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: 8f8d28e ("net/packet: fix overflow in check for tp_frame_nr") Signed-off-by: Kal Conley <[email protected]> Signed-off-by: David S. Miller <[email protected]>
openbmc · Feb 12, 2019 · fc62814 · fc62814
1 parent 1ec17db
commit fc62814
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
@@ -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))