[Syzbot reported two possible deadlocks]
The first possible deadlock is:
WARNING: possible recursive locking detected
6.12.0-rc1-syzkaller-00027-g4a9fe2a8ac53 #0 Not tainted
--------------------------------------------
syz-executor363/2651 is trying to acquire lock:
ffffffff89b120e8 (chaoskey_list_lock){+.+.}-{3:3}, at: chaoskey_release+0x15d/0x2c0 drivers/usb/misc/chaoskey.c:322
but task is already holding lock:
ffffffff89b120e8 (chaoskey_list_lock){+.+.}-{3:3}, at: chaoskey_release+0x7f/0x2c0 drivers/usb/misc/chaoskey.c:299
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(chaoskey_list_lock);
lock(chaoskey_list_lock);
*** DEADLOCK ***
The second possible deadlock is:
WARNING: possible circular locking dependency detected
6.12.0-rc1-syzkaller-00027-g4a9fe2a8ac53 #0 Not tainted
------------------------------------------------------
kworker/0:2/804 is trying to acquire lock:
ffffffff899dadb0 (minor_rwsem){++++}-{3:3}, at: usb_deregister_dev+0x7c/0x1e0 drivers/usb/core/file.c:186
but task is already holding lock:
ffffffff89b120e8 (chaoskey_list_lock){+.+.}-{3:3}, at: chaoskey_disconnect+0xa8/0x2a0 drivers/usb/misc/chaoskey.c:235
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (chaoskey_list_lock){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
chaoskey_open+0xdd/0x220 drivers/usb/misc/chaoskey.c:274
usb_open+0x186/0x220 drivers/usb/core/file.c:47
chrdev_open+0x237/0x6a0 fs/char_dev.c:414
do_dentry_open+0x6cb/0x1390 fs/open.c:958
vfs_open+0x82/0x3f0 fs/open.c:1088
do_open fs/namei.c:3774 [inline]
path_openat+0x1e6a/0x2d60 fs/namei.c:3933
do_filp_open+0x1dc/0x430 fs/namei.c:3960
do_sys_openat2+0x17a/0x1e0 fs/open.c:1415
do_sys_open fs/open.c:1430 [inline]
__do_sys_openat fs/open.c:1446 [inline]
__se_sys_openat fs/open.c:1441 [inline]
__x64_sys_openat+0x175/0x210 fs/open.c:1441
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (minor_rwsem){++++}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3161 [inline]
check_prevs_add kernel/locking/lockdep.c:3280 [inline]
validate_chain kernel/locking/lockdep.c:3904 [inline]
__lock_acquire+0x250b/0x3ce0 kernel/locking/lockdep.c:5202
lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5825
down_write+0x93/0x200 kernel/locking/rwsem.c:1577
usb_deregister_dev+0x7c/0x1e0 drivers/usb/core/file.c:186
chaoskey_disconnect+0xb7/0x2a0 drivers/usb/misc/chaoskey.c:236
usb_unbind_interface+0x1e8/0x970 drivers/usb/core/driver.c:461
device_remove drivers/base/dd.c:569 [inline]
device_remove+0x122/0x170 drivers/base/dd.c:561
__device_release_driver drivers/base/dd.c:1273 [inline]
device_release_driver_internal+0x44a/0x610 drivers/base/dd.c:1296
bus_remove_device+0x22f/0x420 drivers/base/bus.c:576
device_del+0x396/0x9f0 drivers/base/core.c:3864
usb_disable_device+0x36c/0x7f0 drivers/usb/core/message.c:1418
usb_disconnect+0x2e1/0x920 drivers/usb/core/hub.c:2304
hub_port_connect drivers/usb/core/hub.c:5361 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5661 [inline]
port_event drivers/usb/core/hub.c:5821 [inline]
hub_event+0x1bed/0x4f40 drivers/usb/core/hub.c:5903
process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229
process_scheduled_works kernel/workqueue.c:3310 [inline]
worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391
kthread+0x2c1/0x3a0 kernel/kthread.c:389
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(chaoskey_list_lock);
lock(minor_rwsem);
lock(chaoskey_list_lock);
lock(minor_rwsem);
*** DEADLOCK ***
[Analysis]
The first is AA lock, it because wrong logic, it need a unlock.
The second is AB lock, it needs to rearrange the order of lock usage.
Fixes: 422dc0a4d1 ("USB: chaoskey: fail open after removal")
Reported-by: syzbot+685e14d04fe35692d3bc@syzkaller.appspotmail.com
Reported-by: syzbot+1f8ca5ee82576ec01f12@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=685e14d04fe35692d3bc
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
Tested-by: syzbot+685e14d04fe35692d3bc@syzkaller.appspotmail.com
Reported-by: syzbot+5f1ce62e956b7b19610e@syzkaller.appspotmail.com
Tested-by: syzbot+5f1ce62e956b7b19610e@syzkaller.appspotmail.com
Tested-by: syzbot+1f8ca5ee82576ec01f12@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/tencent_84EB865C89862EC22EE94CB3A7C706C59206@qq.com
Cc: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
chaoskey_open() takes the lock only to increase the
counter of openings. That means that the mutual exclusion
with chaoskey_disconnect() cannot prevent an increase
of the counter and chaoskey_open() returning a success.
If that race is hit, chaoskey_disconnect() will happily
free all resources associated with the device after
it has dropped the lock, as it has read the counter
as zero.
To prevent this race chaoskey_open() has to check
the presence of the device under the lock.
However, the current per device lock cannot be used,
because it is a part of the data structure to be
freed. Hence an additional global mutex is needed.
The issue is as old as the driver.
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Reported-by: syzbot+422188bce66e76020e55@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=422188bce66e76020e55
Fixes: 66e3e59189 ("usb: Add driver for Altus Metrum ChaosKey device (v2)")
Rule: add
Link: https://lore.kernel.org/stable/20241002132201.552578-1-oneukum%40suse.com
Link: https://lore.kernel.org/r/20241002132201.552578-1-oneukum@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Most hw_random devices return entropy which is assumed to be of full
quality, but driver authors don't bother setting the quality knob. Some
hw_random devices return less than full quality entropy, and then driver
authors set the quality knob. Therefore, the entropy crediting should be
opt-out rather than opt-in per-driver, to reflect the actual reality on
the ground.
For example, the two Raspberry Pi RNG drivers produce full entropy
randomness, and both EDK2 and U-Boot's drivers for these treat them as
such. The result is that EFI then uses these numbers and passes the to
Linux, and Linux credits them as boot, thereby initializing the RNG.
Yet, in Linux, the quality knob was never set to anything, and so on the
chance that Linux is booted without EFI, nothing is ever credited.
That's annoying.
The same pattern appears to repeat itself throughout various drivers. In
fact, very very few drivers have bothered setting quality=1024.
Looking at the git history of existing drivers and corresponding mailing
list discussion, this conclusion tracks. There's been a decent amount of
discussion about drivers that set quality < 1024 -- somebody read and
interepreted a datasheet, or made some back of the envelope calculation
somehow. But there's been very little, if any, discussion about most
drivers where the quality is just set to 1024 or unset (or set to 1000
when the authors misunderstood the API and assumed it was base-10 rather
than base-2); in both cases the intent was fairly clear of, "this is a
hardware random device; it's fine."
So let's invert this logic. A hw_random struct's quality knob now
controls the maximum quality a driver can produce, or 0 to specify 1024.
Then, the module-wide switch called "default_quality" is changed to
represent the maximum quality of any driver. By default it's 1024, and
the quality of any particular driver is then given by:
min(default_quality, rng->quality ?: 1024);
This way, the user can still turn this off for weird reasons (and we can
replace whatever driver-specific disabling hacks existed in the past),
yet we get proper crediting for relevant RNGs.
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
In case of a timeout or if a signal aborts a read
communication with the device needs to be ended
lest we overwrite an active URB the next time we
do IO to the device, as the URB may still be active.
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191107142856.16774-1-oneukum@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The driver was accessing its struct usb_interface in its release()
callback without holding a reference. This would lead to a
use-after-free whenever the device was disconnected while the character
device was still open.
Fixes: 66e3e59189 ("usb: Add driver for Altus Metrum ChaosKey device (v2)")
Cc: stable <stable@vger.kernel.org> # 4.1
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20191009153848.8664-3-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Instead of kmalloc() with manually calculated values followed by
multiple strcpy()/strcat() calls, just fold it all into a single
kasprintf() call.
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Assign true or false to boolean variables instead of an integer value.
This issue was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now that the SPDX tag is in all USB files, that identifies the license
in a specific and legally-defined manner. So the extra GPL text wording
can be removed as it is no longer needed at all.
This is done on a quest to remove the 700+ different ways that files in
the kernel describe the GPL license text. And there's unneeded stuff
like the address (sometimes incorrect) for the FSF which is never
needed.
No copyright headers or other non-license-description text was removed.
Cc: Keith Packard <keithp@keithp.com>
Cc: Juergen Stuber <starblue@users.sourceforge.net>
Cc: Cesar Miquel <miquel@df.uba.ar>
Cc: Richard Leitner <richard.leitner@skidata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.
Update the drivers/usb/ and include/linux/usb* files with the correct
SPDX license identifier based on the license text in the file itself.
The SPDX identifier is a legally binding shorthand, which can be used
instead of the full boiler plate text.
This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Acked-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
MODULE_VERSION is useless for in-kernel drivers, so just remove all
usage of it in the USB misc drivers. Along with this, some
DRIVER_VERSION macros were removed as they are also pointless.
Cc: Keith Packard <keithp@keithp.com>
Cc: Juergen Stuber <starblue@users.sourceforge.net>
Cc: Cesar Miquel <miquel@df.uba.ar>
Acked-by: Richard Leitner <richard.leitner@skidata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add missing endianness conversion when applying the Alea timeout quirk.
Found using sparse:
warning: restricted __le16 degrades to integer
Fixes: e4a886e811 ("hwrng: chaoskey - Fix URB warning due to timeout on Alea")
Cc: stable <stable@vger.kernel.org> # 4.8
Cc: Bob Ham <bob.ham@collabora.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Keith Packard <keithp@keithp.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use the new endpoint helpers to lookup the required bulk-in endpoint.
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The hwrng core used to mask 'quality' with 1023; that has been removed
in commit 506bf0c046 ("hwrng: core - allow
perfect entropy from hardware devices"), so we can now just set quality
to 1024.
Signed-off-by: Julien Cristau <jcristau@debian.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Adds support for the Araneus Alea I USB hardware Random Number
Generator which is interfaced with in exactly the same way as the
Altus Metrum ChaosKey. We just add the appropriate device ID and
modify the config help text.
Signed-off-by: Bob Ham <bob.ham@collabora.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
To allow for and clean handling of signals an URB is introduced.
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Shares the cleanup code between all probe failure paths, instead of
having per-failure cleanup at each point in the function.
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Rng reads in chaoskey driver could return the same data under
the certain conditions.
Signed-off-by: Alexander Inyukhin <shurick@sectorb.msk.ru>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> drivers/usb/misc/chaoskey.c: In function 'chaoskey_read':
> >> drivers/usb/misc/chaoskey.c:412:3: error: implicit declaration of function 'copy_to_user'
> >> [-Werror=implicit-function-declaration]
> remain = copy_to_user(buffer, dev->buf + dev->used, this_time);
I was unable to reproduce this locally, but added an explicit
#include <linux/uaccess.h>
which should ensure the definition on all architectures.
> sparse warnings: (new ones prefixed by >>)
>
> >> drivers/usb/misc/chaoskey.c:117:30: sparse: incorrect type in assignment (different base types)
> drivers/usb/misc/chaoskey.c:117:30: expected int [signed] size
> drivers/usb/misc/chaoskey.c:117:30: got restricted __le16 [usertype] wMaxPacketSize
Switched the code to using the USB descriptor accessor functions.
Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is a hardware random number generator. The driver provides both a
/dev/chaoskeyX entry and hooks the entropy source up to the kernel
hwrng interface. More information about the device can be found at
http://chaoskey.org
The USB ID for ChaosKey was allocated from the OpenMoko USB vendor
space and is visible as 'USBtrng' here:
http://wiki.openmoko.org/wiki/USB_Product_IDs
v2: Respond to review from Oliver Neukum <oneukum@suse.de>
* Delete extensive debug infrastructure and replace it with calls to
dev_dbg.
* Allocate I/O buffer separately from device structure to obey
requirements for non-coherant architectures.
* Initialize mutexes before registering device to ensure that open
cannot be invoked before the device is ready to proceed.
* Return number of bytes read instead of -EINTR when partial read
operation is aborted due to a signal.
* Make sure device mutex is unlocked in read error paths.
* Add MAINTAINERS entry for the driver
Signed-off-by: Keith Packard <keithp@keithp.com>
Cc: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
