[PATCH 0/2] lib/crypto: chacha: Handle lengths of 2 GiB or more on 32-bit arm and MIPS

[Vladimir Kukharenko via B4 Relay <devnull+vladimir.genproof.com@kernel.org>]

On 32-bit arm (the scalar code) and 32-bit MIPS, the ChaCha assembly
treats the length as signed, so lengths of 2 GiB or more are still
mishandled after "lib/crypto: chacha: Use size_t length", since size_t
is 32 bits there.

Patch 1 makes the arm assembly use unsigned conditions.  The MIPS
assembly relies on the sign of the remaining length, so patch 2 instead
limits each call to 1 GiB from C.

This applies on top of
https://lore.kernel.org/r/20261014152604.323310-1-ebiggers@kernel.org
Feel free to fold these into your series instead.

Tested with the lib/crypto KUnit tests in QEMU on arm (Cortex-A7 and
Cortex-A15) and 32-bit MIPS, plus a temporary 2 GiB test on the
Cortex-A7 and QEMU user mode runs of the MIPS assembly.

An LLM review found these bugs; I used an LLM-based assistant to write
the patches and reviewed its work.

---
Vladimir Kukharenko (2):
      lib/crypto: arm/chacha: Handle lengths of 2 GiB or more in scalar code
      lib/crypto: mips/chacha: Handle lengths of 2 GiB or more

 lib/crypto/arm/chacha-scalar-core.S |  8 ++++----
 lib/crypto/arm/chacha.h             |  2 +-
 lib/crypto/mips/chacha-core.S       |  8 ++++----
 lib/crypto/mips/chacha.h            | 20 +++++++++++++++++++-
 4 files changed, 28 insertions(+), 10 deletions(-)
---
base-commit: 40f47fa10a1d19c74f48a13d97b2eb19d5fb938d
change-id: 20261014-libcrypto-chacha-32bit-2gib-5a3e5e36a061
prerequisite-message-id: <20261014152604.323310-1-ebiggers@kernel.org>
prerequisite-patch-id: f66d78884d3d0cf68e1efc9635c084c6b700352f
prerequisite-patch-id: 64c39ea52fe4e25501701ffa262fb3525af29f0b

Best regards,
--  
Vladimir Kukharenko <vladimir@genproof.com>