From 9ef5932f8a1134b9d93676ee26701b2be90c7a95 Mon Sep 17 00:00:00 2001
From: Kees Cook <keescook@chromium.org>
Date: Wed, 12 Jul 2017 14:34:56 -0700
Subject: [PATCH 07/20] ipc/msg: do not use ipc_rcu_free()
Git-commit: 9ef5932f8a1134b9d93676ee26701b2be90c7a95
Patch-mainline: v4.13-rc1
References: bsc#1050323

Avoid using ipc_rcu_free, since it just re-finds the original structure
pointer.  For the pre-list-init failure path, there is no RCU needed,
since it was just allocated.  It can be directly freed.

Link: http://lkml.kernel.org/r/20170525185107.12869-8-manfred@colorfullife.com
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>

---
 ipc/msg.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/ipc/msg.c b/ipc/msg.c
index 0ed7dae7d4e8..25d43e27ef12 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -95,13 +95,18 @@ static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
 	ipc_rmid(&msg_ids(ns), &s->q_perm);
 }
 
+static void __msg_free(struct msg_queue *msq)
+{
+	kvfree(msq);
+}
+
 static void msg_rcu_free(struct rcu_head *head)
 {
 	struct kern_ipc_perm *p = container_of(head, struct kern_ipc_perm, rcu);
 	struct msg_queue *msq = container_of(p, struct msg_queue, q_perm);
 
 	security_msg_queue_free(msq);
-	ipc_rcu_free(head);
+	__msg_free(msq);
 }
 
 /**
@@ -131,7 +136,7 @@ static int newque(struct ipc_namespace *ns, struct ipc_params *params)
 	msq->q_perm.security = NULL;
 	retval = security_msg_queue_alloc(msq);
 	if (retval) {
-		ipc_rcu_putref(&msq->q_perm, ipc_rcu_free);
+		__msg_free(msq);
 		return retval;
 	}
 
-- 
2.12.0