4.9-stable review patch. If anyone has any objections, please let me know.
------------------
[ Upstream commit e75913c93f7cd5f338ab373c34c93a655bd309cb ]
Follow those steps: # ip addr add 2001:123::1/32 dev eth0 # ip addr add 2001:123:456::2/64 dev eth0 # ip addr del 2001:123::1/32 dev eth0 # ip addr del 2001:123:456::2/64 dev eth0 and then prefix route of 2001:123::1/32 will still exist.
This is because ipv6_prefix_equal in check_cleanup_prefix_route func does not check whether two IPv6 addresses have the same prefix length. If the prefix of one address starts with another shorter address prefix, even though their prefix lengths are different, the return value of ipv6_prefix_equal is true.
Here I add a check of whether two addresses have the same prefix to decide whether their prefixes are equal.
Fixes: 5b84efecb7d9 ("ipv6 addrconf: don't cleanup prefix route for IFA_F_NOPREFIXROUTE") Signed-off-by: Zhiqiang Liu liuzhiqiang26@huawei.com Reported-by: Wenhao Zhang zhangwenhao8@huawei.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/ipv6/addrconf.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 8f79f0414bc3f..4ce7f91951510 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -1074,7 +1074,8 @@ check_cleanup_prefix_route(struct inet6_ifaddr *ifp, unsigned long *expires) list_for_each_entry(ifa, &idev->addr_list, if_list) { if (ifa == ifp) continue; - if (!ipv6_prefix_equal(&ifa->addr, &ifp->addr, + if (ifa->prefix_len != ifp->prefix_len || + !ipv6_prefix_equal(&ifa->addr, &ifp->addr, ifp->prefix_len)) continue; if (ifa->flags & (IFA_F_PERMANENT | IFA_F_NOPREFIXROUTE))