crypto: arm/neon - memzero_explicit aes-cbc key

At function exit, do not leave the expanded key in the rk struct
which got allocated on the stack.
Signed-off-by: Torsten Duwe <duwe@suse.de>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

arch/arm/crypto/aes-neonbs-glue.c

@@ -138,6 +138,7 @@ static int aesbs_cbc_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
 	kernel_neon_begin();
 	aesbs_convert_key(ctx->key.rk, rk.key_enc, ctx->key.rounds);
 	kernel_neon_end();
+	memzero_explicit(&rk, sizeof(rk));
 
 	return crypto_cipher_setkey(ctx->enc_tfm, in_key, key_len);
 }

arch/arm64/crypto/aes-neonbs-glue.c

@@ -151,6 +151,7 @@ static int aesbs_cbc_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
 	kernel_neon_begin();
 	aesbs_convert_key(ctx->key.rk, rk.key_enc, ctx->key.rounds);
 	kernel_neon_end();
+	memzero_explicit(&rk, sizeof(rk));
 
 	return 0;
 }