In the Linux kernel, the following vulnerability has been resolved: tap: fix stack info leak in...

In the Linux kernel, the following vulnerability has been resolved:

tap: fix stack info leak in tap_ioctl() SIOCGIFHWADDR

In the SIOCGIFHWADDR path, tap_ioctl() copies 16 bytes of an uninitialised on-stack struct sockaddr_storage to userspace via ifr_hwaddr, but netif_get_mac_address() only writes sa_family and dev->addr_len (6 for Ethernet) bytes, leaving sa_data[6..13] uninitialised.

Those 8 trailing bytes leak kernel stack contents; SIOCGIFHWADDR on a macvtap chardev returns kernel .text and direct-map pointers, defeating KASLR.

Initialise ss at declaration.