DEBUG == 2
		printk(KERN_ERR "%s:%d(:%d): __putname(%p)\n",
		       __FILE__, __LINE__, context->serial, name);
		if (context->name_count) {
			int i;
			for (i = 0; i < context->name_count; i++)
				printk(KERN_ERR "name[%d] = %p = %s\n", i,
				       context->names[i].name,
				       context->names[i].name ?: "(null)");
		}
#endif
		__putname(name);
	}
#if AUDIT_DEBUG
	else {
		++context->put_count;
		if (context->put_count > context->name_count) {
			printk(KERN_ERR "%s:%d(:%d): major=%d"
			       " in_syscall=%d putname(%p) name_count=%d"
			       " put_count=%d\n",
			       __FILE__, __LINE__,
			       context->serial, context->major,
			       context->in_syscall, name, context->name_count,
			       context->put_count);
			dump_stack();
		}
	}
#endif
}

static int audit_inc_name_count(struct audit_context *context,
				const struct inode *inode)
{
	if (context->name_count >= AUDIT_NAMES) {
		if (inode)
			printk(KERN_DEBUG "name_count maxed, losing inode data: "
			       "dev=%02x:%02x, inode=%lu",
			       MAJOR(inode->i_sb->s_dev),
			       MINOR(inode->i_sb->s_dev),
			       inode->i_ino);

		else
			printk(KERN_DEBUG "name_count maxed, losing inode data");
		return 1;
	}
	context->name_count++;
#if AUDIT_DEBUG
	context->ino_count++;
#endif
	return 0;
}

/* Copy inode data into an audit_names. */
static void audit_copy_inode(struct audit_names *name, const struct inode *inode)
{
	name->ino   = inode->i_ino;
	name->dev   = inode->i_sb->s_dev;
	name->mode  = inode->i_mode;
	name->uid   = inode->i_uid;
	name->gid   = inode->i_gid;
	name->rdev  = inode->i_rdev;
	selinux_get_inode_sid(inode, &name->osid);
}

/**
 * audit_inode - store the inode and device from a lookup
 * @name: name being audited
 * @inode: inode being audited
 *
 * Called from fs/namei.c:path_lookup().
 */
void __audit_inode(const char *name, const struct inode *inode)
{
	int idx;
	struct audit_context *context = current->audit_context;

	if (!context->in_syscall)
		return;
	if (context->name_count
	    && context->names[context->name_count-1].name
	    && context->names[context->name_count-1].name == name)
		idx = context->name_count - 1;
	else if (context->name_count > 1
		 && context->names[context->name_count-2].name
		 && context->names[context->name_count-2].name == name)
		idx = context->name_count - 2;
	else {
		/* FIXME: how much do we care about inodes that have no
		 * associated name? */
		if (audit_inc_name_count(context, inode))
			return;
		idx = context->name_count - 1;
		context->names[idx].name = NULL;
	}
	audit_copy_inode(&context->names[idx], inode);
}

/**
 * audit_inode_child - collect inode info for created/removed objects
 * @dname: inode's dentry name
 * @inode: inode being audited
 * @parent: inode of dentry parent
 *
 * For syscalls that create or remove filesystem objects, audit_inode
 * can only collect information for the filesystem object's parent.
 * This call updates the audit context with the child's information.
 * Syscalls that create a new filesystem object must be hooked after
 * the object is created.  Syscalls that remove a filesystem object
 * must be hooked prior, in order to capture the target inode during
 * unsuccessful attempts.
 */
void __audit_inode_child(const char *dname, const struct inode *inode,
			 const struct inode *parent)
{
	int idx;
	struct audit_context *context = current->audit_context;
	const char *found_parent = NULL, *found_child = NULL;
	int dirlen = 0;

	if (!context->in_syscall)
		return;

	/* determine matching parent */
	if (!dname)
		goto add_names;

	/* parent is more likely, look for it first */
	for (idx = 0; idx < context->name_count; idx++) {
		struct audit_names *n = &context->names[idx];

		if (!n->name)
			continue;

		if (n->ino == parent->i_ino &&
		    !audit_compare_dname_path(dname, n->name, &dirlen)) {
			n->name_len = dirlen; /* update parent data in place */
			found_parent = n->name;
			goto add_names;
		}
	}

	/* no matching parent, look for matching child */
	for (idx = 0; idx < context->name_count; idx++) {
		struct audit_names *n = &context->names[idx];

		if (!n->name)
			continue;

		/* strcmp() is the more likely scenario */
		if (!strcmp(dname, n->name) ||
		     !audit_compare_dname_path(dname, n->name, &dirlen)) {
			if (inode)
				audit_copy_inode(n, inode);
			else
				n->ino = (unsigned long)-1;
			found_child = n->name;
			goto add_names;
		}
	}

add_names:
	if (!found_parent) {
		if (audit_inc_name_count(context, parent))
			return;
		idx = context->name_count - 1;
		context->names[idx].name = NULL;
		audit_copy_inode(&context->names[idx], parent);
	}

	if (!found_child) {
		if (audit_inc_name_count(context, inode))
			return;
		idx = context->name_count - 1;

		/* Re-use the name belonging to the slot for a matching parent
		 * directory. All names for this context are relinquished in
		 * audit_free_names() */
		if (found_parent) {
			context->names[idx].name = found_parent;
			context->names[idx].name_len = AUDIT_NAME_FULL;
			/* don't call __putname() */
			context->names[idx].name_put = 0;
		} else {
			context->names[idx].name = NULL;
		}

		if (inode)
			audit_copy_inode(&context->names[idx], inode);
		else
			context->names[idx].ino = (unsigned long)-1;
	}
}

/**
 * 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)
{
	if (!ctx->serial)
		ctx->serial = audit_serial();
	t->tv_sec  = ctx->ctime.tv_sec;
	t->tv_nsec = ctx->ctime.tv_nsec;
	*serial    = ctx->serial;
	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)
{
	struct audit_context *context = task->audit_context;

	if (context) {
		/* Only log if audit is enabled */
		if (context->in_syscall) {
			struct audit_buffer *ab;

			ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_LOGIN);
			if (ab) {
				audit_log_format(ab, "login pid=%d uid=%u "
					"old auid=%u new auid=%u",
					task->pid, task->uid,
					context->loginuid, loginuid);
				audit_log_end(ab);
			}
		}
		context->loginuid = 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.
 */