kernel/linux.git/net/ethtool/ioctl.c, branch v6.6.131

ethtool: Avoid overflowing userspace buffer on stats query

2026-01-11T14:21:47+00:00

[ Upstream commit 7b07be1ff1cb6c49869910518650e8d0abc7d25f ] The ethtool -S command operates across three ioctl calls: ETHTOOL_GSSET_INFO for the size, ETHTOOL_GSTRINGS for the names, and ETHTOOL_GSTATS for the values. If the number of stats changes between these calls (e.g., due to device reconfiguration), userspace's buffer allocation will be incorrect, potentially leading to buffer overflow. Drivers are generally expected to maintain stable stat counts, but some drivers (e.g., mlx5, bnx2x, bna, ksz884x) use dynamic counters, making this scenario possible. Some drivers try to handle this internally: - bnad_get_ethtool_stats() returns early in case stats.n_stats is not equal to the driver's stats count. - micrel/ksz884x also makes sure not to write anything beyond stats.n_stats and overflow the buffer. However, both use stats.n_stats which is already assigned with the value returned from get_sset_count(), hence won't solve the issue described here. Change ethtool_get_strings(), ethtool_get_stats(), ethtool_get_phy_stats() to not return anything in case of a mismatch between userspace's size and get_sset_size(), to prevent buffer overflow. The returned n_stats value will be equal to zero, to reflect that nothing has been returned. This could result in one of two cases when using upstream ethtool, depending on when the size change is detected: 1. When detected in ethtool_get_strings(): # ethtool -S eth2 no stats available 2. When detected in get stats, all stats will be reported as zero. Both cases are presumably transient, and a subsequent ethtool call should succeed. Other than the overflow avoidance, these two cases are very evident (no output/cleared stats), which is arguably better than presenting incorrect/shifted stats. I also considered returning an error instead of a "silent" response, but that seems more destructive towards userspace apps. Notes: - This patch does not claim to fix the inherent race, it only makes sure that we do not overflow the userspace buffer, and makes for a more predictable behavior. - RTNL lock is held during each ioctl, the race window exists between the separate ioctl calls when the lock is released. - Userspace ethtool always fills stats.n_stats, but it is likely that these stats ioctls are implemented in other userspace applications which might not fill it. The added code checks that it's not zero, to prevent any regressions. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reviewed-by: Dragos Tatulea Reviewed-by: Tariq Toukan Signed-off-by: Gal Pressman Link: https://patch.msgid.link/20251208121901.3203692-1-gal@nvidia.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

ethtool: check device is present when getting link settings

2024-09-04T11:28:26+00:00

[ Upstream commit a699781c79ecf6cfe67fb00a0331b4088c7c8466 ] A sysfs reader can race with a device reset or removal, attempting to read device state when the device is not actually present. eg: [exception RIP: qed_get_current_link+17] #8 [ffffb9e4f2907c48] qede_get_link_ksettings at ffffffffc07a994a [qede] #9 [ffffb9e4f2907cd8] __rh_call_get_link_ksettings at ffffffff992b01a3 #10 [ffffb9e4f2907d38] __ethtool_get_link_ksettings at ffffffff992b04e4 #11 [ffffb9e4f2907d90] duplex_show at ffffffff99260300 #12 [ffffb9e4f2907e38] dev_attr_show at ffffffff9905a01c #13 [ffffb9e4f2907e50] sysfs_kf_seq_show at ffffffff98e0145b #14 [ffffb9e4f2907e68] seq_read at ffffffff98d902e3 #15 [ffffb9e4f2907ec8] vfs_read at ffffffff98d657d1 #16 [ffffb9e4f2907f00] ksys_read at ffffffff98d65c3f #17 [ffffb9e4f2907f38] do_syscall_64 at ffffffff98a052fb crash> struct net_device.state ffff9a9d21336000 state = 5, state 5 is __LINK_STATE_START (0b1) and __LINK_STATE_NOCARRIER (0b100). The device is not present, note lack of __LINK_STATE_PRESENT (0b10). This is the same sort of panic as observed in commit 4224cfd7fb65 ("net-sysfs: add check for netdevice being present to speed_show"). There are many other callers of __ethtool_get_link_ksettings() which don't have a device presence check. Move this check into ethtool to protect all callers. Fixes: d519e17e2d01 ("net: export device speed and duplex via sysfs") Fixes: 4224cfd7fb65 ("net-sysfs: add check for netdevice being present to speed_show") Signed-off-by: Jamie Bainbridge Link: https://patch.msgid.link/8bae218864beaa44ed01628140475b9bf641c5b0.1724393671.git.jamie.bainbridge@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: ethtool: fix the error condition in ethtool_get_phy_stats_ethtool()

2024-06-21T12:38:20+00:00

[ Upstream commit 0dcc53abf58d572d34c5313de85f607cd33fc691 ] Clang static checker (scan-build) warning: net/ethtool/ioctl.c:line 2233, column 2 Called function pointer is null (null dereference). Return '-EOPNOTSUPP' when 'ops->get_ethtool_phy_stats' is NULL to fix this typo error. Fixes: 201ed315f967 ("net/ethtool/ioctl: split ethtool_get_phy_stats into multiple helpers") Signed-off-by: Su Hui Reviewed-by: Przemek Kitszel Reviewed-by: Hariprasad Kelam Link: https://lore.kernel.org/r/20240605034742.921751-1-suhui@nfschina.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

net: flow_dissector: Use 64bits for used_keys

2023-07-31T08:11:24+00:00

As 32bits of dissector->used_keys are exhausted, increase the size to 64bits. This is base change for ESP/AH flow dissector patch. Please find patch and discussions at https://lore.kernel.org/netdev/ZMDNjD46BvZ5zp5I@corigine.com/T/#t Signed-off-by: Ratheesh Kannoth Reviewed-by: Petr Machata # for mlxsw Tested-by: Petr Machata Reviewed-by: Martin Habets Reviewed-by: Simon Horman Reviewed-by: Vladimir Oltean Signed-off-by: David S. Miller

net: ethtool: Unify ETHTOOL_{G,S}RXFH rxnfc copy

2023-07-28T08:35:53+00:00

ETHTOOL_GRXFH correctly copies in the full struct ethtool_rxnfc when FLOW_RSS is set; ETHTOOL_SRXFH needs a similar code path to handle the FLOW_RSS case so that ethtool can set the flow hash for custom RSS contexts (if supported by the driver). The copy code from ETHTOOL_GRXFH has been pulled out in to a helper so that it can be called in both ETHTOOL_{G,S}RXFH code paths. Acked-by: Edward Cree Signed-off-by: Joe Damato Signed-off-by: David S. Miller

ethtool: ioctl: account for sopass diff in set_wol

2023-06-14T05:05:52+00:00

sopass won't be set if wolopt doesn't change. This means the following will fail to set the correct sopass. ethtool -s eth0 wol s sopass 11:22:33:44:55:66 ethtool -s eth0 wol s sopass 22:44:55:66:77:88 Make sure we call into the driver layer set_wol if sopass is different. Fixes: 55b24334c0f2 ("ethtool: ioctl: improve error checking for set_wol") Signed-off-by: Justin Chen Link: https://lore.kernel.org/r/1686605822-34544-1-git-send-email-justin.chen@broadcom.com Signed-off-by: Jakub Kicinski

ethtool: ioctl: improve error checking for set_wol

2023-06-09T02:24:54+00:00

The netlink version of set_wol checks for not supported wolopts and avoids setting wol when the correct wolopt is already set. If we do the same with the ioctl version then we can remove these checks from the driver layer. Reviewed-by: Simon Horman Signed-off-by: Justin Chen Reviewed-by: Florian Fainelli Link: https://lore.kernel.org/r/1686179653-29750-1-git-send-email-justin.chen@broadcom.com Signed-off-by: Jakub Kicinski

ethtool: Fix uninitialized number of lanes

2023-05-03T08:13:20+00:00

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: 012ce4dd3102 ("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 Signed-off-by: Ido Schimmel Reviewed-by: Leon Romanovsky Signed-off-by: David S. Miller

ipv6: Remove in6addr_any alternatives.

2023-03-29T07:22:52+00:00

Some code defines the IPv6 wildcard address as a local variable and use it with memcmp() or ipv6_addr_equal(). Let's use in6addr_any and ipv6_addr_any() instead. Signed-off-by: Kuniyuki Iwashima Reviewed-by: Mark Bloch Reviewed-by: David Ahern Signed-off-by: David S. Miller

net/ethtool/ioctl: split ethtool_get_phy_stats into multiple helpers

2022-12-28T11:55:24+00:00

So that it's easier to follow and make sense of the branching and various conditions. Stats retrieval has been split into two separate functions ethtool_get_phy_stats_phydev & ethtool_get_phy_stats_ethtool. The former attempts to retrieve the stats using phydev & phy_ops, while the latter uses ethtool_ops. Actual n_stats validation & array allocation has been moved into a new ethtool_vzalloc_stats_array helper. This also fixes a potential NULL dereference of ops->get_ethtool_phy_stats where it was getting called in an else branch unconditionally without making sure it was actually present. Found by Linux Verification Center (linuxtesting.org) with the SVACE static analysis tool. Signed-off-by: Daniil Tatianin Reviewed-by: Andrew Lunn Signed-off-by: David S. Miller