1 files changed, 76 insertions, 3 deletions

diff --git a/crypto/xts.c b/crypto/xts.c
index 8517054..ca1608f 100644
--- a/crypto/xts.c
+++ b/crypto/xts.c
@@ -21,6 +21,7 @@
 #include <linux/scatterlist.h>
 #include <linux/slab.h>
 
+#include <crypto/xts.h>
 #include <crypto/b128ops.h>
 #include <crypto/gf128mul.h>
 
@@ -96,7 +97,7 @@ static int crypt(struct blkcipher_desc *d,
 {
 	int err;
 	unsigned int avail;
-	const int bs = crypto_cipher_blocksize(ctx->child);
+	const int bs = XTS_BLOCK_SIZE;
 	struct sinfo s = {
 		.tfm = crypto_cipher_tfm(ctx->child),
 		.fn = fn
@@ -165,6 +166,78 @@ static int decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
 		     crypto_cipher_alg(ctx->child)->cia_decrypt);
 }
 
+int xts_crypt(struct blkcipher_desc *desc, struct scatterlist *sdst,
+	      struct scatterlist *ssrc, unsigned int nbytes,
+	      struct xts_crypt_req *req)
+{
+	const unsigned int bsize = XTS_BLOCK_SIZE;
+	const unsigned int max_blks = req->tbuflen / bsize;
+	struct blkcipher_walk walk;
+	unsigned int nblocks;
+	be128 *src, *dst, *t;
+	be128 *t_buf = req->tbuf;
+	int err, i;
+
+	BUG_ON(max_blks < 1);
+
+	blkcipher_walk_init(&walk, sdst, ssrc, nbytes);
+
+	err = blkcipher_walk_virt(desc, &walk);
+	nbytes = walk.nbytes;
+	if (!nbytes)
+		return err;
+
+	nblocks = min(nbytes / bsize, max_blks);
+	src = (be128 *)walk.src.virt.addr;
+	dst = (be128 *)walk.dst.virt.addr;
+
+	/* calculate first value of T */
+	req->tweak_fn(req->tweak_ctx, (u8 *)&t_buf[0], walk.iv);
+
+	i = 0;
+	goto first;
+
+	for (;;) {
+		do {
+			for (i = 0; i < nblocks; i++) {
+				gf128mul_x_ble(&t_buf[i], t);
+first:
+				t = &t_buf[i];
+
+				/* PP <- T xor P */
+				be128_xor(dst + i, t, src + i);
+			}
+
+			/* CC <- E(Key2,PP) */
+			req->crypt_fn(req->crypt_ctx, (u8 *)dst,
+				      nblocks * bsize);
+
+			/* C <- T xor CC */
+			for (i = 0; i < nblocks; i++)
+				be128_xor(dst + i, dst + i, &t_buf[i]);
+
+			src += nblocks;
+			dst += nblocks;
+			nbytes -= nblocks * bsize;
+			nblocks = min(nbytes / bsize, max_blks);
+		} while (nblocks > 0);
+
+		*(be128 *)walk.iv = *t;
+
+		err = blkcipher_walk_done(desc, &walk, nbytes);
+		nbytes = walk.nbytes;
+		if (!nbytes)
+			break;
+
+		nblocks = min(nbytes / bsize, max_blks);
+		src = (be128 *)walk.src.virt.addr;
+		dst = (be128 *)walk.dst.virt.addr;
+	}
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(xts_crypt);
+
 static int init_tfm(struct crypto_tfm *tfm)
 {
 	struct crypto_cipher *cipher;
@@ -177,7 +250,7 @@ static int init_tfm(struct crypto_tfm *tfm)
 	if (IS_ERR(cipher))
 		return PTR_ERR(cipher);
 
-	if (crypto_cipher_blocksize(cipher) != 16) {
+	if (crypto_cipher_blocksize(cipher) != XTS_BLOCK_SIZE) {
 		*flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
 		crypto_free_cipher(cipher);
 		return -EINVAL;
@@ -192,7 +265,7 @@ static int init_tfm(struct crypto_tfm *tfm)
 	}
 
 	/* this check isn't really needed, leave it here just in case */
-	if (crypto_cipher_blocksize(cipher) != 16) {
+	if (crypto_cipher_blocksize(cipher) != XTS_BLOCK_SIZE) {
 		crypto_free_cipher(cipher);
 		crypto_free_cipher(ctx->child);
 		*flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;