9ce0c09dc2
[ Upstream commit 1a3241ff10d038ecd096d03380327f2a0b5840a6 ]
strscpy() performs the word-at-a-time optimistic reads. So it may may
access the memory past the end of the object, which is perfectly fine
since strscpy() doesn't use that (past-the-end) data and makes sure the
optimistic read won't cross a page boundary.
Use new read_word_at_a_time() to shut up the KASAN.
Note that this potentially could hide some bugs. In example bellow,
stscpy() will copy more than we should (1-3 extra uninitialized bytes):
char dst[8];
char *src;
src = kmalloc(5, GFP_KERNEL);
memset(src, 0xff, 5);
strscpy(dst, src, 8);
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.