From dcafeb49b2538cc7118cb64f62c685980c106b48 Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Tue, 6 Mar 2018 11:35:28 +0100 Subject: [PATCH] ip-link: Fix use after free in nl_get_ll_addr_len() Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1550097 Upstream Status: iproute2.git commit 06867c3719587 commit 06867c371958773e39b4ccac07cfe3e2fff2ea55 Author: Phil Sutter Date: Thu Mar 1 10:35:12 2018 +0100 ip-link: Fix use after free in nl_get_ll_addr_len() Immediately after freeing the buffer returned from rtnl_talk(), it is accessed again via pointer in struct rtattr array. This leads to some builds not allowing to set an interface's MAC address because the expected length value is garbage. Fixes: 86bf43c7c2fdc ("lib/libnetlink: update rtnl_talk to support malloc buff at run time") Signed-off-by: Phil Sutter --- ip/iplink.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/ip/iplink.c b/ip/iplink.c index 193997c..db5b2c9 100644 --- a/ip/iplink.c +++ b/ip/iplink.c @@ -268,8 +268,9 @@ static int nl_get_ll_addr_len(unsigned int dev_index) return -1; } + len = RTA_PAYLOAD(tb[IFLA_ADDRESS]); free(answer); - return RTA_PAYLOAD(tb[IFLA_ADDRESS]); + return len; } static void iplink_parse_vf_vlan_info(int vf, int *argcp, char ***argvp, -- 1.8.3.1