Vulnerabilidad en kernel de Linux (CVE-2024-50035)

En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ppp: se corrige el acceso ilegal a ppp_async_encode() syzbot informó un problema en ppp_async_encode() [1] En este caso, se llama a pppoe_sendmsg() con un tamaño cero. Luego, se llama a ppp_async_encode() con un skb vacío. ERROR: KMSAN: valor no inicializado en ppp_async_encode drivers/net/ppp/ppp_async.c:545 [en línea] ERROR: KMSAN: valor no inicializado en ppp_async_push+0xb4f/0x2660 drivers/net/ppp/ppp_async.c:675 ppp_async_encode drivers/net/ppp/ppp_async.c:545 [en línea] ppp_async_push+0xb4f/0x2660 drivers/net/ppp/ppp_async.c:675 ppp_async_send+0x130/0x1b0 drivers/net/ppp/ppp_async.c:634 ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2280 [en línea] ppp_input+0x1f1/0xe60 drivers/net/ppp/ppp_generic.c:2304 pppoe_rcv_core+0x1d3/0x720 drivers/net/ppp/pppoe.c:379 sk_backlog_rcv+0x13b/0x420 include/net/sock.h:1113 __release_sock+0x1da/0x330 net/core/sock.c:3072 release_sock+0x6b/0x250 net/core/sock.c:3626 pppoe_sendmsg+0x2b8/0xb90 drivers/net/ppp/pppoe.c:903 sock_sendmsg_nosec net/socket.c:729 [en línea] __sock_sendmsg+0x30f/0x380 red/socket.c:744 ____sys_sendmsg+0x903/0xb60 red/socket.c:2602 ___sys_sendmsg+0x28d/0x3c0 red/socket.c:2656 __sys_sendmmsg+0x3c1/0x960 red/socket.c:2742 __do_sys_sendmmsg red/socket.c:2771 [en línea] __se_sys_sendmmsg red/socket.c:2768 [en línea] __x64_sys_sendmmsg+0xbc/0x120 red/socket.c:2768 x64_sys_call+0xb6e/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:308 do_syscall_x64 arch/x86/entry/common.c:52 [en línea] do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit se creó en: slab_post_alloc_hook mm/slub.c:4092 [en línea] slab_alloc_node mm/slub.c:4135 [en línea] kmem_cache_alloc_node_noprof+0x6bf/0xb80 mm/slub.c:4187 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:587 __alloc_skb+0x363/0x7b0 red/core/skbuff.c:678 alloc_skb include/linux/skbuff.h:1322 [en línea] sock_wmalloc+0xfe/0x1a0 red/core/sock.c:2732 pppoe_sendmsg+0x3a7/0xb90 drivers/net/ppp/pppoe.c:867 sock_sendmsg_nosec red/socket.c:729 [en línea] __sock_sendmsg+0x30f/0x380 red/socket.c:744 ____sys_sendmsg+0x903/0xb60 red/socket.c:2602 ___sys_sendmsg+0x28d/0x3c0 red/socket.c:2656 __sys_sendmmsg+0x3c1/0x960 red/socket.c:2742 __do_sys_sendmmsg red/socket.c:2771 [en línea] __se_sys_sendmmsg red/socket.c:2768 [en línea] __x64_sys_sendmmsg+0xbc/0x120 red/socket.c:2768 x64_sys_call+0xb6e/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:308 do_syscall_x64 arch/x86/entry/common.c:52 [en línea] do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f CPU: 1 UID: 0 PID: 5411 Comm: syz.1.14 No contaminado 6.12.0-rc1-syzkaller-00165-g360c1f1f24c6 #0 Nombre del hardware: Google Google Compute Engine/Google Compute Engine, BIOS Google 13/09/2024