linux

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Kees Cook 0e108725f6 string: Adjust strtomem() logic to allow for smaller sources

Arnd noticed we have a case where a shorter source string is being copied
into a destination byte array, but this results in a strnlen() call that
exceeds the size of the source. This is seen with -Wstringop-overread:

In file included from ../include/linux/uuid.h:11,
                 from ../include/linux/mod_devicetable.h:14,
                 from ../include/linux/cpufeature.h:12,
                 from ../arch/x86/coco/tdx/tdx.c:7:
../arch/x86/coco/tdx/tdx.c: In function 'tdx_panic.constprop':
../include/linux/string.h:284:9: error: 'strnlen' specified bound 64 exceeds source size 60 [-Werror=stringop-overread]
  284 |         memcpy_and_pad(dest, _dest_len, src, strnlen(src, _dest_len), pad); \
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../arch/x86/coco/tdx/tdx.c:124:9: note: in expansion of macro 'strtomem_pad'
  124 |         strtomem_pad(message.str, msg, '\0');
      |         ^~~~~~~~~~~~

Use the smaller of the two buffer sizes when calling strnlen(). When
src length is unknown (SIZE_MAX), it is adjusted to use dest length,
which is what the original code did.

Reported-by: Arnd Bergmann <arnd@arndb.de>
Fixes: dfbafa70bde2 ("string: Introduce strtomem() and strtomem_pad()")
Tested-by: Arnd Bergmann <arnd@arndb.de>
Cc: Andy Shevchenko <andy@kernel.org>
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>

2023-10-18 17:56:32 -07:00

acpi

Merge branches 'acpi-scan', 'acpi-tad', 'acpi-extlog' and 'acpi-misc'

2023-08-25 20:49:52 +02:00

asm-generic

ata changes for 6.6

2023-09-05 12:37:28 -07:00

clocksource

…

crypto

This update includes the following changes:

2023-08-29 11:23:29 -07:00