| Message ID | 1463761270-8955-1-git-send-email-ezequiel@vanguardiasur.com.ar |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> Date: Fri, 20 May 2016 13:21:10 -0300 > 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 <ezequiel@vanguardiasur.com.ar> Applied and queued up for -stable, thanks.
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index 2e6e65fc4d20..8d334816f89d 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -1697,6 +1697,14 @@ 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:
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 <ezequiel@vanguardiasur.com.ar> --- net/ipv4/af_inet.c | 8 ++++++++ net/ipv4/sysctl_net_ipv4.c | 4 ---- 2 files changed, 8 insertions(+), 4 deletions(-)