diff options
| author | Brian Johannesmeyer <bjohannesmeyer@gmail.com> | 2024-05-24 00:50:29 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-09-12 12:12:51 +0300 |
| commit | 86e99aab7e18377590a9d0135b5aa7f792272284 (patch) | |
| tree | d4b5457ae83443e09f4cde6f07d94d4ed08aa568 | |
| parent | c8cb076f865fc780bdfbdde4fd6802bf07e6923c (diff) | |
| download | linux-86e99aab7e18377590a9d0135b5aa7f792272284.tar.xz | |
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>
| -rw-r--r-- | arch/x86/lib/iomem.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/x86/lib/iomem.c b/arch/x86/lib/iomem.c index e0411a3774d4..5eecb45d05d5 100644 --- a/arch/x86/lib/iomem.c +++ b/arch/x86/lib/iomem.c @@ -25,6 +25,9 @@ static __always_inline void rep_movs(void *to, const void *from, size_t n) static void string_memcpy_fromio(void *to, const volatile void __iomem *from, size_t n) { + const void *orig_to = to; + const size_t orig_n = n; + if (unlikely(!n)) return; @@ -39,7 +42,7 @@ static void string_memcpy_fromio(void *to, const volatile void __iomem *from, si } rep_movs(to, (const void *)from, n); /* KMSAN must treat values read from devices as initialized. */ - kmsan_unpoison_memory(to, n); + kmsan_unpoison_memory(orig_to, orig_n); } static void string_memcpy_toio(volatile void __iomem *to, const void *from, size_t n) |