[RFC PATCH ghak59 V1 4/6] audit: hand taken context to audit_kill_trees for syscall logging

[Richard Guy Briggs]

Since the context is taken from the task in __audit_syscall_exit() and
__audit_free(), hand it 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
(which has been taken).

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

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@xxxxxxxxxx>
---
 kernel/audit.h      |  4 ++--
 kernel/audit_tree.c | 18 ++++++++++--------
 kernel/auditsc.c    |  4 ++--
 3 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/kernel/audit.h b/kernel/audit.h
index 214e149..f39f7aa 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -312,7 +312,7 @@ extern void audit_log_d_path_exe(struct audit_buffer *ab,
 extern int audit_tag_tree(char *old, char *new);
 extern const char *audit_tree_path(struct audit_tree *tree);
 extern void audit_put_tree(struct audit_tree *tree);
-extern void audit_kill_trees(struct list_head *list);
+extern void audit_kill_trees(struct audit_context *context);
 #else
 #define audit_remove_tree_rule(rule) BUG()
 #define audit_add_tree_rule(rule) -EINVAL
@@ -321,7 +321,7 @@ extern void audit_log_d_path_exe(struct audit_buffer *ab,
 #define audit_put_tree(tree) (void)0
 #define audit_tag_tree(old, new) -EINVAL
 #define audit_tree_path(rule) ""	/* never called */
-#define audit_kill_trees(list) BUG()
+#define audit_kill_trees(context) BUG()
 #endif
 
 extern char *audit_unpack_string(void **bufp, size_t *remain, size_t len);
diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c
index a01b9da..2d3e1071 100644
--- a/kernel/audit_tree.c
+++ b/kernel/audit_tree.c
@@ -493,13 +493,13 @@ 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(audit_context(), 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");
@@ -510,7 +510,7 @@ 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;
@@ -521,7 +521,7 @@ 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;
@@ -584,7 +584,7 @@ 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);
@@ -924,8 +924,10 @@ 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);
 
@@ -933,7 +935,7 @@ 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);
@@ -972,7 +974,7 @@ 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 {
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index ceb1c45..2590c9e 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1490,7 +1490,7 @@ void __audit_free(struct task_struct *tsk)
 	if (context->in_syscall && context->current_state == AUDIT_RECORD_CONTEXT)
 		audit_log_exit(context, tsk);
 	if (!list_empty(&context->killed_trees))
-		audit_kill_trees(&context->killed_trees);
+		audit_kill_trees(context);
 
 	audit_free_context(context);
 }
@@ -1577,7 +1577,7 @@ void __audit_syscall_exit(int success, long return_code)
 	context->prio = context->state == AUDIT_RECORD_CONTEXT ? ~0ULL : 0;
 
 	if (!list_empty(&context->killed_trees))
-		audit_kill_trees(&context->killed_trees);
+		audit_kill_trees(context);
 
 	audit_free_names(context);
 	unroll_tree_refs(context, NULL, 0);
-- 
1.8.3.1