1 files changed, 605 insertions, 0 deletions

diff --git a/crypto/lrw.c b/crypto/lrw.c
new file mode 100644
index 000000000..d55c9ee18
--- /dev/null
+++ b/crypto/lrw.c
@@ -0,0 +1,605 @@
+/* LRW: as defined by Cyril Guyot in
+ *	http://grouper.ieee.org/groups/1619/email/pdf00017.pdf
+ *
+ * Copyright (c) 2006 Rik Snel <rsnel@cube.dyndns.org>
+ *
+ * Based on ecb.c
+ * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ */
+/* This implementation is checked against the test vectors in the above
+ * document and by a test vector provided by Ken Buchanan at
+ * http://www.mail-archive.com/stds-p1619@listserv.ieee.org/msg00173.html
+ *
+ * The test vectors are included in the testing module tcrypt.[ch] */
+
+#include <crypto/internal/skcipher.h>
+#include <crypto/scatterwalk.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/scatterlist.h>
+#include <linux/slab.h>
+
+#include <crypto/b128ops.h>
+#include <crypto/gf128mul.h>
+
+#define LRW_BUFFER_SIZE 128u
+
+#define LRW_BLOCK_SIZE 16
+
+struct priv {
+	struct crypto_skcipher *child;
+
+	/*
+	 * optimizes multiplying a random (non incrementing, as at the
+	 * start of a new sector) value with key2, we could also have
+	 * used 4k optimization tables or no optimization at all. In the
+	 * latter case we would have to store key2 here
+	 */
+	struct gf128mul_64k *table;
+
+	/*
+	 * stores:
+	 *  key2*{ 0,0,...0,0,0,0,1 }, key2*{ 0,0,...0,0,0,1,1 },
+	 *  key2*{ 0,0,...0,0,1,1,1 }, key2*{ 0,0,...0,1,1,1,1 }
+	 *  key2*{ 0,0,...1,1,1,1,1 }, etc
+	 * needed for optimized multiplication of incrementing values
+	 * with key2
+	 */
+	be128 mulinc[128];
+};
+
+struct rctx {
+	be128 buf[LRW_BUFFER_SIZE / sizeof(be128)];
+
+	be128 t;
+
+	be128 *ext;
+
+	struct scatterlist srcbuf[2];
+	struct scatterlist dstbuf[2];
+	struct scatterlist *src;
+	struct scatterlist *dst;
+
+	unsigned int left;
+
+	struct skcipher_request subreq;
+};
+
+static inline void setbit128_bbe(void *b, int bit)
+{
+	__set_bit(bit ^ (0x80 -
+#ifdef __BIG_ENDIAN
+			 BITS_PER_LONG
+#else
+			 BITS_PER_BYTE
+#endif
+			), b);
+}
+
+static int setkey(struct crypto_skcipher *parent, const u8 *key,
+		  unsigned int keylen)
+{
+	struct priv *ctx = crypto_skcipher_ctx(parent);
+	struct crypto_skcipher *child = ctx->child;
+	int err, bsize = LRW_BLOCK_SIZE;
+	const u8 *tweak = key + keylen - bsize;
+	be128 tmp = { 0 };
+	int i;
+
+	crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
+	crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &
+					 CRYPTO_TFM_REQ_MASK);
+	err = crypto_skcipher_setkey(child, key, keylen - bsize);
+	crypto_skcipher_set_flags(parent, crypto_skcipher_get_flags(child) &
+					  CRYPTO_TFM_RES_MASK);
+	if (err)
+		return err;
+
+	if (ctx->table)
+		gf128mul_free_64k(ctx->table);
+
+	/* initialize multiplication table for Key2 */
+	ctx->table = gf128mul_init_64k_bbe((be128 *)tweak);
+	if (!ctx->table)
+		return -ENOMEM;
+
+	/* initialize optimization table */
+	for (i = 0; i < 128; i++) {
+		setbit128_bbe(&tmp, i);
+		ctx->mulinc[i] = tmp;
+		gf128mul_64k_bbe(&ctx->mulinc[i], ctx->table);
+	}
+
+	return 0;
+}
+
+static inline void inc(be128 *iv)
+{
+	be64_add_cpu(&iv->b, 1);
+	if (!iv->b)
+		be64_add_cpu(&iv->a, 1);
+}
+
+/* this returns the number of consequative 1 bits starting
+ * from the right, get_index128(00 00 00 00 00 00 ... 00 00 10 FB) = 2 */
+static inline int get_index128(be128 *block)
+{
+	int x;
+	__be32 *p = (__be32 *) block;
+
+	for (p += 3, x = 0; x < 128; p--, x += 32) {
+		u32 val = be32_to_cpup(p);
+
+		if (!~val)
+			continue;
+
+		return x + ffz(val);
+	}
+
+	/*
+	 * If we get here, then x == 128 and we are incrementing the counter
+	 * from all ones to all zeros. This means we must return index 127, i.e.
+	 * the one corresponding to key2*{ 1,...,1 }.
+	 */
+	return 127;
+}
+
+static int post_crypt(struct skcipher_request *req)
+{
+	struct rctx *rctx = skcipher_request_ctx(req);
+	be128 *buf = rctx->ext ?: rctx->buf;
+	struct skcipher_request *subreq;
+	const int bs = LRW_BLOCK_SIZE;
+	struct skcipher_walk w;
+	struct scatterlist *sg;
+	unsigned offset;
+	int err;
+
+	subreq = &rctx->subreq;
+	err = skcipher_walk_virt(&w, subreq, false);
+
+	while (w.nbytes) {
+		unsigned int avail = w.nbytes;
+		be128 *wdst;
+
+		wdst = w.dst.virt.addr;
+
+		do {
+			be128_xor(wdst, buf++, wdst);
+			wdst++;
+		} while ((avail -= bs) >= bs);
+
+		err = skcipher_walk_done(&w, avail);
+	}
+
+	rctx->left -= subreq->cryptlen;
+
+	if (err || !rctx->left)
+		goto out;
+
+	rctx->dst = rctx->dstbuf;
+
+	scatterwalk_done(&w.out, 0, 1);
+	sg = w.out.sg;
+	offset = w.out.offset;
+
+	if (rctx->dst != sg) {
+		rctx->dst[0] = *sg;
+		sg_unmark_end(rctx->dst);
+		scatterwalk_crypto_chain(rctx->dst, sg_next(sg), 2);
+	}
+	rctx->dst[0].length -= offset - sg->offset;
+	rctx->dst[0].offset = offset;
+
+out:
+	return err;
+}
+
+static int pre_crypt(struct skcipher_request *req)
+{
+	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+	struct rctx *rctx = skcipher_request_ctx(req);
+	struct priv *ctx = crypto_skcipher_ctx(tfm);
+	be128 *buf = rctx->ext ?: rctx->buf;
+	struct skcipher_request *subreq;
+	const int bs = LRW_BLOCK_SIZE;
+	struct skcipher_walk w;
+	struct scatterlist *sg;
+	unsigned cryptlen;
+	unsigned offset;
+	be128 *iv;
+	bool more;
+	int err;
+
+	subreq = &rctx->subreq;
+	skcipher_request_set_tfm(subreq, tfm);
+
+	cryptlen = subreq->cryptlen;
+	more = rctx->left > cryptlen;
+	if (!more)
+		cryptlen = rctx->left;
+
+	skcipher_request_set_crypt(subreq, rctx->src, rctx->dst,
+				   cryptlen, req->iv);
+
+	err = skcipher_walk_virt(&w, subreq, false);
+	iv = w.iv;
+
+	while (w.nbytes) {
+		unsigned int avail = w.nbytes;
+		be128 *wsrc;
+		be128 *wdst;
+
+		wsrc = w.src.virt.addr;
+		wdst = w.dst.virt.addr;
+
+		do {
+			*buf++ = rctx->t;
+			be128_xor(wdst++, &rctx->t, wsrc++);
+
+			/* T <- I*Key2, using the optimization
+			 * discussed in the specification */
+			be128_xor(&rctx->t, &rctx->t,
+				  &ctx->mulinc[get_index128(iv)]);
+			inc(iv);
+		} while ((avail -= bs) >= bs);
+
+		err = skcipher_walk_done(&w, avail);
+	}
+
+	skcipher_request_set_tfm(subreq, ctx->child);
+	skcipher_request_set_crypt(subreq, rctx->dst, rctx->dst,
+				   cryptlen, NULL);
+
+	if (err || !more)
+		goto out;
+
+	rctx->src = rctx->srcbuf;
+
+	scatterwalk_done(&w.in, 0, 1);
+	sg = w.in.sg;
+	offset = w.in.offset;
+
+	if (rctx->src != sg) {
+		rctx->src[0] = *sg;
+		sg_unmark_end(rctx->src);
+		scatterwalk_crypto_chain(rctx->src, sg_next(sg), 2);
+	}
+	rctx->src[0].length -= offset - sg->offset;
+	rctx->src[0].offset = offset;
+
+out:
+	return err;
+}
+
+static int init_crypt(struct skcipher_request *req, crypto_completion_t done)
+{
+	struct priv *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
+	struct rctx *rctx = skcipher_request_ctx(req);
+	struct skcipher_request *subreq;
+	gfp_t gfp;
+
+	subreq = &rctx->subreq;
+	skcipher_request_set_callback(subreq, req->base.flags, done, req);
+
+	gfp = req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL :
+							   GFP_ATOMIC;
+	rctx->ext = NULL;
+
+	subreq->cryptlen = LRW_BUFFER_SIZE;
+	if (req->cryptlen > LRW_BUFFER_SIZE) {
+		unsigned int n = min(req->cryptlen, (unsigned int)PAGE_SIZE);
+
+		rctx->ext = kmalloc(n, gfp);
+		if (rctx->ext)
+			subreq->cryptlen = n;
+	}
+
+	rctx->src = req->src;
+	rctx->dst = req->dst;
+	rctx->left = req->cryptlen;
+
+	/* calculate first value of T */
+	memcpy(&rctx->t, req->iv, sizeof(rctx->t));
+
+	/* T <- I*Key2 */
+	gf128mul_64k_bbe(&rctx->t, ctx->table);
+
+	return 0;
+}
+
+static void exit_crypt(struct skcipher_request *req)
+{
+	struct rctx *rctx = skcipher_request_ctx(req);
+
+	rctx->left = 0;
+
+	if (rctx->ext)
+		kzfree(rctx->ext);
+}
+
+static int do_encrypt(struct skcipher_request *req, int err)
+{
+	struct rctx *rctx = skcipher_request_ctx(req);
+	struct skcipher_request *subreq;
+
+	subreq = &rctx->subreq;
+
+	while (!err && rctx->left) {
+		err = pre_crypt(req) ?:
+		      crypto_skcipher_encrypt(subreq) ?:
+		      post_crypt(req);
+
+		if (err == -EINPROGRESS || err == -EBUSY)
+			return err;
+	}
+
+	exit_crypt(req);
+	return err;
+}
+
+static void encrypt_done(struct crypto_async_request *areq, int err)
+{
+	struct skcipher_request *req = areq->data;
+	struct skcipher_request *subreq;
+	struct rctx *rctx;
+
+	rctx = skcipher_request_ctx(req);
+
+	if (err == -EINPROGRESS) {
+		if (rctx->left != req->cryptlen)
+			return;
+		goto out;
+	}
+
+	subreq = &rctx->subreq;
+	subreq->base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;
+
+	err = do_encrypt(req, err ?: post_crypt(req));
+	if (rctx->left)
+		return;
+
+out:
+	skcipher_request_complete(req, err);
+}
+
+static int encrypt(struct skcipher_request *req)
+{
+	return do_encrypt(req, init_crypt(req, encrypt_done));
+}
+
+static int do_decrypt(struct skcipher_request *req, int err)
+{
+	struct rctx *rctx = skcipher_request_ctx(req);
+	struct skcipher_request *subreq;
+
+	subreq = &rctx->subreq;
+
+	while (!err && rctx->left) {
+		err = pre_crypt(req) ?:
+		      crypto_skcipher_decrypt(subreq) ?:
+		      post_crypt(req);
+
+		if (err == -EINPROGRESS || err == -EBUSY)
+			return err;
+	}
+
+	exit_crypt(req);
+	return err;
+}
+
+static void decrypt_done(struct crypto_async_request *areq, int err)
+{
+	struct skcipher_request *req = areq->data;
+	struct skcipher_request *subreq;
+	struct rctx *rctx;
+
+	rctx = skcipher_request_ctx(req);
+
+	if (err == -EINPROGRESS) {
+		if (rctx->left != req->cryptlen)
+			return;
+		goto out;
+	}
+
+	subreq = &rctx->subreq;
+	subreq->base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;
+
+	err = do_decrypt(req, err ?: post_crypt(req));
+	if (rctx->left)
+		return;
+
+out:
+	skcipher_request_complete(req, err);
+}
+
+static int decrypt(struct skcipher_request *req)
+{
+	return do_decrypt(req, init_crypt(req, decrypt_done));
+}
+
+static int init_tfm(struct crypto_skcipher *tfm)
+{
+	struct skcipher_instance *inst = skcipher_alg_instance(tfm);
+	struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);
+	struct priv *ctx = crypto_skcipher_ctx(tfm);
+	struct crypto_skcipher *cipher;
+
+	cipher = crypto_spawn_skcipher(spawn);
+	if (IS_ERR(cipher))
+		return PTR_ERR(cipher);
+
+	ctx->child = cipher;
+
+	crypto_skcipher_set_reqsize(tfm, crypto_skcipher_reqsize(cipher) +
+					 sizeof(struct rctx));
+
+	return 0;
+}
+
+static void exit_tfm(struct crypto_skcipher *tfm)
+{
+	struct priv *ctx = crypto_skcipher_ctx(tfm);
+
+	if (ctx->table)
+		gf128mul_free_64k(ctx->table);
+	crypto_free_skcipher(ctx->child);
+}
+
+static void free_inst(struct skcipher_instance *inst)
+{
+	crypto_drop_skcipher(skcipher_instance_ctx(inst));
+	kfree(inst);
+}
+
+static int create(struct crypto_template *tmpl, struct rtattr **tb)
+{
+	struct crypto_skcipher_spawn *spawn;
+	struct skcipher_instance *inst;
+	struct crypto_attr_type *algt;
+	struct skcipher_alg *alg;
+	const char *cipher_name;
+	char ecb_name[CRYPTO_MAX_ALG_NAME];
+	int err;
+
+	algt = crypto_get_attr_type(tb);
+	if (IS_ERR(algt))
+		return PTR_ERR(algt);
+
+	if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
+		return -EINVAL;
+
+	cipher_name = crypto_attr_alg_name(tb[1]);
+	if (IS_ERR(cipher_name))
+		return PTR_ERR(cipher_name);
+
+	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
+	if (!inst)
+		return -ENOMEM;
+
+	spawn = skcipher_instance_ctx(inst);
+
+	crypto_set_skcipher_spawn(spawn, skcipher_crypto_instance(inst));
+	err = crypto_grab_skcipher(spawn, cipher_name, 0,
+				   crypto_requires_sync(algt->type,
+							algt->mask));
+	if (err == -ENOENT) {
+		err = -ENAMETOOLONG;
+		if (snprintf(ecb_name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
+			     cipher_name) >= CRYPTO_MAX_ALG_NAME)
+			goto err_free_inst;
+
+		err = crypto_grab_skcipher(spawn, ecb_name, 0,
+					   crypto_requires_sync(algt->type,
+								algt->mask));
+	}
+
+	if (err)
+		goto err_free_inst;
+
+	alg = crypto_skcipher_spawn_alg(spawn);
+
+	err = -EINVAL;
+	if (alg->base.cra_blocksize != LRW_BLOCK_SIZE)
+		goto err_drop_spawn;
+
+	if (crypto_skcipher_alg_ivsize(alg))
+		goto err_drop_spawn;
+
+	err = crypto_inst_setname(skcipher_crypto_instance(inst), "lrw",
+				  &alg->base);
+	if (err)
+		goto err_drop_spawn;
+
+	err = -EINVAL;
+	cipher_name = alg->base.cra_name;
+
+	/* Alas we screwed up the naming so we have to mangle the
+	 * cipher name.
+	 */
+	if (!strncmp(cipher_name, "ecb(", 4)) {
+		unsigned len;
+
+		len = strlcpy(ecb_name, cipher_name + 4, sizeof(ecb_name));
+		if (len < 2 || len >= sizeof(ecb_name))
+			goto err_drop_spawn;
+
+		if (ecb_name[len - 1] != ')')
+			goto err_drop_spawn;
+
+		ecb_name[len - 1] = 0;
+
+		if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
+			     "lrw(%s)", ecb_name) >= CRYPTO_MAX_ALG_NAME) {
+			err = -ENAMETOOLONG;
+			goto err_drop_spawn;
+		}
+	} else
+		goto err_drop_spawn;
+
+	inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
+	inst->alg.base.cra_priority = alg->base.cra_priority;
+	inst->alg.base.cra_blocksize = LRW_BLOCK_SIZE;
+	inst->alg.base.cra_alignmask = alg->base.cra_alignmask |
+				       (__alignof__(u64) - 1);
+
+	inst->alg.ivsize = LRW_BLOCK_SIZE;
+	inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) +
+				LRW_BLOCK_SIZE;
+	inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) +
+				LRW_BLOCK_SIZE;
+
+	inst->alg.base.cra_ctxsize = sizeof(struct priv);
+
+	inst->alg.init = init_tfm;
+	inst->alg.exit = exit_tfm;
+
+	inst->alg.setkey = setkey;
+	inst->alg.encrypt = encrypt;
+	inst->alg.decrypt = decrypt;
+
+	inst->free = free_inst;
+
+	err = skcipher_register_instance(tmpl, inst);
+	if (err)
+		goto err_drop_spawn;
+
+out:
+	return err;
+
+err_drop_spawn:
+	crypto_drop_skcipher(spawn);
+err_free_inst:
+	kfree(inst);
+	goto out;
+}
+
+static struct crypto_template crypto_tmpl = {
+	.name = "lrw",
+	.create = create,
+	.module = THIS_MODULE,
+};
+
+static int __init crypto_module_init(void)
+{
+	return crypto_register_template(&crypto_tmpl);
+}
+
+static void __exit crypto_module_exit(void)
+{
+	crypto_unregister_template(&crypto_tmpl);
+}
+
+module_init(crypto_module_init);
+module_exit(crypto_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("LRW block cipher mode");
+MODULE_ALIAS_CRYPTO("lrw");