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Upgrade the ChaCha functions from 32-bit lengths to size_t.
'size_t' is the best practice for buffer lengths, and it's what the rest
of the crypto library uses.
Moreover, all the 64-bit ChaCha assembly functions actually already
treated the length as 64-bit, despite it being declared as 32-bit in C
on arm64, ppc64, and x86_64. For arm64 and x86_64, this caused
unspecified behavior due to the high 32 bits of the corresponding
register having an unspecified value in those architectures' ABIs.
However, in practice these bits are always zero and no issue occurred.
(ppc64 was fine too, since there the ABI zero-extends 32-bit arguments.)
These issues date to the original introduction of the ChaCha code.
However, as noted above, they don't have any real-world impact
currently; so this is an API robustness improvement only.
Reported-by: Vladimir Kukharenko <vladimir@genproof.com>
Closes: https://lore.kernel.org/r/20261012-libcrypto-4gib-lengths-v1-0-ea566c129a2e@genproof.com
Tested-by: Vladimir Kukharenko <vladimir@genproof.com>
Link: https://patch.msgid.link/20261014152604.323310-3-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
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Consolidate the ChaCha code into a single module (excluding
chacha-block-generic.c which remains always built-in for random.c),
similar to various other algorithms:
- Each arch now provides a header file lib/crypto/$(SRCARCH)/chacha.h,
replacing lib/crypto/$(SRCARCH)/chacha*.c. The header defines
chacha_crypt_arch() and hchacha_block_arch(). It is included by
lib/crypto/chacha.c, and thus the code gets built into the single
libchacha module, with improved inlining in some cases.
- Whether arch-optimized ChaCha is buildable is now controlled centrally
by lib/crypto/Kconfig instead of by lib/crypto/$(SRCARCH)/Kconfig.
The conditions for enabling it remain the same as before, and it
remains enabled by default.
- Any additional arch-specific translation units for the optimized
ChaCha code, such as assembly files, are now compiled by
lib/crypto/Makefile instead of lib/crypto/$(SRCARCH)/Makefile.
This removes the last use for the Makefile and Kconfig files in the
arm64, mips, powerpc, riscv, and s390 subdirectories of lib/crypto/. So
also remove those files and the references to them.
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20250827151131.27733-7-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
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