Commit bd68177f authored Jul 25, 2020 by Xiyu Yang Committed by Greg Kroah-Hartman Aug 11, 2020

ipv6: Fix nexthop refcnt leak when creating ipv6 route info



[ Upstream commit 706ec919164622ff5ce822065472d0f30a9e9dd2 ]

ip6_route_info_create() invokes nexthop_get(), which increases the
refcount of the "nh".

When ip6_route_info_create() returns, local variable "nh" becomes
invalid, so the refcount should be decreased to keep refcount balanced.

The reference counting issue happens in one exception handling path of
ip6_route_info_create(). When nexthops can not be used with source
routing, the function forgets to decrease the refcnt increased by
nexthop_get(), causing a refcnt leak.

Fix this issue by pulling up the error source routing handling when
nexthops can not be used with source routing.

Fixes: f88d8ea6 ("ipv6: Plumb support for nexthop object in a fib6_info")
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 89c12bc3

net/ipv6/route.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -3686,14 +3686,14 @@ static struct fib6_info ip6_route_info_create(struct fib6_config cfg,
		rt->fib6_src.plen = cfg->fc_src_len;
		#endif
		if (nh) {
		if (!nexthop_get(nh)) {
		NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
		goto out;
		}
		if (rt->fib6_src.plen) {
		NL_SET_ERR_MSG(extack, "Nexthops can not be used with source routing");
		goto out;
		}
		if (!nexthop_get(nh)) {
		NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
		goto out;
		}
		rt->nh = nh;
		fib6_nh = nexthop_fib6_nh(rt->nh);
		} else {