[PATCH 3.16 192/212] net/packet: fix overflow in check for tp_reserve

[Ben Hutchings]

3.16.44-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Andrey Konovalov <andreyk...@google.com>

commit bcc5364bdcfe131e6379363f089e7b4108d35b70 upstream.

When calculating po->tp_hdrlen + po->tp_reserve the result can overflow.

Fix by checking that tp_reserve <= INT_MAX on assign.

Signed-off-by: Andrey Konovalov <andreyk...@google.com>
Acked-by: Eric Dumazet <eduma...@google.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
 net/packet/af_packet.c | 2 ++
 1 file changed, 2 insertions(+)

--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -3349,6 +3349,8 @@ packet_setsockopt(struct socket *sock, i
                        return -EBUSY;
                if (copy_from_user(&val, optval, sizeof(val)))
                        return -EFAULT;
+               if (val > INT_MAX)
+                       return -EINVAL;
                po->tp_reserve = val;
                return 0;
        }