CVE-2021-47297

En el kernel de Linux, se resolvió la siguiente vulnerabilidad: net: corrige el valor uninit en caif_seqpkt_sendmsg. Cuando nr_segs es igual a cero en iovec_from_user, el objeto msg->msg_iter.iov es la memoria de pila uninit en caif_seqpkt_sendmsg que está definida en ___sys_sendmsg. Entonces no podemos simplemente juzgar msg->msg_iter.iov->base directamente. Podemos usar nr_segs para juzgar si msg en caif_seqpkt_sendmsg tiene buffers de datos. ==================================================== === BUG: KMSAN: valor uninit en caif_seqpkt_sendmsg+0x693/0xf60 net/caif/caif_socket.c:542 Seguimiento de llamadas: __dump_stack lib/dump_stack.c:77 [en línea] dump_stack+0x1c9/0x220 lib/dump_stack.c: 118 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:118 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215 caif_seqpkt_sendmsg+0x693/0xf60 net/caif/caif_socket.c:542 sock_sendmsg_nosec net/so cket.c: 652 [en línea] sock_sendmsg net/socket.c:672 [en línea] ____sys_sendmsg+0x12b6/0x1350 net/socket.c:2343 ___sys_sendmsg net/socket.c:2397 [en línea] __sys_sendmmsg+0x808/0xc90 80 __compat_sys_sendmmsg net/compat.c:656 [en línea]

In the Linux kernel, the following vulnerability has been resolved: net: fix uninit-value in caif_seqpkt_sendmsg When nr_segs equal to zero in iovec_from_user, the object msg->msg_iter.iov is uninit stack memory in caif_seqpkt_sendmsg which is defined in ___sys_sendmsg. So we cann't just judge msg->msg_iter.iov->base directlly. We can use nr_segs to judge msg in caif_seqpkt_sendmsg whether has data buffers. ===================================================== BUG: KMSAN: uninit-value in caif_seqpkt_sendmsg+0x693/0xf60 net/caif/caif_socket.c:542 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1c9/0x220 lib/dump_stack.c:118 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:118 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215 caif_seqpkt_sendmsg+0x693/0xf60 net/caif/caif_socket.c:542 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg net/socket.c:672 [inline] ____sys_sendmsg+0x12b6/0x1350 net/socket.c:2343 ___sys_sendmsg net/socket.c:2397 [inline] __sys_sendmmsg+0x808/0xc90 net/socket.c:2480 __compat_sys_sendmmsg net/compat.c:656 [inline]