[PATCH 3.12 102/103] ipv4: initialise the itag variable in __mkroute_input

[Jiri Slaby]

From: Li RongQing <roy.qing.li@xxxxxxxxx>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

[ Upstream commit fbdc0ad095c0a299e9abf5d8ac8f58374951149a ]

the value of itag is a random value from stack, and may not be initiated by
fib_validate_source, which called fib_combine_itag if CONFIG_IP_ROUTE_CLASSID
is not set

This will make the cached dst uncertainty

Signed-off-by: Li RongQing <roy.qing.li@xxxxxxxxx>
Acked-by: Alexei Starovoitov <ast@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
 net/ipv4/route.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index ae8aadbbb3c7..2b681867164d 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1525,7 +1525,7 @@ static int __mkroute_input(struct sk_buff *skb,
 	struct in_device *out_dev;
 	unsigned int flags = 0;
 	bool do_cache;
-	u32 itag;
+	u32 itag = 0;
 
 	/* get a working reference to the output device */
 	out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
-- 
1.9.3

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