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Alan Stern
2a52d55c86
commitabf76d3239upstream. The chaoskey driver has a use-after-free bug in its release routine. If the user closes the device file after the USB device has been unplugged, a debugging log statement will try to access the usb_interface structure after it has been deallocated: BUG: KASAN: slab-use-after-free in dev_driver_string (drivers/base/core.c:2406) Read of size 8 at addr ffff888168e8a0b8 by task chaoskey_raw_re/10106 Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: <TASK> dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120) print_report (mm/kasan/report.c:378 mm/kasan/report.c:482) kasan_report (mm/kasan/report.c:595) dev_driver_string (drivers/base/core.c:2406) __dynamic_dev_dbg (lib/dynamic_debug.c:906) chaoskey_release (drivers/usb/misc/chaoskey.c:323) __fput (fs/file_table.c:510) fput_close_sync (fs/file_table.c:615) __x64_sys_close (fs/open.c:1507 fs/open.c:1492 fs/open.c:1492) do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) The driver's last reference to the interface structure is dropped in the chaoskey_free() routine, so the code must not use the interface -- even in a debugging statement -- after that routine returns. (Exception: If we know that another reference is held by someone else, such as the device core while the disconnect routine runs, there's no problem. Thanks to Johan Hovold for pointing this out.) Since the bad access is part of an unimportant debugging statement, we can fix the problem simply by removing the whole statement. Reported-by: Shuangpeng Bai <shuangpeng.kernel@gmail.com> Closes: https://lore.kernel.org/linux-usb/20EC9664-054E-438B-B411-2145D347F97B@gmail.com/ Tested-by: Shuangpeng Bai <shuangpeng.kernel@gmail.com> Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Fixes:66e3e59189("usb: Add driver for Altus Metrum ChaosKey device (v2)") Cc: stable <stable@kernel.org> Reviewed-by: Johan Hovold <johan@kernel.org> Link: https://patch.msgid.link/bb5b1dc6-eb59-43e1-8d26-51e658e88bbe@rowland.harvard.edu Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 reStructuredText 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.