CVE-2024-26635

CVE Details

Release Date:

2024-03-18

Description

In the Linux kernel, the following vulnerability has been resolved:\nllc: Drop support for ETH_P_TR_802_2.\nsyzbot reported an uninit-value bug below. [0]\nllc supports ETH_P_802_2 (0x0004) and used to support ETH_P_TR_802_2\n(0x0011), and syzbot abused the latter to trigger the bug.\nwrite(r0, &(0x7f0000000040)={@val={0x0, 0x11}, @val, @mpls={[], @llc={@snap={0xaa, 0x1, ')', '90e5dd'}}}}, 0x16)\nllc_conn_handler() initialises local variables {saddr,daddr}.mac\nbased on skb in llc_pdu_decode_sa()/llc_pdu_decode_da() and passes\nthem to __llc_lookup().\nHowever, the initialisation is done only when skb->protocol is\nhtons(ETH_P_802_2), otherwise, __llc_lookup_established() and\n__llc_lookup_listener() will read garbage.\nThe missing initialisation existed prior to commit 211ed865108e\n('net: delete all instances of special processing for token ring').\nIt removed the part to kick out the token ring stuff but forgot to\nclose the door allowing ETH_P_TR_802_2 packets to sneak into llc_rcv().\nLet's remove llc_tr_packet_type and complete the deprecation.\n[0]:\nBUG: KMSAN: uninit-value in __llc_lookup_established+0xe9d/0xf90\n__llc_lookup_established+0xe9d/0xf90\n__llc_lookup net/llc/llc_conn.c:611 [inline]\nllc_conn_handler+0x4bd/0x1360 net/llc/llc_conn.c:791\nllc_rcv+0xfbb/0x14a0 net/llc/llc_input.c:206\n__netif_receive_skb_one_core net/core/dev.c:5527 [inline]\n__netif_receive_skb+0x1a6/0x5a0 net/core/dev.c:5641\nnetif_receive_skb_internal net/core/dev.c:5727 [inline]\nnetif_receive_skb+0x58/0x660 net/core/dev.c:5786\ntun_rx_batched+0x3ee/0x980 drivers/net/tun.c:1555\ntun_get_user+0x53af/0x66d0 drivers/net/tun.c:2002\ntun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2048\ncall_write_iter include/linux/fs.h:2020 [inline]\nnew_sync_write fs/read_write.c:491 [inline]\nvfs_write+0x8ef/0x1490 fs/read_write.c:584\nksys_write+0x20f/0x4c0 fs/read_write.c:637\n__do_sys_write fs/read_write.c:649 [inline]\n__se_sys_write fs/read_write.c:646 [inline]\n__x64_sys_write+0x93/0xd0 fs/read_write.c:646\ndo_syscall_x64 arch/x86/entry/common.c:51 [inline]\ndo_syscall_64+0x44/0x110 arch/x86/entry/common.c:82\nentry_SYSCALL_64_after_hwframe+0x63/0x6b\nLocal variable daddr created at:\nllc_conn_handler+0x53/0x1360 net/llc/llc_conn.c:783\nllc_rcv+0xfbb/0x14a0 net/llc/llc_input.c:206\nCPU: 1 PID: 5004 Comm: syz-executor994 Not tainted 6.6.0-syzkaller-14500-g1c41041124bd #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023

See more information about CVE-2024-26635 from MITRE CVE dictionary and NIST NVD

CVSS Scoring

NOTE: The following CVSS v3.1 metrics and score provided are preliminary and subject to review.

Base Score:	5.5	CVSS Vector:	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector:	Local network	Attack Complexity:	Low
Privileges Required:	Low	User Interaction:	None
Scope:	Unchanged	Confidentiality Impact:	None
Integrity Impact:	None	Availability Impact:	High

Errata information

Platform	Errata	Release Date
Oracle Linux version 6 (kernel-uek)	ELSA-2024-12606	2024-09-02
Oracle Linux version 7 (kernel-uek)	ELSA-2024-12606	2024-09-02
Oracle VM version 3 (kernel-uek)	OVMSA-2024-0011	2024-09-03