Commit f796a8de authored by Jiaming Zhang's avatar Jiaming Zhang Committed by Jakub Kicinski
Browse files

net: core: prevent NULL deref in generic_hwtstamp_ioctl_lower() 

The ethtool tsconfig Netlink path can trigger a null pointer
dereference. A call chain such as:

  tsconfig_prepare_data() ->
  dev_get_hwtstamp_phylib() ->
  vlan_hwtstamp_get() ->
  generic_hwtstamp_get_lower() ->
  generic_hwtstamp_ioctl_lower()

results in generic_hwtstamp_ioctl_lower() being called with
kernel_cfg->ifr as NULL.

The generic_hwtstamp_ioctl_lower() function does not expect
a NULL ifr and dereferences it, leading to a system crash.

Fix this by adding a NULL check for kernel_cfg->ifr in
generic_hwtstamp_ioctl_lower(). If ifr is NULL, return -EINVAL.

Fixes: 6e9e2eed ("net: ethtool: Add support for tsconfig command to get/set hwtstamp config")
Closes: https://lore.kernel.org/cd6a7056-fa6d-43f8-b78a-f5e811247ba8@linux.dev


Signed-off-by: default avatarJiaming Zhang <r772577952@gmail.com>
Reviewed-by: default avatarKory Maincent <kory.maincent@bootlin.com>
Link: https://patch.msgid.link/20251111173652.749159-2-r772577952@gmail.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 7410c86f

net/core/dev_ioctl.c

+3 −0
Original line number Diff line number Diff line
@@ -443,6 +443,9 @@ static int generic_hwtstamp_ioctl_lower(struct net_device *dev, int cmd, 
	struct ifreq ifrr;

	int err;



	if (!kernel_cfg->ifr)

		return -EINVAL;



	strscpy_pad(ifrr.ifr_name, dev->name, IFNAMSIZ);

	ifrr.ifr_ifru = kernel_cfg->ifr->ifr_ifru;