diff mbox series

net/packet: fix 4gb buffer limit due to overflow check

Message ID 20190209203701.27252-1-kal.conley@dectris.com
State Changes Requested
Delegated to: David Miller
Headers show
Series net/packet: fix 4gb buffer limit due to overflow check | expand

Commit Message

Kal Conley Feb. 9, 2019, 8:37 p.m. UTC 
When calculating rb->frames_per_block * req->tp_block_nr the result
can overflow. Check it for overflow without limiting the total buffer
size to UINT_MAX.

This change fixes support for packet ring buffers >= UINT_MAX.
---
 net/packet/af_packet.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

David Miller Feb. 10, 2019, 3:01 a.m. UTC | #1 
From: Kal Conley <kal.conley@dectris.com>
Date: Sat,  9 Feb 2019 21:37:00 +0100

> When calculating rb->frames_per_block * req->tp_block_nr the result
> can overflow. Check it for overflow without limiting the total buffer
> size to UINT_MAX.
> 
> This change fixes support for packet ring buffers >= UINT_MAX.

Please resubmit with a proper signoff and also an appropriate Fixes:
tag.
diff mbox series

Patch

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index d0945253f43b..d603a430378e 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -4291,7 +4291,7 @@  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))
+		if (unlikely(rb->frames_per_block > UINT_MAX / req->tp_block_nr))
 			goto out;
 		if (unlikely((rb->frames_per_block * req->tp_block_nr) !=
 					req->tp_frame_nr))