CVE-2024-26635

En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: llc: Eliminación del soporte para ETH_P_TR_802_2. syzbot informó un error de valor uninit a continuación. [0] llc admite ETH_P_802_2 (0x0004) y solía admitir ETH_P_TR_802_2 (0x0011), y syzbot abusó de este último para desencadenar el error. escribir$tun(r0, &(0x7f0000000040)={@val={0x0, 0x11}, @val, @mpls={[], @llc={@snap={0xaa, 0x1, ')', "90e5dd" }}}}, 0x16) llc_conn_handler() inicializa las variables locales {saddr,daddr}.mac basadas en skb en llc_pdu_decode_sa()/llc_pdu_decode_da() y las pasa a __llc_lookup(). Sin embargo, la inicialización se realiza solo cuando skb->protocol es htons(ETH_P_802_2); de lo contrario, __llc_lookup_establecido() y __llc_lookup_listener() leerán basura. La inicialización faltante existía antes de el commit 211ed865108e ("net: eliminar todas las instancias de procesamiento especial para Token Ring"). Quitó la parte para expulsar el token ring, pero se olvidó de cerrar la puerta permitiendo que los paquetes ETH_P_TR_802_2 se colaran en llc_rcv(). Eliminemos llc_tr_packet_type y completemos la desaprobación. [0]: ERROR: KMSAN: valor uninit en __llc_lookup_establecido+0xe9d/0xf90 __llc_lookup_establecido+0xe9d/0xf90 __llc_lookup net/llc/llc_conn.c:611 [en línea] llc_conn_handler+0x4bd/0x1360 net/llc/llc_conn.c:79 1 llc_rcv +0xfbb/0x14a0 net/llc/llc_input.c:206 __netif_receive_skb_one_core net/core/dev.c:5527 [en línea] __netif_receive_skb+0x1a6/0x5a0 net/core/dev.c:5641 netif_receive_skb_internal net/core/dev.c:5727 [en línea] netif_receive_skb+0x58/0x660 net/core/dev.c:5786 tun_rx_batched+0x3ee/0x980 drivers/net/tun.c:1555 tun_get_user+0x53af/0x66d0 drivers/net/tun.c:2002 tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2048 call_write_iter include/linux/fs.h:2020 [en línea] new_sync_write fs/read_write.c:491 [en línea] vfs_write+0x8ef/0x1490 fs/read_write.c:584 ksys_write+0x20f/0x4c0 fs/read_write.c:637 __do_sys_write fs/read_write.c:649 [en línea] __se_sys_write fs/read_write.c:646 [en línea] __x64_sys_write+0x93/0xd0 fs/read_write.c:646 do_syscall_x64 arch/x86/entry/common. c: 51 [en línea] do_syscall_64+0x44/0x110 arch/x86/entry/comunes.c: 82 entry_syscall_64_after_hwframe+0x63/0x6b local variable daddr creado FBB /0x14a0 net/llc/llc_input.c:206 CPU: 1 PID: 5004 Comm: syz-executor994 No contaminado 6.6.0-syzkaller-14500-g1c41041124bd #0 Nombre de hardware: Google Google Compute Engine/Google Compute Engine, BIOS Google 10 /09/2023

In the Linux kernel, the following vulnerability has been resolved: llc: Drop support for ETH_P_TR_802_2. syzbot reported an uninit-value bug below. [0] llc supports ETH_P_802_2 (0x0004) and used to support ETH_P_TR_802_2 (0x0011), and syzbot abused the latter to trigger the bug. write$tun(r0, &(0x7f0000000040)={@val={0x0, 0x11}, @val, @mpls={[], @llc={@snap={0xaa, 0x1, ')', "90e5dd"}}}}, 0x16) llc_conn_handler() initialises local variables {saddr,daddr}.mac based on skb in llc_pdu_decode_sa()/llc_pdu_decode_da() and passes them to __llc_lookup(). However, the initialisation is done only when skb->protocol is htons(ETH_P_802_2), otherwise, __llc_lookup_established() and __llc_lookup_listener() will read garbage. The missing initialisation existed prior to commit 211ed865108e ("net: delete all instances of special processing for token ring"). It removed the part to kick out the token ring stuff but forgot to close the door allowing ETH_P_TR_802_2 packets to sneak into llc_rcv(). Let's remove llc_tr_packet_type and complete the deprecation. [0]: BUG: KMSAN: uninit-value in __llc_lookup_established+0xe9d/0xf90 __llc_lookup_established+0xe9d/0xf90 __llc_lookup net/llc/llc_conn.c:611 [inline] llc_conn_handler+0x4bd/0x1360 net/llc/llc_conn.c:791 llc_rcv+0xfbb/0x14a0 net/llc/llc_input.c:206 __netif_receive_skb_one_core net/core/dev.c:5527 [inline] __netif_receive_skb+0x1a6/0x5a0 net/core/dev.c:5641 netif_receive_skb_internal net/core/dev.c:5727 [inline] netif_receive_skb+0x58/0x660 net/core/dev.c:5786 tun_rx_batched+0x3ee/0x980 drivers/net/tun.c:1555 tun_get_user+0x53af/0x66d0 drivers/net/tun.c:2002 tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2048 call_write_iter include/linux/fs.h:2020 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x8ef/0x1490 fs/read_write.c:584 ksys_write+0x20f/0x4c0 fs/read_write.c:637 __do_sys_write fs/read_write.c:649 [inline] __se_sys_write fs/read_write.c:646 [inline] __x64_sys_write+0x93/0xd0 fs/read_write.c:646 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b Local variable daddr created at: llc_conn_handler+0x53/0x1360 net/llc/llc_conn.c:783 llc_rcv+0xfbb/0x14a0 net/llc/llc_input.c:206 CPU: 1 PID: 5004 Comm: syz-executor994 Not tainted 6.6.0-syzkaller-14500-g1c41041124bd #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023

Zheng Wang discovered that the Broadcom FullMAC WLAN driver in the Linux kernel contained a race condition during device removal, leading to a use- after-free vulnerability. A physically proximate attacker could possibly use this to cause a denial of service. Sander Wiebing, Alvise de Faveri Tron, Herbert Bos, and Cristiano Giuffrida discovered that the Linux kernel mitigations for the initial Branch History Injection vulnerability were insufficient for Intel processors. A local attacker could potentially use this to expose sensitive information.