From: Andrey Konovalov Date: Wed, 29 Mar 2017 16:11:21 +0200 Subject: net/packet: fix overflow in check for tp_frame_nr Origin: https://patchwork.ozlabs.org/patch/744812/ Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2017-7308 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 Acked-by: Eric Dumazet --- net/packet/af_packet.c | 2 ++ 1 file changed, 2 insertions(+) --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -4247,6 +4247,8 @@ static int packet_set_ring(struct sock * 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;