f183708e8e
commit e23e50e7acc8d8f16498e9c129db33e6a00e80eb upstream.
The sizeof(struct whitehat_dr_info) can be 4 bytes under CONFIG_AEABI=n
due to "-mabi=apcs-gnu", even though it has a single u8:
whiteheat_private {
__u8 mcr; /* 0 1 */
/* size: 4, cachelines: 1, members: 1 */
/* padding: 3 */
/* last cacheline: 4 bytes */
};
The result is technically harmless, as both the source and the
destinations are currently the same allocation size (4 bytes) and don't
use their padding, but if anything were to ever be added after the
"mcr" member in "struct whiteheat_private", it would be overwritten. The
structs both have a single u8 "mcr" member, but are 4 bytes in padded
size. The memcpy() destination was explicitly targeting the u8 member
(size 1) with the length of the whole structure (size 4), triggering
the memcpy buffer overflow warning:
In file included from include/linux/string.h:253,
from include/linux/bitmap.h:11,
from include/linux/cpumask.h:12,
from include/linux/smp.h:13,
from include/linux/lockdep.h:14,
from include/linux/spinlock.h:62,
from include/linux/mmzone.h:8,
from include/linux/gfp.h:6,
from include/linux/slab.h:15,
from drivers/usb/serial/whiteheat.c:17:
In function 'fortify_memcpy_chk',
inlined from 'firm_send_command' at drivers/usb/serial/whiteheat.c:587:4:
include/linux/fortify-string.h:328:25: warning: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning]
328 | __write_overflow_field(p_size_field, size);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Instead, just assign the one byte directly.
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/lkml/202204142318.vDqjjSFn-lkp@intel.com
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220421001234.2421107-1-keescook@chromium.org
Signed-off-by: Johan Hovold <johan@kernel.org>
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 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.