"value":"In the Linux kernel, the following vulnerability has been resolved:\n\nlist: fix a data-race around ep->rdllist\n\nep_poll() first calls ep_events_available() with no lock held and checks\nif ep->rdllist is empty by list_empty_careful(), which reads\nrdllist->prev. Thus all accesses to it need some protection to avoid\nstore/load-tearing.\n\nNote INIT_LIST_HEAD_RCU() already has the annotation for both prev\nand next.\n\nCommit bf3b9f6372c4 (\"epoll: Add busy poll support to epoll with socket\nfds.\") added the first lockless ep_events_available(), and commit\nc5a282e9635e (\"fs/epoll: reduce the scope of wq lock in epoll_wait()\")\nmade some ep_events_available() calls lockless and added single call under\na lock, finally commit e59d3c64cba6 (\"epoll: eliminate unnecessary lock\nfor zero timeout\") made the last ep_events_available() lockless.\n\nBUG: KCSAN: data-race in do_epoll_wait / do_epoll_wait\n\nwrite to 0xffff88810480c7d8 of 8 bytes by task 1802 on cpu 0:\n INIT_LIST_HEAD include/linux/list.h:38 [inline]\n list_splice_init include/linux/list.h:492 [inline]\n ep_start_scan fs/eventpoll.c:622 [inline]\n ep_send_events fs/eventpoll.c:1656 [inline]\n ep_poll fs/eventpoll.c:1806 [inline]\n do_epoll_wait+0x4eb/0xf40 fs/eventpoll.c:2234\n do_epoll_pwait fs/eventpoll.c:2268 [inline]\n __do_sys_epoll_pwait fs/eventpoll.c:2281 [inline]\n __se_sys_epoll_pwait+0x12b/0x240 fs/eventpoll.c:2275\n __x64_sys_epoll_pwait+0x74/0x80 fs/eventpoll.c:2275\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x44/0xae\n\nread to 0xffff88810480c7d8 of 8 bytes by task 1799 on cpu 1:\n list_empty_careful include/linux/list.h:329 [inline]\n ep_events_available fs/eventpoll.c:381 [inline]\n ep_poll fs/eventpoll.c:1797 [inline]\n do_epoll_wait+0x279/0xf40 fs/eventpoll.c:2234\n do_epoll_pwait fs/eventpoll.c:2268 [inline]\n __do_sys_epoll_pwait fs/eventpoll.c:2281 [inline]\n __se_sys_epoll_pwait+0x12b/0x240 fs/eventpoll.c:2275\n __x64_sys_epoll_pwait+0x74/0x80 fs/eventpoll.c:2275\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x44/0xae\n\nvalue changed: 0xffff88810480c7d0 -> 0xffff888103c15098\n\nReported by Kernel Concurrency Sanitizer on:\nCPU: 1 PID: 1799 Comm: syz-fuzzer Tainted: G W 5.17.0-rc7-syzkaller-dirty #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011"
"value":"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: list: se corrige una ejecuci\u00f3n de datos alrededor de ep->rdllist ep_poll() primero llama a ep_events_available() sin bloqueo mantenido y verifica si ep->rdllist est\u00e1 vac\u00edo mediante list_empty_careful(), que lee rdllist->prev. Por lo tanto, todos los accesos a \u00e9l necesitan alguna protecci\u00f3n para evitar el desgarro de almacenamiento/carga. Tenga en cuenta que INIT_LIST_HEAD_RCU() ya tiene la anotaci\u00f3n tanto para prev como para next. El commit bf3b9f6372c4 (\"epoll: Agregar soporte de sondeo ocupado a epoll con fds de socket\") agreg\u00f3 el primer ep_events_available() sin bloqueo, y el commit c5a282e9635e (\"fs/epoll: reducir el alcance del bloqueo wq en epoll_wait()\") hizo que algunas llamadas ep_events_available() no tuvieran bloqueo y agreg\u00f3 una sola llamada bajo un bloqueo, finalmente el commit e59d3c64cba6 (\"epoll: eliminar el bloqueo innecesario para tiempo de espera cero\") hizo que el \u00faltimo ep_events_available() no tuviera bloqueo. ERROR: KCSAN: data-race in do_epoll_wait / do_epoll_wait write to 0xffff88810480c7d8 of 8 bytes by task 1802 on cpu 0: INIT_LIST_HEAD include/linux/list.h:38 [inline] list_splice_init include/linux/list.h:492 [inline] ep_start_scan fs/eventpoll.c:622 [inline] ep_send_events fs/eventpoll.c:1656 [inline] ep_poll fs/eventpoll.c:1806 [inline] do_epoll_wait+0x4eb/0xf40 fs/eventpoll.c:2234 do_epoll_pwait fs/eventpoll.c:2268 [inline] __do_sys_epoll_pwait fs/eventpoll.c:2281 [inline] __se_sys_epoll_pwait+0x12b/0x240 fs/eventpoll.c:2275 __x64_sys_epoll_pwait+0x74/0x80 fs/eventpoll.c:2275 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff88810480c7d8 of 8 bytes by task 1799 on cpu 1: list_empty_careful include/linux/list.h:329 [inline] ep_events_available fs/eventpoll.c:381 [inline] ep_poll fs/eventpoll.c:1797 [inline] do_epoll_wait+0x279/0xf40 fs/eventpoll.c:2234 do_epoll_pwait fs/eventpoll.c:2268 [inline] __do_sys_epoll_pwait fs/eventpoll.c:2281 [inline] __se_sys_epoll_pwait+0x12b/0x240 fs/eventpoll.c:2275 __x64_sys_epoll_pwait+0x74/0x80 fs/eventpoll.c:2275 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae value changed: 0xffff88810480c7d0 -> 0xffff888103c15098 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 1799 Comm: syz-fuzzer Tainted: G W 5.17.0-rc7-syzkaller-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 "