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Subject[PATCH] crypto: algapi - convert cra_refcnt to refcount_t
Date
From: Eric Biggers <ebiggers@google.com>

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>
---
crypto/algapi.c | 8 ++++----
crypto/api.c | 2 +-
crypto/crypto_user.c | 4 ++--
crypto/internal.h | 4 ++--
crypto/proc.c | 2 +-
include/linux/crypto.h | 2 +-
6 files changed, 11 insertions(+), 11 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");
diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index 78508ca4b108..231e59f90d32 100644
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -447,7 +447,7 @@ struct crypto_alg {
unsigned int cra_alignmask;

int cra_priority;
- atomic_t cra_refcnt;
+ refcount_t cra_refcnt;

char cra_name[CRYPTO_MAX_ALG_NAME];
char cra_driver_name[CRYPTO_MAX_ALG_NAME];
--
2.15.1
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