vulnerability

Amazon Linux AMI: CVE-2022-48651: Security patch for kernel (ALAS-2022-1645)

Severity
7
CVSS
(AV:L/AC:L/Au:N/C:N/I:C/A:C)
Published
12/01/2022
Added
07/04/2024
Modified
02/18/2025

Description

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



ipvlan: Fix out-of-bound bugs caused by unset skb->mac_header



If an AF_PACKET socket is used to send packets through ipvlan and the


default xmit function of the AF_PACKET socket is changed from


dev_queue_xmit() to packet_direct_xmit() via setsockopt() with the option


name of PACKET_QDISC_BYPASS, the skb->mac_header may not be reset and


remains as the initial value of 65535, this may trigger slab-out-of-bounds


bugs 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+ #6


ardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33


all Trace:


print_address_description.constprop.0+0x1d/0x160


print_report.cold+0x4f/0x112


kasan_report+0xa3/0x130


ipvlan_xmit_mode_l2+0xdb/0x330 [ipvlan]


ipvlan_start_xmit+0x29/0xa0 [ipvlan]


__dev_direct_xmit+0x2e2/0x380


packet_direct_xmit+0x22/0x60


packet_snd+0x7c9/0xc40


sock_sendmsg+0x9a/0xa0


__sys_sendto+0x18a/0x230


__x64_sys_sendto+0x74/0x90


do_syscall_64+0x3b/0x90


entry_SYSCALL_64_after_hwframe+0x63/0xcd



The 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() is


called. So when ipvlan_xmit_mode_l2() gets mac header with eth_hdr() which


use "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.

Solution

amazon-linux-upgrade-kernel
Title
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