crypto: aegis128/neon - move final tag check to SIMD domain

Instead of calculating the tag and returning it to the caller on
decryption, use a SIMD compare and min across vector to perform
the comparison. This is slightly more efficient, and removes the
need on the caller's part to wipe the tag from memory if the
decryption failed.

While at it, switch to unsigned int when passing cryptlen and
assoclen - we don't support input sizes where it matters anyway.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Ondrej Mosnacek <omosnacek@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 15 insertions, 6 deletions

diff --git a/crypto/aegis128-neon.c b/crypto/aegis128-neon.c
index 8271b1fa..94d591a0 100644
--- a/crypto/aegis128-neon.c
+++ b/crypto/aegis128-neon.c
@@ -14,8 +14,10 @@ void crypto_aegis128_encrypt_chunk_neon(void *state, void *dst, const void *src,
 					unsigned int size);
 void crypto_aegis128_decrypt_chunk_neon(void *state, void *dst, const void *src,
 					unsigned int size);
-void crypto_aegis128_final_neon(void *state, void *tag_xor, uint64_t assoclen,
-				uint64_t cryptlen);
+int crypto_aegis128_final_neon(void *state, void *tag_xor,
+			       unsigned int assoclen,
+			       unsigned int cryptlen,
+			       unsigned int authsize);
 
 int aegis128_have_aes_insn __ro_after_init;
 
@@ -60,11 +62,18 @@ void crypto_aegis128_decrypt_chunk_simd(union aegis_block *state, u8 *dst,
 	kernel_neon_end();
 }
 
-void crypto_aegis128_final_simd(union aegis_block *state,
-				union aegis_block *tag_xor,
-				u64 assoclen, u64 cryptlen)
+int crypto_aegis128_final_simd(union aegis_block *state,
+			       union aegis_block *tag_xor,
+			       unsigned int assoclen,
+			       unsigned int cryptlen,
+			       unsigned int authsize)
 {
+	int ret;
+
 	kernel_neon_begin();
-	crypto_aegis128_final_neon(state, tag_xor, assoclen, cryptlen);
+	ret = crypto_aegis128_final_neon(state, tag_xor, assoclen, cryptlen,
+					 authsize);
 	kernel_neon_end();
+
+	return ret;
 }