Re: [PATCH v2 04/13] RISC-V: crypto: add Zvkned accelerated AES implementation

Eric Biggers
2023-11-28T03:56:50Z

On Mon, Nov 27, 2023 at 03:06:54PM +0800, Jerry Shih wrote:
> +int riscv64_aes_setkey(struct crypto_aes_ctx *ctx, const u8 *key,
> + unsigned int keylen)
> +{
> + int ret;
> +
> + ret = aes_check_keylen(keylen);
> + if (ret < 0)
> + return -EINVAL;
> +
> + /*
> + * The RISC-V AES vector crypto key expanding doesn't support AES-192.
> + * Use the generic software key expanding for that case.
> + */
> + if ((keylen == 16 || keylen == 32) && crypto_simd_usable()) {
> + /*
> + * All zvkned-based functions use encryption expanding keys for both
> + * encryption and decryption.
> + */
> + kernel_vector_begin();
> + rv64i_zvkned_set_encrypt_key(key, keylen, ctx);
> + kernel_vector_end();
> + } else {
> + ret = aes_expandkey(ctx, key, keylen);
> + }

rv64i_zvkned_set_encrypt_key() does not initialize crypto_aes_ctx::key_dec.
So, decryption results will be incorrect if !crypto_simd_usable() later.

> +static int aes_setkey(struct crypto_tfm *tfm, const u8 *key,
> + unsigned int keylen)

It's best to avoid generic-sounding function names like this that could collide
with functions in crypto/ or lib/crypto/. A better name for this function, for
example, would be aes_setkey_zvkned().

> diff --git a/arch/riscv/crypto/aes-riscv64-zvkned.pl b/arch/riscv/crypto/aes-riscv64-zvkned.pl
> new file mode 100644
> index 000000000000..303e82d9f6f0
> --- /dev/null
> +++ b/arch/riscv/crypto/aes-riscv64-zvkned.pl
[...]
> +L_enc_128:
[...]
> +L_enc_192:
[...]
> +L_enc_256:

There's some severe source code duplication going on in the AES assembly, with
the three AES variants having separate source code. You can just leave this
as-is since this is what was merged into OpenSSL and we are borrowing that for
now, but I do expect that we'll want to clean this up later.

- Eric