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 <[email protected]>
Cc: Huazhong Tan <[email protected]>
Cc: Andrew Lunn <[email protected]>
Cc: Heiner Kallweit <[email protected]>
Signed-off-by: Julian Wiedmann <[email protected]>
---
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
Hello:
This patch was applied to netdev/net.git (master)
by Jakub Kicinski <[email protected]>:
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!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html