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| author | Jamie Bainbridge <jamie.bainbridge@gmail.com> | 2024-08-23 09:26:58 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2024-08-27 00:03:02 +0300 |
| commit | a699781c79ecf6cfe67fb00a0331b4088c7c8466 (patch) | |
| tree | baf43993872e70ff7388dea84d6543244fe74bc0 | |
| parent | 31a972959ae57691a1e4f539399b2674ae576086 (diff) | |
| download | linux-a699781c79ecf6cfe67fb00a0331b4088c7c8466.tar.xz | |
ethtool: check device is present when getting link settings
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 <jamie.bainbridge@gmail.com>
Link: https://patch.msgid.link/8bae218864beaa44ed01628140475b9bf641c5b0.1724393671.git.jamie.bainbridge@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/core/net-sysfs.c | 2 | ||||
| -rw-r--r-- | net/ethtool/ioctl.c | 3 |
2 files changed, 4 insertions, 1 deletions
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index 0e2084ce7b75..444f23e74f8e 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -235,7 +235,7 @@ static ssize_t speed_show(struct device *dev, if (!rtnl_trylock()) return restart_syscall(); - if (netif_running(netdev) && netif_device_present(netdev)) { + if (netif_running(netdev)) { struct ethtool_link_ksettings cmd; if (!__ethtool_get_link_ksettings(netdev, &cmd)) diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c index e18823bf2330..ae041f51cd2d 100644 --- a/net/ethtool/ioctl.c +++ b/net/ethtool/ioctl.c @@ -442,6 +442,9 @@ int __ethtool_get_link_ksettings(struct net_device *dev, if (!dev->ethtool_ops->get_link_ksettings) return -EOPNOTSUPP; + if (!netif_device_present(dev)) + return -ENODEV; + memset(link_ksettings, 0, sizeof(*link_ksettings)); return dev->ethtool_ops->get_link_ksettings(dev, link_ksettings); } |