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authorJulian Wiedmann <jwi@linux.ibm.com>2021-11-26 18:55:43 +0100
committerJakub Kicinski <kuba@kernel.org>2021-11-26 11:17:47 -0800
commit0276af2176c78771da7f311621a25d7608045827 (patch)
tree06475cc9bb118ed3cdc85bc8ec51391df235f7b9 /net
parentc26381f97e2a7df43826150dc7d4c207bd6794a5 (diff)
ethtool: ioctl: fix potential NULL deref in ethtool_set_coalesce()
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> Link: https://lore.kernel.org/r/20211126175543.28000-1-jwi@linux.ibm.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/ethtool/ioctl.c2
1 files changed, 1 insertions, 1 deletions
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,