commit 838e4631cb26618df8b2e3ed3d3b6801c4cd1424
author Richard Henderson <richard.henderson@linaro.org> Fri Aug 28 10:05:17 2020 -0700
committer Daniel P. Berrangé <berrange@redhat.com> Thu Sep 10 11:02:23 2020 +0100
tree 717e62f9636b26c800ac0d62f9bd97c613fedb61
parent e46064a4c610daf185e1de6e5210dd7556591faf

crypto/builtin: Remove odd-sized AES block handling

We verified that the data block is properly sized modulo
AES_BLOCK_SIZE within qcrypto_builtin_cipher_{en,de}crypt.
Therefore we will never have to handle odd sized blocks.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

crypto/cipher-builtin.c.inc

diff --git a/crypto/cipher-builtin.c.inc b/crypto/cipher-builtin.c.inc
index 1444139..e2ae5d0 100644
--- a/crypto/cipher-builtin.c.inc
+++ b/crypto/cipher-builtin.c.inc
@@ -80,21 +80,13 @@
 {
     const uint8_t *inptr = in;
     uint8_t *outptr = out;
+
+    /* We have already verified that len % AES_BLOCK_SIZE == 0. */
     while (len) {
-        if (len > AES_BLOCK_SIZE) {
-            AES_encrypt(inptr, outptr, key);
-            inptr += AES_BLOCK_SIZE;
-            outptr += AES_BLOCK_SIZE;
-            len -= AES_BLOCK_SIZE;
-        } else {
-            uint8_t tmp1[AES_BLOCK_SIZE], tmp2[AES_BLOCK_SIZE];
-            memcpy(tmp1, inptr, len);
-            /* Fill with 0 to avoid valgrind uninitialized reads */
-            memset(tmp1 + len, 0, sizeof(tmp1) - len);
-            AES_encrypt(tmp1, tmp2, key);
-            memcpy(outptr, tmp2, len);
-            len = 0;
-        }
+        AES_encrypt(inptr, outptr, key);
+        inptr += AES_BLOCK_SIZE;
+        outptr += AES_BLOCK_SIZE;
+        len -= AES_BLOCK_SIZE;
     }
 }
 
@@ -106,21 +98,13 @@
 {
     const uint8_t *inptr = in;
     uint8_t *outptr = out;
+
+    /* We have already verified that len % AES_BLOCK_SIZE == 0. */
     while (len) {
-        if (len > AES_BLOCK_SIZE) {
-            AES_decrypt(inptr, outptr, key);
-            inptr += AES_BLOCK_SIZE;
-            outptr += AES_BLOCK_SIZE;
-            len -= AES_BLOCK_SIZE;
-        } else {
-            uint8_t tmp1[AES_BLOCK_SIZE], tmp2[AES_BLOCK_SIZE];
-            memcpy(tmp1, inptr, len);
-            /* Fill with 0 to avoid valgrind uninitialized reads */
-            memset(tmp1 + len, 0, sizeof(tmp1) - len);
-            AES_decrypt(tmp1, tmp2, key);
-            memcpy(outptr, tmp2, len);
-            len = 0;
-        }
+        AES_decrypt(inptr, outptr, key);
+        inptr += AES_BLOCK_SIZE;
+        outptr += AES_BLOCK_SIZE;
+        len -= AES_BLOCK_SIZE;
     }
 }