From 049bbf589ec651685205bd8ce73221fdd62345cf Mon Sep 17 00:00:00 2001 From: Ezequiel Garcia Date: Fri, 20 May 2016 13:21:10 -0300 Subject: [PATCH] ipv4: Fix non-initialized TTL when CONFIG_SYSCTL=n Commit fa50d974d104 ("ipv4: Namespaceify ip_default_ttl sysctl knob") moves the default TTL assignment, and as side-effect IPv4 TTL now has a default value only if sysctl support is enabled (CONFIG_SYSCTL=y). The sysctl_ip_default_ttl is fundamental for IP to work properly, as it provides the TTL to be used as default. The defautl TTL may be used in ip_selected_ttl, through the following flow: ip_select_ttl ip4_dst_hoplimit net->ipv4.sysctl_ip_default_ttl This commit fixes the issue by assigning net->ipv4.sysctl_ip_default_ttl in net_init_net, called during ipv4's initialization. Without this commit, a kernel built without sysctl support will send all IP packets with zero TTL (unless a TTL is explicitly set, e.g. with setsockopt). Given a similar issue might appear on the other knobs that were namespaceify, this commit also moves them. Fixes: fa50d974d104 ("ipv4: Namespaceify ip_default_ttl sysctl knob") Signed-off-by: Ezequiel Garcia Signed-off-by: David S. Miller --- net/ipv4/af_inet.c | 8 ++++++++ net/ipv4/sysctl_net_ipv4.c | 4 ---- 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index 377424ea17a4..d39e9e47a26e 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -1681,6 +1681,14 @@ static __net_init int inet_init_net(struct net *net) */ net->ipv4.ping_group_range.range[0] = make_kgid(&init_user_ns, 1); net->ipv4.ping_group_range.range[1] = make_kgid(&init_user_ns, 0); + + /* Default values for sysctl-controlled parameters. + * We set them here, in case sysctl is not compiled. + */ + net->ipv4.sysctl_ip_default_ttl = IPDEFTTL; + net->ipv4.sysctl_ip_dynaddr = 0; + net->ipv4.sysctl_ip_early_demux = 1; + return 0; } diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index bb0419582b8d..1cb67de106fe 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -999,10 +999,6 @@ static __net_init int ipv4_sysctl_init_net(struct net *net) if (!net->ipv4.sysctl_local_reserved_ports) goto err_ports; - net->ipv4.sysctl_ip_default_ttl = IPDEFTTL; - net->ipv4.sysctl_ip_dynaddr = 0; - net->ipv4.sysctl_ip_early_demux = 1; - return 0; err_ports: