[PATCH 4.7 011/184] net: ipv6: Do not keep IPv6 addresses when IPv6 is disabled

[Greg Kroah-Hartman]

4.7-stable review patch.  If anyone has any objections, please let me know.

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

From: Mike Manning <mmanning@xxxxxxxxxxx>


[ Upstream commit bc561632dddd5af0c4444d919f01cbf6d553aa0a ]

If IPv6 is disabled when the option is set to keep IPv6
addresses on link down, userspace is unaware of this as
there is no such indication via netlink. The solution is to
remove the IPv6 addresses in this case, which results in
netlink messages indicating removal of addresses in the
usual manner. This fix also makes the behavior consistent
with the case of having IPv6 disabled first, which stops
IPv6 addresses from being added.

Fixes: f1705ec197e7 ("net: ipv6: Make address flushing on ifdown optional")
Signed-off-by: Mike Manning <mmanning@xxxxxxxxxxx>
Acked-by: David Ahern <dsa@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/ipv6/addrconf.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -3469,7 +3469,7 @@ static int addrconf_ifdown(struct net_de
 	/* combine the user config with event to determine if permanent
 	 * addresses are to be removed from address hash table
 	 */
-	keep_addr = !(how || _keep_addr <= 0);
+	keep_addr = !(how || _keep_addr <= 0 || idev->cnf.disable_ipv6);
 
 	/* Step 2: clear hash table */
 	for (i = 0; i < IN6_ADDR_HSIZE; i++) {
@@ -3525,7 +3525,7 @@ restart:
 	/* re-combine the user config with event to determine if permanent
 	 * addresses are to be removed from the interface list
 	 */
-	keep_addr = (!how && _keep_addr > 0);
+	keep_addr = (!how && _keep_addr > 0 && !idev->cnf.disable_ipv6);
 
 	INIT_LIST_HEAD(&del_list);
 	list_for_each_entry_safe(ifa, tmp, &idev->addr_list, if_list) {