From 7b0bac64cd5b74d6f1147524c26216de13a501fd Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Sun, 21 Sep 2008 06:52:53 +0900 Subject: [PATCH] crypto: api - Rebirth of crypto_alloc_tfm This patch reintroduces a completely revamped crypto_alloc_tfm. The biggest change is that we now take two crypto_type objects when allocating a tfm, a frontend and a backend. In fact this simply formalises what we've been doing behind the API's back. For example, as it stands crypto_alloc_ahash may use an actual ahash algorithm or a crypto_hash algorithm. Putting this in the API allows us to do this much more cleanly. The existing types will be converted across gradually. Signed-off-by: Herbert Xu --- crypto/api.c | 108 ++++++++++++++++++++++++++++++++++++++++ crypto/internal.h | 2 + include/crypto/algapi.h | 10 ++++ include/linux/crypto.h | 4 +- 4 files changed, 123 insertions(+), 1 deletion(-) diff --git a/crypto/api.c b/crypto/api.c index cbaaf346ad1..9975a7bd246 100644 --- a/crypto/api.c +++ b/crypto/api.c @@ -403,6 +403,9 @@ EXPORT_SYMBOL_GPL(__crypto_alloc_tfm); * @type: Type of algorithm * @mask: Mask for type comparison * + * This function should not be used by new algorithm types. + * Plesae 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 @@ -449,6 +452,111 @@ err: return ERR_PTR(err); } EXPORT_SYMBOL_GPL(crypto_alloc_base); + +struct crypto_tfm *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, frontend); + + 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, frontend); + 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: + tfm = ERR_PTR(err); +out: + return tfm; +} +EXPORT_SYMBOL_GPL(crypto_create_tfm); + +/* + * 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. + */ +struct crypto_tfm *crypto_alloc_tfm(const char *alg_name, + const struct crypto_type *frontend, + u32 type, u32 mask) +{ + struct crypto_alg *(*lookup)(const char *name, u32 type, u32 mask); + struct crypto_tfm *tfm; + int err; + + type &= frontend->maskclear; + mask &= frontend->maskclear; + type |= frontend->type; + mask |= frontend->maskset; + + lookup = frontend->lookup ?: crypto_alg_mod_lookup; + + for (;;) { + struct crypto_alg *alg; + + alg = lookup(alg_name, 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 (signal_pending(current)) { + err = -EINTR; + break; + } + } + + return ERR_PTR(err); +} +EXPORT_SYMBOL_GPL(crypto_alloc_tfm); /* * crypto_free_tfm - Free crypto transform diff --git a/crypto/internal.h b/crypto/internal.h index 8ef72d76092..3c19a27a756 100644 --- a/crypto/internal.h +++ b/crypto/internal.h @@ -109,6 +109,8 @@ void crypto_alg_tested(const char *name, int err); void crypto_shoot_alg(struct crypto_alg *alg); struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type, u32 mask); +struct crypto_tfm *crypto_create_tfm(struct crypto_alg *alg, + const struct crypto_type *frontend); int crypto_register_instance(struct crypto_template *tmpl, struct crypto_instance *inst); diff --git a/include/crypto/algapi.h b/include/crypto/algapi.h index 5fb6d8618d4..986db68548f 100644 --- a/include/crypto/algapi.h +++ b/include/crypto/algapi.h @@ -22,8 +22,18 @@ struct seq_file; struct crypto_type { unsigned int (*ctxsize)(struct crypto_alg *alg, u32 type, u32 mask); + unsigned int (*extsize)(struct crypto_alg *alg, + const struct crypto_type *frontend); int (*init)(struct crypto_tfm *tfm, u32 type, u32 mask); + int (*init_tfm)(struct crypto_tfm *tfm, + const struct crypto_type *frontend); void (*show)(struct seq_file *m, struct crypto_alg *alg); + struct crypto_alg *(*lookup)(const char *name, u32 type, u32 mask); + + unsigned int type; + unsigned int maskclear; + unsigned int maskset; + unsigned int tfmsize; }; struct crypto_instance { diff --git a/include/linux/crypto.h b/include/linux/crypto.h index ea52cd944fd..ffaaa418cf5 100644 --- a/include/linux/crypto.h +++ b/include/linux/crypto.h @@ -546,7 +546,9 @@ struct crypto_attr_u32 { * Transform user interface. */ -struct crypto_tfm *crypto_alloc_tfm(const char *alg_name, u32 tfm_flags); +struct crypto_tfm *crypto_alloc_tfm(const char *alg_name, + const struct crypto_type *frontend, + u32 type, u32 mask); struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask); void crypto_free_tfm(struct crypto_tfm *tfm); -- 2.41.1