From 44c23d71599f81a1c7fe8389e0319822dd50c37c Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 15 Jan 2020 08:20:39 -0800 Subject: [PATCH] net/sched: act_ife: initalize ife->metalist earlier It seems better to init ife->metalist earlier in tcf_ife_init() to avoid the following crash : kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 10483 Comm: syz-executor216 Not tainted 5.5.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:_tcf_ife_cleanup net/sched/act_ife.c:412 [inline] RIP: 0010:tcf_ife_cleanup+0x6e/0x400 net/sched/act_ife.c:431 Code: 48 c1 ea 03 80 3c 02 00 0f 85 94 03 00 00 49 8b bd f8 00 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8d 67 e8 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 5c 03 00 00 48 bb 00 00 00 00 00 fc ff df 48 8b RSP: 0018:ffffc90001dc6d00 EFLAGS: 00010246 RAX: dffffc0000000000 RBX: ffffffff864619c0 RCX: ffffffff815bfa09 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000000 RBP: ffffc90001dc6d50 R08: 0000000000000004 R09: fffff520003b8d8e R10: fffff520003b8d8d R11: 0000000000000003 R12: ffffffffffffffe8 R13: ffff8880a79fc000 R14: ffff88809aba0e00 R15: 0000000000000000 FS: 0000000001b51880(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000563f52cce140 CR3: 0000000093541000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: tcf_action_cleanup+0x62/0x1b0 net/sched/act_api.c:119 __tcf_action_put+0xfa/0x130 net/sched/act_api.c:135 __tcf_idr_release net/sched/act_api.c:165 [inline] __tcf_idr_release+0x59/0xf0 net/sched/act_api.c:145 tcf_idr_release include/net/act_api.h:171 [inline] tcf_ife_init+0x97c/0x1870 net/sched/act_ife.c:616 tcf_action_init_1+0x6b6/0xa40 net/sched/act_api.c:944 tcf_action_init+0x21a/0x330 net/sched/act_api.c:1000 tcf_action_add+0xf5/0x3b0 net/sched/act_api.c:1410 tc_ctl_action+0x390/0x488 net/sched/act_api.c:1465 rtnetlink_rcv_msg+0x45e/0xaf0 net/core/rtnetlink.c:5424 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5442 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x58c/0x7d0 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:639 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:659 ____sys_sendmsg+0x753/0x880 net/socket.c:2330 ___sys_sendmsg+0x100/0x170 net/socket.c:2384 __sys_sendmsg+0x105/0x1d0 net/socket.c:2417 __do_sys_sendmsg net/socket.c:2426 [inline] __se_sys_sendmsg net/socket.c:2424 [inline] __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2424 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe Fixes: 11a94d7fd80f ("net/sched: act_ife: validate the control action inside init()") Signed-off-by: Eric Dumazet Reported-by: syzbot Cc: Davide Caratti Reviewed-by: Davide Caratti Acked-by: Cong Wang Signed-off-by: David S. Miller --- net/sched/act_ife.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/net/sched/act_ife.c b/net/sched/act_ife.c index 5e63790..c1fcd85 100644 --- a/net/sched/act_ife.c +++ b/net/sched/act_ife.c @@ -537,6 +537,9 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla, } ife = to_ife(*a); + if (ret == ACT_P_CREATED) + INIT_LIST_HEAD(&ife->metalist); + err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack); if (err < 0) goto release_idr; @@ -566,10 +569,6 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla, p->eth_type = ife_type; } - - if (ret == ACT_P_CREATED) - INIT_LIST_HEAD(&ife->metalist); - if (tb[TCA_IFE_METALST]) { err = nla_parse_nested_deprecated(tb2, IFE_META_MAX, tb[TCA_IFE_METALST], NULL, -- 2.7.4