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

[Chang S. Bae]

On 3/12/2024 12:46 AM, Ard Biesheuvel wrote:
> On Mon, 11 Mar 2024 at 22:48, Chang S. Bae <chang.seok.bae@xxxxxxxxx> 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;
 }

Thanks,
Chang