Title: kernel de Linux
Description: En el kernel de Linux, se resolvió la siguiente vulnerabilidad: af_unix: corrige el bloqueo positivo en sk_diag_dump_icons() syzbot informó un bloqueo del bloqueo [1]. La confirmación culpada insinuó la posible violación de lockdep y el código usó unix_state_lock_nested() en un intento de silenciar lockdep. No es suficiente, porque unix_state_lock_nested() ya se usa desde unix_state_double_lock(). Necesitamos usar una subclase separada. Este parche agrega una enumeración distinta para hacer las cosas más explícitas. Utilice también swap() en unix_state_double_lock() como limpieza. v2: agregue una palabra clave en línea faltante a unix_state_lock_nested() [1] ADVERTENCIA: se detectó posible dependencia de bloqueo circular 6.8.0-rc1-syzkaller-00356-g8a696a29c690 #0 No contaminado syz-executor.1/2542 está intentando adquirir el bloqueo: ffff88808b5df9e8 (rlock-AF_UNIX){+.+.}-{2:2}, en: skb_queue_tail+0x36/0x120 net/core/skbuff.c:3863 pero la tarea ya mantiene el bloqueo: ffff88808b5dfe70 (&u->lock/1) {+.+.}-{2:2}, en: unix_dgram_sendmsg+0xfc7/0x2200 net/unix/af_unix.c:2089 cuyo bloqueo ya depende del nuevo bloqueo. la cadena de dependencia existente (en orden inverso) es: -> #1 (&u->lock/1){+.+.}-{2:2}: lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754 _raw_spin_lock_nested+0x31/0x40 kernel/locking/spinlock.c:378 sk_diag_dump_icons net/unix/diag.c:87 [en línea] sk_diag_fill+0x6ea/0xfe0 net/unix/diag.c:157 sk_diag_dump net/unix/diag.c: 196 [en línea] unix_diag_dump+0x3e9/0x630 net/unix/diag.c:220 netlink_dump+0x5c1/0xcd0 net/netlink/af_netlink.c:2264 __netlink_dump_start+0x5d7/0x780 net/netlink/af_netlink.c:2370 netlink_dump_start include/linux /netlink.h:338 [en línea] unix_diag_handler_dump+0x1c3/0x8f0 net/unix/diag.c:319 sock_diag_rcv_msg+0xe3/0x400 netlink_rcv_skb+0x1df/0x430 net/netlink/af_netlink.c:2543 sock_diag_rcv+0x2a/0x 40 neto/núcleo /sock_diag.c:280 netlink_unicast_kernel net/netlink/af_netlink.c:1341 [en línea] netlink_unicast+0x7e6/0x980 net/netlink/af_netlink.c:1367 netlink_sendmsg+0xa37/0xd70 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/ socket.c:730 [en línea] __sock_sendmsg net/socket.c:745 [en línea] sock_write_iter+0x39a/0x520 net/socket.c:1160 call_write_iter include/linux/fs.h:2085 [en línea] new_sync_write fs/read_write.c :497 [en línea] vfs_write+0xa74/0xca0 fs/read_write.c:590 ksys_write+0x1a0/0x2c0 fs/read_write.c:643 do_syscall_x64 arch/x86/entry/common.c:52 [en línea] do_syscall_64+0xf5/0x230 arch /x86/entry/common.c:83 Entry_SYSCALL_64_after_hwframe+0x63/0x6b -> #0 (rlock-AF_UNIX){+.+.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3134 [en línea] check_prevs_add kernel/locking/lockdep.c:3253 [en línea] validar_chain+0x1909/0x5ab0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1345/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1e3/0x530 kernel/locking/ lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [en línea] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 skb_queue_tail+0x36/0x120 net/core/skbuff.c:3863 unix_dgram_send mensaje+0x15d9/ 0x2200 net/unix/af_unix.c:2112 sock_sendmsg_nosec net/socket.c:730 [en línea] __sock_sendmsg net/socket.c:745 [en línea] ____sys_sendmsg+0x592/0x890 net/socket.c:2584 ___sys_sendmsg net/socket.c :2638 [en línea] __sys_sendmmsg+0x3b2/0x730 net/socket.c:2724 __do_sys_sendmmsg net/socket.c:2753 [en línea] __se_sys_sendmmsg net/socket.c:2750 [en línea] __x64_sys_sendmmsg+0xa0/0xb0 net /socket.c: 2750 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x230 arch/x86/entry/common.c:83 Entry_SYSCALL_64_after_hwframe+0x63/0x6b otra información que podría ayudarnos a depurar esto: Posible escenario de bloqueo inseguro : CPU0 ---truncado---

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

af_unix: fix lockdep positive in sk_diag_dump_icons()

syzbot reported a lockdep splat [1].

Blamed commit hinted about the possible lockdep
violation, and code used unix_state_lock_nested()
in an attempt to silence lockdep.

It is not sufficient, because unix_state_lock_nested()
is already used from unix_state_double_lock().

We need to use a separate subclass.

This patch adds a distinct enumeration to make things
more explicit.

Also use swap() in unix_state_double_lock() as a clean up.

v2: add a missing inline keyword to unix_state_lock_nested()

[1]
WARNING: possible circular locking dependency detected
6.8.0-rc1-syzkaller-00356-g8a696a29c690 #0 Not tainted

syz-executor.1/2542 is trying to acquire lock:
 ffff88808b5df9e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: skb_queue_tail+0x36/0x120 net/core/skbuff.c:3863

but task is already holding lock:
 ffff88808b5dfe70 (&u->lock/1){+.+.}-{2:2}, at: unix_dgram_sendmsg+0xfc7/0x2200 net/unix/af_unix.c:2089

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&u->lock/1){+.+.}-{2:2}:
        lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754
        _raw_spin_lock_nested+0x31/0x40 kernel/locking/spinlock.c:378
        sk_diag_dump_icons net/unix/diag.c:87 [inline]
        sk_diag_fill+0x6ea/0xfe0 net/unix/diag.c:157
        sk_diag_dump net/unix/diag.c:196 [inline]
        unix_diag_dump+0x3e9/0x630 net/unix/diag.c:220
        netlink_dump+0x5c1/0xcd0 net/netlink/af_netlink.c:2264
        __netlink_dump_start+0x5d7/0x780 net/netlink/af_netlink.c:2370
        netlink_dump_start include/linux/netlink.h:338 [inline]
        unix_diag_handler_dump+0x1c3/0x8f0 net/unix/diag.c:319
       sock_diag_rcv_msg+0xe3/0x400
        netlink_rcv_skb+0x1df/0x430 net/netlink/af_netlink.c:2543
        sock_diag_rcv+0x2a/0x40 net/core/sock_diag.c:280
        netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline]
        netlink_unicast+0x7e6/0x980 net/netlink/af_netlink.c:1367
        netlink_sendmsg+0xa37/0xd70 net/netlink/af_netlink.c:1908
        sock_sendmsg_nosec net/socket.c:730 [inline]
        __sock_sendmsg net/socket.c:745 [inline]
        sock_write_iter+0x39a/0x520 net/socket.c:1160
        call_write_iter include/linux/fs.h:2085 [inline]
        new_sync_write fs/read_write.c:497 [inline]
        vfs_write+0xa74/0xca0 fs/read_write.c:590
        ksys_write+0x1a0/0x2c0 fs/read_write.c:643
        do_syscall_x64 arch/x86/entry/common.c:52 [inline]
        do_syscall_64+0xf5/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x63/0x6b

-> #0 (rlock-AF_UNIX){+.+.}-{2:2}:
        check_prev_add kernel/locking/lockdep.c:3134 [inline]
        check_prevs_add kernel/locking/lockdep.c:3253 [inline]
        validate_chain+0x1909/0x5ab0 kernel/locking/lockdep.c:3869
        __lock_acquire+0x1345/0x1fd0 kernel/locking/lockdep.c:5137
        lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754
        __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
        _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
        skb_queue_tail+0x36/0x120 net/core/skbuff.c:3863
        unix_dgram_sendmsg+0x15d9/0x2200 net/unix/af_unix.c:2112
        sock_sendmsg_nosec net/socket.c:730 [inline]
        __sock_sendmsg net/socket.c:745 [inline]
        ____sys_sendmsg+0x592/0x890 net/socket.c:2584
        ___sys_sendmsg net/socket.c:2638 [inline]
        __sys_sendmmsg+0x3b2/0x730 net/socket.c:2724
        __do_sys_sendmmsg net/socket.c:2753 [inline]
        __se_sys_sendmmsg net/socket.c:2750 [inline]
        __x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2750
        do_syscall_x64 arch/x86/entry/common.c:52 [inline]
        do_syscall_64+0xf5/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x63/0x6b

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0             
---truncated---

Rejected reason: This CVE ID has been rejected or withdrawn by its CVE Numbering Authority.

kernel.org https://git.kernel.org/stable/c/4d322dce82a1d44f8c83f0f54f95dd1b8dcf46c9

kernel.org https://git.kernel.org/stable/c/5e7f3e0381c002cb2abde42f09ad511991a8ebaf

kernel.org https://git.kernel.org/stable/c/875f31aaa67e306098befa5e798a049075910fa7

kernel.org https://git.kernel.org/stable/c/a2104f43876408b164be5fd58f9b6a3a73b77746

kernel.org https://git.kernel.org/stable/c/b169ffde733c5adf01788ae091c377f0eca44806

kernel.org https://git.kernel.org/stable/c/c2d272a9a1e8f22ba584589219f6fe1886a3595f

kernel.org https://git.kernel.org/stable/c/c8f6b3b864cb876e9ee21666a391c9ee290682ac

kernel.org https://git.kernel.org/stable/c/f199018dc762dfa501f6d96a424468a0f3c10d9e