crypto: algapi - convert cra_refcnt to refcount_t

Reference counters should use refcount_t rather than atomic_t, since the
refcount_t implementation can prevent overflows, reducing the
exploitability of reference leak bugs.  crypto_alg.cra_refcount is a
reference counter with the usual semantics, so switch it over to
refcount_t.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

5 files changed, 10 insertions, 10 deletions

diff --git a/crypto/algapi.c b/crypto/algapi.c
index 60d7366ed343..8084a76e01d8 100644
--- a/crypto/algapi.c
+++ b/crypto/algapi.c
@@ -62,7 +62,7 @@ static int crypto_check_alg(struct crypto_alg *alg)
         if (alg->cra_priority < 0)
                 return -EINVAL;
 
-        atomic_set(&alg->cra_refcnt, 1);
+        refcount_set(&alg->cra_refcnt, 1);
 
         return crypto_set_driver_name(alg);
 }
@@ -224,7 +224,7 @@ static struct crypto_larval *__crypto_register_alg(struct crypto_alg *alg)
         if (!larval->adult)
                 goto free_larval;
 
-        atomic_set(&larval->alg.cra_refcnt, 1);
+        refcount_set(&larval->alg.cra_refcnt, 1);
         memcpy(larval->alg.cra_driver_name, alg->cra_driver_name,
                CRYPTO_MAX_ALG_NAME);
         larval->alg.cra_priority = alg->cra_priority;
@@ -399,7 +399,7 @@ int crypto_unregister_alg(struct crypto_alg *alg)
         if (ret)
                 return ret;
 
-        BUG_ON(atomic_read(&alg->cra_refcnt) != 1);
+        BUG_ON(refcount_read(&alg->cra_refcnt) != 1);
         if (alg->cra_destroy)
                 alg->cra_destroy(alg);
 
@@ -490,7 +490,7 @@ void crypto_unregister_template(struct crypto_template *tmpl)
         up_write(&crypto_alg_sem);
 
         hlist_for_each_entry_safe(inst, n, list, list) {
-                BUG_ON(atomic_read(&inst->alg.cra_refcnt) != 1);
+                BUG_ON(refcount_read(&inst->alg.cra_refcnt) != 1);
                 crypto_free_instance(inst);
         }
         crypto_remove_final(&users);
diff --git a/crypto/api.c b/crypto/api.c
index 6da802d7be67..70a894e52ff3 100644
--- a/crypto/api.c
+++ b/crypto/api.c
@@ -137,7 +137,7 @@ static struct crypto_alg *crypto_larval_add(const char *name, u32 type,
         if (IS_ERR(larval))
                 return ERR_CAST(larval);
 
-        atomic_set(&larval->alg.cra_refcnt, 2);
+        refcount_set(&larval->alg.cra_refcnt, 2);
 
         down_write(&crypto_alg_sem);
         alg = __crypto_alg_lookup(name, type, mask);
diff --git a/crypto/crypto_user.c b/crypto/crypto_user.c
index 0dbe2be7f783..5c291eedaa70 100644
--- a/crypto/crypto_user.c
+++ b/crypto/crypto_user.c
@@ -169,7 +169,7 @@ static int crypto_report_one(struct crypto_alg *alg,
         ualg->cru_type = 0;
         ualg->cru_mask = 0;
         ualg->cru_flags = alg->cra_flags;
-        ualg->cru_refcnt = atomic_read(&alg->cra_refcnt);
+        ualg->cru_refcnt = refcount_read(&alg->cra_refcnt);
 
         if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
                 goto nla_put_failure;
@@ -387,7 +387,7 @@ static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
                 goto drop_alg;
 
         err = -EBUSY;
-        if (atomic_read(&alg->cra_refcnt) > 2)
+        if (refcount_read(&alg->cra_refcnt) > 2)
                 goto drop_alg;
 
         err = crypto_unregister_instance((struct crypto_instance *)alg);
diff --git a/crypto/internal.h b/crypto/internal.h
index ae65e5fcaa59..1388af6da85a 100644
--- a/crypto/internal.h
+++ b/crypto/internal.h
@@ -105,13 +105,13 @@ int crypto_type_has_alg(const char *name, const struct crypto_type *frontend,
 
 static inline struct crypto_alg *crypto_alg_get(struct crypto_alg *alg)
 {
-        atomic_inc(&alg->cra_refcnt);
+        refcount_inc(&alg->cra_refcnt);
         return alg;
 }
 
 static inline void crypto_alg_put(struct crypto_alg *alg)
 {
-        if (atomic_dec_and_test(&alg->cra_refcnt) && alg->cra_destroy)
+        if (refcount_dec_and_test(&alg->cra_refcnt) && alg->cra_destroy)
                 alg->cra_destroy(alg);
 }
 
diff --git a/crypto/proc.c b/crypto/proc.c
index 2cc10c96d753..822fcef6d91c 100644
--- a/crypto/proc.c
+++ b/crypto/proc.c
@@ -46,7 +46,7 @@ static int c_show(struct seq_file *m, void *p)
         seq_printf(m, "driver       : %s\n", alg->cra_driver_name);
         seq_printf(m, "module       : %s\n", module_name(alg->cra_module));
         seq_printf(m, "priority     : %d\n", alg->cra_priority);
-        seq_printf(m, "refcnt       : %d\n", atomic_read(&alg->cra_refcnt));
+        seq_printf(m, "refcnt       : %u\n", refcount_read(&alg->cra_refcnt));
         seq_printf(m, "selftest     : %s\n",
                    (alg->cra_flags & CRYPTO_ALG_TESTED) ?
                    "passed" : "unknown");