* [PATCH net] bonding: limit BOND_MODE_8023AD to Ethernet devices
@ 2026-01-13 19:12 Eric Dumazet
2026-01-13 20:25 ` Jay Vosburgh
2026-01-16 4:00 ` patchwork-bot+netdevbpf
0 siblings, 2 replies; 3+ messages in thread
From: Eric Dumazet @ 2026-01-13 19:12 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: Simon Horman, netdev, eric.dumazet, Eric Dumazet,
syzbot+9c081b17773615f24672, Jay Vosburgh, Andrew Lunn
BOND_MODE_8023AD makes sense for ARPHRD_ETHER only.
syzbot reported:
BUG: KASAN: global-out-of-bounds in __hw_addr_create net/core/dev_addr_lists.c:63 [inline]
BUG: KASAN: global-out-of-bounds in __hw_addr_add_ex+0x25d/0x760 net/core/dev_addr_lists.c:118
Read of size 16 at addr ffffffff8bf94040 by task syz.1.3580/19497
CPU: 1 UID: 0 PID: 19497 Comm: syz.1.3580 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xca/0x240 mm/kasan/report.c:482
kasan_report+0x118/0x150 mm/kasan/report.c:595
check_region_inline mm/kasan/generic.c:-1 [inline]
kasan_check_range+0x2b0/0x2c0 mm/kasan/generic.c:200
__asan_memcpy+0x29/0x70 mm/kasan/shadow.c:105
__hw_addr_create net/core/dev_addr_lists.c:63 [inline]
__hw_addr_add_ex+0x25d/0x760 net/core/dev_addr_lists.c:118
__dev_mc_add net/core/dev_addr_lists.c:868 [inline]
dev_mc_add+0xa1/0x120 net/core/dev_addr_lists.c:886
bond_enslave+0x2b8b/0x3ac0 drivers/net/bonding/bond_main.c:2180
do_set_master+0x533/0x6d0 net/core/rtnetlink.c:2963
do_setlink+0xcf0/0x41c0 net/core/rtnetlink.c:3165
rtnl_changelink net/core/rtnetlink.c:3776 [inline]
__rtnl_newlink net/core/rtnetlink.c:3935 [inline]
rtnl_newlink+0x161c/0x1c90 net/core/rtnetlink.c:4072
rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6958
netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg+0x21c/0x270 net/socket.c:742
____sys_sendmsg+0x505/0x820 net/socket.c:2592
___sys_sendmsg+0x21f/0x2a0 net/socket.c:2646
__sys_sendmsg+0x164/0x220 net/socket.c:2678
do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
__do_fast_syscall_32+0x1dc/0x560 arch/x86/entry/syscall_32.c:307
do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:332
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
</TASK>
The buggy address belongs to the variable:
lacpdu_mcast_addr+0x0/0x40
Fixes: 872254dd6b1f ("net/bonding: Enable bonding to enslave non ARPHRD_ETHER")
Reported-by: syzbot+9c081b17773615f24672@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/6966946b.a70a0220.245e30.0002.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jay Vosburgh <jv@jvosburgh.net>
Cc: Andrew Lunn <andrew+netdev@lunn.ch>
---
drivers/net/bonding/bond_main.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 3d56339a8a10d97664e6d8cb8b41a681e6e9efc5..0aca6c937297def91d5740dfd456800432b5e343 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1862,6 +1862,12 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev,
*/
if (!bond_has_slaves(bond)) {
if (bond_dev->type != slave_dev->type) {
+ if (slave_dev->type != ARPHRD_ETHER &&
+ BOND_MODE(bond) == BOND_MODE_8023AD) {
+ SLAVE_NL_ERR(bond_dev, slave_dev, extack,
+ "8023AD mode requires Ethernet devices");
+ return -EINVAL;
+ }
slave_dbg(bond_dev, slave_dev, "change device type from %d to %d\n",
bond_dev->type, slave_dev->type);
--
2.52.0.457.g6b5491de43-goog
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH net] bonding: limit BOND_MODE_8023AD to Ethernet devices
2026-01-13 19:12 [PATCH net] bonding: limit BOND_MODE_8023AD to Ethernet devices Eric Dumazet
@ 2026-01-13 20:25 ` Jay Vosburgh
2026-01-16 4:00 ` patchwork-bot+netdevbpf
1 sibling, 0 replies; 3+ messages in thread
From: Jay Vosburgh @ 2026-01-13 20:25 UTC (permalink / raw)
To: Eric Dumazet
Cc: David S . Miller, Jakub Kicinski, Paolo Abeni, Simon Horman,
netdev, eric.dumazet, syzbot+9c081b17773615f24672, Andrew Lunn
Eric Dumazet <edumazet@google.com> wrote:
>BOND_MODE_8023AD makes sense for ARPHRD_ETHER only.
Agreed.
There are likely other ARPHRD_* types that don't make sense,
either.
Assuming from the szybot logs that an interface named
"ip6gretap" means ARPHRD_IP6GRE, I don't see how ARPHRD_IP6GRE could
work for balance-alb or balance-tlb modes (which expect an Ethernet
header in the packets), and maybe not at all for bonding.
Still, whether it works usefully is a separate question from
whether it panics, so this patch is certainly correct.
Acked-by: Jay Vosburgh <jv@jvosburgh.net>
-J
>syzbot reported:
>
> BUG: KASAN: global-out-of-bounds in __hw_addr_create net/core/dev_addr_lists.c:63 [inline]
> BUG: KASAN: global-out-of-bounds in __hw_addr_add_ex+0x25d/0x760 net/core/dev_addr_lists.c:118
>Read of size 16 at addr ffffffff8bf94040 by task syz.1.3580/19497
>
>CPU: 1 UID: 0 PID: 19497 Comm: syz.1.3580 Tainted: G L syzkaller #0 PREEMPT(full)
>Tainted: [L]=SOFTLOCKUP
>Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
>Call Trace:
> <TASK>
> dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
> print_address_description mm/kasan/report.c:378 [inline]
> print_report+0xca/0x240 mm/kasan/report.c:482
> kasan_report+0x118/0x150 mm/kasan/report.c:595
> check_region_inline mm/kasan/generic.c:-1 [inline]
> kasan_check_range+0x2b0/0x2c0 mm/kasan/generic.c:200
> __asan_memcpy+0x29/0x70 mm/kasan/shadow.c:105
> __hw_addr_create net/core/dev_addr_lists.c:63 [inline]
> __hw_addr_add_ex+0x25d/0x760 net/core/dev_addr_lists.c:118
> __dev_mc_add net/core/dev_addr_lists.c:868 [inline]
> dev_mc_add+0xa1/0x120 net/core/dev_addr_lists.c:886
> bond_enslave+0x2b8b/0x3ac0 drivers/net/bonding/bond_main.c:2180
> do_set_master+0x533/0x6d0 net/core/rtnetlink.c:2963
> do_setlink+0xcf0/0x41c0 net/core/rtnetlink.c:3165
> rtnl_changelink net/core/rtnetlink.c:3776 [inline]
> __rtnl_newlink net/core/rtnetlink.c:3935 [inline]
> rtnl_newlink+0x161c/0x1c90 net/core/rtnetlink.c:4072
> rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6958
> netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550
> netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
> netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344
> netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894
> sock_sendmsg_nosec net/socket.c:727 [inline]
> __sock_sendmsg+0x21c/0x270 net/socket.c:742
> ____sys_sendmsg+0x505/0x820 net/socket.c:2592
> ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2646
> __sys_sendmsg+0x164/0x220 net/socket.c:2678
> do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
> __do_fast_syscall_32+0x1dc/0x560 arch/x86/entry/syscall_32.c:307
> do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:332
> entry_SYSENTER_compat_after_hwframe+0x84/0x8e
> </TASK>
>
>The buggy address belongs to the variable:
> lacpdu_mcast_addr+0x0/0x40
>
>Fixes: 872254dd6b1f ("net/bonding: Enable bonding to enslave non ARPHRD_ETHER")
>Reported-by: syzbot+9c081b17773615f24672@syzkaller.appspotmail.com
>Closes: https://lore.kernel.org/netdev/6966946b.a70a0220.245e30.0002.GAE@google.com/T/#u
>Signed-off-by: Eric Dumazet <edumazet@google.com>
>Cc: Jay Vosburgh <jv@jvosburgh.net>
>Cc: Andrew Lunn <andrew+netdev@lunn.ch>
>---
> drivers/net/bonding/bond_main.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
>diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
>index 3d56339a8a10d97664e6d8cb8b41a681e6e9efc5..0aca6c937297def91d5740dfd456800432b5e343 100644
>--- a/drivers/net/bonding/bond_main.c
>+++ b/drivers/net/bonding/bond_main.c
>@@ -1862,6 +1862,12 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev,
> */
> if (!bond_has_slaves(bond)) {
> if (bond_dev->type != slave_dev->type) {
>+ if (slave_dev->type != ARPHRD_ETHER &&
>+ BOND_MODE(bond) == BOND_MODE_8023AD) {
>+ SLAVE_NL_ERR(bond_dev, slave_dev, extack,
>+ "8023AD mode requires Ethernet devices");
>+ return -EINVAL;
>+ }
> slave_dbg(bond_dev, slave_dev, "change device type from %d to %d\n",
> bond_dev->type, slave_dev->type);
>
>--
>2.52.0.457.g6b5491de43-goog
>
---
-Jay Vosburgh, jv@jvosburgh.net
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH net] bonding: limit BOND_MODE_8023AD to Ethernet devices
2026-01-13 19:12 [PATCH net] bonding: limit BOND_MODE_8023AD to Ethernet devices Eric Dumazet
2026-01-13 20:25 ` Jay Vosburgh
@ 2026-01-16 4:00 ` patchwork-bot+netdevbpf
1 sibling, 0 replies; 3+ messages in thread
From: patchwork-bot+netdevbpf @ 2026-01-16 4:00 UTC (permalink / raw)
To: Eric Dumazet
Cc: davem, kuba, pabeni, horms, netdev, eric.dumazet,
syzbot+9c081b17773615f24672, jv, andrew+netdev
Hello:
This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:
On Tue, 13 Jan 2026 19:12:01 +0000 you wrote:
> BOND_MODE_8023AD makes sense for ARPHRD_ETHER only.
>
> syzbot reported:
>
> BUG: KASAN: global-out-of-bounds in __hw_addr_create net/core/dev_addr_lists.c:63 [inline]
> BUG: KASAN: global-out-of-bounds in __hw_addr_add_ex+0x25d/0x760 net/core/dev_addr_lists.c:118
> Read of size 16 at addr ffffffff8bf94040 by task syz.1.3580/19497
>
> [...]
Here is the summary with links:
- [net] bonding: limit BOND_MODE_8023AD to Ethernet devices
https://git.kernel.org/netdev/net/c/c84fcb79e5db
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 3+ messages in thread
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2026-01-13 19:12 [PATCH net] bonding: limit BOND_MODE_8023AD to Ethernet devices Eric Dumazet
2026-01-13 20:25 ` Jay Vosburgh
2026-01-16 4:00 ` patchwork-bot+netdevbpf
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