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>