From 1c825dacb615430cb384e0e3be07700013291742 Mon Sep 17 00:00:00 2001 From: Marcelo Leitner Date: Mon, 23 Feb 2015 11:17:13 -0300 Subject: [PATCH] ipv6: addrconf: validate new MTU before applying it commit 77751427a1ff25b27d47a4c36b12c3c8667855ac upstream. Currently we don't check if the new MTU is valid or not and this allows one to configure a smaller than minimum allowed by RFCs or even bigger than interface own MTU, which is a problem as it may lead to packet drops. If you have a daemon like NetworkManager running, this may be exploited by remote attackers by forging RA packets with an invalid MTU, possibly leading to a DoS. (NetworkManager currently only validates for values too small, but not for too big ones.) The fix is just to make sure the new value is valid. That is, between IPV6_MIN_MTU and interface's MTU. Note that similar check is already performed at ndisc_router_discovery(), for when kernel itself parses the RA. Signed-off-by: Marcelo Ricardo Leitner Signed-off-by: Sabrina Dubroca Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- Reading git-format-patch failed