diff --git a/include/uapi/linux/seccomp.h b/include/uapi/linux/seccomp.h
index 90734aa5aa36..61fbbb7c1ee9 100644
--- a/include/uapi/linux/seccomp.h
+++ b/include/uapi/linux/seccomp.h
@@ -76,6 +76,34 @@ struct seccomp_notif {
 	struct seccomp_data data;
 };
 
+/*
+ * Valid flags for struct seccomp_notif_resp
+ *
+ * Note, the SECCOMP_USER_NOTIF_FLAG_CONTINUE flag must be used with caution!
+ * If set by the process supervising the syscalls of another process the
+ * syscall will continue. This is problematic because of an inherent TOCTOU.
+ * An attacker can exploit the time while the supervised process is waiting on
+ * a response from the supervising process to rewrite syscall arguments which
+ * are passed as pointers of the intercepted syscall.
+ * It should be absolutely clear that this means that the seccomp notifier
+ * _cannot_ be used to implement a security policy! It should only ever be used
+ * in scenarios where a more privileged process supervises the syscalls of a
+ * lesser privileged process to get around kernel-enforced security
+ * restrictions when the privileged process deems this safe. In other words,
+ * in order to continue a syscall the supervising process should be sure that
+ * another security mechanism or the kernel itself will sufficiently block
+ * syscalls if arguments are rewritten to something unsafe.
+ *
+ * Similar precautions should be applied when stacking SECCOMP_RET_USER_NOTIF.
+ * For SECCOMP_RET_USER_NOTIF filters acting on the same syscall the uppermost
+ * filter takes precedence. This means that the uppermost
+ * SECCOMP_RET_USER_NOTIF filter can override any SECCOMP_IOCTL_NOTIF_SEND from
+ * lower filters essentially allowing all syscalls to pass by using
+ * SECCOMP_USER_NOTIF_FLAG_CONTINUE. Note that SECCOMP_RET_USER_NOTIF can
+ * equally be overriden by SECCOMP_USER_NOTIF_FLAG_CONTINUE.
+ */
+#define SECCOMP_USER_NOTIF_FLAG_CONTINUE BIT(0)
+
 struct seccomp_notif_resp {
 	__u64 id;
 	__s64 val;
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index dba52a7db5e8..12d2227e5786 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -75,6 +75,7 @@ struct seccomp_knotif {
 	/* The return values, only valid when in SECCOMP_NOTIFY_REPLIED */
 	int error;
 	long val;
+	u32 flags;
 
 	/* Signals when this has entered SECCOMP_NOTIFY_REPLIED */
 	struct completion ready;
@@ -732,11 +733,12 @@ static u64 seccomp_next_notify_id(struct seccomp_filter *filter)
 	return filter->notif->next_id++;
 }
 
-static void seccomp_do_user_notification(int this_syscall,
-					 struct seccomp_filter *match,
-					 const struct seccomp_data *sd)
+static int seccomp_do_user_notification(int this_syscall,
+					struct seccomp_filter *match,
+					const struct seccomp_data *sd)
 {
 	int err;
+	u32 flags = 0;
 	long ret = 0;
 	struct seccomp_knotif n = {};
 
@@ -764,6 +766,7 @@ static void seccomp_do_user_notification(int this_syscall,
 	if (err == 0) {
 		ret = n.val;
 		err = n.error;
+		flags = n.flags;
 	}
 
 	/*
@@ -780,8 +783,14 @@ static void seccomp_do_user_notification(int this_syscall,
 		list_del(&n.list);
 out:
 	mutex_unlock(&match->notify_lock);
+
+	/* Userspace requests to continue the syscall. */
+	if (flags & SECCOMP_USER_NOTIF_FLAG_CONTINUE)
+		return 0;
+
 	syscall_set_return_value(current, task_pt_regs(current),
 				 err, ret);
+	return -1;
 }
 
 static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd,
@@ -867,8 +876,10 @@ static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd,
 		return 0;
 
 	case SECCOMP_RET_USER_NOTIF:
-		seccomp_do_user_notification(this_syscall, match, sd);
-		goto skip;
+		if (seccomp_do_user_notification(this_syscall, match, sd))
+			goto skip;
+
+		return 0;
 
 	case SECCOMP_RET_LOG:
 		seccomp_log(this_syscall, 0, action, true);
@@ -1087,7 +1098,11 @@ static long seccomp_notify_send(struct seccomp_filter *filter,
 	if (copy_from_user(&resp, buf, sizeof(resp)))
 		return -EFAULT;
 
-	if (resp.flags)
+	if (resp.flags & ~SECCOMP_USER_NOTIF_FLAG_CONTINUE)
+		return -EINVAL;
+
+	if ((resp.flags & SECCOMP_USER_NOTIF_FLAG_CONTINUE) &&
+	    (resp.error || resp.val))
 		return -EINVAL;
 
 	ret = mutex_lock_interruptible(&filter->notify_lock);
@@ -1116,6 +1131,7 @@ static long seccomp_notify_send(struct seccomp_filter *filter,
 	knotif->state = SECCOMP_NOTIFY_REPLIED;
 	knotif->error = resp.error;
 	knotif->val = resp.val;
+	knotif->flags = resp.flags;
 	complete(&knotif->ready);
 out:
 	mutex_unlock(&filter->notify_lock);
