* [PATCH net] ethtool: ioctl: fix potential NULL deref in ethtool_set_coalesce()
@ 2021-11-26 17:55 Julian Wiedmann
2021-11-26 19:30 ` patchwork-bot+netdevbpf
0 siblings, 1 reply; 2+ messages in thread
From: Julian Wiedmann @ 2021-11-26 17:55 UTC (permalink / raw)
To: David S. Miller, Jakub Kicinski, Yufeng Mo, Huazhong Tan
Cc: Julian Wiedmann, Andrew Lunn, Heiner Kallweit, netdev, linux-kernel
ethtool_set_coalesce() now uses both the .get_coalesce() and
.set_coalesce() callbacks. But the check for their availability is
buggy, so changing the coalesce settings on a device where the driver
provides only _one_ of the callbacks results in a NULL pointer
dereference instead of an -EOPNOTSUPP.
Fix the condition so that the availability of both callbacks is
ensured. This also matches the netlink code.
Note that reproducing this requires some effort - it only affects the
legacy ioctl path, and needs a specific combination of driver options:
- have .get_coalesce() and .coalesce_supported but no
.set_coalesce(), or
- have .set_coalesce() but no .get_coalesce(). Here eg. ethtool doesn't
cause the crash as it first attempts to call ethtool_get_coalesce()
and bails out on error.
Fixes: f3ccfda19319 ("ethtool: extend coalesce setting uAPI with CQE mode")
Cc: Yufeng Mo <moyufeng@huawei.com>
Cc: Huazhong Tan <tanhuazhong@huawei.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
---
net/ethtool/ioctl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 65e9bc1058b5..20bcf86970ff 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -1719,7 +1719,7 @@ static noinline_for_stack int ethtool_set_coalesce(struct net_device *dev,
struct ethtool_coalesce coalesce;
int ret;
- if (!dev->ethtool_ops->set_coalesce && !dev->ethtool_ops->get_coalesce)
+ if (!dev->ethtool_ops->set_coalesce || !dev->ethtool_ops->get_coalesce)
return -EOPNOTSUPP;
ret = dev->ethtool_ops->get_coalesce(dev, &coalesce, &kernel_coalesce,
--
2.32.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH net] ethtool: ioctl: fix potential NULL deref in ethtool_set_coalesce()
2021-11-26 17:55 [PATCH net] ethtool: ioctl: fix potential NULL deref in ethtool_set_coalesce() Julian Wiedmann
@ 2021-11-26 19:30 ` patchwork-bot+netdevbpf
0 siblings, 0 replies; 2+ messages in thread
From: patchwork-bot+netdevbpf @ 2021-11-26 19:30 UTC (permalink / raw)
To: Julian Wiedmann
Cc: davem, kuba, moyufeng, tanhuazhong, andrew, hkallweit1, netdev,
linux-kernel
Hello:
This patch was applied to netdev/net.git (master)
by Jakub Kicinski <kuba@kernel.org>:
On Fri, 26 Nov 2021 18:55:43 +0100 you wrote:
> ethtool_set_coalesce() now uses both the .get_coalesce() and
> .set_coalesce() callbacks. But the check for their availability is
> buggy, so changing the coalesce settings on a device where the driver
> provides only _one_ of the callbacks results in a NULL pointer
> dereference instead of an -EOPNOTSUPP.
>
> Fix the condition so that the availability of both callbacks is
> ensured. This also matches the netlink code.
>
> [...]
Here is the summary with links:
- [net] ethtool: ioctl: fix potential NULL deref in ethtool_set_coalesce()
https://git.kernel.org/netdev/net/c/0276af2176c7
You are awesome, thank you!
--
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