netdev - [PATCH net] net: sched: Don't free f before it is allocated in route4

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Date:	Thu, 24 Oct 2013 16:50:50 +0200
From:	Christoph Paasch <christoph.paasch@...il.com>
To:	netdev@...r.kernel.org
Cc:	Eric Dumazet <eric.dumazet@...il.com>,
	David Miller <davem@...emloft.net>,
	Jamal Hadi Salim <jhs@...atatu.com>,
	Jing Wang <windsdaemon@...il.com>
Subject: [PATCH net] net: sched: Don't free f before it is allocated in route4_change

f is set to *arg in route4_change at the beginning, which points to a
route4_filter in the hash-table (gotten through route4_get, called by
tc_ctl_filter). If the alloc of head fails, we should not goto errout,
because this will free f and thus freed memory will be referenced by
the hash-table.
Only later the pointer f will change to an allocated route4_filter.

This patch returns err if the allocation of head fails as f has not yet
been allocated inside route4_change.

Seems the code has been like this since Linus's original git-commit.

Signed-off-by: Christoph Paasch <christoph.paasch@...ouvain.be>
---
 net/sched/cls_route.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sched/cls_route.c b/net/sched/cls_route.c
index 37da567..f17c67f 100644
--- a/net/sched/cls_route.c
+++ b/net/sched/cls_route.c
@@ -470,7 +470,7 @@ static int route4_change(struct net *net, struct sk_buff *in_skb,
 	if (head == NULL) {
 		head = kzalloc(sizeof(struct route4_head), GFP_KERNEL);
 		if (head == NULL)
-			goto errout;
+			return err;

 		tcf_tree_lock(tp);
 		tp->root = head;
-- 
1.8.3.2

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