4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Paolo Abeni <pabeni@xxxxxxxxxx>
[ Upstream commit bf1dc8bad1d42287164d216d8efb51c5cd381b18 ]
We need a RCU critical section around rt6_info->from deference, and
proper annotation.
Fixes: 4ed591c8ab44 ("net/ipv6: Allow onlink routes to have a device mismatch if it is the default route")
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Reviewed-by: David Ahern <dsahern@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv6/route.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2808,20 +2808,24 @@ static int ip6_route_check_nh_onlink(str
u32 tbid = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN;
const struct in6_addr *gw_addr = &cfg->fc_gateway;
u32 flags = RTF_LOCAL | RTF_ANYCAST | RTF_REJECT;
+ struct fib6_info *from;
struct rt6_info *grt;
int err;
err = 0;
grt = ip6_nh_lookup_table(net, cfg, gw_addr, tbid, 0);
if (grt) {
+ rcu_read_lock();
+ from = rcu_dereference(grt->from);
if (!grt->dst.error &&
/* ignore match if it is the default route */
- grt->from && !ipv6_addr_any(&grt->from->fib6_dst.addr) &&
+ from && !ipv6_addr_any(&from->fib6_dst.addr) &&
(grt->rt6i_flags & flags || dev != grt->dst.dev)) {
NL_SET_ERR_MSG(extack,
"Nexthop has invalid gateway or device mismatch");
err = -EINVAL;
}
+ rcu_read_unlock();
ip6_rt_put(grt);
}
