1 files changed, 89 insertions, 250 deletions

diff --git a/crypto/lrw.c b/crypto/lrw.c
index 393a782679c7..0430ccd08728 100644
--- a/crypto/lrw.c
+++ b/crypto/lrw.c
@@ -29,8 +29,6 @@
 #include <crypto/b128ops.h>
 #include <crypto/gf128mul.h>
 
-#define LRW_BUFFER_SIZE 128u
-
 #define LRW_BLOCK_SIZE 16
 
 struct priv {
@@ -56,19 +54,7 @@ struct priv {
 };
 
 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;
 };
 
@@ -120,112 +106,68 @@ static int setkey(struct crypto_skcipher *parent, const u8 *key,
 	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)
+/*
+ * Returns the number of trailing '1' bits in the words of the counter, which is
+ * represented by 4 32-bit words, arranged from least to most significant.
+ * At the same time, increments the counter by one.
+ *
+ * For example:
+ *
+ * u32 counter[4] = { 0xFFFFFFFF, 0x1, 0x0, 0x0 };
+ * int i = next_index(&counter);
+ * // i == 33, counter == { 0x0, 0x2, 0x0, 0x0 }
+ */
+static int next_index(u32 *counter)
 {
-	int x;
-	__be32 *p = (__be32 *) block;
+	int i, res = 0;
 
-	for (p += 3, x = 0; x < 128; p--, x += 32) {
-		u32 val = be32_to_cpup(p);
+	for (i = 0; i < 4; i++) {
+		if (counter[i] + 1 != 0)
+			return res + ffz(counter[i]++);
 
-		if (!~val)
-			continue;
-
-		return x + ffz(val);
+		counter[i] = 0;
+		res += 32;
 	}
 
-	return x;
+	/*
+	 * 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)
+/*
+ * We compute the tweak masks twice (both before and after the ECB encryption or
+ * decryption) to avoid having to allocate a temporary buffer and/or make
+ * mutliple calls to the 'ecb(..)' instance, which usually would be slower than
+ * just doing the next_index() calls again.
+ */
+static int xor_tweak(struct skcipher_request *req, bool second_pass)
 {
-	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 rctx *rctx = skcipher_request_ctx(req);
+	be128 t = rctx->t;
 	struct skcipher_walk w;
-	struct scatterlist *sg;
-	unsigned cryptlen;
-	unsigned offset;
-	be128 *iv;
-	bool more;
+	__be32 *iv;
+	u32 counter[4];
 	int err;
 
-	subreq = &rctx->subreq;
-	skcipher_request_set_tfm(subreq, tfm);
-
-	cryptlen = subreq->cryptlen;
-	more = rctx->left > cryptlen;
-	if (!more)
-		cryptlen = rctx->left;
+	if (second_pass) {
+		req = &rctx->subreq;
+		/* set to our TFM to enforce correct alignment: */
+		skcipher_request_set_tfm(req, tfm);
+	}
 
-	skcipher_request_set_crypt(subreq, rctx->src, rctx->dst,
-				   cryptlen, req->iv);
+	err = skcipher_walk_virt(&w, req, false);
+	iv = (__be32 *)w.iv;
 
-	err = skcipher_walk_virt(&w, subreq, false);
-	iv = w.iv;
+	counter[0] = be32_to_cpu(iv[3]);
+	counter[1] = be32_to_cpu(iv[2]);
+	counter[2] = be32_to_cpu(iv[1]);
+	counter[3] = be32_to_cpu(iv[0]);
 
 	while (w.nbytes) {
 		unsigned int avail = w.nbytes;
@@ -236,188 +178,85 @@ static int pre_crypt(struct skcipher_request *req)
 		wdst = w.dst.virt.addr;
 
 		do {
-			*buf++ = rctx->t;
-			be128_xor(wdst++, &rctx->t, wsrc++);
+			be128_xor(wdst++, &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);
+			be128_xor(&t, &t, &ctx->mulinc[next_index(counter)]);
 		} 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 (second_pass && w.nbytes == w.total) {
+			iv[0] = cpu_to_be32(counter[3]);
+			iv[1] = cpu_to_be32(counter[2]);
+			iv[2] = cpu_to_be32(counter[1]);
+			iv[3] = cpu_to_be32(counter[0]);
+		}
 
-	if (rctx->src != sg) {
-		rctx->src[0] = *sg;
-		sg_unmark_end(rctx->src);
-		scatterwalk_crypto_chain(rctx->src, sg_next(sg), 2);
+		err = skcipher_walk_done(&w, avail);
 	}
-	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)
+static int xor_tweak_pre(struct skcipher_request *req)
 {
-	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;
+	return xor_tweak(req, false);
 }
 
-static void exit_crypt(struct skcipher_request *req)
+static int xor_tweak_post(struct skcipher_request *req)
 {
-	struct rctx *rctx = skcipher_request_ctx(req);
-
-	rctx->left = 0;
-
-	if (rctx->ext)
-		kzfree(rctx->ext);
+	return xor_tweak(req, true);
 }
 
-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)
+static void crypt_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)
+		err = xor_tweak_post(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)
+static void init_crypt(struct skcipher_request *req)
 {
+	struct priv *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
 	struct rctx *rctx = skcipher_request_ctx(req);
-	struct skcipher_request *subreq;
-
-	subreq = &rctx->subreq;
+	struct skcipher_request *subreq = &rctx->subreq;
 
-	while (!err && rctx->left) {
-		err = pre_crypt(req) ?:
-		      crypto_skcipher_decrypt(subreq) ?:
-		      post_crypt(req);
+	skcipher_request_set_tfm(subreq, ctx->child);
+	skcipher_request_set_callback(subreq, req->base.flags, crypt_done, req);
+	/* pass req->iv as IV (will be used by xor_tweak, ECB will ignore it) */
+	skcipher_request_set_crypt(subreq, req->dst, req->dst,
+				   req->cryptlen, req->iv);
 
-		if (err == -EINPROGRESS || err == -EBUSY)
-			return err;
-	}
+	/* calculate first value of T */
+	memcpy(&rctx->t, req->iv, sizeof(rctx->t));
 
-	exit_crypt(req);
-	return err;
+	/* T <- I*Key2 */
+	gf128mul_64k_bbe(&rctx->t, ctx->table);
 }
 
-static void decrypt_done(struct crypto_async_request *areq, int err)
+static int encrypt(struct skcipher_request *req)
 {
-	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;
+	struct rctx *rctx = skcipher_request_ctx(req);
+	struct skcipher_request *subreq = &rctx->subreq;
 
-out:
-	skcipher_request_complete(req, err);
+	init_crypt(req);
+	return xor_tweak_pre(req) ?:
+		crypto_skcipher_encrypt(subreq) ?:
+		xor_tweak_post(req);
 }
 
 static int decrypt(struct skcipher_request *req)
 {
-	return do_decrypt(req, init_crypt(req, decrypt_done));
+	struct rctx *rctx = skcipher_request_ctx(req);
+	struct skcipher_request *subreq = &rctx->subreq;
+
+	init_crypt(req);
+	return xor_tweak_pre(req) ?:
+		crypto_skcipher_decrypt(subreq) ?:
+		xor_tweak_post(req);
 }
 
 static int init_tfm(struct crypto_skcipher *tfm)
@@ -543,7 +382,7 @@ static int create(struct crypto_template *tmpl, struct rtattr **tb)
 	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);
+				       (__alignof__(__be32) - 1);
 
 	inst->alg.ivsize = LRW_BLOCK_SIZE;
 	inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) +