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Subject[PATCH 29/36] net, sctp: convert sctp_auth_bytes.refcnt from atomic_t to refcount_t
Date
refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
---
include/net/sctp/auth.h | 5 +++--
net/sctp/auth.c | 4 ++--
2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/include/net/sctp/auth.h b/include/net/sctp/auth.h
index 171244b..e5c57d0 100644
--- a/include/net/sctp/auth.h
+++ b/include/net/sctp/auth.h
@@ -31,6 +31,7 @@
#define __sctp_auth_h__

#include <linux/list.h>
+#include <linux/refcount.h>

struct sctp_endpoint;
struct sctp_association;
@@ -53,7 +54,7 @@ struct sctp_hmac {
* over SCTP-AUTH
*/
struct sctp_auth_bytes {
- atomic_t refcnt;
+ refcount_t refcnt;
__u32 len;
__u8 data[];
};
@@ -76,7 +77,7 @@ static inline void sctp_auth_key_hold(struct sctp_auth_bytes *key)
if (!key)
return;

- atomic_inc(&key->refcnt);
+ refcount_inc(&key->refcnt);
}

void sctp_auth_key_put(struct sctp_auth_bytes *key);
diff --git a/net/sctp/auth.c b/net/sctp/auth.c
index 8ffa598..e001b01 100644
--- a/net/sctp/auth.c
+++ b/net/sctp/auth.c
@@ -63,7 +63,7 @@ void sctp_auth_key_put(struct sctp_auth_bytes *key)
if (!key)
return;

- if (atomic_dec_and_test(&key->refcnt)) {
+ if (refcount_dec_and_test(&key->refcnt)) {
kzfree(key);
SCTP_DBG_OBJCNT_DEC(keys);
}
@@ -84,7 +84,7 @@ static struct sctp_auth_bytes *sctp_auth_create_key(__u32 key_len, gfp_t gfp)
return NULL;

key->len = key_len;
- atomic_set(&key->refcnt, 1);
+ refcount_set(&key->refcnt, 1);
SCTP_DBG_OBJCNT_INC(keys);

return key;
--
2.7.4
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