From: Jianchao Wang Date: Fri, 4 May 2018 08:01:57 +0000 (+0800) Subject: nvme: fix use-after-free in nvme_free_ns_head X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=12d9f07022dcde261ad16e9a11f45096dc68b03c;p=openwrt%2Fstaging%2Fblogic.git nvme: fix use-after-free in nvme_free_ns_head Currently only nvme_ctrl will take a reference counter of nvme_subsystem, nvme_ns_head also needs it. Otherwise nvme_free_ns_head will access the nvme_subsystem.ns_ida which has been freed by __nvme_release_subsystem after all the reference of nvme_subsystem have been released by nvme_free_ctrl. This could cause memory corruption. BUG: KASAN: use-after-free in radix_tree_next_chunk+0x9f/0x4b0 Read of size 8 at addr ffff88036494d2e8 by task fio/1815 CPU: 1 PID: 1815 Comm: fio Kdump: loaded Tainted: G W 4.17.0-rc1+ #18 Hardware name: LENOVO 10MLS0E339/3106, BIOS M1AKT22A 06/27/2017 Call Trace: dump_stack+0x91/0xeb print_address_description+0x6b/0x290 kasan_report+0x261/0x360 radix_tree_next_chunk+0x9f/0x4b0 ida_remove+0x8b/0x180 ida_simple_remove+0x26/0x40 nvme_free_ns_head+0x58/0xc0 __blkdev_put+0x30a/0x3a0 blkdev_close+0x44/0x50 __fput+0x184/0x380 task_work_run+0xaf/0xe0 do_exit+0x501/0x1440 do_group_exit+0x89/0x140 __x64_sys_exit_group+0x28/0x30 do_syscall_64+0x72/0x230 Signed-off-by: Jianchao Wang Reviewed-by: Christoph Hellwig Signed-off-by: Keith Busch --- diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index a3771c5729f5..2cbc378bc0d6 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -99,6 +99,7 @@ static struct class *nvme_subsys_class; static void nvme_ns_remove(struct nvme_ns *ns); static int nvme_revalidate_disk(struct gendisk *disk); +static void nvme_put_subsystem(struct nvme_subsystem *subsys); int nvme_reset_ctrl(struct nvme_ctrl *ctrl) { @@ -350,6 +351,7 @@ static void nvme_free_ns_head(struct kref *ref) ida_simple_remove(&head->subsys->ns_ida, head->instance); list_del_init(&head->entry); cleanup_srcu_struct(&head->srcu); + nvme_put_subsystem(head->subsys); kfree(head); } @@ -2861,6 +2863,9 @@ static struct nvme_ns_head *nvme_alloc_ns_head(struct nvme_ctrl *ctrl, goto out_cleanup_srcu; list_add_tail(&head->entry, &ctrl->subsys->nsheads); + + kref_get(&ctrl->subsys->ref); + return head; out_cleanup_srcu: cleanup_srcu_struct(&head->srcu);