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Filename Latest commit message Latest commit date
Alan Stern 2282a6eb6d usb: gadget: Fix use-after-free bug by not setting udc->dev.driver
commit 16b1941eac2bd499f065a6739a40ce0011a3d740 upstream.

The syzbot fuzzer found a use-after-free bug:

BUG: KASAN: use-after-free in dev_uevent+0x712/0x780 drivers/base/core.c:2320
Read of size 8 at addr ffff88802b934098 by task udevd/3689

CPU: 2 PID: 3689 Comm: udevd Not tainted 5.17.0-rc4-syzkaller-00229-g4f12b742eb2b #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description.constprop.0.cold+0x8d/0x303 mm/kasan/report.c:255
 __kasan_report mm/kasan/report.c:442 [inline]
 kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
 dev_uevent+0x712/0x780 drivers/base/core.c:2320
 uevent_show+0x1b8/0x380 drivers/base/core.c:2391
 dev_attr_show+0x4b/0x90 drivers/base/core.c:2094

Although the bug manifested in the driver core, the real cause was a
race with the gadget core.  dev_uevent() does:

	if (dev->driver)
		add_uevent_var(env, "DRIVER=%s", dev->driver->name);

and between the test and the dereference of dev->driver, the gadget
core sets dev->driver to NULL.

The race wouldn't occur if the gadget core registered its devices on
a real bus, using the standard synchronization techniques of the
driver core.  However, it's not necessary to make such a large change
in order to fix this bug; all we need to do is make sure that
udc->dev.driver is always NULL.

In fact, there is no reason for udc->dev.driver ever to be set to
anything, let alone to the value it currently gets: the address of the
gadget's driver.  After all, a gadget driver only knows how to manage
a gadget, not how to manage a UDC.

This patch simply removes the statements in the gadget core that touch
udc->dev.driver.

Fixes: 2ccea03a8f ("usb: gadget: introduce UDC Class")
CC: <stable@vger.kernel.org>
Reported-and-tested-by: syzbot+348b571beb5eeb70a582@syzkaller.appspotmail.com
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/YiQgukfFFbBnwJ/9@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-23 09:12:07 +01:00
arch arm64: fix clang warning about TRAMP_VALIAS 2022-03-23 09:12:07 +01:00
block block: Fix fsync always failed if once failed 2022-03-08 19:07:47 +01:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2021-09-15 09:47:29 +02:00
crypto crypto: pcrypt - Delay write to padata->info 2021-11-17 09:48:40 +01:00
Documentation x86/speculation: Update link to AMD speculation whitepaper 2022-03-11 11:22:37 +01:00
drivers usb: gadget: Fix use-after-free bug by not setting udc->dev.driver 2022-03-23 09:12:07 +01:00
fs ocfs2: fix crash when initialize filecheck kobj fails 2022-03-23 09:12:06 +01:00
include net: handle ARPHRD_PIMREG in dev_is_mac_header_xmit() 2022-03-23 09:12:07 +01:00
init bpf: Add kconfig knob for disabling unpriv bpf by default 2022-02-16 12:52:49 +01:00
ipc shm: extend forced shm destroy to support objects from several IPC nses 2021-12-01 09:23:35 +01:00
kernel tracing: Ensure trace buffer is at least 4096 bytes large 2022-03-16 13:21:47 +01:00
lib ARM: 9178/1: fix unmet dependency on BITREVERSE for HAVE_ARCH_BITREVERSE 2022-03-19 13:40:16 +01:00
LICENSES
mm memfd: fix F_SEAL_WRITE after shmem huge page allocated 2022-03-08 19:07:49 +01:00
net net: dsa: Add missing of_node_put() in dsa_port_parse_of 2022-03-23 09:12:07 +01:00
samples samples/kretprobes: Fix return value if register_kretprobe() failed 2021-11-17 09:48:39 +01:00
scripts kconfig: fix failing to generate auto.conf 2022-02-23 12:00:01 +01:00
security ima: Do not print policy rule with inactive LSM labels 2022-02-16 12:52:47 +01:00
sound ASoC: cs4265: Fix the duplicated control name 2022-03-08 19:07:49 +01:00
tools kselftest/vm: fix tests build with old libc 2022-03-19 13:40:17 +01:00
usr
virt KVM: arm64: Allow SMCCC_ARCH_WORKAROUND_3 to be discovered and migrated 2022-03-19 13:40:15 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.186 2022-03-19 13:40:17 +01:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.