kernel/linux.git/drivers/mtd/ubi/vmt.c, branch v6.4

ubi: Fix possible null-ptr-deref in ubi_free_volume()

2023-02-02T20:13:44+00:00

It willl cause null-ptr-deref in the following case: uif_init() ubi_add_volume() cdev_add() -> if it fails, call kill_volumes() device_register() kill_volumes() -> if ubi_add_volume() fails call this function ubi_free_volume() cdev_del() device_unregister() -> trying to delete a not added device, it causes null-ptr-deref So in ubi_free_volume(), it delete devices whether they are added or not, it will causes null-ptr-deref. Handle the error case whlie calling ubi_add_volume() to fix this problem. If add volume fails, set the corresponding vol to null, so it can not be accessed in kill_volumes() and release the resource in ubi_add_volume() error path. Fixes: 801c135ce73d ("UBI: Unsorted Block Images") Suggested-by: Zhihao Cheng Signed-off-by: Yang Yingliang Reviewed-by: Zhihao Cheng Signed-off-by: Richard Weinberger

ubi: Fix unreferenced object reported by kmemleak in ubi_resize_volume()

2023-02-02T20:13:42+00:00

There is a memory leaks problem reported by kmemleak: unreferenced object 0xffff888102007a00 (size 128): comm "ubirsvol", pid 32090, jiffies 4298464136 (age 2361.231s) hex dump (first 32 bytes): ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ backtrace: [] __kmalloc+0x4d/0x150 [] ubi_eba_create_table+0x76/0x170 [ubi] [] ubi_resize_volume+0x1be/0xbc0 [ubi] [] ubi_cdev_ioctl+0x701/0x1850 [ubi] [] __x64_sys_ioctl+0x11d/0x170 [] do_syscall_64+0x35/0x80 [] entry_SYSCALL_64_after_hwframe+0x46/0xb0 This is due to a mismatch between create and destroy interfaces, and in detail that "new_eba_tbl" created by ubi_eba_create_table() but destroyed by kfree(), while will causing "new_eba_tbl->entries" not freed. Fix it by replacing kfree(new_eba_tbl) with ubi_eba_destroy_table(new_eba_tbl) Fixes: 799dca34ac54 ("UBI: hide EBA internals") Signed-off-by: Li Zetao Reviewed-by: Zhihao Cheng Signed-off-by: Richard Weinberger

ubi: Fix use-after-free when volume resizing failed

2023-02-02T20:13:41+00:00

There is an use-after-free problem reported by KASAN: ================================================================== BUG: KASAN: use-after-free in ubi_eba_copy_table+0x11f/0x1c0 [ubi] Read of size 8 at addr ffff888101eec008 by task ubirsvol/4735 CPU: 2 PID: 4735 Comm: ubirsvol Not tainted 6.1.0-rc1-00003-g84fa3304a7fc-dirty #14 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014 Call Trace: dump_stack_lvl+0x34/0x44 print_report+0x171/0x472 kasan_report+0xad/0x130 ubi_eba_copy_table+0x11f/0x1c0 [ubi] ubi_resize_volume+0x4f9/0xbc0 [ubi] ubi_cdev_ioctl+0x701/0x1850 [ubi] __x64_sys_ioctl+0x11d/0x170 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 When ubi_change_vtbl_record() returns an error in ubi_resize_volume(), "new_eba_tbl" will be freed on error handing path, but it is holded by "vol->eba_tbl" in ubi_eba_replace_table(). It means that the liftcycle of "vol->eba_tbl" and "vol" are different, so when resizing volume in next time, it causing an use-after-free fault. Fix it by not freeing "new_eba_tbl" after it replaced in ubi_eba_replace_table(), while will be freed in next volume resizing. Fixes: 801c135ce73d ("UBI: Unsorted Block Images") Signed-off-by: Li Zetao Reviewed-by: Zhihao Cheng Signed-off-by: Richard Weinberger

mtd: ubi: drop unexpected word 'a' in comments

2022-09-21T09:32:38+00:00

there is an unexpected word 'a' in the comments that need to be dropped file - drivers/mtd/ubi/vmt.c line - 626,779 * Returns zero if volume is all right and a a negative error code if not. changed to: * Returns zero if volume is all right and a negative error code if not. Signed-off-by: Jiang Jian Signed-off-by: Richard Weinberger

ubi: ubi_create_volume: Fix use-after-free when volume creation failed

2022-05-27T14:49:41+00:00

There is an use-after-free problem for 'eba_tbl' in ubi_create_volume()'s error handling path: ubi_eba_replace_table(vol, eba_tbl) vol->eba_tbl = tbl out_mapping: ubi_eba_destroy_table(eba_tbl) // Free 'eba_tbl' out_unlock: put_device(&vol->dev) vol_release kfree(tbl->entries) // UAF Fix it by removing redundant 'eba_tbl' releasing. Fetch a reproducer in [Link]. Fixes: 493cfaeaa0c9b ("mtd: utilize new cdev_device_add helper function") Link: https://bugzilla.kernel.org/show_bug.cgi?id=215965 Signed-off-by: Zhihao Cheng Signed-off-by: Richard Weinberger

ubi: Fix race condition between ctrl_cdev_ioctl and ubi_cdev_ioctl

2022-01-09T20:13:28+00:00

Hulk Robot reported a KASAN report about use-after-free: ================================================================== BUG: KASAN: use-after-free in __list_del_entry_valid+0x13d/0x160 Read of size 8 at addr ffff888035e37d98 by task ubiattach/1385 [...] Call Trace: klist_dec_and_del+0xa7/0x4a0 klist_put+0xc7/0x1a0 device_del+0x4d4/0xed0 cdev_device_del+0x1a/0x80 ubi_attach_mtd_dev+0x2951/0x34b0 [ubi] ctrl_cdev_ioctl+0x286/0x2f0 [ubi] Allocated by task 1414: device_add+0x60a/0x18b0 cdev_device_add+0x103/0x170 ubi_create_volume+0x1118/0x1a10 [ubi] ubi_cdev_ioctl+0xb7f/0x1ba0 [ubi] Freed by task 1385: cdev_device_del+0x1a/0x80 ubi_remove_volume+0x438/0x6c0 [ubi] ubi_cdev_ioctl+0xbf4/0x1ba0 [ubi] [...] ================================================================== The lock held by ctrl_cdev_ioctl is ubi_devices_mutex, but the lock held by ubi_cdev_ioctl is ubi->device_mutex. Therefore, the two locks can be concurrent. ctrl_cdev_ioctl contains two operations: ubi_attach and ubi_detach. ubi_detach is bug-free because it uses reference counting to prevent concurrency. However, uif_init and uif_close in ubi_attach may race with ubi_cdev_ioctl. uif_init will race with ubi_cdev_ioctl as in the following stack. cpu1 cpu2 cpu3 _______________________|________________________|______________________ ctrl_cdev_ioctl ubi_attach_mtd_dev uif_init ubi_cdev_ioctl ubi_create_volume cdev_device_add ubi_add_volume // sysfs exist kill_volumes ubi_cdev_ioctl ubi_remove_volume cdev_device_del // first free ubi_free_volume cdev_del // double free cdev_device_del And uif_close will race with ubi_cdev_ioctl as in the following stack. cpu1 cpu2 cpu3 _______________________|________________________|______________________ ctrl_cdev_ioctl ubi_attach_mtd_dev uif_init ubi_cdev_ioctl ubi_create_volume cdev_device_add ubi_debugfs_init_dev //error goto out_uif; uif_close kill_volumes ubi_cdev_ioctl ubi_remove_volume cdev_device_del // first free ubi_free_volume // double free The cause of this problem is that commit 714fb87e8bc0 make device "available" before it becomes accessible via sysfs. Therefore, we roll back the modification. We will fix the race condition between ubi device creation and udev by removing ubi_get_device in vol_attribute_show and dev_attribute_show.This avoids accessing uninitialized ubi_devices[ubi_num]. ubi_get_device is used to prevent devices from being deleted during sysfs execution. However, now kernfs ensures that devices will not be deleted before all reference counting are released. The key process is shown in the following stack. device_del device_remove_attrs device_remove_groups sysfs_remove_groups sysfs_remove_group remove_files kernfs_remove_by_name kernfs_remove_by_name_ns __kernfs_remove kernfs_drain Fixes: 714fb87e8bc0 ("ubi: Fix race condition between ubi device creation and udev") Reported-by: Hulk Robot Signed-off-by: Baokun Li Signed-off-by: Richard Weinberger

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156

2019-05-30T18:26:35+00:00

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 59 temple place suite 330 boston ma 02111 1307 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1334 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Reviewed-by: Richard Fontana Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de Signed-off-by: Greg Kroah-Hartman

ubi: expose the volume CRC check skip flag

2018-08-14T22:25:21+00:00

Now that we have the logic for skipping CRC check for static UBI volumes in the core, let's expose it to users. This makes use of a padding byte in the volume description data structure as a flag. This flag only tell for now whether we should skip the CRC check of a volume. This checks the UBI volume for which we are trying to skip the CRC check is static. Let's also make sure that the flags passed to verify_mkvol_req are valid. We voluntarily do not take into account the skip_check flag in vol_cdev_write() as we want to make sure what we wrote was correctly written. Suggested-by: Boris Brezillon Signed-off-by: Quentin Schulz Reviewed-by: Boris Brezillon Signed-off-by: Richard Weinberger

ubi: provide a way to skip CRC checks

2018-08-14T22:25:20+00:00

Some users of static UBI volumes implement their own integrity check, thus making the volume CRC check done at open time useless. For instance, this is the case when one use the ubiblock + dm-verity + squashfs combination, where dm-verity already checks integrity of the block device but this time at the block granularity instead of verifying the whole volume. Skipping this test drastically improves the boot-time. Suggested-by: Boris Brezillon Signed-off-by: Quentin Schulz Reviewed-by: Boris Brezillon Reviewed-by: Richard Weinberger Signed-off-by: Richard Weinberger

ubi: fastmap: Check each mapping only once

2018-06-07T13:53:16+00:00

Maintain a bitmap to keep track of which LEB->PEB mapping was checked already. That way we have to read back VID headers only once. Signed-off-by: Richard Weinberger