500 lines
11 KiB
C
500 lines
11 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/err.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/module.h>
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#include <linux/param.h>
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#include <linux/sched.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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EXPORT_SYMBOL_GPL(crypto_alg_list);
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DECLARE_RWSEM(crypto_alg_sem);
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EXPORT_SYMBOL_GPL(crypto_alg_sem);
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BLOCKING_NOTIFIER_HEAD(crypto_chain);
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EXPORT_SYMBOL_GPL(crypto_chain);
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static inline struct crypto_alg *crypto_alg_get(struct crypto_alg *alg)
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{
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atomic_inc(&alg->cra_refcnt);
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return alg;
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}
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struct crypto_alg *crypto_mod_get(struct crypto_alg *alg)
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{
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return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL;
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}
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EXPORT_SYMBOL_GPL(crypto_mod_get);
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void crypto_mod_put(struct crypto_alg *alg)
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{
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crypto_alg_put(alg);
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module_put(alg->cra_module);
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}
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EXPORT_SYMBOL_GPL(crypto_mod_put);
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struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type, u32 mask)
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{
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struct crypto_alg *q, *alg = NULL;
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int best = -2;
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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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if (crypto_is_moribund(q))
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continue;
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if ((q->cra_flags ^ type) & mask)
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continue;
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if (crypto_is_larval(q) &&
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((struct crypto_larval *)q)->mask != mask)
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continue;
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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_mod_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_mod_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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return alg;
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}
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EXPORT_SYMBOL_GPL(__crypto_alg_lookup);
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static void crypto_larval_destroy(struct crypto_alg *alg)
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{
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struct crypto_larval *larval = (void *)alg;
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BUG_ON(!crypto_is_larval(alg));
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if (larval->adult)
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crypto_mod_put(larval->adult);
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kfree(larval);
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}
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static struct crypto_alg *crypto_larval_alloc(const char *name, u32 type,
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u32 mask)
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{
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struct crypto_alg *alg;
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struct crypto_larval *larval;
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larval = kzalloc(sizeof(*larval), GFP_KERNEL);
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if (!larval)
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return ERR_PTR(-ENOMEM);
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larval->mask = mask;
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larval->alg.cra_flags = CRYPTO_ALG_LARVAL | type;
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larval->alg.cra_priority = -1;
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larval->alg.cra_destroy = crypto_larval_destroy;
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atomic_set(&larval->alg.cra_refcnt, 2);
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strlcpy(larval->alg.cra_name, name, CRYPTO_MAX_ALG_NAME);
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init_completion(&larval->completion);
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down_write(&crypto_alg_sem);
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alg = __crypto_alg_lookup(name, type, mask);
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if (!alg) {
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alg = &larval->alg;
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list_add(&alg->cra_list, &crypto_alg_list);
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}
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up_write(&crypto_alg_sem);
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if (alg != &larval->alg)
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kfree(larval);
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return alg;
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}
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static void crypto_larval_kill(struct crypto_alg *alg)
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{
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struct crypto_larval *larval = (void *)alg;
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down_write(&crypto_alg_sem);
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list_del(&alg->cra_list);
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up_write(&crypto_alg_sem);
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complete(&larval->completion);
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crypto_alg_put(alg);
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}
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static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg)
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{
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struct crypto_larval *larval = (void *)alg;
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wait_for_completion_interruptible_timeout(&larval->completion, 60 * HZ);
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alg = larval->adult;
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if (alg) {
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if (!crypto_mod_get(alg))
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alg = ERR_PTR(-EAGAIN);
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} else
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alg = ERR_PTR(-ENOENT);
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crypto_mod_put(&larval->alg);
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return alg;
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}
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static struct crypto_alg *crypto_alg_lookup(const char *name, u32 type,
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u32 mask)
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{
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struct crypto_alg *alg;
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down_read(&crypto_alg_sem);
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alg = __crypto_alg_lookup(name, type, mask);
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up_read(&crypto_alg_sem);
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return alg;
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}
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struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
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{
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struct crypto_alg *alg;
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struct crypto_alg *larval;
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int ok;
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if (!name)
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return ERR_PTR(-ENOENT);
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mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
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type &= mask;
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alg = try_then_request_module(crypto_alg_lookup(name, type, mask),
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name);
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if (alg)
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return crypto_is_larval(alg) ? crypto_larval_wait(alg) : alg;
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larval = crypto_larval_alloc(name, type, mask);
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if (IS_ERR(larval) || !crypto_is_larval(larval))
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return larval;
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ok = crypto_notify(CRYPTO_MSG_ALG_REQUEST, larval);
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if (ok == NOTIFY_DONE) {
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request_module("cryptomgr");
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ok = crypto_notify(CRYPTO_MSG_ALG_REQUEST, larval);
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}
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if (ok == NOTIFY_STOP)
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alg = crypto_larval_wait(larval);
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else {
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crypto_mod_put(larval);
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alg = ERR_PTR(-ENOENT);
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}
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crypto_larval_kill(larval);
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return alg;
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}
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EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);
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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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}
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return 0;
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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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const struct crypto_type *type = tfm->__crt_alg->cra_type;
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if (type)
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return type->init(tfm);
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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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const struct crypto_type *type = tfm->__crt_alg->cra_type;
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if (type) {
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if (type->exit)
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type->exit(tfm);
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return;
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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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const struct crypto_type *type = alg->cra_type;
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unsigned int len;
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len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
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if (type)
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return len + type->ctxsize(alg);
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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;
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}
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void crypto_shoot_alg(struct crypto_alg *alg)
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{
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down_write(&crypto_alg_sem);
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alg->cra_flags |= CRYPTO_ALG_DYING;
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up_write(&crypto_alg_sem);
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}
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EXPORT_SYMBOL_GPL(crypto_shoot_alg);
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struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 flags)
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{
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struct crypto_tfm *tfm = NULL;
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unsigned int tfm_size;
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int err = -ENOMEM;
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tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, flags);
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tfm = kzalloc(tfm_size, GFP_KERNEL);
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if (tfm == NULL)
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goto out_err;
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tfm->__crt_alg = alg;
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err = crypto_init_flags(tfm, flags);
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if (err)
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goto out_free_tfm;
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err = crypto_init_ops(tfm);
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if (err)
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goto out_free_tfm;
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if (alg->cra_init && (err = alg->cra_init(tfm))) {
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if (err == -EAGAIN)
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crypto_shoot_alg(alg);
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goto cra_init_failed;
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}
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goto out;
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cra_init_failed:
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crypto_exit_ops(tfm);
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out_free_tfm:
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kfree(tfm);
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out_err:
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tfm = ERR_PTR(err);
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out:
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return tfm;
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}
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EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
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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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int err;
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do {
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struct crypto_alg *alg;
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alg = crypto_alg_mod_lookup(name, 0, CRYPTO_ALG_ASYNC);
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err = PTR_ERR(alg);
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if (IS_ERR(alg))
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continue;
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tfm = __crypto_alloc_tfm(alg, flags);
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err = 0;
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if (IS_ERR(tfm)) {
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crypto_mod_put(alg);
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err = PTR_ERR(tfm);
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tfm = NULL;
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}
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} while (err == -EAGAIN && !signal_pending(current));
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return tfm;
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}
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/*
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* crypto_alloc_base - Locate algorithm and allocate transform
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* @alg_name: Name of algorithm
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* @type: Type of algorithm
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* @mask: Mask for type comparison
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*
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* crypto_alloc_base() will first attempt to locate an already loaded
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* algorithm. If that fails and the kernel supports dynamically loadable
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* modules, it will then attempt to load a module of the same name or
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* alias. If that fails it will send a query to any loaded crypto manager
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* to construct an algorithm on the fly. A refcount is grabbed on the
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* algorithm which is then associated with the new transform.
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*
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* The returned transform is of a non-determinate type. Most people
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* should use one of the more specific allocation functions such as
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* crypto_alloc_blkcipher.
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*
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* In case of error the return value is an error pointer.
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*/
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struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
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{
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struct crypto_tfm *tfm;
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int err;
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for (;;) {
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struct crypto_alg *alg;
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alg = crypto_alg_mod_lookup(alg_name, type, mask);
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if (IS_ERR(alg)) {
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err = PTR_ERR(alg);
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goto err;
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}
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tfm = __crypto_alloc_tfm(alg, 0);
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if (!IS_ERR(tfm))
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return tfm;
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crypto_mod_put(alg);
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err = PTR_ERR(tfm);
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err:
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if (err != -EAGAIN)
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break;
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if (signal_pending(current)) {
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err = -EINTR;
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break;
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}
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}
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return ERR_PTR(err);
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}
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EXPORT_SYMBOL_GPL(crypto_alloc_base);
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/*
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* crypto_free_tfm - Free crypto transform
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* @tfm: Transform to free
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*
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* crypto_free_tfm() frees up the transform and any associated resources,
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* then drops the refcount on the associated algorithm.
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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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if (alg->cra_exit)
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alg->cra_exit(tfm);
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crypto_exit_ops(tfm);
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crypto_mod_put(alg);
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memset(tfm, 0, size);
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kfree(tfm);
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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, 0,
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CRYPTO_ALG_ASYNC);
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if (!IS_ERR(alg)) {
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crypto_mod_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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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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int crypto_has_alg(const char *name, u32 type, u32 mask)
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{
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int ret = 0;
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struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);
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if (!IS_ERR(alg)) {
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crypto_mod_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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EXPORT_SYMBOL_GPL(crypto_has_alg);
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