Re: [PATCH] crypto: x86/aesni - Update aesni_set_key() to return void

Ard Biesheuvel
2024-03-12T15:18:20Z

On Tue, 12 Mar 2024 at 16:03, Chang S. Bae <chang.seok.bae@intel.com> wrote:
>
> On 3/12/2024 12:46 AM, Ard Biesheuvel wrote:
> > On Mon, 11 Mar 2024 at 22:48, Chang S. Bae <chang.seok.bae@intel.com> wrote:
> >>
> >> @@ -241,7 +241,7 @@ static int aes_set_key_common(struct crypto_aes_ctx *ctx,
> >> err = aes_expandkey(ctx, in_key, key_len);
> >> else {
> >> kernel_fpu_begin();
> >> - err = aesni_set_key(ctx, in_key, key_len);
> >> + aesni_set_key(ctx, in_key, key_len);
> >
> > This will leave 'err' uninitialized.
>
> Ah, right. Thanks for catching it.
>
> Also, upon reviewing aes_expandkey(), I noticed there's no error case,
> except for the key length sanity check.
>
> While addressing this, perhaps additional cleanup is considerable like:
>
> @@ -233,19 +233,20 @@ static int aes_set_key_common(struct
> crypto_aes_ctx *ctx,
> {
> int err;
>
> - if (key_len != AES_KEYSIZE_128 && key_len != AES_KEYSIZE_192 &&
> - key_len != AES_KEYSIZE_256)
> - return -EINVAL;
> + err = aes_check_keylen(key_len);
> + if (err)
> + return err;
>
> if (!crypto_simd_usable())
> - err = aes_expandkey(ctx, in_key, key_len);
> + /* no error with a valid key length */
> + aes_expandkey(ctx, in_key, key_len);
> else {
> kernel_fpu_begin();
> - err = aesni_set_key(ctx, in_key, key_len);
> + aesni_set_key(ctx, in_key, key_len);
> kernel_fpu_end();
> }
>
> - return err;
> + return 0;
> }
>

I wonder whether we need aesni_set_key() at all.