[4.2.y-ckt stable] Patch "net/route: enforce hoplimit max value" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    net/route: enforce hoplimit max value

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    https://git.launchpad.net/~canonical-kernel/linux/+git/linux-stable-ckt/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt11.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From be947577a695ccf9ee2872ec4c95751695440bb3 Mon Sep 17 00:00:00 2001
From: Paolo Abeni <pabeni at redhat.com>
Date: Fri, 13 May 2016 18:33:41 +0200
Subject: net/route: enforce hoplimit max value

[ Upstream commit 626abd59e51d4d8c6367e03aae252a8aa759ac78 ]

Currently, when creating or updating a route, no check is performed
in both ipv4 and ipv6 code to the hoplimit value.

The caller can i.e. set hoplimit to 256, and when such route will
 be used, packets will be sent with hoplimit/ttl equal to 0.

This commit adds checks for the RTAX_HOPLIMIT value, in both ipv4
ipv6 route code, substituting any value greater than 255 with 255.

This is consistent with what is currently done for ADVMSS and MTU
in the ipv4 code.

Signed-off-by: Paolo Abeni <pabeni at redhat.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 net/ipv4/fib_semantics.c | 2 ++
 net/ipv6/route.c         | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 71bad5c..fa767ed 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -858,6 +858,8 @@ struct fib_info *fib_create_info(struct fib_config *cfg)
 					val = 65535 - 40;
 				if (type == RTAX_MTU && val > 65535 - 15)
 					val = 65535 - 15;
+				if (type == RTAX_HOPLIMIT && val > 255)
+					val = 255;
 				fi->fib_metrics[type - 1] = val;
 			}
 		}
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index e36b7fe..e5ed7ed 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1728,6 +1728,8 @@ static int ip6_convert_metrics(struct mx6_config *mxc,
 			} else {
 				val = nla_get_u32(nla);
 			}
+			if (type == RTAX_HOPLIMIT && val > 255)
+				val = 255;

 			mp[type - 1] = val;
 			__set_bit(type - 1, mxc->mx_valid);
--
2.7.4