From 9ac80ef7cc411c8db08fc67858e90f34a2421826 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Mon, 13 Sep 2021 11:08:36 -0700
Subject: [PATCH] net-caif: avoid user-triggerable WARN_ON(1)
Git-commit: 550ac9c1aaaaf51fd42e20d461f0b1cdbd55b3d2
Patch-mainline: v5.15-rc2
References: stable-5.14.7
commit 550ac9c1aaaaf51fd42e20d461f0b1cdbd55b3d2 upstream.
syszbot triggers this warning, which looks something
we can easily prevent.
If we initialize priv->list_field in chnl_net_init(),
then always use list_del_init(), we can remove robust_list_del()
completely.
Warning: CPU: 0 PID: 3233 at net/caif/chnl_net.c:67 robust_list_del net/caif/chnl_net.c:67 [inline]
Warning: CPU: 0 PID: 3233 at net/caif/chnl_net.c:67 chnl_net_uninit+0xc9/0x2e0 net/caif/chnl_net.c:375
Modules linked in:
Cpu: 0 PID: 3233 Comm: syz-executor.3 Not tainted 5.14.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Rip: 0010:robust_list_del net/caif/chnl_net.c:67 [inline]
Rip: 0010:chnl_net_uninit+0xc9/0x2e0 net/caif/chnl_net.c:375
Code: 89 eb e8 3a a3 ba f8 48 89 d8 48 c1 e8 03 42 80 3c 28 00 0f 85 bf 01 00 00 48 81 fb 00 14 4e 8d 48 8b 2b 75 d0 e8 17 a3 ba f8 <0f> 0b 5b 5d 41 5c 41 5d e9 0a a3 ba f8 4c 89 e3 e8 02 a3 ba f8 4c
Rsp: 0018:ffffc90009067248 EFLAGS: 00010202
Rax: 0000000000008780 RBX: ffffffff8d4e1400 RCX: ffffc9000fd34000
Rdx: 0000000000040000 RSI: ffffffff88bb6e49 RDI: 0000000000000003
Rbp: ffff88802cd9ee08 R08: 0000000000000000 R09: ffffffff8d0e6647
R10: ffffffff88bb6dc2 R11: 0000000000000000 R12: ffff88803791ae08
R13: dffffc0000000000 R14: 00000000e600ffce R15: ffff888073ed3480
Fs: 00007fed10fa0700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
Cs: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Cr2: 0000001b2c322000 CR3: 00000000164a6000 CR4: 00000000001506e0
Dr0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
Dr3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
register_netdevice+0xadf/0x1500 net/core/dev.c:10347
ipcaif_newlink+0x4c/0x260 net/caif/chnl_net.c:468
__rtnl_newlink+0x106d/0x1750 net/core/rtnetlink.c:3458
rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3506
rtnetlink_rcv_msg+0x413/0xb80 net/core/rtnetlink.c:5572
netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504
netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1340
netlink_sendmsg+0x86d/0xdb0 net/netlink/af_netlink.c:1929
sock_sendmsg_nosec net/socket.c:704 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:724
__sys_sendto+0x21c/0x320 net/socket.c:2036
__do_sys_sendto net/socket.c:2048 [inline]
__se_sys_sendto net/socket.c:2044 [inline]
__x64_sys_sendto+0xdd/0x1b0 net/socket.c:2044
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
Fixes: cc36a070b590 ("net-caif: add CAIF netdevice")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
net/caif/chnl_net.c | 19 +++----------------
1 file changed, 3 insertions(+), 16 deletions(-)
diff --git a/net/caif/chnl_net.c b/net/caif/chnl_net.c
index 37b67194c0df..414dc5671c45 100644
--- a/net/caif/chnl_net.c
+++ b/net/caif/chnl_net.c
@@ -53,20 +53,6 @@ struct chnl_net {
enum caif_states state;
};
-static void robust_list_del(struct list_head *delete_node)
-{
- struct list_head *list_node;
- struct list_head *n;
- ASSERT_RTNL();
- list_for_each_safe(list_node, n, &chnl_net_list) {
- if (list_node == delete_node) {
- list_del(list_node);
- return;
- }
- }
- WARN_ON(1);
-}
-
static int chnl_recv_cb(struct cflayer *layr, struct cfpkt *pkt)
{
struct sk_buff *skb;
@@ -364,6 +350,7 @@ static int chnl_net_init(struct net_device *dev)
ASSERT_RTNL();
priv = netdev_priv(dev);
strncpy(priv->name, dev->name, sizeof(priv->name));
+ INIT_LIST_HEAD(&priv->list_field);
return 0;
}
@@ -372,7 +359,7 @@ static void chnl_net_uninit(struct net_device *dev)
struct chnl_net *priv;
ASSERT_RTNL();
priv = netdev_priv(dev);
- robust_list_del(&priv->list_field);
+ list_del_init(&priv->list_field);
}
static const struct net_device_ops netdev_ops = {
@@ -537,7 +524,7 @@ static void __exit chnl_exit_module(void)
rtnl_lock();
list_for_each_safe(list_node, _tmp, &chnl_net_list) {
dev = list_entry(list_node, struct chnl_net, list_field);
- list_del(list_node);
+ list_del_init(list_node);
delete_device(dev);
}
rtnl_unlock();
--
2.26.2