linux-stable/net/ethtool
Ido Schimmel 9ad685dbfe ethtool: Fix uninitialized number of lanes
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: 012ce4dd31 ("ethtool: Extend link modes settings uAPI with lanes")
Reported-and-tested-by: syzbot+ef6edd9f1baaa54d6235@syzkaller.appspotmail.com
Link: https://lore.kernel.org/netdev/0000000000004bb41105fa70f361@google.com/
Reviewed-by: Danielle Ratson <danieller@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2023-05-03 09:13:20 +01:00
..
bitset.c ethtool: fix stack overflow in ethnl_parse_bitset() 2020-12-09 15:50:38 -08:00
bitset.h ethtool: add ethnl_parse_bitset() helper 2020-03-12 15:32:32 -07:00
cabletest.c net: delete extra space and tab in blank line 2022-07-25 19:38:31 -07:00
channels.c ethtool: netlink: convert commands to common SET 2023-01-27 12:24:32 +00:00
coalesce.c net: ethtool: coalesce: try to make user settings stick twice 2023-04-24 18:09:49 -07:00
common.c drivers/net/phy: add the link modes for the 10BASE-T1S Ethernet PHY 2023-01-11 08:35:02 +00:00
common.h net: ethtool: netlink: retrieve stats from multiple sources (eMAC, pMAC) 2023-01-23 12:44:18 +00:00
debug.c ethtool: netlink: convert commands to common SET 2023-01-27 12:24:32 +00:00
eee.c ethtool: netlink: convert commands to common SET 2023-01-27 12:24:32 +00:00
eeprom.c ethtool: eeprom: fix null-deref on genl_info in dump 2022-10-24 19:08:07 -07:00
features.c ethtool: use ethnl_parse_header_dev_put() 2021-12-15 10:27:47 +00:00
fec.c ethtool: netlink: convert commands to common SET 2023-01-27 12:24:32 +00:00
ioctl.c ethtool: Fix uninitialized number of lanes 2023-05-03 09:13:20 +01:00
linkinfo.c ethtool: netlink: convert commands to common SET 2023-01-27 12:24:32 +00:00
linkmodes.c ethtool: reset #lanes when lanes is omitted 2023-04-04 18:57:10 -07:00
linkstate.c ethtool: linkstate: add a statistic for PHY down events 2022-11-08 10:36:54 +01:00
Makefile net: ethtool: add support for MAC Merge layer 2023-01-23 12:44:18 +00:00
mm.c net: ethtool: mm: sanitize some UAPI configurations 2023-04-20 20:03:21 -07:00
module.c ethtool: netlink: convert commands to common SET 2023-01-27 12:24:32 +00:00
netlink.c ethtool: netlink: convert commands to common SET 2023-01-27 12:24:32 +00:00
netlink.h ethtool: Add support for configuring tx_push_buf_len 2023-03-27 19:49:58 -07:00
pause.c ethtool: netlink: handle SET intro/outro in the common code 2023-01-27 12:24:31 +00:00
phc_vclocks.c ethtool: add a new command for getting PHC virtual clocks 2021-07-01 13:08:18 -07:00
plca.c ethtool: netlink: convert commands to common SET 2023-01-27 12:24:32 +00:00
privflags.c ethtool: netlink: convert commands to common SET 2023-01-27 12:24:32 +00:00
pse-pd.c ethtool: pse-pd: Fix double word in comments 2023-02-21 09:02:13 -08:00
rings.c ethtool: Add support for configuring tx_push_buf_len 2023-03-27 19:49:58 -07:00
rss.c ethtool: add netlink attr in rss get reply only if value is not null 2023-01-12 21:52:46 -08:00
stats.c net: ethtool: fix NULL pointer dereference in stats_prepare_data() 2023-01-25 09:56:31 +00:00
strset.c ethtool: strset: report missing ETHTOOL_A_STRINGSET_ID via ext_ack 2022-08-30 12:20:43 +02:00
tsinfo.c ethtool: link up ethnl_header_policy as a nested policy 2020-10-06 06:25:55 -07:00
tunnels.c ethtool: tunnels: check the return value of nla_nest_start() 2022-09-22 19:28:10 -07:00
wol.c ethtool: netlink: convert commands to common SET 2023-01-27 12:24:32 +00:00