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Blame SOURCES/kvm-crypto-remove-code-duplication-in-tweak-encrypt-decr.patch

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From cfa8288b73c3a2856a56bef220b7468b402905c3 Mon Sep 17 00:00:00 2001
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From: "Daniel P. Berrange" <berrange@redhat.com>
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Date: Wed, 24 Apr 2019 09:56:37 +0100
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Subject: [PATCH 3/9] crypto: remove code duplication in tweak encrypt/decrypt
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Daniel P. Berrange <berrange@redhat.com>
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Message-id: <20190424095643.796-4-berrange@redhat.com>
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Patchwork-id: 85881
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O-Subject: [RHEL-8.1.0 qemu-kvm PATCH 3/9] crypto: remove code duplication in tweak encrypt/decrypt
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Bugzilla: 1680231
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RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
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RH-Acked-by: John Snow <jsnow@redhat.com>
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RH-Acked-by: Eric Blake <eblake@redhat.com>
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The tweak encrypt/decrypt functions are identical except for the
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comments, so can be merged. Profiling data shows that the compiler is
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in fact already merging the two merges in the object files.
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Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
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Reviewed-by: Alberto Garcia <berto@igalia.com>
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Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
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(cherry picked from commit 299ec87838babdf38be618cf2d81aef2500758bd)
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Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
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---
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 crypto/xts.c | 64 ++++++++++++++----------------------------------------------
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 1 file changed, 15 insertions(+), 49 deletions(-)
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diff --git a/crypto/xts.c b/crypto/xts.c
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index 9521234..3c1a92f 100644
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--- a/crypto/xts.c
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+++ b/crypto/xts.c
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@@ -43,20 +43,20 @@ static void xts_mult_x(uint8_t *I)
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 /**
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- * xts_tweak_uncrypt:
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+ * xts_tweak_encdec:
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  * @param ctxt: the cipher context
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  * @param func: the cipher function
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- * @src: buffer providing the cipher text of XTS_BLOCK_SIZE bytes
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- * @dst: buffer to output the plain text of XTS_BLOCK_SIZE bytes
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+ * @src: buffer providing the input text of XTS_BLOCK_SIZE bytes
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+ * @dst: buffer to output the output text of XTS_BLOCK_SIZE bytes
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  * @iv: the initialization vector tweak of XTS_BLOCK_SIZE bytes
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  *
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- * Decrypt data with a tweak
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+ * Encrypt/decrypt data with a tweak
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  */
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-static void xts_tweak_decrypt(const void *ctx,
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-                              xts_cipher_func *func,
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-                              const uint8_t *src,
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-                              uint8_t *dst,
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-                              uint8_t *iv)
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+static void xts_tweak_encdec(const void *ctx,
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+                             xts_cipher_func *func,
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+                             const uint8_t *src,
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+                             uint8_t *dst,
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+                             uint8_t *iv)
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 {
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     unsigned long x;
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@@ -105,7 +105,7 @@ void xts_decrypt(const void *datactx,
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     encfunc(tweakctx, XTS_BLOCK_SIZE, T, iv);
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     for (i = 0; i < lim; i++) {
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-        xts_tweak_decrypt(datactx, decfunc, src, dst, T);
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+        xts_tweak_encdec(datactx, decfunc, src, dst, T);
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         src += XTS_BLOCK_SIZE;
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         dst += XTS_BLOCK_SIZE;
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@@ -117,7 +117,7 @@ void xts_decrypt(const void *datactx,
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         xts_mult_x(CC);
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         /* PP = tweak decrypt block m-1 */
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-        xts_tweak_decrypt(datactx, decfunc, src, PP, CC);
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+        xts_tweak_encdec(datactx, decfunc, src, PP, CC);
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         /* Pm = first length % XTS_BLOCK_SIZE bytes of PP */
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         for (i = 0; i < mo; i++) {
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@@ -129,7 +129,7 @@ void xts_decrypt(const void *datactx,
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         }
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         /* Pm-1 = Tweak uncrypt CC */
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-        xts_tweak_decrypt(datactx, decfunc, CC, dst, T);
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+        xts_tweak_encdec(datactx, decfunc, CC, dst, T);
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     }
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     /* Decrypt the iv back */
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@@ -137,40 +137,6 @@ void xts_decrypt(const void *datactx,
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 }
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-/**
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- * xts_tweak_crypt:
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- * @param ctxt: the cipher context
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- * @param func: the cipher function
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- * @src: buffer providing the plain text of XTS_BLOCK_SIZE bytes
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- * @dst: buffer to output the cipher text of XTS_BLOCK_SIZE bytes
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- * @iv: the initialization vector tweak of XTS_BLOCK_SIZE bytes
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- *
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- * Encrypt data with a tweak
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- */
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-static void xts_tweak_encrypt(const void *ctx,
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-                              xts_cipher_func *func,
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-                              const uint8_t *src,
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-                              uint8_t *dst,
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-                              uint8_t *iv)
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-{
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-    unsigned long x;
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-
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-    /* tweak encrypt block i */
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-    for (x = 0; x < XTS_BLOCK_SIZE; x++) {
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-        dst[x] = src[x] ^ iv[x];
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-    }
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-
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-    func(ctx, XTS_BLOCK_SIZE, dst, dst);
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-
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-    for (x = 0; x < XTS_BLOCK_SIZE; x++) {
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-        dst[x] = dst[x] ^ iv[x];
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-    }
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-
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-    /* LFSR the tweak */
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-    xts_mult_x(iv);
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-}
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-
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-
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 void xts_encrypt(const void *datactx,
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                  const void *tweakctx,
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                  xts_cipher_func *encfunc,
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@@ -200,7 +166,7 @@ void xts_encrypt(const void *datactx,
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     encfunc(tweakctx, XTS_BLOCK_SIZE, T, iv);
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     for (i = 0; i < lim; i++) {
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-        xts_tweak_encrypt(datactx, encfunc, src, dst, T);
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+        xts_tweak_encdec(datactx, encfunc, src, dst, T);
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         dst += XTS_BLOCK_SIZE;
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         src += XTS_BLOCK_SIZE;
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@@ -209,7 +175,7 @@ void xts_encrypt(const void *datactx,
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     /* if length is not a multiple of XTS_BLOCK_SIZE then */
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     if (mo > 0) {
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         /* CC = tweak encrypt block m-1 */
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-        xts_tweak_encrypt(datactx, encfunc, src, CC, T);
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+        xts_tweak_encdec(datactx, encfunc, src, CC, T);
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         /* Cm = first length % XTS_BLOCK_SIZE bytes of CC */
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         for (i = 0; i < mo; i++) {
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@@ -222,7 +188,7 @@ void xts_encrypt(const void *datactx,
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         }
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         /* Cm-1 = Tweak encrypt PP */
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-        xts_tweak_encrypt(datactx, encfunc, PP, dst, T);
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+        xts_tweak_encdec(datactx, encfunc, PP, dst, T);
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     }
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     /* Decrypt the iv back */
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-- 
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1.8.3.1
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