audit: hand taken context to audit_kill_trees for syscall logging

Since the context is derived from the task parameter handed to
__audit_free(), hand the context to audit_kill_trees() so it can be used
to associate with a syscall record.  This requires adding the context
parameter to kill_rules() rather than using the current audit_context.

The callers of trim_marked() and evict_chunk() still have their context.

The EOE record was being issued prior to the pruning of the killed_tree
list.

Move the kill_trees call before the audit_log_exit call in
__audit_free() and __audit_syscall_exit() so that any pruned trees
CONFIG_CHANGE records are included with the associated syscall event by
the user library due to the EOE record flagging the end of the event.

See: https://github.com/linux-audit/audit-kernel/issues/50
See: https://github.com/linux-audit/audit-kernel/issues/59

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
[PM: fixed merge fuzz in kernel/audit_tree.c]
Signed-off-by: Paul Moore <paul@paul-moore.com>

1 files changed, 11 insertions, 8 deletions

diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c
index d4af4d97f847..abfb112f26aa 100644
--- a/kernel/audit_tree.c
+++ b/kernel/audit_tree.c
@@ -524,13 +524,14 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree)
 	return 0;
 }
 
-static void audit_tree_log_remove_rule(struct audit_krule *rule)
+static void audit_tree_log_remove_rule(struct audit_context *context,
+				       struct audit_krule *rule)
 {
 	struct audit_buffer *ab;
 
 	if (!audit_enabled)
 		return;
-	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
+	ab = audit_log_start(context, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
 	if (unlikely(!ab))
 		return;
 	audit_log_format(ab, "op=remove_rule dir=");
@@ -540,7 +541,7 @@ static void audit_tree_log_remove_rule(struct audit_krule *rule)
 	audit_log_end(ab);
 }
 
-static void kill_rules(struct audit_tree *tree)
+static void kill_rules(struct audit_context *context, struct audit_tree *tree)
 {
 	struct audit_krule *rule, *next;
 	struct audit_entry *entry;
@@ -551,7 +552,7 @@ static void kill_rules(struct audit_tree *tree)
 		list_del_init(&rule->rlist);
 		if (rule->tree) {
 			/* not a half-baked one */
-			audit_tree_log_remove_rule(rule);
+			audit_tree_log_remove_rule(context, rule);
 			if (entry->rule.exe)
 				audit_remove_mark(entry->rule.exe);
 			rule->tree = NULL;
@@ -633,7 +634,7 @@ static void trim_marked(struct audit_tree *tree)
 		tree->goner = 1;
 		spin_unlock(&hash_lock);
 		mutex_lock(&audit_filter_mutex);
-		kill_rules(tree);
+		kill_rules(audit_context(), tree);
 		list_del_init(&tree->list);
 		mutex_unlock(&audit_filter_mutex);
 		prune_one(tree);
@@ -973,8 +974,10 @@ static void audit_schedule_prune(void)
  * ... and that one is done if evict_chunk() decides to delay until the end
  * of syscall.  Runs synchronously.
  */
-void audit_kill_trees(struct list_head *list)
+void audit_kill_trees(struct audit_context *context)
 {
+	struct list_head *list = &context->killed_trees;
+
 	audit_ctl_lock();
 	mutex_lock(&audit_filter_mutex);
 
@@ -982,7 +985,7 @@ void audit_kill_trees(struct list_head *list)
 		struct audit_tree *victim;
 
 		victim = list_entry(list->next, struct audit_tree, list);
-		kill_rules(victim);
+		kill_rules(context, victim);
 		list_del_init(&victim->list);
 
 		mutex_unlock(&audit_filter_mutex);
@@ -1017,7 +1020,7 @@ static void evict_chunk(struct audit_chunk *chunk)
 		list_del_init(&owner->same_root);
 		spin_unlock(&hash_lock);
 		if (!postponed) {
-			kill_rules(owner);
+			kill_rules(audit_context(), owner);
 			list_move(&owner->list, &prune_list);
 			need_prune = 1;
 		} else {