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net: convert unix_address.refcnt from atomic_t to refcount_t

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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>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Reshetova, Elena 2017-06-30 13:08:05 +03:00 committed by David S. Miller
parent 433cea4d9b
commit 8c9814b970
2 changed files with 6 additions and 5 deletions
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3
include/net/af_unix.h
View file

@ -4,6 +4,7 @@
#include <linux/socket.h>
#include <linux/un.h>
#include <linux/mutex.h>
#include <linux/refcount.h>
#include <net/sock.h>
void unix_inflight(struct user_struct *user, struct file *fp);
@ -21,7 +22,7 @@ extern spinlock_t unix_table_lock;
extern struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];
struct unix_address {
atomic_t refcnt;
refcount_t refcnt;
int len;
unsigned int hash;
struct sockaddr_un name[0];

8
net/unix/af_unix.c
View file

@ -212,7 +212,7 @@ EXPORT_SYMBOL_GPL(unix_peer_get);
static inline void unix_release_addr(struct unix_address *addr)
{
if (atomic_dec_and_test(&addr->refcnt))
if (refcount_dec_and_test(&addr->refcnt))
kfree(addr);
}
@ -864,7 +864,7 @@ static int unix_autobind(struct socket *sock)
goto out;
addr->name->sun_family = AF_UNIX;
atomic_set(&addr->refcnt, 1);
refcount_set(&addr->refcnt, 1);
retry:
addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
@ -1040,7 +1040,7 @@ static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
memcpy(addr->name, sunaddr, addr_len);
addr->len = addr_len;
addr->hash = hash ^ sk->sk_type;
atomic_set(&addr->refcnt, 1);
refcount_set(&addr->refcnt, 1);
if (sun_path[0]) {
addr->hash = UNIX_HASH_SIZE;
@ -1335,7 +1335,7 @@ restart:
/* copy address information from listening to new sock*/
if (otheru->addr) {
atomic_inc(&otheru->addr->refcnt);
refcount_inc(&otheru->addr->refcnt);
newu->addr = otheru->addr;
}
if (otheru->path.dentry) {