[CRYPTO] api: Added spawns

Spawns lock a specific crypto algorithm in place.  They can then be used
with crypto_spawn_tfm to allocate a tfm for that algorithm.  When the base
algorithm of a spawn is deregistered, all its spawns will be automatically
removed.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/crypto/algapi.c b/crypto/algapi.c
index acea250..36c4f1b 100644 (file)
--- a/crypto/algapi.c
+++ b/crypto/algapi.c
@@ -10,6 +10,7 @@
  *
  */
 
+#include <linux/err.h>
 #include <linux/errno.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
@@ -73,27 +74,96 @@ static int crypto_check_alg(struct crypto_alg *alg)
        return crypto_set_driver_name(alg);
 }
 
-static int __crypto_register_alg(struct crypto_alg *alg)
+static void crypto_destroy_instance(struct crypto_alg *alg)
+{
+       struct crypto_instance *inst = (void *)alg;
+       struct crypto_template *tmpl = inst->tmpl;
+
+       tmpl->free(inst);
+       crypto_tmpl_put(tmpl);
+}
+
+static void crypto_remove_spawns(struct list_head *spawns,
+                                struct list_head *list)
+{
+       struct crypto_spawn *spawn, *n;
+
+       list_for_each_entry_safe(spawn, n, spawns, list) {
+               struct crypto_instance *inst = spawn->inst;
+               struct crypto_template *tmpl = inst->tmpl;
+
+               list_del_init(&spawn->list);
+               spawn->alg = NULL;
+
+               if (crypto_is_dead(&inst->alg))
+                       continue;
+
+               inst->alg.cra_flags |= CRYPTO_ALG_DEAD;
+               if (!tmpl || !crypto_tmpl_get(tmpl))
+                       continue;
+
+               crypto_notify(CRYPTO_MSG_ALG_UNREGISTER, &inst->alg);
+               list_move(&inst->alg.cra_list, list);
+               hlist_del(&inst->list);
+               inst->alg.cra_destroy = crypto_destroy_instance;
+
+               if (!list_empty(&inst->alg.cra_users)) {
+                       if (&n->list == spawns)
+                               n = list_entry(inst->alg.cra_users.next,
+                                              typeof(*n), list);
+                       __list_splice(&inst->alg.cra_users, spawns->prev);
+               }
+       }
+}
+
+static int __crypto_register_alg(struct crypto_alg *alg,
+                                struct list_head *list)
 {
        struct crypto_alg *q;
-       int ret = -EEXIST;
+       int ret = -EAGAIN;
+
+       if (crypto_is_dead(alg))
+               goto out;
+
+       INIT_LIST_HEAD(&alg->cra_users);
+
+       ret = -EEXIST;
 
        atomic_set(&alg->cra_refcnt, 1);
        list_for_each_entry(q, &crypto_alg_list, cra_list) {
                if (q == alg)
                        goto out;
-               if (crypto_is_larval(q) &&
-                   (!strcmp(alg->cra_name, q->cra_name) ||
-                    !strcmp(alg->cra_driver_name, q->cra_name))) {
+
+               if (crypto_is_moribund(q))
+                       continue;
+
+               if (crypto_is_larval(q)) {
                        struct crypto_larval *larval = (void *)q;
 
+                       if (strcmp(alg->cra_name, q->cra_name) &&
+                           strcmp(alg->cra_driver_name, q->cra_name))
+                               continue;
+
+                       if (larval->adult)
+                               continue;
                        if ((q->cra_flags ^ alg->cra_flags) & larval->mask)
                                continue;
                        if (!crypto_mod_get(alg))
                                continue;
+
                        larval->adult = alg;
                        complete(&larval->completion);
+                       continue;
                }
+
+               if (strcmp(alg->cra_name, q->cra_name))
+                       continue;
+
+               if (strcmp(alg->cra_driver_name, q->cra_driver_name) &&
+                   q->cra_priority > alg->cra_priority)
+                       continue;
+
+               crypto_remove_spawns(&q->cra_users, list);
        }
        
        list_add(&alg->cra_list, &crypto_alg_list);
@@ -105,8 +175,20 @@ out:
        return ret;
 }
 
+static void crypto_remove_final(struct list_head *list)
+{
+       struct crypto_alg *alg;
+       struct crypto_alg *n;
+
+       list_for_each_entry_safe(alg, n, list, cra_list) {
+               list_del_init(&alg->cra_list);
+               crypto_alg_put(alg);
+       }
+}
+
 int crypto_register_alg(struct crypto_alg *alg)
 {
+       LIST_HEAD(list);
        int err;
 
        err = crypto_check_alg(alg);
@@ -114,23 +196,35 @@ int crypto_register_alg(struct crypto_alg *alg)
                return err;
 
        down_write(&crypto_alg_sem);
-       err = __crypto_register_alg(alg);
+       err = __crypto_register_alg(alg, &list);
        up_write(&crypto_alg_sem);
 
+       crypto_remove_final(&list);
        return err;
 }
 EXPORT_SYMBOL_GPL(crypto_register_alg);
 
+static int crypto_remove_alg(struct crypto_alg *alg, struct list_head *list)
+{
+       if (unlikely(list_empty(&alg->cra_list)))
+               return -ENOENT;
+
+       alg->cra_flags |= CRYPTO_ALG_DEAD;
+
+       crypto_notify(CRYPTO_MSG_ALG_UNREGISTER, alg);
+       list_del_init(&alg->cra_list);
+       crypto_remove_spawns(&alg->cra_users, list);
+
+       return 0;
+}
+
 int crypto_unregister_alg(struct crypto_alg *alg)
 {
-       int ret = -ENOENT;
+       int ret;
+       LIST_HEAD(list);
        
        down_write(&crypto_alg_sem);
-       if (likely(!list_empty(&alg->cra_list))) {
-               list_del_init(&alg->cra_list);
-               ret = 0;
-       }
-       crypto_notify(CRYPTO_MSG_ALG_UNREGISTER, alg);
+       ret = crypto_remove_alg(alg, &list);
        up_write(&crypto_alg_sem);
 
        if (ret)
@@ -140,6 +234,7 @@ int crypto_unregister_alg(struct crypto_alg *alg)
        if (alg->cra_destroy)
                alg->cra_destroy(alg);
 
+       crypto_remove_final(&list);
        return 0;
 }
 EXPORT_SYMBOL_GPL(crypto_unregister_alg);
@@ -170,6 +265,7 @@ void crypto_unregister_template(struct crypto_template *tmpl)
        struct crypto_instance *inst;
        struct hlist_node *p, *n;
        struct hlist_head *list;
+       LIST_HEAD(users);
 
        down_write(&crypto_alg_sem);
 
@@ -178,9 +274,8 @@ void crypto_unregister_template(struct crypto_template *tmpl)
 
        list = &tmpl->instances;
        hlist_for_each_entry(inst, p, list, list) {
-               BUG_ON(list_empty(&inst->alg.cra_list));
-               list_del_init(&inst->alg.cra_list);
-               crypto_notify(CRYPTO_MSG_ALG_UNREGISTER, &inst->alg);
+               int err = crypto_remove_alg(&inst->alg, &users);
+               BUG_ON(err);
        }
 
        crypto_notify(CRYPTO_MSG_TMPL_UNREGISTER, tmpl);
@@ -191,6 +286,7 @@ void crypto_unregister_template(struct crypto_template *tmpl)
                BUG_ON(atomic_read(&inst->alg.cra_refcnt) != 1);
                tmpl->free(inst);
        }
+       crypto_remove_final(&users);
 }
 EXPORT_SYMBOL_GPL(crypto_unregister_template);
 
@@ -222,6 +318,7 @@ EXPORT_SYMBOL_GPL(crypto_lookup_template);
 int crypto_register_instance(struct crypto_template *tmpl,
                             struct crypto_instance *inst)
 {
+       LIST_HEAD(list);
        int err = -EINVAL;
 
        if (inst->alg.cra_destroy)
@@ -235,7 +332,7 @@ int crypto_register_instance(struct crypto_template *tmpl,
 
        down_write(&crypto_alg_sem);
 
-       err = __crypto_register_alg(&inst->alg);
+       err = __crypto_register_alg(&inst->alg, &list);
        if (err)
                goto unlock;
 
@@ -245,11 +342,67 @@ int crypto_register_instance(struct crypto_template *tmpl,
 unlock:
        up_write(&crypto_alg_sem);
 
+       crypto_remove_final(&list);
+
 err:
        return err;
 }
 EXPORT_SYMBOL_GPL(crypto_register_instance);
 
+int crypto_init_spawn(struct crypto_spawn *spawn, struct crypto_alg *alg,
+                     struct crypto_instance *inst)
+{
+       int err = -EAGAIN;
+
+       spawn->inst = inst;
+
+       down_write(&crypto_alg_sem);
+       if (!crypto_is_moribund(alg)) {
+               list_add(&spawn->list, &alg->cra_users);
+               spawn->alg = alg;
+               err = 0;
+       }
+       up_write(&crypto_alg_sem);
+
+       return err;
+}
+EXPORT_SYMBOL_GPL(crypto_init_spawn);
+
+void crypto_drop_spawn(struct crypto_spawn *spawn)
+{
+       down_write(&crypto_alg_sem);
+       list_del(&spawn->list);
+       up_write(&crypto_alg_sem);
+}
+EXPORT_SYMBOL_GPL(crypto_drop_spawn);
+
+struct crypto_tfm *crypto_spawn_tfm(struct crypto_spawn *spawn)
+{
+       struct crypto_alg *alg;
+       struct crypto_alg *alg2;
+       struct crypto_tfm *tfm;
+
+       down_read(&crypto_alg_sem);
+       alg = spawn->alg;
+       alg2 = alg;
+       if (alg2)
+               alg2 = crypto_mod_get(alg2);
+       up_read(&crypto_alg_sem);
+
+       if (!alg2) {
+               if (alg)
+                       crypto_shoot_alg(alg);
+               return ERR_PTR(-EAGAIN);
+       }
+
+       tfm = __crypto_alloc_tfm(alg, 0);
+       if (IS_ERR(tfm))
+               crypto_mod_put(alg);
+
+       return tfm;
+}
+EXPORT_SYMBOL_GPL(crypto_spawn_tfm);
+
 int crypto_register_notifier(struct notifier_block *nb)
 {
        return blocking_notifier_chain_register(&crypto_chain, nb);

diff --git a/crypto/api.c b/crypto/api.c
index ddf6a76..7e5522c 100644 (file)
--- a/crypto/api.c
+++ b/crypto/api.c
@@ -15,11 +15,13 @@
  *
  */
 
+#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.h>
 #include <linux/slab.h>
 #include <linux/string.h>
 #include "internal.h"
@@ -38,12 +40,6 @@ static inline struct crypto_alg *crypto_alg_get(struct crypto_alg *alg)
        return alg;
 }
 
-static inline void crypto_alg_put(struct crypto_alg *alg)
-{
-       if (atomic_dec_and_test(&alg->cra_refcnt) && alg->cra_destroy)
-               alg->cra_destroy(alg);
-}
-
 struct crypto_alg *crypto_mod_get(struct crypto_alg *alg)
 {
        return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL;
@@ -65,6 +61,9 @@ struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type, u32 mask)
        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;
 
@@ -111,7 +110,7 @@ static struct crypto_alg *crypto_larval_alloc(const char *name, u32 type,
 
        larval = kzalloc(sizeof(*larval), GFP_KERNEL);
        if (!larval)
-               return NULL;
+               return ERR_PTR(-ENOMEM);
 
        larval->mask = mask;
        larval->alg.cra_flags = CRYPTO_ALG_LARVAL | type;
@@ -153,8 +152,11 @@ static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg)
 
        wait_for_completion_interruptible_timeout(&larval->completion, 60 * HZ);
        alg = larval->adult;
-       if (alg && !crypto_mod_get(alg))
-               alg = NULL;
+       if (alg) {
+               if (!crypto_mod_get(alg))
+                       alg = ERR_PTR(-EAGAIN);
+       } else
+               alg = ERR_PTR(-ENOENT);
        crypto_mod_put(&larval->alg);
 
        return alg;
@@ -165,9 +167,6 @@ static struct crypto_alg *crypto_alg_lookup(const char *name, u32 type,
 {
        struct crypto_alg *alg;
 
-       if (!name)
-               return NULL;
-
        down_read(&crypto_alg_sem);
        alg = __crypto_alg_lookup(name, type, mask);
        up_read(&crypto_alg_sem);
@@ -181,7 +180,10 @@ struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
        struct crypto_alg *larval;
        int ok;
 
-       mask &= ~CRYPTO_ALG_LARVAL;
+       if (!name)
+               return ERR_PTR(-ENOENT);
+
+       mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
        type &= mask;
 
        alg = try_then_request_module(crypto_alg_lookup(name, type, mask),
@@ -190,7 +192,7 @@ struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
                return crypto_is_larval(alg) ? crypto_larval_wait(alg) : alg;
 
        larval = crypto_larval_alloc(name, type, mask);
-       if (!larval || !crypto_is_larval(larval))
+       if (IS_ERR(larval) || !crypto_is_larval(larval))
                return larval;
 
        ok = crypto_notify(CRYPTO_MSG_ALG_REQUEST, larval);
@@ -203,7 +205,7 @@ struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
                alg = crypto_larval_wait(larval);
        else {
                crypto_mod_put(larval);
-               alg = NULL;
+               alg = ERR_PTR(-ENOENT);
        }
        crypto_larval_kill(larval);
        return alg;
@@ -298,31 +300,40 @@ static unsigned int crypto_ctxsize(struct crypto_alg *alg, int flags)
        return len + (alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1));
 }
 
-struct crypto_tfm *crypto_alloc_tfm(const char *name, u32 flags)
+void crypto_shoot_alg(struct crypto_alg *alg)
+{
+       down_write(&crypto_alg_sem);
+       alg->cra_flags |= CRYPTO_ALG_DYING;
+       up_write(&crypto_alg_sem);
+}
+EXPORT_SYMBOL_GPL(crypto_shoot_alg);
+
+struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 flags)
 {
        struct crypto_tfm *tfm = NULL;
-       struct crypto_alg *alg;
        unsigned int tfm_size;
-
-       alg = crypto_alg_mod_lookup(name, 0, 0);
-       if (alg == NULL)
-               goto out;
+       int err = -ENOMEM;
 
        tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, flags);
        tfm = kzalloc(tfm_size, GFP_KERNEL);
        if (tfm == NULL)
-               goto out_put;
+               goto out;
 
        tfm->__crt_alg = alg;
-       
-       if (crypto_init_flags(tfm, flags))
+
+       err = crypto_init_flags(tfm, flags);
+       if (err)
                goto out_free_tfm;
                
-       if (crypto_init_ops(tfm))
+       err = crypto_init_ops(tfm);
+       if (err)
                goto out_free_tfm;
 
-       if (alg->cra_init && alg->cra_init(tfm))
+       if (alg->cra_init && (err = alg->cra_init(tfm))) {
+               if (err == -EAGAIN)
+                       crypto_shoot_alg(alg);
                goto cra_init_failed;
+       }
 
        goto out;
 
@@ -330,12 +341,36 @@ cra_init_failed:
        crypto_exit_ops(tfm);
 out_free_tfm:
        kfree(tfm);
-       tfm = NULL;
-out_put:
-       crypto_mod_put(alg);
+       tfm = ERR_PTR(err);
 out:
        return tfm;
 }
+EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
+
+struct crypto_tfm *crypto_alloc_tfm(const char *name, u32 flags)
+{
+       struct crypto_tfm *tfm = NULL;
+       int err;
+
+       do {
+               struct crypto_alg *alg;
+
+               alg = crypto_alg_mod_lookup(name, 0, 0);
+               err = PTR_ERR(alg);
+               if (IS_ERR(alg))
+                       continue;
+
+               tfm = __crypto_alloc_tfm(alg, flags);
+               err = 0;
+               if (IS_ERR(tfm)) {
+                       crypto_mod_put(alg);
+                       err = PTR_ERR(tfm);
+                       tfm = NULL;
+               }
+       } while (err == -EAGAIN && !signal_pending(current));
+
+       return tfm;
+}
 
 void crypto_free_tfm(struct crypto_tfm *tfm)
 {
@@ -361,7 +396,7 @@ int crypto_alg_available(const char *name, u32 flags)
        int ret = 0;
        struct crypto_alg *alg = crypto_alg_mod_lookup(name, 0, 0);
        
-       if (alg) {
+       if (!IS_ERR(alg)) {
                crypto_mod_put(alg);
                ret = 1;
        }

diff --git a/crypto/cryptomgr.c b/crypto/cryptomgr.c
index ae54942..9b5b156 100644 (file)
--- a/crypto/cryptomgr.c
+++ b/crypto/cryptomgr.c
@@ -17,6 +17,7 @@
 #include <linux/module.h>
 #include <linux/notifier.h>
 #include <linux/rtnetlink.h>
+#include <linux/sched.h>
 #include <linux/string.h>
 #include <linux/workqueue.h>
 
@@ -44,21 +45,25 @@ static void cryptomgr_probe(void *data)
        struct cryptomgr_param *param = data;
        struct crypto_template *tmpl;
        struct crypto_instance *inst;
+       int err;
 
        tmpl = crypto_lookup_template(param->template);
        if (!tmpl)
                goto err;
 
-       inst = tmpl->alloc(&param->alg, sizeof(param->alg));
-       if (IS_ERR(inst))
-               goto err;
-       else if ((err = crypto_register_instance(tmpl, inst))) {
-               tmpl->free(inst);
-               goto err;
-       }
+       do {
+               inst = tmpl->alloc(&param->alg, sizeof(param->alg));
+               if (IS_ERR(inst))
+                       err = PTR_ERR(inst);
+               else if ((err = crypto_register_instance(tmpl, inst)))
+                       tmpl->free(inst);
+       } while (err == -EAGAIN && !signal_pending(current));
 
        crypto_tmpl_put(tmpl);
 
+       if (err)
+               goto err;
+
 out:
        kfree(param);
        return;

diff --git a/crypto/internal.h b/crypto/internal.h
index c08d93b..03c00b0 100644 (file)
--- a/crypto/internal.h
+++ b/crypto/internal.h
@@ -142,12 +142,21 @@ void crypto_exit_compress_ops(struct crypto_tfm *tfm);
 
 void crypto_larval_error(const char *name, u32 type, u32 mask);
 
+void crypto_shoot_alg(struct crypto_alg *alg);
+struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 flags);
+
 int crypto_register_instance(struct crypto_template *tmpl,
                             struct crypto_instance *inst);
 
 int crypto_register_notifier(struct notifier_block *nb);
 int crypto_unregister_notifier(struct notifier_block *nb);
 
+static inline void crypto_alg_put(struct crypto_alg *alg)
+{
+       if (atomic_dec_and_test(&alg->cra_refcnt) && alg->cra_destroy)
+               alg->cra_destroy(alg);
+}
+
 static inline int crypto_tmpl_get(struct crypto_template *tmpl)
 {
        return try_module_get(tmpl->module);
@@ -163,6 +172,16 @@ static inline int crypto_is_larval(struct crypto_alg *alg)
        return alg->cra_flags & CRYPTO_ALG_LARVAL;
 }
 
+static inline int crypto_is_dead(struct crypto_alg *alg)
+{
+       return alg->cra_flags & CRYPTO_ALG_DEAD;
+}
+
+static inline int crypto_is_moribund(struct crypto_alg *alg)
+{
+       return alg->cra_flags & (CRYPTO_ALG_DEAD | CRYPTO_ALG_DYING);
+}
+
 static inline int crypto_notify(unsigned long val, void *v)
 {
        return blocking_notifier_call_chain(&crypto_chain, val, v);

diff --git a/include/crypto/algapi.h b/include/crypto/algapi.h
index ffec530..b20f4bd 100644 (file)
--- a/include/crypto/algapi.h
+++ b/include/crypto/algapi.h
@@ -36,10 +36,21 @@ struct crypto_template {
        char name[CRYPTO_MAX_ALG_NAME];
 };
 
+struct crypto_spawn {
+       struct list_head list;
+       struct crypto_alg *alg;
+       struct crypto_instance *inst;
+};
+
 int crypto_register_template(struct crypto_template *tmpl);
 void crypto_unregister_template(struct crypto_template *tmpl);
 struct crypto_template *crypto_lookup_template(const char *name);
 
+int crypto_init_spawn(struct crypto_spawn *spawn, struct crypto_alg *alg,
+                     struct crypto_instance *inst);
+void crypto_drop_spawn(struct crypto_spawn *spawn);
+struct crypto_tfm *crypto_spawn_tfm(struct crypto_spawn *spawn);
+
 static inline void *crypto_instance_ctx(struct crypto_instance *inst)
 {
        return inst->__ctx;

diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index 85f73c3..40a6330 100644 (file)
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -35,6 +35,8 @@
 #define CRYPTO_ALG_TYPE_COMPRESS       0x00000004
 
 #define CRYPTO_ALG_LARVAL              0x00000010
+#define CRYPTO_ALG_DEAD                        0x00000020
+#define CRYPTO_ALG_DYING               0x00000040
 
 /*
  * Transform masks and values (for crt_flags).
@@ -145,6 +147,8 @@ struct compress_alg {
 
 struct crypto_alg {
        struct list_head cra_list;
+       struct list_head cra_users;
+
        u32 cra_flags;
        unsigned int cra_blocksize;
        unsigned int cra_ctxsize;