Commit fc62814d authored Feb 10, 2019 by Kal Conley Committed by David S. Miller Feb 12, 2019

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



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.

Fixes: 8f8d28e4 ("net/packet: fix overflow in check for tp_frame_nr")
Signed-off-by: Kal Conley <kal.conley@dectris.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 1ec17dbd

net/packet/af_packet.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -4292,7 +4292,7 @@ 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))

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