"value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix use-after-free of block device file in __btrfs_free_extra_devids()\n\nMounting btrfs from two images (which have the same one fsid and two\ndifferent dev_uuids) in certain executing order may trigger an UAF for\nvariable 'device->bdev_file' in __btrfs_free_extra_devids(). And\nfollowing are the details:\n\n1. Attach image_1 to loop0, attach image_2 to loop1, and scan btrfs\n devices by ioctl(BTRFS_IOC_SCAN_DEV):\n\n / btrfs_device_1 \u2192 loop0\n fs_device\n \\ btrfs_device_2 \u2192 loop1\n2. mount /dev/loop0 /mnt\n btrfs_open_devices\n btrfs_device_1->bdev_file = btrfs_get_bdev_and_sb(loop0)\n btrfs_device_2->bdev_file = btrfs_get_bdev_and_sb(loop1)\n btrfs_fill_super\n open_ctree\n fail: btrfs_close_devices // -ENOMEM\n\t btrfs_close_bdev(btrfs_device_1)\n fput(btrfs_device_1->bdev_file)\n\t // btrfs_device_1->bdev_file is freed\n\t btrfs_close_bdev(btrfs_device_2)\n fput(btrfs_device_2->bdev_file)\n\n3. mount /dev/loop1 /mnt\n btrfs_open_devices\n btrfs_get_bdev_and_sb(&bdev_file)\n // EIO, btrfs_device_1->bdev_file is not assigned,\n // which points to a freed memory area\n btrfs_device_2->bdev_file = btrfs_get_bdev_and_sb(loop1)\n btrfs_fill_super\n open_ctree\n btrfs_free_extra_devids\n if (btrfs_device_1->bdev_file)\n fput(btrfs_device_1->bdev_file) // UAF !\n\nFix it by setting 'device->bdev_file' as 'NULL' after closing the\nbtrfs_device in btrfs_close_one_device()."
"value":"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: btrfs: se corrige el use-after-free del archivo del dispositivo de bloque en __btrfs_free_extra_devids(). Montar btrfs desde dos im\u00e1genes (que tienen el mismo fsid y dos dev_uuids diferentes) en cierto orden de ejecuci\u00f3n puede activar un UAF para la variable 'device->bdev_file' en __btrfs_free_extra_devids(). Y a continuaci\u00f3n se muestran los detalles: 1. Adjunte image_1 a loop0, adjunte image_2 a loop1 y escanee los dispositivos btrfs con ioctl(BTRFS_IOC_SCAN_DEV): / btrfs_device_1 ? loop0 fs_device \\ btrfs_device_2 ? loop1 2. monte /dev/loop0 /mnt btrfs_open_devices btrfs_device_1->bdev_file = btrfs_get_bdev_and_sb(loop0) btrfs_device_2->bdev_file = btrfs_get_bdev_and_sb(loop1) btrfs_fill_super open_ctree fail: btrfs_close_devices // -ENOMEM btrfs_close_bdev(btrfs_device_1) fput(btrfs_device_1->bdev_file) // btrfs_device_1->bdev_file se libera btrfs_close_bdev(btrfs_device_2) fput(btrfs_device_2->bdev_file) 3. mount /dev/loop1 /mnt btrfs_open_devices btrfs_get_bdev_and_sb(&bdev_file) // EIO, btrfs_device_1->bdev_file no est\u00e1 asignado, // lo que apunta a un \u00e1rea de memoria liberada btrfs_device_2->bdev_file = btrfs_get_bdev_and_sb(loop1) btrfs_fill_super open_ctree btrfs_free_extra_devids if (btrfs_device_1->bdev_file) fput(btrfs_device_1->bdev_file) // UAF! Arr\u00e9glelo configurando 'device->bdev_file' como 'NULL' despu\u00e9s de cerrar btrfs_device en btrfs_close_one_device()."