Brian Johannesmeyer dbb9f9e736 x86/kmsan: Fix hook for unaligned accesses
[ Upstream commit bf6ab33d8487f5e2a0998ce75286eae65bb0a6d6 ]

When called with a 'from' that is not 4-byte-aligned, string_memcpy_fromio()
calls the movs() macro to copy the first few bytes, so that 'from' becomes
4-byte-aligned before calling rep_movs(). This movs() macro modifies 'to', and
the subsequent line modifies 'n'.

As a result, on unaligned accesses, kmsan_unpoison_memory() uses the updated
(aligned) values of 'to' and 'n'. Hence, it does not unpoison the entire
region.

Save the original values of 'to' and 'n', and pass those to
kmsan_unpoison_memory(), so that the entire region is unpoisoned.

Signed-off-by: Brian Johannesmeyer <bjohannesmeyer@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Alexander Potapenko <glider@google.com>
Link: https://lore.kernel.org/r/20240523215029.4160518-1-bjohannesmeyer@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-09-12 11:10:19 +02:00
2022-09-28 09:02:20 +02:00
2022-09-28 09:02:20 +02:00
2024-09-08 07:53:13 +02:00

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.
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