media: solo6x10: Check for out of bounds chip_id

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[ Upstream commit 0fdf6323c3 ]

Clang with CONFIG_UBSAN_SHIFT=y noticed a condition where a signed type
(literal "1" is an "int") could end up being shifted beyond 32 bits,
so instrumentation was added (and due to the double is_tw286x() call
seen via inlining), Clang decides the second one must now be undefined
behavior and elides the rest of the function[1]. This is a known problem
with Clang (that is still being worked on), but we can avoid the entire
problem by actually checking the existing max chip ID, and now there is
no runtime instrumentation added at all since everything is known to be
within bounds.

Additionally use an unsigned value for the shift to remove the
instrumentation even without the explicit bounds checking.

Link: https://github.com/ClangBuiltLinux/linux/issues/2144 [1]
Suggested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Kees Cook <kees@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
[hverkuil: fix checkpatch warning for is_tw286x]
Signed-off-by: Sasha Levin <sashal@kernel.org>

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Kees Cook 2025-12-11 19:00:35 -08:00 • committed by Sasha Levin

parent 2011929f0e

commit d29f33b2cf

1 changed files with 7 additions and 1 deletions

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drivers/media/pci/solo6x10/solo6x10-tw28.c

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