Initial import

1 files changed, 743 insertions, 0 deletions

diff --git a/crypto/blkcipher.c b/crypto/blkcipher.c
new file mode 100644
index 000000000..0122bec38
--- /dev/null
+++ b/crypto/blkcipher.c
@@ -0,0 +1,743 @@
+/*
+ * Block chaining cipher operations.
+ * 
+ * Generic encrypt/decrypt wrapper for ciphers, handles operations across
+ * multiple page boundaries by using temporary blocks.  In user context,
+ * the kernel is given a chance to schedule us once per page.
+ *
+ * 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.
+ *
+ */
+
+#include <crypto/internal/skcipher.h>
+#include <crypto/scatterwalk.h>
+#include <linux/errno.h>
+#include <linux/hardirq.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/scatterlist.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/cryptouser.h>
+#include <net/netlink.h>
+
+#include "internal.h"
+
+enum {
+	BLKCIPHER_WALK_PHYS = 1 << 0,
+	BLKCIPHER_WALK_SLOW = 1 << 1,
+	BLKCIPHER_WALK_COPY = 1 << 2,
+	BLKCIPHER_WALK_DIFF = 1 << 3,
+};
+
+static int blkcipher_walk_next(struct blkcipher_desc *desc,
+			       struct blkcipher_walk *walk);
+static int blkcipher_walk_first(struct blkcipher_desc *desc,
+				struct blkcipher_walk *walk);
+
+static inline void blkcipher_map_src(struct blkcipher_walk *walk)
+{
+	walk->src.virt.addr = scatterwalk_map(&walk->in);
+}
+
+static inline void blkcipher_map_dst(struct blkcipher_walk *walk)
+{
+	walk->dst.virt.addr = scatterwalk_map(&walk->out);
+}
+
+static inline void blkcipher_unmap_src(struct blkcipher_walk *walk)
+{
+	scatterwalk_unmap(walk->src.virt.addr);
+}
+
+static inline void blkcipher_unmap_dst(struct blkcipher_walk *walk)
+{
+	scatterwalk_unmap(walk->dst.virt.addr);
+}
+
+/* Get a spot of the specified length that does not straddle a page.
+ * The caller needs to ensure that there is enough space for this operation.
+ */
+static inline u8 *blkcipher_get_spot(u8 *start, unsigned int len)
+{
+	u8 *end_page = (u8 *)(((unsigned long)(start + len - 1)) & PAGE_MASK);
+	return max(start, end_page);
+}
+
+static inline unsigned int blkcipher_done_slow(struct blkcipher_walk *walk,
+					       unsigned int bsize)
+{
+	u8 *addr;
+
+	addr = (u8 *)ALIGN((unsigned long)walk->buffer, walk->alignmask + 1);
+	addr = blkcipher_get_spot(addr, bsize);
+	scatterwalk_copychunks(addr, &walk->out, bsize, 1);
+	return bsize;
+}
+
+static inline unsigned int blkcipher_done_fast(struct blkcipher_walk *walk,
+					       unsigned int n)
+{
+	if (walk->flags & BLKCIPHER_WALK_COPY) {
+		blkcipher_map_dst(walk);
+		memcpy(walk->dst.virt.addr, walk->page, n);
+		blkcipher_unmap_dst(walk);
+	} else if (!(walk->flags & BLKCIPHER_WALK_PHYS)) {
+		if (walk->flags & BLKCIPHER_WALK_DIFF)
+			blkcipher_unmap_dst(walk);
+		blkcipher_unmap_src(walk);
+	}
+
+	scatterwalk_advance(&walk->in, n);
+	scatterwalk_advance(&walk->out, n);
+
+	return n;
+}
+
+int blkcipher_walk_done(struct blkcipher_desc *desc,
+			struct blkcipher_walk *walk, int err)
+{
+	unsigned int nbytes = 0;
+
+	if (likely(err >= 0)) {
+		unsigned int n = walk->nbytes - err;
+
+		if (likely(!(walk->flags & BLKCIPHER_WALK_SLOW)))
+			n = blkcipher_done_fast(walk, n);
+		else if (WARN_ON(err)) {
+			err = -EINVAL;
+			goto err;
+		} else
+			n = blkcipher_done_slow(walk, n);
+
+		nbytes = walk->total - n;
+		err = 0;
+	}
+
+	scatterwalk_done(&walk->in, 0, nbytes);
+	scatterwalk_done(&walk->out, 1, nbytes);
+
+err:
+	walk->total = nbytes;
+	walk->nbytes = nbytes;
+
+	if (nbytes) {
+		crypto_yield(desc->flags);
+		return blkcipher_walk_next(desc, walk);
+	}
+
+	if (walk->iv != desc->info)
+		memcpy(desc->info, walk->iv, walk->ivsize);
+	if (walk->buffer != walk->page)
+		kfree(walk->buffer);
+	if (walk->page)
+		free_page((unsigned long)walk->page);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(blkcipher_walk_done);
+
+static inline int blkcipher_next_slow(struct blkcipher_desc *desc,
+				      struct blkcipher_walk *walk,
+				      unsigned int bsize,
+				      unsigned int alignmask)
+{
+	unsigned int n;
+	unsigned aligned_bsize = ALIGN(bsize, alignmask + 1);
+
+	if (walk->buffer)
+		goto ok;
+
+	walk->buffer = walk->page;
+	if (walk->buffer)
+		goto ok;
+
+	n = aligned_bsize * 3 - (alignmask + 1) +
+	    (alignmask & ~(crypto_tfm_ctx_alignment() - 1));
+	walk->buffer = kmalloc(n, GFP_ATOMIC);
+	if (!walk->buffer)
+		return blkcipher_walk_done(desc, walk, -ENOMEM);
+
+ok:
+	walk->dst.virt.addr = (u8 *)ALIGN((unsigned long)walk->buffer,
+					  alignmask + 1);
+	walk->dst.virt.addr = blkcipher_get_spot(walk->dst.virt.addr, bsize);
+	walk->src.virt.addr = blkcipher_get_spot(walk->dst.virt.addr +
+						 aligned_bsize, bsize);
+
+	scatterwalk_copychunks(walk->src.virt.addr, &walk->in, bsize, 0);
+
+	walk->nbytes = bsize;
+	walk->flags |= BLKCIPHER_WALK_SLOW;
+
+	return 0;
+}
+
+static inline int blkcipher_next_copy(struct blkcipher_walk *walk)
+{
+	u8 *tmp = walk->page;
+
+	blkcipher_map_src(walk);
+	memcpy(tmp, walk->src.virt.addr, walk->nbytes);
+	blkcipher_unmap_src(walk);
+
+	walk->src.virt.addr = tmp;
+	walk->dst.virt.addr = tmp;
+
+	return 0;
+}
+
+static inline int blkcipher_next_fast(struct blkcipher_desc *desc,
+				      struct blkcipher_walk *walk)
+{
+	unsigned long diff;
+
+	walk->src.phys.page = scatterwalk_page(&walk->in);
+	walk->src.phys.offset = offset_in_page(walk->in.offset);
+	walk->dst.phys.page = scatterwalk_page(&walk->out);
+	walk->dst.phys.offset = offset_in_page(walk->out.offset);
+
+	if (walk->flags & BLKCIPHER_WALK_PHYS)
+		return 0;
+
+	diff = walk->src.phys.offset - walk->dst.phys.offset;
+	diff |= walk->src.virt.page - walk->dst.virt.page;
+
+	blkcipher_map_src(walk);
+	walk->dst.virt.addr = walk->src.virt.addr;
+
+	if (diff) {
+		walk->flags |= BLKCIPHER_WALK_DIFF;
+		blkcipher_map_dst(walk);
+	}
+
+	return 0;
+}
+
+static int blkcipher_walk_next(struct blkcipher_desc *desc,
+			       struct blkcipher_walk *walk)
+{
+	unsigned int bsize;
+	unsigned int n;
+	int err;
+
+	n = walk->total;
+	if (unlikely(n < walk->cipher_blocksize)) {
+		desc->flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
+		return blkcipher_walk_done(desc, walk, -EINVAL);
+	}
+
+	walk->flags &= ~(BLKCIPHER_WALK_SLOW | BLKCIPHER_WALK_COPY |
+			 BLKCIPHER_WALK_DIFF);
+	if (!scatterwalk_aligned(&walk->in, walk->alignmask) ||
+	    !scatterwalk_aligned(&walk->out, walk->alignmask)) {
+		walk->flags |= BLKCIPHER_WALK_COPY;
+		if (!walk->page) {
+			walk->page = (void *)__get_free_page(GFP_ATOMIC);
+			if (!walk->page)
+				n = 0;
+		}
+	}
+
+	bsize = min(walk->walk_blocksize, n);
+	n = scatterwalk_clamp(&walk->in, n);
+	n = scatterwalk_clamp(&walk->out, n);
+
+	if (unlikely(n < bsize)) {
+		err = blkcipher_next_slow(desc, walk, bsize, walk->alignmask);
+		goto set_phys_lowmem;
+	}
+
+	walk->nbytes = n;
+	if (walk->flags & BLKCIPHER_WALK_COPY) {
+		err = blkcipher_next_copy(walk);
+		goto set_phys_lowmem;
+	}
+
+	return blkcipher_next_fast(desc, walk);
+
+set_phys_lowmem:
+	if (walk->flags & BLKCIPHER_WALK_PHYS) {
+		walk->src.phys.page = virt_to_page(walk->src.virt.addr);
+		walk->dst.phys.page = virt_to_page(walk->dst.virt.addr);
+		walk->src.phys.offset &= PAGE_SIZE - 1;
+		walk->dst.phys.offset &= PAGE_SIZE - 1;
+	}
+	return err;
+}
+
+static inline int blkcipher_copy_iv(struct blkcipher_walk *walk)
+{
+	unsigned bs = walk->walk_blocksize;
+	unsigned aligned_bs = ALIGN(bs, walk->alignmask + 1);
+	unsigned int size = aligned_bs * 2 +
+			    walk->ivsize + max(aligned_bs, walk->ivsize) -
+			    (walk->alignmask + 1);
+	u8 *iv;
+
+	size += walk->alignmask & ~(crypto_tfm_ctx_alignment() - 1);
+	walk->buffer = kmalloc(size, GFP_ATOMIC);
+	if (!walk->buffer)
+		return -ENOMEM;
+
+	iv = (u8 *)ALIGN((unsigned long)walk->buffer, walk->alignmask + 1);
+	iv = blkcipher_get_spot(iv, bs) + aligned_bs;
+	iv = blkcipher_get_spot(iv, bs) + aligned_bs;
+	iv = blkcipher_get_spot(iv, walk->ivsize);
+
+	walk->iv = memcpy(iv, walk->iv, walk->ivsize);
+	return 0;
+}
+
+int blkcipher_walk_virt(struct blkcipher_desc *desc,
+			struct blkcipher_walk *walk)
+{
+	walk->flags &= ~BLKCIPHER_WALK_PHYS;
+	walk->walk_blocksize = crypto_blkcipher_blocksize(desc->tfm);
+	walk->cipher_blocksize = walk->walk_blocksize;
+	walk->ivsize = crypto_blkcipher_ivsize(desc->tfm);
+	walk->alignmask = crypto_blkcipher_alignmask(desc->tfm);
+	return blkcipher_walk_first(desc, walk);
+}
+EXPORT_SYMBOL_GPL(blkcipher_walk_virt);
+
+int blkcipher_walk_phys(struct blkcipher_desc *desc,
+			struct blkcipher_walk *walk)
+{
+	walk->flags |= BLKCIPHER_WALK_PHYS;
+	walk->walk_blocksize = crypto_blkcipher_blocksize(desc->tfm);
+	walk->cipher_blocksize = walk->walk_blocksize;
+	walk->ivsize = crypto_blkcipher_ivsize(desc->tfm);
+	walk->alignmask = crypto_blkcipher_alignmask(desc->tfm);
+	return blkcipher_walk_first(desc, walk);
+}
+EXPORT_SYMBOL_GPL(blkcipher_walk_phys);
+
+static int blkcipher_walk_first(struct blkcipher_desc *desc,
+				struct blkcipher_walk *walk)
+{
+	if (WARN_ON_ONCE(in_irq()))
+		return -EDEADLK;
+
+	walk->nbytes = walk->total;
+	if (unlikely(!walk->total))
+		return 0;
+
+	walk->buffer = NULL;
+	walk->iv = desc->info;
+	if (unlikely(((unsigned long)walk->iv & walk->alignmask))) {
+		int err = blkcipher_copy_iv(walk);
+		if (err)
+			return err;
+	}
+
+	scatterwalk_start(&walk->in, walk->in.sg);
+	scatterwalk_start(&walk->out, walk->out.sg);
+	walk->page = NULL;
+
+	return blkcipher_walk_next(desc, walk);
+}
+
+int blkcipher_walk_virt_block(struct blkcipher_desc *desc,
+			      struct blkcipher_walk *walk,
+			      unsigned int blocksize)
+{
+	walk->flags &= ~BLKCIPHER_WALK_PHYS;
+	walk->walk_blocksize = blocksize;
+	walk->cipher_blocksize = crypto_blkcipher_blocksize(desc->tfm);
+	walk->ivsize = crypto_blkcipher_ivsize(desc->tfm);
+	walk->alignmask = crypto_blkcipher_alignmask(desc->tfm);
+	return blkcipher_walk_first(desc, walk);
+}
+EXPORT_SYMBOL_GPL(blkcipher_walk_virt_block);
+
+int blkcipher_aead_walk_virt_block(struct blkcipher_desc *desc,
+				   struct blkcipher_walk *walk,
+				   struct crypto_aead *tfm,
+				   unsigned int blocksize)
+{
+	walk->flags &= ~BLKCIPHER_WALK_PHYS;
+	walk->walk_blocksize = blocksize;
+	walk->cipher_blocksize = crypto_aead_blocksize(tfm);
+	walk->ivsize = crypto_aead_ivsize(tfm);
+	walk->alignmask = crypto_aead_alignmask(tfm);
+	return blkcipher_walk_first(desc, walk);
+}
+EXPORT_SYMBOL_GPL(blkcipher_aead_walk_virt_block);
+
+static int setkey_unaligned(struct crypto_tfm *tfm, const u8 *key,
+			    unsigned int keylen)
+{
+	struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher;
+	unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
+	int ret;
+	u8 *buffer, *alignbuffer;
+	unsigned long absize;
+
+	absize = keylen + alignmask;
+	buffer = kmalloc(absize, GFP_ATOMIC);
+	if (!buffer)
+		return -ENOMEM;
+
+	alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
+	memcpy(alignbuffer, key, keylen);
+	ret = cipher->setkey(tfm, alignbuffer, keylen);
+	memset(alignbuffer, 0, keylen);
+	kfree(buffer);
+	return ret;
+}
+
+static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
+{
+	struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher;
+	unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
+
+	if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
+		tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
+		return -EINVAL;
+	}
+
+	if ((unsigned long)key & alignmask)
+		return setkey_unaligned(tfm, key, keylen);
+
+	return cipher->setkey(tfm, key, keylen);
+}
+
+static int async_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
+			unsigned int keylen)
+{
+	return setkey(crypto_ablkcipher_tfm(tfm), key, keylen);
+}
+
+static int async_encrypt(struct ablkcipher_request *req)
+{
+	struct crypto_tfm *tfm = req->base.tfm;
+	struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
+	struct blkcipher_desc desc = {
+		.tfm = __crypto_blkcipher_cast(tfm),
+		.info = req->info,
+		.flags = req->base.flags,
+	};
+
+
+	return alg->encrypt(&desc, req->dst, req->src, req->nbytes);
+}
+
+static int async_decrypt(struct ablkcipher_request *req)
+{
+	struct crypto_tfm *tfm = req->base.tfm;
+	struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
+	struct blkcipher_desc desc = {
+		.tfm = __crypto_blkcipher_cast(tfm),
+		.info = req->info,
+		.flags = req->base.flags,
+	};
+
+	return alg->decrypt(&desc, req->dst, req->src, req->nbytes);
+}
+
+static unsigned int crypto_blkcipher_ctxsize(struct crypto_alg *alg, u32 type,
+					     u32 mask)
+{
+	struct blkcipher_alg *cipher = &alg->cra_blkcipher;
+	unsigned int len = alg->cra_ctxsize;
+
+	if ((mask & CRYPTO_ALG_TYPE_MASK) == CRYPTO_ALG_TYPE_MASK &&
+	    cipher->ivsize) {
+		len = ALIGN(len, (unsigned long)alg->cra_alignmask + 1);
+		len += cipher->ivsize;
+	}
+
+	return len;
+}
+
+static int crypto_init_blkcipher_ops_async(struct crypto_tfm *tfm)
+{
+	struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
+	struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
+
+	crt->setkey = async_setkey;
+	crt->encrypt = async_encrypt;
+	crt->decrypt = async_decrypt;
+	if (!alg->ivsize) {
+		crt->givencrypt = skcipher_null_givencrypt;
+		crt->givdecrypt = skcipher_null_givdecrypt;
+	}
+	crt->base = __crypto_ablkcipher_cast(tfm);
+	crt->ivsize = alg->ivsize;
+
+	return 0;
+}
+
+static int crypto_init_blkcipher_ops_sync(struct crypto_tfm *tfm)
+{
+	struct blkcipher_tfm *crt = &tfm->crt_blkcipher;
+	struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
+	unsigned long align = crypto_tfm_alg_alignmask(tfm) + 1;
+	unsigned long addr;
+
+	crt->setkey = setkey;
+	crt->encrypt = alg->encrypt;
+	crt->decrypt = alg->decrypt;
+
+	addr = (unsigned long)crypto_tfm_ctx(tfm);
+	addr = ALIGN(addr, align);
+	addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align);
+	crt->iv = (void *)addr;
+
+	return 0;
+}
+
+static int crypto_init_blkcipher_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
+{
+	struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
+
+	if (alg->ivsize > PAGE_SIZE / 8)
+		return -EINVAL;
+
+	if ((mask & CRYPTO_ALG_TYPE_MASK) == CRYPTO_ALG_TYPE_MASK)
+		return crypto_init_blkcipher_ops_sync(tfm);
+	else
+		return crypto_init_blkcipher_ops_async(tfm);
+}
+
+#ifdef CONFIG_NET
+static int crypto_blkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
+{
+	struct crypto_report_blkcipher rblkcipher;
+
+	strncpy(rblkcipher.type, "blkcipher", sizeof(rblkcipher.type));
+	strncpy(rblkcipher.geniv, alg->cra_blkcipher.geniv ?: "<default>",
+		sizeof(rblkcipher.geniv));
+
+	rblkcipher.blocksize = alg->cra_blocksize;
+	rblkcipher.min_keysize = alg->cra_blkcipher.min_keysize;
+	rblkcipher.max_keysize = alg->cra_blkcipher.max_keysize;
+	rblkcipher.ivsize = alg->cra_blkcipher.ivsize;
+
+	if (nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
+		    sizeof(struct crypto_report_blkcipher), &rblkcipher))
+		goto nla_put_failure;
+	return 0;
+
+nla_put_failure:
+	return -EMSGSIZE;
+}
+#else
+static int crypto_blkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
+{
+	return -ENOSYS;
+}
+#endif
+
+static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg)
+	__attribute__ ((unused));
+static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg)
+{
+	seq_printf(m, "type         : blkcipher\n");
+	seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
+	seq_printf(m, "min keysize  : %u\n", alg->cra_blkcipher.min_keysize);
+	seq_printf(m, "max keysize  : %u\n", alg->cra_blkcipher.max_keysize);
+	seq_printf(m, "ivsize       : %u\n", alg->cra_blkcipher.ivsize);
+	seq_printf(m, "geniv        : %s\n", alg->cra_blkcipher.geniv ?:
+					     "<default>");
+}
+
+const struct crypto_type crypto_blkcipher_type = {
+	.ctxsize = crypto_blkcipher_ctxsize,
+	.init = crypto_init_blkcipher_ops,
+#ifdef CONFIG_PROC_FS
+	.show = crypto_blkcipher_show,
+#endif
+	.report = crypto_blkcipher_report,
+};
+EXPORT_SYMBOL_GPL(crypto_blkcipher_type);
+
+static int crypto_grab_nivcipher(struct crypto_skcipher_spawn *spawn,
+				const char *name, u32 type, u32 mask)
+{
+	struct crypto_alg *alg;
+	int err;
+
+	type = crypto_skcipher_type(type);
+	mask = crypto_skcipher_mask(mask)| CRYPTO_ALG_GENIV;
+
+	alg = crypto_alg_mod_lookup(name, type, mask);
+	if (IS_ERR(alg))
+		return PTR_ERR(alg);
+
+	err = crypto_init_spawn(&spawn->base, alg, spawn->base.inst, mask);
+	crypto_mod_put(alg);
+	return err;
+}
+
+struct crypto_instance *skcipher_geniv_alloc(struct crypto_template *tmpl,
+					     struct rtattr **tb, u32 type,
+					     u32 mask)
+{
+	struct {
+		int (*setkey)(struct crypto_ablkcipher *tfm, const u8 *key,
+			      unsigned int keylen);
+		int (*encrypt)(struct ablkcipher_request *req);
+		int (*decrypt)(struct ablkcipher_request *req);
+
+		unsigned int min_keysize;
+		unsigned int max_keysize;
+		unsigned int ivsize;
+
+		const char *geniv;
+	} balg;
+	const char *name;
+	struct crypto_skcipher_spawn *spawn;
+	struct crypto_attr_type *algt;
+	struct crypto_instance *inst;
+	struct crypto_alg *alg;
+	int err;
+
+	algt = crypto_get_attr_type(tb);
+	if (IS_ERR(algt))
+		return ERR_CAST(algt);
+
+	if ((algt->type ^ (CRYPTO_ALG_TYPE_GIVCIPHER | CRYPTO_ALG_GENIV)) &
+	    algt->mask)
+		return ERR_PTR(-EINVAL);
+
+	name = crypto_attr_alg_name(tb[1]);
+	if (IS_ERR(name))
+		return ERR_CAST(name);
+
+	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
+	if (!inst)
+		return ERR_PTR(-ENOMEM);
+
+	spawn = crypto_instance_ctx(inst);
+
+	/* Ignore async algorithms if necessary. */
+	mask |= crypto_requires_sync(algt->type, algt->mask);
+
+	crypto_set_skcipher_spawn(spawn, inst);
+	err = crypto_grab_nivcipher(spawn, name, type, mask);
+	if (err)
+		goto err_free_inst;
+
+	alg = crypto_skcipher_spawn_alg(spawn);
+
+	if ((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
+	    CRYPTO_ALG_TYPE_BLKCIPHER) {
+		balg.ivsize = alg->cra_blkcipher.ivsize;
+		balg.min_keysize = alg->cra_blkcipher.min_keysize;
+		balg.max_keysize = alg->cra_blkcipher.max_keysize;
+
+		balg.setkey = async_setkey;
+		balg.encrypt = async_encrypt;
+		balg.decrypt = async_decrypt;
+
+		balg.geniv = alg->cra_blkcipher.geniv;
+	} else {
+		balg.ivsize = alg->cra_ablkcipher.ivsize;
+		balg.min_keysize = alg->cra_ablkcipher.min_keysize;
+		balg.max_keysize = alg->cra_ablkcipher.max_keysize;
+
+		balg.setkey = alg->cra_ablkcipher.setkey;
+		balg.encrypt = alg->cra_ablkcipher.encrypt;
+		balg.decrypt = alg->cra_ablkcipher.decrypt;
+
+		balg.geniv = alg->cra_ablkcipher.geniv;
+	}
+
+	err = -EINVAL;
+	if (!balg.ivsize)
+		goto err_drop_alg;
+
+	/*
+	 * This is only true if we're constructing an algorithm with its
+	 * default IV generator.  For the default generator we elide the
+	 * template name and double-check the IV generator.
+	 */
+	if (algt->mask & CRYPTO_ALG_GENIV) {
+		if (!balg.geniv)
+			balg.geniv = crypto_default_geniv(alg);
+		err = -EAGAIN;
+		if (strcmp(tmpl->name, balg.geniv))
+			goto err_drop_alg;
+
+		memcpy(inst->alg.cra_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
+		memcpy(inst->alg.cra_driver_name, alg->cra_driver_name,
+		       CRYPTO_MAX_ALG_NAME);
+	} else {
+		err = -ENAMETOOLONG;
+		if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
+			     "%s(%s)", tmpl->name, alg->cra_name) >=
+		    CRYPTO_MAX_ALG_NAME)
+			goto err_drop_alg;
+		if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
+			     "%s(%s)", tmpl->name, alg->cra_driver_name) >=
+		    CRYPTO_MAX_ALG_NAME)
+			goto err_drop_alg;
+	}
+
+	inst->alg.cra_flags = CRYPTO_ALG_TYPE_GIVCIPHER | CRYPTO_ALG_GENIV;
+	inst->alg.cra_flags |= alg->cra_flags & CRYPTO_ALG_ASYNC;
+	inst->alg.cra_priority = alg->cra_priority;
+	inst->alg.cra_blocksize = alg->cra_blocksize;
+	inst->alg.cra_alignmask = alg->cra_alignmask;
+	inst->alg.cra_type = &crypto_givcipher_type;
+
+	inst->alg.cra_ablkcipher.ivsize = balg.ivsize;
+	inst->alg.cra_ablkcipher.min_keysize = balg.min_keysize;
+	inst->alg.cra_ablkcipher.max_keysize = balg.max_keysize;
+	inst->alg.cra_ablkcipher.geniv = balg.geniv;
+
+	inst->alg.cra_ablkcipher.setkey = balg.setkey;
+	inst->alg.cra_ablkcipher.encrypt = balg.encrypt;
+	inst->alg.cra_ablkcipher.decrypt = balg.decrypt;
+
+out:
+	return inst;
+
+err_drop_alg:
+	crypto_drop_skcipher(spawn);
+err_free_inst:
+	kfree(inst);
+	inst = ERR_PTR(err);
+	goto out;
+}
+EXPORT_SYMBOL_GPL(skcipher_geniv_alloc);
+
+void skcipher_geniv_free(struct crypto_instance *inst)
+{
+	crypto_drop_skcipher(crypto_instance_ctx(inst));
+	kfree(inst);
+}
+EXPORT_SYMBOL_GPL(skcipher_geniv_free);
+
+int skcipher_geniv_init(struct crypto_tfm *tfm)
+{
+	struct crypto_instance *inst = (void *)tfm->__crt_alg;
+	struct crypto_ablkcipher *cipher;
+
+	cipher = crypto_spawn_skcipher(crypto_instance_ctx(inst));
+	if (IS_ERR(cipher))
+		return PTR_ERR(cipher);
+
+	tfm->crt_ablkcipher.base = cipher;
+	tfm->crt_ablkcipher.reqsize += crypto_ablkcipher_reqsize(cipher);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(skcipher_geniv_init);
+
+void skcipher_geniv_exit(struct crypto_tfm *tfm)
+{
+	crypto_free_ablkcipher(tfm->crt_ablkcipher.base);
+}
+EXPORT_SYMBOL_GPL(skcipher_geniv_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Generic block chaining cipher type");