4.4-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
commit 77d36398d99f2565c0a8d43a86fd520a82e64bb8 upstream.
syzbot complained :
BUG: KMSAN: uninit-value in memcmp+0x119/0x180 lib/string.c:861 CPU: 0 PID: 3 Comm: kworker/0:0 Not tainted 4.16.0+ #82 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: ipv6_addrconf addrconf_dad_work Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x185/0x1d0 lib/dump_stack.c:53 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:676 memcmp+0x119/0x180 lib/string.c:861 __hw_addr_add_ex net/core/dev_addr_lists.c:60 [inline] __dev_mc_add+0x1c2/0x8e0 net/core/dev_addr_lists.c:670 dev_mc_add+0x6d/0x80 net/core/dev_addr_lists.c:687 igmp6_group_added+0x2db/0xa00 net/ipv6/mcast.c:662 ipv6_dev_mc_inc+0xe9e/0x1130 net/ipv6/mcast.c:914 addrconf_join_solict net/ipv6/addrconf.c:2078 [inline] addrconf_dad_begin net/ipv6/addrconf.c:3828 [inline] addrconf_dad_work+0x427/0x2150 net/ipv6/addrconf.c:3954 process_one_work+0x12c6/0x1f60 kernel/workqueue.c:2113 worker_thread+0x113c/0x24f0 kernel/workqueue.c:2247 kthread+0x539/0x720 kernel/kthread.c:239
Fixes: f001fde5eadd ("net: introduce a list of device addresses dev_addr_list (v6)") Signed-off-by: Eric Dumazet edumazet@google.com Reported-by: syzbot syzkaller@googlegroups.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/core/dev_addr_lists.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/net/core/dev_addr_lists.c +++ b/net/core/dev_addr_lists.c @@ -57,8 +57,8 @@ static int __hw_addr_add_ex(struct netde return -EINVAL;
list_for_each_entry(ha, &list->list, list) { - if (!memcmp(ha->addr, addr, addr_len) && - ha->type == addr_type) { + if (ha->type == addr_type && + !memcmp(ha->addr, addr, addr_len)) { if (global) { /* check if addr is already used as global */ if (ha->global_use)