From: Jiaming Zhang Date: Tue, 11 Nov 2025 17:36:52 +0000 (+0800) Subject: net: core: prevent NULL deref in generic_hwtstamp_ioctl_lower() X-Git-Tag: v6.18-rc7~25^2~24 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f796a8dec9beafcc0f6f0d3478ed685a15c5e062;p=thirdparty%2Flinux.git 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: 6e9e2eed4f39 ("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: Jiaming Zhang Reviewed-by: Kory Maincent Link: https://patch.msgid.link/20251111173652.749159-2-r772577952@gmail.com Signed-off-by: Jakub Kicinski --- diff --git a/net/core/dev_ioctl.c b/net/core/dev_ioctl.c index ad54b12d4b4c..8bb71a10dba0 100644 --- a/net/core/dev_ioctl.c +++ b/net/core/dev_ioctl.c @@ -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;