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9ad685dbfe
It is not possible to set the number of lanes when setting link modes
using the legacy IOCTL ethtool interface. Since 'struct
ethtool_link_ksettings' is not initialized in this path, drivers receive
an uninitialized number of lanes in 'struct
ethtool_link_ksettings::lanes'.
When this information is later queried from drivers, it results in the
ethtool code making decisions based on uninitialized memory, leading to
the following KMSAN splat [1]. In practice, this most likely only
happens with the tun driver that simply returns whatever it got in the
set operation.
As far as I can tell, this uninitialized memory is not leaked to user
space thanks to the 'ethtool_ops->cap_link_lanes_supported' check in
linkmodes_prepare_data().
Fix by initializing the structure in the IOCTL path. Did not find any
more call sites that pass an uninitialized structure when calling
'ethtool_ops::set_link_ksettings()'.
[1]
BUG: KMSAN: uninit-value in ethnl_update_linkmodes net/ethtool/linkmodes.c:273 [inline]
BUG: KMSAN: uninit-value in ethnl_set_linkmodes+0x190b/0x19d0 net/ethtool/linkmodes.c:333
ethnl_update_linkmodes net/ethtool/linkmodes.c:273 [inline]
ethnl_set_linkmodes+0x190b/0x19d0 net/ethtool/linkmodes.c:333
ethnl_default_set_doit+0x88d/0xde0 net/ethtool/netlink.c:640
genl_family_rcv_msg_doit net/netlink/genetlink.c:968 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline]
genl_rcv_msg+0x141a/0x14c0 net/netlink/genetlink.c:1065
netlink_rcv_skb+0x3f8/0x750 net/netlink/af_netlink.c:2577
genl_rcv+0x40/0x60 net/netlink/genetlink.c:1076
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0xf41/0x1270 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x127d/0x1430 net/netlink/af_netlink.c:1942
sock_sendmsg_nosec net/socket.c:724 [inline]
sock_sendmsg net/socket.c:747 [inline]
____sys_sendmsg+0xa24/0xe40 net/socket.c:2501
___sys_sendmsg+0x2a1/0x3f0 net/socket.c:2555
__sys_sendmsg net/socket.c:2584 [inline]
__do_sys_sendmsg net/socket.c:2593 [inline]
__se_sys_sendmsg net/socket.c:2591 [inline]
__x64_sys_sendmsg+0x36b/0x540 net/socket.c:2591
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Uninit was stored to memory at:
tun_get_link_ksettings+0x37/0x60 drivers/net/tun.c:3544
__ethtool_get_link_ksettings+0x17b/0x260 net/ethtool/ioctl.c:441
ethnl_set_linkmodes+0xee/0x19d0 net/ethtool/linkmodes.c:327
ethnl_default_set_doit+0x88d/0xde0 net/ethtool/netlink.c:640
genl_family_rcv_msg_doit net/netlink/genetlink.c:968 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline]
genl_rcv_msg+0x141a/0x14c0 net/netlink/genetlink.c:1065
netlink_rcv_skb+0x3f8/0x750 net/netlink/af_netlink.c:2577
genl_rcv+0x40/0x60 net/netlink/genetlink.c:1076
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0xf41/0x1270 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x127d/0x1430 net/netlink/af_netlink.c:1942
sock_sendmsg_nosec net/socket.c:724 [inline]
sock_sendmsg net/socket.c:747 [inline]
____sys_sendmsg+0xa24/0xe40 net/socket.c:2501
___sys_sendmsg+0x2a1/0x3f0 net/socket.c:2555
__sys_sendmsg net/socket.c:2584 [inline]
__do_sys_sendmsg net/socket.c:2593 [inline]
__se_sys_sendmsg net/socket.c:2591 [inline]
__x64_sys_sendmsg+0x36b/0x540 net/socket.c:2591
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Uninit was stored to memory at:
tun_set_link_ksettings+0x37/0x60 drivers/net/tun.c:3553
ethtool_set_link_ksettings+0x600/0x690 net/ethtool/ioctl.c:609
__dev_ethtool net/ethtool/ioctl.c:3024 [inline]
dev_ethtool+0x1db9/0x2a70 net/ethtool/ioctl.c:3078
dev_ioctl+0xb07/0x1270 net/core/dev_ioctl.c:524
sock_do_ioctl+0x295/0x540 net/socket.c:1213
sock_ioctl+0x729/0xd90 net/socket.c:1316
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0x222/0x400 fs/ioctl.c:856
__x64_sys_ioctl+0x96/0xe0 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Local variable link_ksettings created at:
ethtool_set_link_ksettings+0x54/0x690 net/ethtool/ioctl.c:577
__dev_ethtool net/ethtool/ioctl.c:3024 [inline]
dev_ethtool+0x1db9/0x2a70 net/ethtool/ioctl.c:3078
Fixes:
|
||
|---|---|---|
| .. | ||
| 6lowpan | ||
| 9p | ||
| 802 | ||
| 8021q | ||
| appletalk | ||
| atm | ||
| ax25 | ||
| batman-adv | ||
| bluetooth | ||
| bpf | ||
| bpfilter | ||
| bridge | ||
| caif | ||
| can | ||
| ceph | ||
| core | ||
| dcb | ||
| dccp | ||
| devlink | ||
| dns_resolver | ||
| dsa | ||
| ethernet | ||
| ethtool | ||
| handshake | ||
| hsr | ||
| ieee802154 | ||
| ife | ||
| ipv4 | ||
| ipv6 | ||
| iucv | ||
| kcm | ||
| key | ||
| l2tp | ||
| l3mdev | ||
| lapb | ||
| llc | ||
| mac80211 | ||
| mac802154 | ||
| mctp | ||
| mpls | ||
| mptcp | ||
| ncsi | ||
| netfilter | ||
| netlabel | ||
| netlink | ||
| netrom | ||
| nfc | ||
| nsh | ||
| openvswitch | ||
| packet | ||
| phonet | ||
| psample | ||
| qrtr | ||
| rds | ||
| rfkill | ||
| rose | ||
| rxrpc | ||
| sched | ||
| sctp | ||
| smc | ||
| strparser | ||
| sunrpc | ||
| switchdev | ||
| tipc | ||
| tls | ||
| unix | ||
| vmw_vsock | ||
| wireless | ||
| x25 | ||
| xdp | ||
| xfrm | ||
| compat.c | ||
| devres.c | ||
| Kconfig | ||
| Kconfig.debug | ||
| Makefile | ||
| socket.c | ||
| sysctl_net.c | ||