CVE-2024-26615

En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: net/smc: corrige el acceso ilegal a rmb_desc en el volcado de conexiones SMC-D Se encontró un bloqueo al volcar conexiones SMC-D. Se puede reproducir mediante los siguientes pasos: - ejecute la prueba nginx/wrk: smc_run nginx smc_run wrk -t 16 -c 1000 -d -H 'Conexión: Cerrar' - volcar continuamente las conexiones SMC-D en paralelo: watch -n 1 'smcss -D' ERROR: desreferencia del puntero NULL del kernel, dirección: 00000000000000030 CPU: 2 PID: 7204 Comm: smcss Kdump: cargado Contaminado: GE 6.7.0+ #55 RIP: 0010:__smc_diag_dump.constprop.0+ 0x5e5/0x620 [smc_diag] Seguimiento de llamadas: ? __morir+0x24/0x70 ? page_fault_oops+0x66/0x150? exc_page_fault+0x69/0x140? asm_exc_page_fault+0x26/0x30? __smc_diag_dump.constprop.0+0x5e5/0x620 [smc_diag] ? __kmalloc_node_track_caller+0x35d/0x430 ? __alloc_skb+0x77/0x170 smc_diag_dump_proto+0xd0/0xf0 [smc_diag] smc_diag_dump+0x26/0x60 [smc_diag] netlink_dump+0x19f/0x320 __netlink_dump_start+0x1dc/0x300 smc_diag_handler_dump+ 0x6a/0x80 [smc_diag] ? __pfx_smc_diag_dump+0x10/0x10 [smc_diag] sock_diag_rcv_msg+0x121/0x140 ? __pfx_sock_diag_rcv_msg+0x10/0x10 netlink_rcv_skb+0x5a/0x110 sock_diag_rcv+0x28/0x40 netlink_unicast+0x22a/0x330 netlink_sendmsg+0x1f8/0x420 __sock_sendmsg+0xb0/0xc0 ____s ys_sendmsg+0x24e/0x300? copy_msghdr_from_user+0x62/0x80 ___sys_sendmsg+0x7c/0xd0 ? __do_fault+0x34/0x160? do_read_fault+0x5f/0x100? do_fault+0xb0/0x110? __handle_mm_fault+0x2b0/0x6c0 __sys_sendmsg+0x4d/0x80 do_syscall_64+0x69/0x180 Entry_SYSCALL_64_after_hwframe+0x6e/0x76 Es posible que la conexión esté en proceso de establecerse cuando la volcamos. Se supone que la conexión ha sido registrada en un grupo de enlaces por smc_conn_create() pero rmb_desc aún no ha sido inicializado por smc_buf_create(), lo que provoca el acceso ilegal a conn->rmb_desc. Así que solucionelo comprobando antes del volcado.

A flaw was found in the Linux kernel in which functions providing information about SMC-D connections caused a NULL pointer dereference. This flaw allows an attacker with permission to read this information to cause a denial of service.

In the Linux kernel, the following vulnerability has been resolved: net/smc: fix illegal rmb_desc access in SMC-D connection dump A crash was found when dumping SMC-D connections. It can be reproduced by following steps: - run nginx/wrk test: smc_run nginx smc_run wrk -t 16 -c 1000 -d <duration> -H 'Connection: Close' <URL> - continuously dump SMC-D connections in parallel: watch -n 1 'smcss -D' BUG: kernel NULL pointer dereference, address: 0000000000000030 CPU: 2 PID: 7204 Comm: smcss Kdump: loaded Tainted: G E 6.7.0+ #55 RIP: 0010:__smc_diag_dump.constprop.0+0x5e5/0x620 [smc_diag] Call Trace: <TASK> ? __die+0x24/0x70 ? page_fault_oops+0x66/0x150 ? exc_page_fault+0x69/0x140 ? asm_exc_page_fault+0x26/0x30 ? __smc_diag_dump.constprop.0+0x5e5/0x620 [smc_diag] ? __kmalloc_node_track_caller+0x35d/0x430 ? __alloc_skb+0x77/0x170 smc_diag_dump_proto+0xd0/0xf0 [smc_diag] smc_diag_dump+0x26/0x60 [smc_diag] netlink_dump+0x19f/0x320 __netlink_dump_start+0x1dc/0x300 smc_diag_handler_dump+0x6a/0x80 [smc_diag] ? __pfx_smc_diag_dump+0x10/0x10 [smc_diag] sock_diag_rcv_msg+0x121/0x140 ? __pfx_sock_diag_rcv_msg+0x10/0x10 netlink_rcv_skb+0x5a/0x110 sock_diag_rcv+0x28/0x40 netlink_unicast+0x22a/0x330 netlink_sendmsg+0x1f8/0x420 __sock_sendmsg+0xb0/0xc0 ____sys_sendmsg+0x24e/0x300 ? copy_msghdr_from_user+0x62/0x80 ___sys_sendmsg+0x7c/0xd0 ? __do_fault+0x34/0x160 ? do_read_fault+0x5f/0x100 ? do_fault+0xb0/0x110 ? __handle_mm_fault+0x2b0/0x6c0 __sys_sendmsg+0x4d/0x80 do_syscall_64+0x69/0x180 entry_SYSCALL_64_after_hwframe+0x6e/0x76 It is possible that the connection is in process of being established when we dump it. Assumed that the connection has been registered in a link group by smc_conn_create() but the rmb_desc has not yet been initialized by smc_buf_create(), thus causing the illegal access to conn->rmb_desc. So fix it by checking before dump.

It was discovered that the Open vSwitch implementation in the Linux kernel could overflow its stack during recursive action operations under certain conditions. A local attacker could 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.