CVE-2022-48651

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ipvlan: Fix out-of-bound bugs caused by unset skb-&gt;mac_header<br /> <br /> If an AF_PACKET socket is used to send packets through ipvlan and the<br /> default xmit function of the AF_PACKET socket is changed from<br /> dev_queue_xmit() to packet_direct_xmit() via setsockopt() with the option<br /> name of PACKET_QDISC_BYPASS, the skb-&gt;mac_header may not be reset and<br /> remains as the initial value of 65535, this may trigger slab-out-of-bounds<br /> bugs as following:<br /> <br /> =================================================================<br /> UG: KASAN: slab-out-of-bounds in ipvlan_xmit_mode_l2+0xdb/0x330 [ipvlan]<br /> PU: 2 PID: 1768 Comm: raw_send Kdump: loaded Not tainted 6.0.0-rc4+ #6<br /> ardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33<br /> all Trace:<br /> print_address_description.constprop.0+0x1d/0x160<br /> print_report.cold+0x4f/0x112<br /> kasan_report+0xa3/0x130<br /> ipvlan_xmit_mode_l2+0xdb/0x330 [ipvlan]<br /> ipvlan_start_xmit+0x29/0xa0 [ipvlan]<br /> __dev_direct_xmit+0x2e2/0x380<br /> packet_direct_xmit+0x22/0x60<br /> packet_snd+0x7c9/0xc40<br /> sock_sendmsg+0x9a/0xa0<br /> __sys_sendto+0x18a/0x230<br /> __x64_sys_sendto+0x74/0x90<br /> do_syscall_64+0x3b/0x90<br /> entry_SYSCALL_64_after_hwframe+0x63/0xcd<br /> <br /> The root cause is:<br /> 1. packet_snd() only reset skb-&gt;mac_header when sock-&gt;type is SOCK_RAW<br /> and skb-&gt;protocol is not specified as in packet_parse_headers()<br /> <br /> 2. packet_direct_xmit() doesn&amp;#39;t reset skb-&gt;mac_header as dev_queue_xmit()<br /> <br /> In this case, skb-&gt;mac_header is 65535 when ipvlan_xmit_mode_l2() is<br /> called. So when ipvlan_xmit_mode_l2() gets mac header with eth_hdr() which<br /> use "skb-&gt;head + skb-&gt;mac_header", out-of-bound access occurs.<br /> <br /> This patch replaces eth_hdr() with skb_eth_hdr() in ipvlan_xmit_mode_l2()<br /> and reset mac header in multicast to solve this out-of-bound bug.