Wind River Support Network

Description

In the Linux kernel, the following vulnerability has been resolved:  net: rtnetlink: zero ifla_vf_broadcast to avoid stack infoleak in rtnl_fill_vfinfo  rtnl_fill_vfinfo() declares struct ifla_vf_broadcast on the stack without initialisation:  	struct ifla_vf_broadcast vf_broadcast;  The struct contains a single fixed 32-byte field:  	/* include/uapi/linux/if_link.h */ 	struct ifla_vf_broadcast { 		__u8 broadcast[32]; 	};  The function then copies dev->broadcast into it using dev->addr_len as the length:  	memcpy(vf_broadcast.broadcast, dev->broadcast, dev->addr_len);  On Ethernet devices (the overwhelming majority of SR-IOV NICs) dev->addr_len is 6, so only the first 6 bytes of broadcast[] are written. The remaining 26 bytes retain whatever was previously on the kernel stack. The full struct is then handed to userspace via:  	nla_put(skb, IFLA_VF_BROADCAST, 		sizeof(vf_broadcast), &vf_broadcast)  leaking up to 26 bytes of uninitialised kernel stack per VF per RTM_GETLINK request, repeatable.  The other vf_* structs in the same function are explicitly zeroed for exactly this reason - see the memset() calls for ivi, vf_vlan_info, node_guid and port_guid a few lines above. vf_broadcast was simply missed when it was added.  Reachability: any unprivileged local process can open AF_NETLINK / NETLINK_ROUTE without capabilities and send RTM_GETLINK with an IFLA_EXT_MASK attribute carrying RTEXT_FILTER_VF. The kernel walks each VF and emits IFLA_VF_BROADCAST, leaking 26 bytes of stack per VF per request. Stack residue at this call site can include return addresses and transient sensitive data; KASAN with stack instrumentation, or KMSAN, will flag the nla_put() when reproduced.  Zero the on-stack struct before the partial memcpy, matching the existing pattern used for the other vf_* structs in the same function.