diff options
Diffstat (limited to 'crypto/api.c')
| -rw-r--r-- | crypto/api.c | 614 |
1 files changed, 614 insertions, 0 deletions
diff --git a/crypto/api.c b/crypto/api.c new file mode 100644 index 000000000..5efd4d6e6 --- /dev/null +++ b/crypto/api.c @@ -0,0 +1,614 @@ +/* + * Scatterlist Cryptographic API. + * + * Copyright (c) 2002 James Morris <jmorris@intercode.com.au> + * Copyright (c) 2002 David S. Miller (davem@redhat.com) + * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au> + * + * Portions derived from Cryptoapi, by Alexander Kjeldaas <astor@fast.no> + * and Nettle, by Niels Möller. + * + * 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 <linux/err.h> +#include <linux/errno.h> +#include <linux/kernel.h> +#include <linux/kmod.h> +#include <linux/module.h> +#include <linux/param.h> +#include <linux/sched/signal.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <linux/completion.h> +#include "internal.h" + +LIST_HEAD(crypto_alg_list); +EXPORT_SYMBOL_GPL(crypto_alg_list); +DECLARE_RWSEM(crypto_alg_sem); +EXPORT_SYMBOL_GPL(crypto_alg_sem); + +BLOCKING_NOTIFIER_HEAD(crypto_chain); +EXPORT_SYMBOL_GPL(crypto_chain); + +static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg); + +struct crypto_alg *crypto_mod_get(struct crypto_alg *alg) +{ + return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL; +} +EXPORT_SYMBOL_GPL(crypto_mod_get); + +void crypto_mod_put(struct crypto_alg *alg) +{ + struct module *module = alg->cra_module; + + crypto_alg_put(alg); + module_put(module); +} +EXPORT_SYMBOL_GPL(crypto_mod_put); + +static inline int crypto_is_test_larval(struct crypto_larval *larval) +{ + return larval->alg.cra_driver_name[0]; +} + +static struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type, + u32 mask) +{ + struct crypto_alg *q, *alg = NULL; + int best = -2; + + list_for_each_entry(q, &crypto_alg_list, cra_list) { + int exact, fuzzy; + + if (crypto_is_moribund(q)) + continue; + + if ((q->cra_flags ^ type) & mask) + continue; + + if (crypto_is_larval(q) && + !crypto_is_test_larval((struct crypto_larval *)q) && + ((struct crypto_larval *)q)->mask != mask) + continue; + + exact = !strcmp(q->cra_driver_name, name); + fuzzy = !strcmp(q->cra_name, name); + if (!exact && !(fuzzy && q->cra_priority > best)) + continue; + + if (unlikely(!crypto_mod_get(q))) + continue; + + best = q->cra_priority; + if (alg) + crypto_mod_put(alg); + alg = q; + + if (exact) + break; + } + + return alg; +} + +static void crypto_larval_destroy(struct crypto_alg *alg) +{ + struct crypto_larval *larval = (void *)alg; + + BUG_ON(!crypto_is_larval(alg)); + if (larval->adult) + crypto_mod_put(larval->adult); + kfree(larval); +} + +struct crypto_larval *crypto_larval_alloc(const char *name, u32 type, u32 mask) +{ + struct crypto_larval *larval; + + larval = kzalloc(sizeof(*larval), GFP_KERNEL); + if (!larval) + return ERR_PTR(-ENOMEM); + + larval->mask = mask; + larval->alg.cra_flags = CRYPTO_ALG_LARVAL | type; + larval->alg.cra_priority = -1; + larval->alg.cra_destroy = crypto_larval_destroy; + + strlcpy(larval->alg.cra_name, name, CRYPTO_MAX_ALG_NAME); + init_completion(&larval->completion); + + return larval; +} +EXPORT_SYMBOL_GPL(crypto_larval_alloc); + +static struct crypto_alg *crypto_larval_add(const char *name, u32 type, + u32 mask) +{ + struct crypto_alg *alg; + struct crypto_larval *larval; + + larval = crypto_larval_alloc(name, type, mask); + if (IS_ERR(larval)) + return ERR_CAST(larval); + + refcount_set(&larval->alg.cra_refcnt, 2); + + down_write(&crypto_alg_sem); + alg = __crypto_alg_lookup(name, type, mask); + if (!alg) { + alg = &larval->alg; + list_add(&alg->cra_list, &crypto_alg_list); + } + up_write(&crypto_alg_sem); + + if (alg != &larval->alg) { + kfree(larval); + if (crypto_is_larval(alg)) + alg = crypto_larval_wait(alg); + } + + return alg; +} + +void crypto_larval_kill(struct crypto_alg *alg) +{ + struct crypto_larval *larval = (void *)alg; + + down_write(&crypto_alg_sem); + list_del(&alg->cra_list); + up_write(&crypto_alg_sem); + complete_all(&larval->completion); + crypto_alg_put(alg); +} +EXPORT_SYMBOL_GPL(crypto_larval_kill); + +static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg) +{ + struct crypto_larval *larval = (void *)alg; + long timeout; + + timeout = wait_for_completion_killable_timeout( + &larval->completion, 60 * HZ); + + alg = larval->adult; + if (timeout < 0) + alg = ERR_PTR(-EINTR); + else if (!timeout) + alg = ERR_PTR(-ETIMEDOUT); + else if (!alg) + alg = ERR_PTR(-ENOENT); + else if (crypto_is_test_larval(larval) && + !(alg->cra_flags & CRYPTO_ALG_TESTED)) + alg = ERR_PTR(-EAGAIN); + else if (!crypto_mod_get(alg)) + alg = ERR_PTR(-EAGAIN); + crypto_mod_put(&larval->alg); + + return alg; +} + +static struct crypto_alg *crypto_alg_lookup(const char *name, u32 type, + u32 mask) +{ + struct crypto_alg *alg; + u32 test = 0; + + if (!((type | mask) & CRYPTO_ALG_TESTED)) + test |= CRYPTO_ALG_TESTED; + + down_read(&crypto_alg_sem); + alg = __crypto_alg_lookup(name, type | test, mask | test); + if (!alg && test) { + alg = __crypto_alg_lookup(name, type, mask); + if (alg && !crypto_is_larval(alg)) { + /* Test failed */ + crypto_mod_put(alg); + alg = ERR_PTR(-ELIBBAD); + } + } + up_read(&crypto_alg_sem); + + return alg; +} + +static struct crypto_alg *crypto_larval_lookup(const char *name, u32 type, + u32 mask) +{ + struct crypto_alg *alg; + + if (!name) + return ERR_PTR(-ENOENT); + + type &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD); + mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD); + + alg = crypto_alg_lookup(name, type, mask); + if (!alg && !(mask & CRYPTO_NOLOAD)) { + request_module("crypto-%s", name); + + if (!((type ^ CRYPTO_ALG_NEED_FALLBACK) & mask & + CRYPTO_ALG_NEED_FALLBACK)) + request_module("crypto-%s-all", name); + + alg = crypto_alg_lookup(name, type, mask); + } + + if (!IS_ERR_OR_NULL(alg) && crypto_is_larval(alg)) + alg = crypto_larval_wait(alg); + else if (!alg) + alg = crypto_larval_add(name, type, mask); + + return alg; +} + +int crypto_probing_notify(unsigned long val, void *v) +{ + int ok; + + ok = blocking_notifier_call_chain(&crypto_chain, val, v); + if (ok == NOTIFY_DONE) { + request_module("cryptomgr"); + ok = blocking_notifier_call_chain(&crypto_chain, val, v); + } + + return ok; +} +EXPORT_SYMBOL_GPL(crypto_probing_notify); + +struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask) +{ + struct crypto_alg *alg; + struct crypto_alg *larval; + int ok; + + /* + * If the internal flag is set for a cipher, require a caller to + * to invoke the cipher with the internal flag to use that cipher. + * Also, if a caller wants to allocate a cipher that may or may + * not be an internal cipher, use type | CRYPTO_ALG_INTERNAL and + * !(mask & CRYPTO_ALG_INTERNAL). + */ + if (!((type | mask) & CRYPTO_ALG_INTERNAL)) + mask |= CRYPTO_ALG_INTERNAL; + + larval = crypto_larval_lookup(name, type, mask); + if (IS_ERR(larval) || !crypto_is_larval(larval)) + return larval; + + ok = crypto_probing_notify(CRYPTO_MSG_ALG_REQUEST, larval); + + if (ok == NOTIFY_STOP) + alg = crypto_larval_wait(larval); + else { + crypto_mod_put(larval); + alg = ERR_PTR(-ENOENT); + } + crypto_larval_kill(larval); + return alg; +} +EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup); + +static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask) +{ + const struct crypto_type *type_obj = tfm->__crt_alg->cra_type; + + if (type_obj) + return type_obj->init(tfm, type, mask); + + switch (crypto_tfm_alg_type(tfm)) { + case CRYPTO_ALG_TYPE_CIPHER: + return crypto_init_cipher_ops(tfm); + + case CRYPTO_ALG_TYPE_COMPRESS: + return crypto_init_compress_ops(tfm); + + default: + break; + } + + BUG(); + return -EINVAL; +} + +static void crypto_exit_ops(struct crypto_tfm *tfm) +{ + const struct crypto_type *type = tfm->__crt_alg->cra_type; + + if (type && tfm->exit) + tfm->exit(tfm); +} + +static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask) +{ + const struct crypto_type *type_obj = alg->cra_type; + unsigned int len; + + len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1); + if (type_obj) + return len + type_obj->ctxsize(alg, type, mask); + + switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) { + default: + BUG(); + + case CRYPTO_ALG_TYPE_CIPHER: + len += crypto_cipher_ctxsize(alg); + break; + + case CRYPTO_ALG_TYPE_COMPRESS: + len += crypto_compress_ctxsize(alg); + break; + } + + return len; +} + +static void crypto_shoot_alg(struct crypto_alg *alg) +{ + down_write(&crypto_alg_sem); + alg->cra_flags |= CRYPTO_ALG_DYING; + up_write(&crypto_alg_sem); +} + +struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type, + u32 mask) +{ + struct crypto_tfm *tfm = NULL; + unsigned int tfm_size; + int err = -ENOMEM; + + tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask); + tfm = kzalloc(tfm_size, GFP_KERNEL); + if (tfm == NULL) + goto out_err; + + tfm->__crt_alg = alg; + + err = crypto_init_ops(tfm, type, mask); + if (err) + goto out_free_tfm; + + if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm))) + goto cra_init_failed; + + goto out; + +cra_init_failed: + crypto_exit_ops(tfm); +out_free_tfm: + if (err == -EAGAIN) + crypto_shoot_alg(alg); + kfree(tfm); +out_err: + tfm = ERR_PTR(err); +out: + return tfm; +} +EXPORT_SYMBOL_GPL(__crypto_alloc_tfm); + +/* + * crypto_alloc_base - Locate algorithm and allocate transform + * @alg_name: Name of algorithm + * @type: Type of algorithm + * @mask: Mask for type comparison + * + * This function should not be used by new algorithm types. + * Please use crypto_alloc_tfm instead. + * + * crypto_alloc_base() will first attempt to locate an already loaded + * algorithm. If that fails and the kernel supports dynamically loadable + * modules, it will then attempt to load a module of the same name or + * alias. If that fails it will send a query to any loaded crypto manager + * to construct an algorithm on the fly. A refcount is grabbed on the + * algorithm which is then associated with the new transform. + * + * The returned transform is of a non-determinate type. Most people + * should use one of the more specific allocation functions such as + * crypto_alloc_blkcipher. + * + * In case of error the return value is an error pointer. + */ +struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask) +{ + struct crypto_tfm *tfm; + int err; + + for (;;) { + struct crypto_alg *alg; + + alg = crypto_alg_mod_lookup(alg_name, type, mask); + if (IS_ERR(alg)) { + err = PTR_ERR(alg); + goto err; + } + + tfm = __crypto_alloc_tfm(alg, type, mask); + if (!IS_ERR(tfm)) + return tfm; + + crypto_mod_put(alg); + err = PTR_ERR(tfm); + +err: + if (err != -EAGAIN) + break; + if (fatal_signal_pending(current)) { + err = -EINTR; + break; + } + } + + return ERR_PTR(err); +} +EXPORT_SYMBOL_GPL(crypto_alloc_base); + +void *crypto_create_tfm(struct crypto_alg *alg, + const struct crypto_type *frontend) +{ + char *mem; + struct crypto_tfm *tfm = NULL; + unsigned int tfmsize; + unsigned int total; + int err = -ENOMEM; + + tfmsize = frontend->tfmsize; + total = tfmsize + sizeof(*tfm) + frontend->extsize(alg); + + mem = kzalloc(total, GFP_KERNEL); + if (mem == NULL) + goto out_err; + + tfm = (struct crypto_tfm *)(mem + tfmsize); + tfm->__crt_alg = alg; + + err = frontend->init_tfm(tfm); + if (err) + goto out_free_tfm; + + if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm))) + goto cra_init_failed; + + goto out; + +cra_init_failed: + crypto_exit_ops(tfm); +out_free_tfm: + if (err == -EAGAIN) + crypto_shoot_alg(alg); + kfree(mem); +out_err: + mem = ERR_PTR(err); +out: + return mem; +} +EXPORT_SYMBOL_GPL(crypto_create_tfm); + +struct crypto_alg *crypto_find_alg(const char *alg_name, + const struct crypto_type *frontend, + u32 type, u32 mask) +{ + if (frontend) { + type &= frontend->maskclear; + mask &= frontend->maskclear; + type |= frontend->type; + mask |= frontend->maskset; + } + + return crypto_alg_mod_lookup(alg_name, type, mask); +} +EXPORT_SYMBOL_GPL(crypto_find_alg); + +/* + * crypto_alloc_tfm - Locate algorithm and allocate transform + * @alg_name: Name of algorithm + * @frontend: Frontend algorithm type + * @type: Type of algorithm + * @mask: Mask for type comparison + * + * crypto_alloc_tfm() will first attempt to locate an already loaded + * algorithm. If that fails and the kernel supports dynamically loadable + * modules, it will then attempt to load a module of the same name or + * alias. If that fails it will send a query to any loaded crypto manager + * to construct an algorithm on the fly. A refcount is grabbed on the + * algorithm which is then associated with the new transform. + * + * The returned transform is of a non-determinate type. Most people + * should use one of the more specific allocation functions such as + * crypto_alloc_blkcipher. + * + * In case of error the return value is an error pointer. + */ +void *crypto_alloc_tfm(const char *alg_name, + const struct crypto_type *frontend, u32 type, u32 mask) +{ + void *tfm; + int err; + + for (;;) { + struct crypto_alg *alg; + + alg = crypto_find_alg(alg_name, frontend, type, mask); + if (IS_ERR(alg)) { + err = PTR_ERR(alg); + goto err; + } + + tfm = crypto_create_tfm(alg, frontend); + if (!IS_ERR(tfm)) + return tfm; + + crypto_mod_put(alg); + err = PTR_ERR(tfm); + +err: + if (err != -EAGAIN) + break; + if (fatal_signal_pending(current)) { + err = -EINTR; + break; + } + } + + return ERR_PTR(err); +} +EXPORT_SYMBOL_GPL(crypto_alloc_tfm); + +/* + * crypto_destroy_tfm - Free crypto transform + * @mem: Start of tfm slab + * @tfm: Transform to free + * + * This function frees up the transform and any associated resources, + * then drops the refcount on the associated algorithm. + */ +void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm) +{ + struct crypto_alg *alg; + + if (IS_ERR_OR_NULL(mem)) + return; + + alg = tfm->__crt_alg; + + if (!tfm->exit && alg->cra_exit) + alg->cra_exit(tfm); + crypto_exit_ops(tfm); + crypto_mod_put(alg); + kzfree(mem); +} +EXPORT_SYMBOL_GPL(crypto_destroy_tfm); + +int crypto_has_alg(const char *name, u32 type, u32 mask) +{ + int ret = 0; + struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask); + + if (!IS_ERR(alg)) { + crypto_mod_put(alg); + ret = 1; + } + + return ret; +} +EXPORT_SYMBOL_GPL(crypto_has_alg); + +void crypto_req_done(struct crypto_async_request *req, int err) +{ + struct crypto_wait *wait = req->data; + + if (err == -EINPROGRESS) + return; + + wait->err = err; + complete(&wait->completion); +} +EXPORT_SYMBOL_GPL(crypto_req_done); + +MODULE_DESCRIPTION("Cryptographic core API"); +MODULE_LICENSE("GPL"); |