1 files changed, 76 insertions, 3 deletions

diff --git a/crypto/xts.c b/crypto/xts.c
index 851705446c82..ca1608f44cb5 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;