audit: fix a memleak caused by auditing load module (95e0b46f) · Commits · 戴 / test

module.name will be allocated unconditionally when auditing load module, and audit_log_start() can fail with other reasons, or audit_log_exit maybe not called, caused module.name is not freed so free module.name in audit_free_context and __audit_syscall_exit unreferenced object 0xffff88af90837d20 (size 8): comm "modprobe", pid 1036, jiffies 4294704867 (age 3069.138s) hex dump (first 8 bytes): 69 78 67 62 65 00 ff ff ixgbe... backtrace: [<0000000008da28fe>] __audit_log_kern_module+0x33/0x80 [<00000000c1491e61>] load_module+0x64f/0x3850 [<000000007fc9ae3f>] __do_sys_init_module+0x218/0x250 [<0000000000d4a478>] do_syscall_64+0x117/0x400 [<000000004924ded8>] entry_SYSCALL_64_after_hwframe+0x49/0xbe [<000000007dc331dd>] 0xffffffffffffffff Fixes: ("audit: log module name on init_module") Signed-off-by:

Zhang Yu <zhangyu31@baidu.com> Signed-off-by:

Li RongQing <lirongqing@baidu.com> [PM: manual merge fixup in __audit_syscall_exit()] Signed-off-by:

Paul Moore <paul@paul-moore.com>

kernel/auditsc.c

+9 −1

Original line number	Diff line number	Diff line
		@@ -840,6 +840,13 @@ static inline void audit_proctitle_free(struct audit_context *context)
		context->proctitle.len = 0;
		}

		static inline void audit_free_module(struct audit_context *context)
		{
		if (context->type == AUDIT_KERN_MODULE) {
		kfree(context->module.name);
		context->module.name = NULL;
		}
		}
		static inline void audit_free_names(struct audit_context *context)
		{
		struct audit_names n, next;
		@@ -923,6 +930,7 @@ int audit_alloc(struct task_struct *tsk)

		static inline void audit_free_context(struct audit_context *context)
		{
		audit_free_module(context);
		audit_free_names(context);
		unroll_tree_refs(context, NULL, 0);
		free_tree_refs(context);
		@@ -1266,7 +1274,6 @@ static void show_special(struct audit_context context, int call_panic)
		audit_log_format(ab, "name=");
		if (context->module.name) {
		audit_log_untrustedstring(ab, context->module.name);
		kfree(context->module.name);
		} else
		audit_log_format(ab, "(null)");

		@@ -1697,6 +1704,7 @@ void __audit_syscall_exit(int success, long return_code)
		context->in_syscall = 0;
		context->prio = context->state == AUDIT_RECORD_CONTEXT ? ~0ULL : 0;

		audit_free_module(context);
		audit_free_names(context);
		unroll_tree_refs(context, NULL, 0);
		audit_free_aux(context);

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