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Subject[22/70] net ipv6: Fix duplicate /proc/sys/net/ipv6/neigh directory entries.
2.6.38-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Eric W. Biederman <ebiederm@aristanetworks.com>

[ Upstream commit 9d2a8fa96a44ba242de3a6f56acaef7a40a97b97 ]

When I was fixing issues with unregisgtering tables under /proc/sys/net/ipv6/neigh
by adding a mount point it appears I missed a critical ordering issue, in the
ipv6 initialization. I had not realized that ipv6_sysctl_register is called
at the very end of the ipv6 initialization and in particular after we call
neigh_sysctl_register from ndisc_init.

"neigh" needs to be initialized in ipv6_static_sysctl_register which is
the first ipv6 table to initialized, and definitely before ndisc_init.
This removes the weirdness of duplicate tables while still providing a
"neigh" mount point which prevents races in sysctl unregistering.

This was initially reported at https://bugzilla.kernel.org/show_bug.cgi?id=31232
Reported-by: sunkan@zappa.cx
Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
net/ipv6/sysctl_net_ipv6.c | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)
--- a/net/ipv6/sysctl_net_ipv6.c
+++ b/net/ipv6/sysctl_net_ipv6.c
@@ -17,6 +17,16 @@

static struct ctl_table empty[1];

+static ctl_table ipv6_static_skeleton[] = {
+ {
+ .procname = "neigh",
+ .maxlen = 0,
+ .mode = 0555,
+ .child = empty,
+ },
+ { }
+};
+
static ctl_table ipv6_table_template[] = {
{
.procname = "route",
@@ -37,12 +47,6 @@ static ctl_table ipv6_table_template[] =
.mode = 0644,
.proc_handler = proc_dointvec
},
- {
- .procname = "neigh",
- .maxlen = 0,
- .mode = 0555,
- .child = empty,
- },
{ }
};

@@ -160,7 +164,7 @@ static struct ctl_table_header *ip6_base

int ipv6_static_sysctl_register(void)
{
- ip6_base = register_sysctl_paths(net_ipv6_ctl_path, empty);
+ ip6_base = register_sysctl_paths(net_ipv6_ctl_path, ipv6_static_skeleton);
if (ip6_base == NULL)
return -ENOMEM;
return 0;



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