[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>

diff --git a/crypto/pcbc.c b/crypto/pcbc.c
index c3ed8a1..fe70477 100644 (file)
--- 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;