[PATCH net v2 3/3] net/packet: fix overflow in check for tp_reserve

From: Andrey Konovalov <andreyknvl@google.com>
To: "David S . Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Willem de Bruijn <willemb@google.com>,
	Craig Gallek <cgallek@google.com>
Cc: netdev@vger.kernel.org, Dmitry Vyukov <dvyukov@google.com>,
	Kostya Serebryany <kcc@google.com>,
	Andrey Konovalov <andreyknvl@google.com>
Subject: [PATCH net v2 3/3] net/packet: fix overflow in check for tp_reserve
Date: Wed, 29 Mar 2017 16:11:22 +0200	[thread overview]
Message-ID: <b6e7f64aa4f58db0c879510e86196534e472f857.1490796500.git.andreyknvl@google.com> (raw)
In-Reply-To: <cover.1490796500.git.andreyknvl@google.com>
In-Reply-To: <cover.1490796500.git.andreyknvl@google.com>

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@google.com>
---
 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 3ac286ebb2f4..8489beff5c25 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -3665,6 +3665,8 @@ 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;
 	}
-- 
2.12.2.564.g063fe858b8-goog
