[PATCH 3.12 64/86] net/packet: fix overflow in check for tp_reserve

[Jiri Slaby]

From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>

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

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

commit bcc5364bdcfe131e6379363f089e7b4108d35b70 upstream.

When calculating po->tp_hdrlen + po->tp_reserve the result can overflow.

Fix by checking that tp_reserve <= INT_MAX on assign.

Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Acked-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
 net/packet/af_packet.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index d6087b4359cc..2455f1b08ac3 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -3167,6 +3167,8 @@ packet_setsockopt(struct socket *sock, int level, int optname, char __user *optv
 			return -EBUSY;
 		if (copy_from_user(&val, optval, sizeof(val)))
 			return -EFAULT;
+		if (val > INT_MAX)
+			return -EINVAL;
 		po->tp_reserve = val;
 		return 0;
 	}
-- 
2.12.2