From: Paolo Abeni Date: Fri, 13 May 2016 16:33:41 +0000 (+0200) Subject: net/route: enforce hoplimit max value X-Git-Tag: v4.5.5~59 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8be13acc8709f013813da8ae36c6f0e538cbcc0f;p=thirdparty%2Fkernel%2Fstable.git 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 Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c index d97268e8ff103..2b68418c71980 100644 --- a/net/ipv4/fib_semantics.c +++ b/net/ipv4/fib_semantics.c @@ -975,6 +975,8 @@ fib_convert_metrics(struct fib_info *fi, const 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; if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK)) return -EINVAL; fi->fib_metrics[type - 1] = val; diff --git a/net/ipv6/route.c b/net/ipv6/route.c index ed446639219c3..18e29e2f88777 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -1737,6 +1737,8 @@ static int ip6_convert_metrics(struct mx6_config *mxc, } else { val = nla_get_u32(nla); } + if (type == RTAX_HOPLIMIT && val > 255) + val = 255; if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK)) goto err;