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root/crypto/blkcipher.c

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DEFINITIONS

This source file includes following definitions.
  1. blkcipher_map_src
  2. blkcipher_map_dst
  3. blkcipher_unmap_src
  4. blkcipher_unmap_dst
  5. blkcipher_get_spot
  6. blkcipher_done_slow
  7. blkcipher_done_fast
  8. blkcipher_walk_done
  9. blkcipher_next_slow
  10. blkcipher_next_copy
  11. blkcipher_next_fast
  12. blkcipher_walk_next
  13. blkcipher_copy_iv
  14. blkcipher_walk_virt
  15. blkcipher_walk_phys
  16. blkcipher_walk_first
  17. blkcipher_walk_virt_block
  18. setkey_unaligned
  19. setkey
  20. async_setkey
  21. async_encrypt
  22. async_decrypt
  23. crypto_blkcipher_ctxsize
  24. crypto_init_blkcipher_ops_async
  25. crypto_init_blkcipher_ops_sync
  26. crypto_init_blkcipher_ops
  27. crypto_blkcipher_show
  28. crypto_grab_nivcipher
  29. skcipher_geniv_alloc
  30. skcipher_geniv_free
  31. skcipher_geniv_init
  32. skcipher_geniv_exit

/*
 * 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 "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, 0);
}

static inline void blkcipher_map_dst(struct blkcipher_walk *walk)
{
        walk->dst.virt.addr = scatterwalk_map(&walk->out, 1);
}

static inline void blkcipher_unmap_src(struct blkcipher_walk *walk)
{
        scatterwalk_unmap(walk->src.virt.addr, 0);
}

static inline void blkcipher_unmap_dst(struct blkcipher_walk *walk)
{
        scatterwalk_unmap(walk->dst.virt.addr, 1);
}

/* 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 crypto_blkcipher *tfm,
                                               struct blkcipher_walk *walk,
                                               unsigned int bsize)
{
        u8 *addr;
        unsigned int alignmask = crypto_blkcipher_alignmask(tfm);

        addr = (u8 *)ALIGN((unsigned long)walk->buffer, 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)) {
                blkcipher_unmap_src(walk);
                if (walk->flags & BLKCIPHER_WALK_DIFF)
                        blkcipher_unmap_dst(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)
{
        struct crypto_blkcipher *tfm = desc->tfm;
        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(tfm, walk, n);

                nbytes = walk->total - n;
                err = 0;
        }

        scatterwalk_done(&walk->in, 0, nbytes);
        scatterwalk_done(&walk->out, 1, nbytes);

        walk->total = nbytes;
        walk->nbytes = nbytes;

        if (nbytes) {
                crypto_yield(desc->flags);
                return blkcipher_walk_next(desc, walk);
        }

err:
        if (walk->iv != desc->info)
                memcpy(desc->info, walk->iv, crypto_blkcipher_ivsize(tfm));
        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)
{
        struct crypto_blkcipher *tfm = desc->tfm;
        unsigned int alignmask = crypto_blkcipher_alignmask(tfm);
        unsigned int bsize;
        unsigned int n;
        int err;

        n = walk->total;
        if (unlikely(n < crypto_blkcipher_blocksize(tfm))) {
                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, alignmask) ||
            !scatterwalk_aligned(&walk->out, 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->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, 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,
                                    struct crypto_blkcipher *tfm,
                                    unsigned int alignmask)
{
        unsigned bs = walk->blocksize;
        unsigned int ivsize = crypto_blkcipher_ivsize(tfm);
        unsigned aligned_bs = ALIGN(bs, alignmask + 1);
        unsigned int size = aligned_bs * 2 + ivsize + max(aligned_bs, ivsize) -
                            (alignmask + 1);
        u8 *iv;

        size += alignmask & ~(crypto_tfm_ctx_alignment() - 1);
        walk->buffer = kmalloc(size, GFP_ATOMIC);
        if (!walk->buffer)
                return -ENOMEM;

        iv = (u8 *)ALIGN((unsigned long)walk->buffer, alignmask + 1);
        iv = blkcipher_get_spot(iv, bs) + aligned_bs;
        iv = blkcipher_get_spot(iv, bs) + aligned_bs;
        iv = blkcipher_get_spot(iv, ivsize);

        walk->iv = memcpy(iv, walk->iv, ivsize);
        return 0;
}

int blkcipher_walk_virt(struct blkcipher_desc *desc,
                        struct blkcipher_walk *walk)
{
        walk->flags &= ~BLKCIPHER_WALK_PHYS;
        walk->blocksize = crypto_blkcipher_blocksize(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->blocksize = crypto_blkcipher_blocksize(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)
{
        struct crypto_blkcipher *tfm = desc->tfm;
        unsigned int alignmask = crypto_blkcipher_alignmask(tfm);

        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 & alignmask))) {
                int err = blkcipher_copy_iv(walk, tfm, alignmask);
                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->blocksize = blocksize;
        return blkcipher_walk_first(desc, walk);
}
EXPORT_SYMBOL_GPL(blkcipher_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);
}

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
};
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);
        err = PTR_ERR(algt);
        if (IS_ERR(algt))
                return ERR_PTR(err);

        if ((algt->type ^ (CRYPTO_ALG_TYPE_GIVCIPHER | CRYPTO_ALG_GENIV)) &
            algt->mask)
                return ERR_PTR(-EINVAL);

        name = crypto_attr_alg_name(tb[1]);
        err = PTR_ERR(name);
        if (IS_ERR(name))
                return ERR_PTR(err);

        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");

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