From: Andrey Konovalov <andreyknvl@google.com>
Date: Wed, 29 Mar 2017 14:11:21 +0000 (+0200)
Subject: net/packet: fix overflow in check for tp_frame_nr
X-Git-Tag: archive/raspbian/4.15.4-1+rpi1~1^2^2^2^2^2^2^2^2^2^2^2^2^2~39
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=ef0a862f13fa6fc30379df0746f98ab722a29c20;p=linux.git

net/packet: fix overflow in check for tp_frame_nr

When calculating rb->frames_per_block * req->tp_block_nr the result
can overflow.

Add a check that tp_block_size * tp_block_nr <= UINT_MAX.

Since frames_per_block <= tp_block_size, the expression would
never overflow.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Gbp-Pq: Topic bugfix/all
Gbp-Pq: Name net-packet-fix-overflow-in-check-for-tp_frame_nr.patch
---

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 8ab0974f4ee..e064e334282 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -4247,6 +4247,8 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
 		rb->frames_per_block = req->tp_block_size / req->tp_frame_size;
 		if (unlikely(rb->frames_per_block == 0))
 			goto out;
+		if (unlikely(req->tp_block_size > UINT_MAX / req->tp_block_nr))
+			goto out;
 		if (unlikely((rb->frames_per_block * req->tp_block_nr) !=
 					req->tp_frame_nr))
 			goto out;