[CRYPTO] pcbc: Use crypto_xor

This patch replaces the custom xor in CBC with the generic crypto_xor.

It changes the operations for in-place encryption slightly to avoid
calling crypto_xor with tmpbuf since it is not necessarily aligned.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 24 insertions, 81 deletions

diff --git a/crypto/pcbc.c b/crypto/pcbc.c
index c3ed8a1c9f46..fe704775f88f 100644
--- a/crypto/pcbc.c
+++ b/crypto/pcbc.c
@@ -24,7 +24,6 @@
 
 struct crypto_pcbc_ctx {
         struct crypto_cipher *child;
-        void (*xor)(u8 *dst, const u8 *src, unsigned int bs);
 };
 
 static int crypto_pcbc_setkey(struct crypto_tfm *parent, const u8 *key,
@@ -45,9 +44,7 @@ static int crypto_pcbc_setkey(struct crypto_tfm *parent, const u8 *key,
 
 static int crypto_pcbc_encrypt_segment(struct blkcipher_desc *desc,
                                        struct blkcipher_walk *walk,
-                                       struct crypto_cipher *tfm,
-                                       void (*xor)(u8 *, const u8 *,
-                                                   unsigned int))
+                                       struct crypto_cipher *tfm)
 {
         void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
                 crypto_cipher_alg(tfm)->cia_encrypt;
@@ -58,10 +55,10 @@ static int crypto_pcbc_encrypt_segment(struct blkcipher_desc *desc,
         u8 *iv = walk->iv;
 
         do {
-                xor(iv, src, bsize);
+                crypto_xor(iv, src, bsize);
                 fn(crypto_cipher_tfm(tfm), dst, iv);
                 memcpy(iv, dst, bsize);
-                xor(iv, src, bsize);
+                crypto_xor(iv, src, bsize);
 
                 src += bsize;
                 dst += bsize;
@@ -72,9 +69,7 @@ static int crypto_pcbc_encrypt_segment(struct blkcipher_desc *desc,
 
 static int crypto_pcbc_encrypt_inplace(struct blkcipher_desc *desc,
                                        struct blkcipher_walk *walk,
-                                       struct crypto_cipher *tfm,
-                                       void (*xor)(u8 *, const u8 *,
-                                                   unsigned int))
+                                       struct crypto_cipher *tfm)
 {
         void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
                 crypto_cipher_alg(tfm)->cia_encrypt;
@@ -86,10 +81,10 @@ static int crypto_pcbc_encrypt_inplace(struct blkcipher_desc *desc,
 
         do {
                 memcpy(tmpbuf, src, bsize);
-                xor(iv, tmpbuf, bsize);
+                crypto_xor(iv, src, bsize);
                 fn(crypto_cipher_tfm(tfm), src, iv);
-                memcpy(iv, src, bsize);
-                xor(iv, tmpbuf, bsize);
+                memcpy(iv, tmpbuf, bsize);
+                crypto_xor(iv, src, bsize);
 
                 src += bsize;
         } while ((nbytes -= bsize) >= bsize);
@@ -107,7 +102,6 @@ static int crypto_pcbc_encrypt(struct blkcipher_desc *desc,
         struct crypto_blkcipher *tfm = desc->tfm;
         struct crypto_pcbc_ctx *ctx = crypto_blkcipher_ctx(tfm);
         struct crypto_cipher *child = ctx->child;
-        void (*xor)(u8 *, const u8 *, unsigned int bs) = ctx->xor;
         int err;
 
         blkcipher_walk_init(&walk, dst, src, nbytes);
@@ -115,11 +109,11 @@ static int crypto_pcbc_encrypt(struct blkcipher_desc *desc,
 
         while ((nbytes = walk.nbytes)) {
                 if (walk.src.virt.addr == walk.dst.virt.addr)
-                        nbytes = crypto_pcbc_encrypt_inplace(desc, &walk, child,
-                                                             xor);
+                        nbytes = crypto_pcbc_encrypt_inplace(desc, &walk,
+                                                             child);
                 else
-                        nbytes = crypto_pcbc_encrypt_segment(desc, &walk, child,
-                                                             xor);
+                        nbytes = crypto_pcbc_encrypt_segment(desc, &walk,
+                                                             child);
                 err = blkcipher_walk_done(desc, &walk, nbytes);
         }
 
@@ -128,9 +122,7 @@ static int crypto_pcbc_encrypt(struct blkcipher_desc *desc,
 
 static int crypto_pcbc_decrypt_segment(struct blkcipher_desc *desc,
                                        struct blkcipher_walk *walk,
-                                       struct crypto_cipher *tfm,
-                                       void (*xor)(u8 *, const u8 *,
-                                                   unsigned int))
+                                       struct crypto_cipher *tfm)
 {
         void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
                 crypto_cipher_alg(tfm)->cia_decrypt;
@@ -142,9 +134,9 @@ static int crypto_pcbc_decrypt_segment(struct blkcipher_desc *desc,
 
         do {
                 fn(crypto_cipher_tfm(tfm), dst, src);
-                xor(dst, iv, bsize);
+                crypto_xor(dst, iv, bsize);
                 memcpy(iv, src, bsize);
-                xor(iv, dst, bsize);
+                crypto_xor(iv, dst, bsize);
 
                 src += bsize;
                 dst += bsize;
@@ -157,9 +149,7 @@ static int crypto_pcbc_decrypt_segment(struct blkcipher_desc *desc,
 
 static int crypto_pcbc_decrypt_inplace(struct blkcipher_desc *desc,
                                        struct blkcipher_walk *walk,
-                                       struct crypto_cipher *tfm,
-                                       void (*xor)(u8 *, const u8 *,
-                                                   unsigned int))
+                                       struct crypto_cipher *tfm)
 {
         void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
                 crypto_cipher_alg(tfm)->cia_decrypt;
@@ -172,9 +162,9 @@ static int crypto_pcbc_decrypt_inplace(struct blkcipher_desc *desc,
         do {
                 memcpy(tmpbuf, src, bsize);
                 fn(crypto_cipher_tfm(tfm), src, src);
-                xor(src, iv, bsize);
+                crypto_xor(src, iv, bsize);
                 memcpy(iv, tmpbuf, bsize);
-                xor(iv, src, bsize);
+                crypto_xor(iv, src, bsize);
 
                 src += bsize;
         } while ((nbytes -= bsize) >= bsize);
@@ -192,7 +182,6 @@ static int crypto_pcbc_decrypt(struct blkcipher_desc *desc,
         struct crypto_blkcipher *tfm = desc->tfm;
         struct crypto_pcbc_ctx *ctx = crypto_blkcipher_ctx(tfm);
         struct crypto_cipher *child = ctx->child;
-        void (*xor)(u8 *, const u8 *, unsigned int bs) = ctx->xor;
         int err;
 
         blkcipher_walk_init(&walk, dst, src, nbytes);
@@ -200,48 +189,17 @@ static int crypto_pcbc_decrypt(struct blkcipher_desc *desc,
 
         while ((nbytes = walk.nbytes)) {
                 if (walk.src.virt.addr == walk.dst.virt.addr)
-                        nbytes = crypto_pcbc_decrypt_inplace(desc, &walk, child,
-                                                             xor);
+                        nbytes = crypto_pcbc_decrypt_inplace(desc, &walk,
+                                                             child);
                 else
-                        nbytes = crypto_pcbc_decrypt_segment(desc, &walk, child,
-                                                             xor);
+                        nbytes = crypto_pcbc_decrypt_segment(desc, &walk,
+                                                             child);
                 err = blkcipher_walk_done(desc, &walk, nbytes);
         }
 
         return err;
 }
 
-static void xor_byte(u8 *a, const u8 *b, unsigned int bs)
-{
-        do {
-                *a++ ^= *b++;
-        } while (--bs);
-}
-
-static void xor_quad(u8 *dst, const u8 *src, unsigned int bs)
-{
-        u32 *a = (u32 *)dst;
-        u32 *b = (u32 *)src;
-
-        do {
-                *a++ ^= *b++;
-        } while ((bs -= 4));
-}
-
-static void xor_64(u8 *a, const u8 *b, unsigned int bs)
-{
-        ((u32 *)a)[0] ^= ((u32 *)b)[0];
-        ((u32 *)a)[1] ^= ((u32 *)b)[1];
-}
-
-static void xor_128(u8 *a, const u8 *b, unsigned int bs)
-{
-        ((u32 *)a)[0] ^= ((u32 *)b)[0];
-        ((u32 *)a)[1] ^= ((u32 *)b)[1];
-        ((u32 *)a)[2] ^= ((u32 *)b)[2];
-        ((u32 *)a)[3] ^= ((u32 *)b)[3];
-}
-
 static int crypto_pcbc_init_tfm(struct crypto_tfm *tfm)
 {
         struct crypto_instance *inst = (void *)tfm->__crt_alg;
@@ -249,22 +207,6 @@ static int crypto_pcbc_init_tfm(struct crypto_tfm *tfm)
         struct crypto_pcbc_ctx *ctx = crypto_tfm_ctx(tfm);
         struct crypto_cipher *cipher;
 
-        switch (crypto_tfm_alg_blocksize(tfm)) {
-        case 8:
-                ctx->xor = xor_64;
-                break;
-
-        case 16:
-                ctx->xor = xor_128;
-                break;
-
-        default:
-                if (crypto_tfm_alg_blocksize(tfm) % 4)
-                        ctx->xor = xor_byte;
-                else
-                        ctx->xor = xor_quad;
-        }
-
         cipher = crypto_spawn_cipher(spawn);
         if (IS_ERR(cipher))
                 return PTR_ERR(cipher);
@@ -304,8 +246,9 @@ static struct crypto_instance *crypto_pcbc_alloc(struct rtattr **tb)
         inst->alg.cra_alignmask = alg->cra_alignmask;
         inst->alg.cra_type = &crypto_blkcipher_type;
 
-        if (!(alg->cra_blocksize % 4))
-                inst->alg.cra_alignmask |= 3;
+        /* We access the data as u32s when xoring. */
+        inst->alg.cra_alignmask |= __alignof__(u32) - 1;
+
         inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;
         inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
         inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;