Entreprise française de cybersécurité depuis 2004
☎ 03 60 47 09 81 - info@securiteinfo.com
☎ 03 60 47 09 81 - info@securiteinfo.com
In the Linux kernel, the following vulnerability has been resolved:ipvlan: Fix out-of-bound bugs caused by unset skb->mac_headerIf an AF_PACKET socket is used to send packets through ipvlan and thedefault xmit function of the AF_PACKET socket is changed fromdev_queue_xmit() to packet_direct_xmit() via setsockopt() with the optionname of PACKET_QDISC_BYPASS, the skb->mac_header may not be reset andremains as the initial value of 65535, this may trigger slab-out-of-boundsbugs as following:=================================================================UG: KASAN: slab-out-of-bounds in ipvlan_xmit_mode_l2+0xdb/0x330 [ipvlan]PU: 2 PID: 1768 Comm: raw_send Kdump: loaded Not tainted 6.0.0-rc4+ #6ardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33all Trace:print_address_description.constprop.0+0x1d/0x160print_report.cold+0x4f/0x112kasan_report+0xa3/0x130ipvlan_xmit_mode_l2+0xdb/0x330 [ipvlan]ipvlan_start_xmit+0x29/0xa0 [ipvlan]__dev_direct_xmit+0x2e2/0x380packet_direct_xmit+0x22/0x60packet_snd+0x7c9/0xc40sock_sendmsg+0x9a/0xa0__sys_sendto+0x18a/0x230__x64_sys_sendto+0x74/0x90do_syscall_64+0x3b/0x90entry_SYSCALL_64_after_hwframe+0x63/0xcdThe root cause is: 1. packet_snd() only reset skb->mac_header when sock->type is SOCK_RAW and skb->protocol is not specified as in packet_parse_headers() 2. packet_direct_xmit() doesn't reset skb->mac_header as dev_queue_xmit()In this case, skb->mac_header is 65535 when ipvlan_xmit_mode_l2() iscalled. So when ipvlan_xmit_mode_l2() gets mac header with eth_hdr() whichuse "skb->head + skb->mac_header", out-of-bound access occurs.This patch replaces eth_hdr() with skb_eth_hdr() in ipvlan_xmit_mode_l2()and reset mac header in multicast to solve this out-of-bound bug.
No PoCs from references.
- https://github.com/fkie-cad/nvd-json-data-feeds