Affected: Linux

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

net: hsr: avoid potential out-of-bound access in fill_frame_info()

syzbot is able to feed a packet with 14 bytes, pretending it is a vlan one.

Since fill_frame_info() is relying on skb->mac_len already, extend the check to cover this case.

BUG: KMSAN: uninit-value in fill_frame_info net/hsr/hsr_forward.c:709 [inline] BUG: KMSAN: uninit-value in hsr_forward_skb+0x9ee/0x3b10 net/hsr/hsr_forward.c:724 fill_frame_info net/hsr/hsr_forward.c:709 [inline] hsr_forward_skb+0x9ee/0x3b10 net/hsr/hsr_forward.c:724 hsr_dev_xmit+0x2f0/0x350 net/hsr/hsr_device.c:235 __netdev_start_xmit include/linux/netdevice.h:5002 [inline] netdev_start_xmit include/linux/netdevice.h:5011 [inline] xmit_one net/core/dev.c:3590 [inline] dev_hard_start_xmit+0x247/0xa20 net/core/dev.c:3606 __dev_queue_xmit+0x366a/0x57d0 net/core/dev.c:4434 dev_queue_xmit include/linux/netdevice.h:3168 [inline] packet_xmit+0x9c/0x6c0 net/packet/af_packet.c:276 packet_snd net/packet/af_packet.c:3146 [inline] packet_sendmsg+0x91ae/0xa6f0 net/packet/af_packet.c:3178 sock_sendmsg_nosec net/socket.c:711 [inline] __sock_sendmsg+0x30f/0x380 net/socket.c:726 __sys_sendto+0x594/0x750 net/socket.c:2197 __do_sys_sendto net/socket.c:2204 [inline] __se_sys_sendto net/socket.c:2200 [inline] __x64_sys_sendto+0x125/0x1d0 net/socket.c:2200 x64_sys_call+0x346a/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:45 do_syscall_x64 arch…