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-rw-r--r--crypto/xts.c79
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;
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