Vulnerabilidad en kernel de Linux (CVE-2023-52446)

En el kernel de Linux, se resolvió la siguiente vulnerabilidad: bpf: corrige una condición de ejecución entre btf_put() y map_free() Al ejecutar `./test_progs -j` en mi máquina virtual local con el último kernel, una vez encontré un error kasan como a continuación: [ 1887.184724] ERROR: KASAN: slab-use-after-free en bpf_rb_root_free+0x1f8/0x2b0 [ 1887.185599] Lectura del tamaño 4 en la dirección ffff888106806910 por tarea kworker/u12:2/2830 [ 1887.186498] [ 1887.186712] CPU: 3 PID: 2830 Comm: kworker/u12:2 Contaminado: G OEL 6.7.0-rc3-00699-g90679706d486-dirty #494 [1887.188034] Nombre de hardware: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0 -0-g155821a1990b-prebuilt.qemu.org 01/04/2014 [1887.189618] Cola de trabajo: events_unbound bpf_map_free_deferred [1887.190341] Seguimiento de llamadas: [1887.190666] [1887.190949] dump_stack_lv l+0xac/0xe0 [ 1887.191423] ? nf_tcp_handle_invalid+0x1b0/0x1b0 [1887.192019]? pánico+0x3c0/0x3c0 [ 1887.192449] print_report+0x14f/0x720 [ 1887.192930] ? preempt_count_sub+0x1c/0xd0 [1887.193459]? __virt_addr_valid+0xac/0x120 [1887.194004]? bpf_rb_root_free+0x1f8/0x2b0 [ 1887.194572] kasan_report+0xc3/0x100 [ 1887.195085] ? bpf_rb_root_free+0x1f8/0x2b0 [ 1887.195668] bpf_rb_root_free+0x1f8/0x2b0 [ 1887.196183] ? __bpf_obj_drop_impl+0xb0/0xb0 [1887.196736]? preempt_count_sub+0x1c/0xd0 [1887.197270]? preempt_count_sub+0x1c/0xd0 [1887.197802]? _raw_spin_unlock+0x1f/0x40 [ 1887.198319] bpf_obj_free_fields+0x1d4/0x260 [ 1887.198883] array_map_free+0x1a3/0x260 [ 1887.199380] bpf_map_free_deferred+0x7b/0xe0 [ 18 87.199943] Process_scheduled_works+0x3a2/0x6c0 [1887.200549] trabajador_thread+0x633/0x890 [1887.201047]? __kthread_parkme+0xd7/0xf0 [ 1887.201574] ? kthread+0x102/0x1d0 [ 1887.202020] kthread+0x1ab/0x1d0 [ 1887.202447] ? pr_cont_work+0x270/0x270 [1887.202954]? kthread_blkcg+0x50/0x50 [ 1887.203444] ret_from_fork+0x34/0x50 [ 1887.203914] ? kthread_blkcg+0x50/0x50 [ 1887.204397] ret_from_fork_asm+0x11/0x20 [ 1887.204913] [ 1887.204913] [ 1887.205209] [ 1887.205416] Asignado por tarea 2197: [1887.205881] kasan_set_track+0x3f/0x60 [1887.206366] __kasan_kmalloc +0x6e/0x80 [ 1887.206856] __kmalloc+0xac/0x1a0 [ 1887.207293] btf_parse_fields+0xa15/0x1480 [ 1887.207836] btf_parse_struct_metas+0x566/0x670 [ 1887.208387 ] btf_new_fd+0x294/0x4d0 [ 1887.208851] __sys_bpf+0x4ba/0x600 [ 1887.209292] __x64_sys_bpf+0x41 /0x50 [ 1887.209762] do_syscall_64+0x4c/0xf0 [ 1887.210222] Entry_SYSCALL_64_after_hwframe+0x63/0x6b [ 1887.210868] [ 1887.211074] Liberado por la tarea 36: [ 1887.21146 0] kasan_set_track+0x3f/0x60 [ 1887.211951] kasan_save_free_info+0x28/0x40 [ 1887.212485] ____kasan_slab_free+ 0x101/0x180 [ 1887.213027] __kmem_cache_free+0xe4/0x210 [ 1887.213514] btf_free+0x5b/0x130 [ 1887.213918] rcu_core+0x638/0xcc0 [ 1887.214347] __do_ softirq+0x114/0x37e El error ocurre en bpf_rb_root_free+0x1f8/0x2b0: 00000000000034c0 : ; { 34c0: f3 0f 1e fa endbr64 34c4: e8 00 00 00 00 callq 0x34c9 34c9: 55 pushq %rbp 34ca: 48 89 e5 movq %rsp, %rbp ... ; if (rec && rec->refcount_off >= 0 && 36aa: 4d 85 ed testq %r13, %r13 36ad: 74 a9 je 0x3658 36af: 49 8d 7d 10 leaq 0x10(%r13), %rdi 36b3 : e8 00 00 00 00 callq 0x36b8 <==== función kasan 36b8: 45 8b 7d 10 movl 0x10(%r13), %r15d <==== carga de uso después de liberación 36bc: 45 85 ff testl %r15d, %r15d 36bf: 78 8c js 0x364d Entonces el problema ---truncado---