From 88af182e389097997c5e2a0b42285b3522796759 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Fri, 19 Feb 2010 13:22:59 +0000 Subject: [PATCH] net: Fix sysctl restarts... Yuck. It turns out that when we restart sysctls we were restarting with the values already changed. Which unfortunately meant that the second time through we thought there was no change and skipped all kinds of work, despite the fact that there was indeed a change. I have fixed this the simplest way possible by restoring the changed values when we restart the sysctl write. One of my coworkers spotted this bug when after disabling forwarding on an interface pings were still forwarded. Signed-off-by: Eric W. Biederman Signed-off-by: David S. Miller --- net/ipv4/devinet.c | 7 ++++++- net/ipv6/addrconf.c | 16 ++++++++++++++-- 2 files changed, 20 insertions(+), 3 deletions(-) diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index 040c4f05b653..26dec2be9615 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -1317,14 +1317,19 @@ static int devinet_sysctl_forward(ctl_table *ctl, int write, { int *valp = ctl->data; int val = *valp; + loff_t pos = *ppos; int ret = proc_dointvec(ctl, write, buffer, lenp, ppos); if (write && *valp != val) { struct net *net = ctl->extra2; if (valp != &IPV4_DEVCONF_DFLT(net, FORWARDING)) { - if (!rtnl_trylock()) + if (!rtnl_trylock()) { + /* Restore the original values before restarting */ + *valp = val; + *ppos = pos; return restart_syscall(); + } if (valp == &IPV4_DEVCONF_ALL(net, FORWARDING)) { inet_forward_change(net); } else if (*valp) { diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index de7a194a64ab..143791da062c 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -502,8 +502,11 @@ static int addrconf_fixup_forwarding(struct ctl_table *table, int *p, int old) if (p == &net->ipv6.devconf_dflt->forwarding) return 0; - if (!rtnl_trylock()) + if (!rtnl_trylock()) { + /* Restore the original values before restarting */ + *p = old; return restart_syscall(); + } if (p == &net->ipv6.devconf_all->forwarding) { __s32 newf = net->ipv6.devconf_all->forwarding; @@ -4028,12 +4031,15 @@ int addrconf_sysctl_forward(ctl_table *ctl, int write, { int *valp = ctl->data; int val = *valp; + loff_t pos = *ppos; int ret; ret = proc_dointvec(ctl, write, buffer, lenp, ppos); if (write) ret = addrconf_fixup_forwarding(ctl, valp, val); + if (ret) + *ppos = pos; return ret; } @@ -4075,8 +4081,11 @@ static int addrconf_disable_ipv6(struct ctl_table *table, int *p, int old) if (p == &net->ipv6.devconf_dflt->disable_ipv6) return 0; - if (!rtnl_trylock()) + if (!rtnl_trylock()) { + /* Restore the original values before restarting */ + *p = old; return restart_syscall(); + } if (p == &net->ipv6.devconf_all->disable_ipv6) { __s32 newf = net->ipv6.devconf_all->disable_ipv6; @@ -4095,12 +4104,15 @@ int addrconf_sysctl_disable(ctl_table *ctl, int write, { int *valp = ctl->data; int val = *valp; + loff_t pos = *ppos; int ret; ret = proc_dointvec(ctl, write, buffer, lenp, ppos); if (write) ret = addrconf_disable_ipv6(ctl, valp, val); + if (ret) + *ppos = pos; return ret; } -- GitLab