326 lines
6.3 KiB
C
326 lines
6.3 KiB
C
/*
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* Scatterlist Cryptographic API.
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*
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* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
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* Copyright (c) 2002 David S. Miller (davem@redhat.com)
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* Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
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*
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* Portions derived from Cryptoapi, by Alexander Kjeldaas <astor@fast.no>
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* and Nettle, by Niels Möller.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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*/
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#include <linux/compiler.h>
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#include <linux/init.h>
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#include <linux/crypto.h>
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/kmod.h>
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#include <linux/rwsem.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#include "internal.h"
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LIST_HEAD(crypto_alg_list);
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DECLARE_RWSEM(crypto_alg_sem);
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static inline int crypto_alg_get(struct crypto_alg *alg)
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{
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return try_module_get(alg->cra_module);
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}
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static inline void crypto_alg_put(struct crypto_alg *alg)
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{
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module_put(alg->cra_module);
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}
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static struct crypto_alg *crypto_alg_lookup(const char *name)
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{
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struct crypto_alg *q, *alg = NULL;
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int best = -1;
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if (!name)
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return NULL;
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down_read(&crypto_alg_sem);
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list_for_each_entry(q, &crypto_alg_list, cra_list) {
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int exact, fuzzy;
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exact = !strcmp(q->cra_driver_name, name);
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fuzzy = !strcmp(q->cra_name, name);
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if (!exact && !(fuzzy && q->cra_priority > best))
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continue;
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if (unlikely(!crypto_alg_get(q)))
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continue;
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best = q->cra_priority;
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if (alg)
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crypto_alg_put(alg);
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alg = q;
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if (exact)
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break;
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}
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up_read(&crypto_alg_sem);
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return alg;
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}
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/* A far more intelligent version of this is planned. For now, just
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* try an exact match on the name of the algorithm. */
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static inline struct crypto_alg *crypto_alg_mod_lookup(const char *name)
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{
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return try_then_request_module(crypto_alg_lookup(name), name);
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}
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static int crypto_init_flags(struct crypto_tfm *tfm, u32 flags)
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{
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tfm->crt_flags = flags & CRYPTO_TFM_REQ_MASK;
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flags &= ~CRYPTO_TFM_REQ_MASK;
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switch (crypto_tfm_alg_type(tfm)) {
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case CRYPTO_ALG_TYPE_CIPHER:
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return crypto_init_cipher_flags(tfm, flags);
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case CRYPTO_ALG_TYPE_DIGEST:
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return crypto_init_digest_flags(tfm, flags);
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case CRYPTO_ALG_TYPE_COMPRESS:
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return crypto_init_compress_flags(tfm, flags);
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default:
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break;
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}
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BUG();
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return -EINVAL;
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}
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static int crypto_init_ops(struct crypto_tfm *tfm)
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{
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switch (crypto_tfm_alg_type(tfm)) {
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case CRYPTO_ALG_TYPE_CIPHER:
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return crypto_init_cipher_ops(tfm);
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case CRYPTO_ALG_TYPE_DIGEST:
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return crypto_init_digest_ops(tfm);
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case CRYPTO_ALG_TYPE_COMPRESS:
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return crypto_init_compress_ops(tfm);
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default:
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break;
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}
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BUG();
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return -EINVAL;
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}
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static void crypto_exit_ops(struct crypto_tfm *tfm)
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{
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switch (crypto_tfm_alg_type(tfm)) {
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case CRYPTO_ALG_TYPE_CIPHER:
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crypto_exit_cipher_ops(tfm);
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break;
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case CRYPTO_ALG_TYPE_DIGEST:
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crypto_exit_digest_ops(tfm);
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break;
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case CRYPTO_ALG_TYPE_COMPRESS:
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crypto_exit_compress_ops(tfm);
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break;
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default:
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BUG();
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}
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}
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static unsigned int crypto_ctxsize(struct crypto_alg *alg, int flags)
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{
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unsigned int len;
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switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
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default:
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BUG();
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case CRYPTO_ALG_TYPE_CIPHER:
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len = crypto_cipher_ctxsize(alg, flags);
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break;
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case CRYPTO_ALG_TYPE_DIGEST:
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len = crypto_digest_ctxsize(alg, flags);
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break;
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case CRYPTO_ALG_TYPE_COMPRESS:
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len = crypto_compress_ctxsize(alg, flags);
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break;
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}
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return len + alg->cra_alignmask;
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}
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struct crypto_tfm *crypto_alloc_tfm(const char *name, u32 flags)
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{
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struct crypto_tfm *tfm = NULL;
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struct crypto_alg *alg;
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unsigned int tfm_size;
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alg = crypto_alg_mod_lookup(name);
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if (alg == NULL)
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goto out;
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tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, flags);
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tfm = kmalloc(tfm_size, GFP_KERNEL);
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if (tfm == NULL)
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goto out_put;
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memset(tfm, 0, tfm_size);
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tfm->__crt_alg = alg;
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if (crypto_init_flags(tfm, flags))
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goto out_free_tfm;
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if (crypto_init_ops(tfm)) {
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crypto_exit_ops(tfm);
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goto out_free_tfm;
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}
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goto out;
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out_free_tfm:
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kfree(tfm);
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tfm = NULL;
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out_put:
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crypto_alg_put(alg);
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out:
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return tfm;
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}
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void crypto_free_tfm(struct crypto_tfm *tfm)
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{
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struct crypto_alg *alg;
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int size;
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if (unlikely(!tfm))
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return;
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alg = tfm->__crt_alg;
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size = sizeof(*tfm) + alg->cra_ctxsize;
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crypto_exit_ops(tfm);
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crypto_alg_put(alg);
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memset(tfm, 0, size);
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kfree(tfm);
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}
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static inline int crypto_set_driver_name(struct crypto_alg *alg)
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{
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static const char suffix[] = "-generic";
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char *driver_name = (char *)alg->cra_driver_name;
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int len;
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if (*driver_name)
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return 0;
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len = strlcpy(driver_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
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if (len + sizeof(suffix) > CRYPTO_MAX_ALG_NAME)
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return -ENAMETOOLONG;
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memcpy(driver_name + len, suffix, sizeof(suffix));
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return 0;
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}
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int crypto_register_alg(struct crypto_alg *alg)
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{
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int ret;
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struct crypto_alg *q;
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if (alg->cra_alignmask & (alg->cra_alignmask + 1))
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return -EINVAL;
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if (alg->cra_alignmask & alg->cra_blocksize)
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return -EINVAL;
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if (alg->cra_blocksize > PAGE_SIZE / 8)
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return -EINVAL;
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if (alg->cra_priority < 0)
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return -EINVAL;
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ret = crypto_set_driver_name(alg);
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if (unlikely(ret))
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return ret;
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down_write(&crypto_alg_sem);
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list_for_each_entry(q, &crypto_alg_list, cra_list) {
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if (!strcmp(q->cra_driver_name, alg->cra_driver_name)) {
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ret = -EEXIST;
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goto out;
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}
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}
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list_add_tail(&alg->cra_list, &crypto_alg_list);
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out:
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up_write(&crypto_alg_sem);
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return ret;
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}
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int crypto_unregister_alg(struct crypto_alg *alg)
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{
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int ret = -ENOENT;
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struct crypto_alg *q;
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BUG_ON(!alg->cra_module);
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down_write(&crypto_alg_sem);
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list_for_each_entry(q, &crypto_alg_list, cra_list) {
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if (alg == q) {
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list_del(&alg->cra_list);
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ret = 0;
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goto out;
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}
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}
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out:
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up_write(&crypto_alg_sem);
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return ret;
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}
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int crypto_alg_available(const char *name, u32 flags)
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{
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int ret = 0;
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struct crypto_alg *alg = crypto_alg_mod_lookup(name);
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if (alg) {
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crypto_alg_put(alg);
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ret = 1;
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}
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return ret;
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}
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static int __init init_crypto(void)
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{
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printk(KERN_INFO "Initializing Cryptographic API\n");
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crypto_init_proc();
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return 0;
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}
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__initcall(init_crypto);
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EXPORT_SYMBOL_GPL(crypto_register_alg);
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EXPORT_SYMBOL_GPL(crypto_unregister_alg);
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EXPORT_SYMBOL_GPL(crypto_alloc_tfm);
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EXPORT_SYMBOL_GPL(crypto_free_tfm);
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EXPORT_SYMBOL_GPL(crypto_alg_available);
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