ipv6: fix another slab-out-of-bounds in fib6_nh_flush_exceptions

While running the self-tests on a KASAN enabled kernel, I observed a
slab-out-of-bounds splat very similar to the one reported in
commit 821bbf79fe46 ("ipv6: Fix KASAN: slab-out-of-bounds Read in
 fib6_nh_flush_exceptions").

We additionally need to take care of fib6_metrics initialization
failure when the caller provides an nh.

The fix is similar, explicitly free the route instead of calling
fib6_info_release on a half-initialized object.

Fixes: f88d8ea67fbdb ("ipv6: Plumb support for nexthop object in a fib6_info")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 7b756a7..b6ddf23 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -3769,7 +3769,7 @@ static struct fib6_info *ip6_route_info_create(struct fib6_config *cfg,
                err = PTR_ERR(rt->fib6_metrics);
                /* Do not leave garbage there. */
                rt->fib6_metrics = (struct dst_metrics *)&dst_default_metrics;
-               goto out;
+               goto out_free;
        }
 
        if (cfg->fc_flags & RTF_ADDRCONF)