kernel/linux.git/drivers/mtd/ubi, branch v4.14.286

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

2022-06-14T14:53:57+00:00

[ Upstream commit 8c03a1c21d72210f81cb369cc528e3fde4b45411 ] 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 Signed-off-by: Sasha Levin

ubi: fastmap: Return error code if memory allocation fails in add_aeb()

2022-04-20T07:08:25+00:00

commit c3c07fc25f37c157fde041b3a0c3dfcb1590cbce upstream. Abort fastmap scanning and return error code if memory allocation fails in add_aeb(). Otherwise ubi will get wrong peb statistics information after scanning. Fixes: dbb7d2a88d2a7b ("UBI: Add fastmap core") Signed-off-by: Zhihao Cheng Signed-off-by: Richard Weinberger Signed-off-by: Greg Kroah-Hartman

ubi: Fix race condition between ctrl_cdev_ioctl and ubi_cdev_ioctl

2022-04-20T07:08:25+00:00

commit 3cbf0e392f173ba0ce425968c8374a6aa3e90f2e upstream. 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 Signed-off-by: Greg Kroah-Hartman

ubi: check kthread_should_stop() after the setting of task state

2020-11-05T10:07:03+00:00

commit d005f8c6588efcfbe88099b6edafc6f58c84a9c1 upstream. A detach hung is possible when a race occurs between the detach process and the ubi background thread. The following sequences outline the race: ubi thread: if (list_empty(&ubi->works)... ubi detach: set_bit(KTHREAD_SHOULD_STOP, &kthread->flags) => by kthread_stop() wake_up_process() => ubi thread is still running, so 0 is returned ubi thread: set_current_state(TASK_INTERRUPTIBLE) schedule() => ubi thread will never be scheduled again ubi detach: wait_for_completion() => hung task! To fix that, we need to check kthread_should_stop() after we set the task state, so the ubi thread will either see the stop bit and exit or the task state is reset to runnable such that it isn't scheduled out indefinitely. Signed-off-by: Zhihao Cheng Cc: Fixes: 801c135ce73d5df1ca ("UBI: Unsorted Block Images") Reported-by: syzbot+853639d0cb16c31c7a14@syzkaller.appspotmail.com Signed-off-by: Richard Weinberger Signed-off-by: Greg Kroah-Hartman

ubi: Fix seq_file usage in detailed_erase_block_info debugfs file

2020-05-27T14:42:53+00:00

[ Upstream commit 0e7572cffe442290c347e779bf8bd4306bb0aa7c ] 3bfa7e141b0b ("fs/seq_file.c: seq_read(): add info message about buggy .next functions") showed that we don't use seq_file correctly. So make sure that our ->next function always updates the position. Fixes: 7bccd12d27b7 ("ubi: Add debugfs file for tracking PEB state") Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin

ubi: Fix an error pointer dereference in error handling code

2020-02-14T21:32:18+00:00

commit 5d3805af279c93ef49a64701f35254676d709622 upstream. If "seen_pebs = init_seen(ubi);" fails then "seen_pebs" is an error pointer and we try to kfree() it which results in an Oops. This patch re-arranges the error handling so now it only frees things which have been allocated successfully. Fixes: daef3dd1f0ae ("UBI: Fastmap: Add self check to detect absent PEBs") Signed-off-by: Dan Carpenter Signed-off-by: Richard Weinberger Signed-off-by: Greg Kroah-Hartman

ubi: fastmap: Fix inverted logic in seen selfcheck

2020-02-14T21:32:18+00:00

commit ef5aafb6e4e9942a28cd300bdcda21ce6cbaf045 upstream. set_seen() sets the bit corresponding to the PEB number in the bitmap, so when self_check_seen() wants to find PEBs that haven't been seen we have to print the PEBs that have their bit cleared, not the ones which have it set. Fixes: 5d71afb00840 ("ubi: Use bitmaps in Fastmap self-check code") Signed-off-by: Sascha Hauer Signed-off-by: Richard Weinberger Signed-off-by: Greg Kroah-Hartman

ubi: Do not drop UBI device reference before using

2019-12-05T14:37:19+00:00

[ Upstream commit e542087701f09418702673631a908429feb3eae0 ] The UBI device reference is dropped but then the device is used as a parameter of ubi_err. The bug is introduced in changing ubi_err's behavior. The old ubi_err does not require a UBI device as its first parameter, but the new one does. Fixes: 32608703310 ("UBI: Extend UBI layer debug/messaging capabilities") Signed-off-by: Pan Bian Reviewed-by: Boris Brezillon Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin

ubi: Put MTD device after it is not used

2019-12-05T14:37:19+00:00

[ Upstream commit b95f83ab762dd6211351b9140f99f43644076ca8 ] The MTD device reference is dropped via put_mtd_device, however its field ->index is read and passed to ubi_msg. To fix this, the patch moves the reference dropping after calling ubi_msg. Signed-off-by: Pan Bian Reviewed-by: Boris Brezillon Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin

ubi: Initialize Fastmap checkmapping correctly

2018-12-05T18:41:09+00:00

commit 25677478474a91fa1b46f19a4a591a9848bca6fb upstream We cannot do it last, otherwithse it will be skipped for dynamic volumes. Reported-by: Lachmann, Juergen Fixes: 34653fd8c46e ("ubi: fastmap: Check each mapping only once") Signed-off-by: Richard Weinberger Signed-off-by: Sudip Mukherjee Signed-off-by: Sasha Levin