https://github.com/torvalds/linux
Revision 16b1941eac2bd499f065a6739a40ce0011a3d740 authored by Alan Stern on 06 March 2022, 02:47:22 UTC, committed by Greg Kroah-Hartman on 15 March 2022, 17:46:01 UTC
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: 2ccea03a8f7e ("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>
1 parent e9b667a
Tip revision: 16b1941eac2bd499f065a6739a40ce0011a3d740 authored by Alan Stern on 06 March 2022, 02:47:22 UTC
usb: gadget: Fix use-after-free bug by not setting udc->dev.driver
usb: gadget: Fix use-after-free bug by not setting udc->dev.driver
Tip revision: 16b1941
File | Mode | Size |
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Documentation | ||
LICENSES | ||
arch | ||
block | ||
certs | ||
crypto | ||
drivers | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.clang-format | -rw-r--r-- | 16.6 KB |
.cocciconfig | -rw-r--r-- | 59 bytes |
.get_maintainer.ignore | -rw-r--r-- | 71 bytes |
.gitattributes | -rw-r--r-- | 62 bytes |
.gitignore | -rw-r--r-- | 1.9 KB |
.mailmap | -rw-r--r-- | 21.7 KB |
COPYING | -rw-r--r-- | 496 bytes |
CREDITS | -rw-r--r-- | 98.8 KB |
Kbuild | -rw-r--r-- | 1.3 KB |
Kconfig | -rw-r--r-- | 555 bytes |
MAINTAINERS | -rw-r--r-- | 627.7 KB |
Makefile | -rw-r--r-- | 63.5 KB |
README | -rw-r--r-- | 727 bytes |
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