sanitize audit_mq_notify()

* don't copy_from_user() twice
* don't bother with allocations
* don't duplicate parts of audit_dummy_context()
* make it return void

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

3 files changed, 27 insertions, 52 deletions

diff --git a/include/linux/audit.h b/include/linux/audit.h
index b7707e577b80..8101d2c4a995 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -453,7 +453,7 @@ extern int audit_set_macxattr(const char *name);
 extern int __audit_mq_open(int oflag, mode_t mode, struct mq_attr __user *u_attr);
 extern int __audit_mq_timedsend(mqd_t mqdes, size_t msg_len, unsigned int msg_prio, const struct timespec __user *u_abs_timeout);
 extern int __audit_mq_timedreceive(mqd_t mqdes, size_t msg_len, unsigned int __user *u_msg_prio, const struct timespec __user *u_abs_timeout);
-extern int __audit_mq_notify(mqd_t mqdes, const struct sigevent __user *u_notification);
+extern void __audit_mq_notify(mqd_t mqdes, const struct sigevent *notification);
 extern void __audit_mq_getsetattr(mqd_t mqdes, struct mq_attr *mqstat);
 extern int __audit_log_bprm_fcaps(struct linux_binprm *bprm,
                                   const struct cred *new,
@@ -494,11 +494,10 @@ static inline int audit_mq_timedreceive(mqd_t mqdes, size_t msg_len, unsigned in
                 return __audit_mq_timedreceive(mqdes, msg_len, u_msg_prio, u_abs_timeout);
         return 0;
 }
-static inline int audit_mq_notify(mqd_t mqdes, const struct sigevent __user *u_notification)
+static inline void audit_mq_notify(mqd_t mqdes, const struct sigevent *notification)
 {
         if (unlikely(!audit_dummy_context()))
-                return __audit_mq_notify(mqdes, u_notification);
-        return 0;
+                __audit_mq_notify(mqdes, notification);
 }
 static inline void audit_mq_getsetattr(mqd_t mqdes, struct mq_attr *mqstat)
 {
@@ -553,7 +552,7 @@ extern int audit_signals;
 #define audit_mq_open(o,m,a) ({ 0; })
 #define audit_mq_timedsend(d,l,p,t) ({ 0; })
 #define audit_mq_timedreceive(d,l,p,t) ({ 0; })
-#define audit_mq_notify(d,n) ({ 0; })
+#define audit_mq_notify(d,n) ((void)0)
 #define audit_mq_getsetattr(d,s) ((void)0)
 #define audit_log_bprm_fcaps(b, ncr, ocr) ({ 0; })
 #define audit_log_capset(pid, ncr, ocr) ({ 0; })
diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index 7563611c6615..e7b2f68f8d77 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -1003,17 +1003,17 @@ asmlinkage long sys_mq_notify(mqd_t mqdes,
         struct mqueue_inode_info *info;
         struct sk_buff *nc;
 
-        ret = audit_mq_notify(mqdes, u_notification);
-        if (ret != 0)
-                return ret;
-
-        nc = NULL;
-        sock = NULL;
-        if (u_notification != NULL) {
+        if (u_notification) {
                 if (copy_from_user(&notification, u_notification,
                                         sizeof(struct sigevent)))
                         return -EFAULT;
+        }
+
+        audit_mq_notify(mqdes, u_notification ? &notification : NULL);
 
+        nc = NULL;
+        sock = NULL;
+        if (u_notification != NULL) {
                 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
                              notification.sigev_notify != SIGEV_SIGNAL &&
                              notification.sigev_notify != SIGEV_THREAD))
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index c50178c7e245..3ece960de894 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -139,12 +139,6 @@ struct audit_aux_data_mq_sendrecv {
         struct timespec         abs_timeout;
 };
 
-struct audit_aux_data_mq_notify {
-        struct audit_aux_data   d;
-        mqd_t                   mqdes;
-        struct sigevent         notification;
-};
-
 struct audit_aux_data_execve {
         struct audit_aux_data   d;
         int argc;
@@ -246,6 +240,10 @@ struct audit_context {
                         mqd_t                   mqdes;
                         struct mq_attr          mqstat;
                 } mq_getsetattr;
+                struct {
+                        mqd_t                   mqdes;
+                        int                     sigev_signo;
+                } mq_notify;
         };
 
 #if AUDIT_DEBUG
@@ -1267,6 +1265,11 @@ static void show_special(struct audit_context *context, int *call_panic)
                                 return;
                 }
                 break; }
+        case AUDIT_MQ_NOTIFY: {
+                audit_log_format(ab, "mqdes=%d sigev_signo=%d",
+                                context->mq_notify.mqdes,
+                                context->mq_notify.sigev_signo);
+                break; }
         case AUDIT_MQ_GETSETATTR: {
                 struct mq_attr *attr = &context->mq_getsetattr.mqstat;
                 audit_log_format(ab,
@@ -1376,14 +1379,6 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts
                                 axi->abs_timeout.tv_sec, axi->abs_timeout.tv_nsec);
                         break; }
 
-                case AUDIT_MQ_NOTIFY: {
-                        struct audit_aux_data_mq_notify *axi = (void *)aux;
-                        audit_log_format(ab,
-                                "mqdes=%d sigev_signo=%d",
-                                axi->mqdes,
-                                axi->notification.sigev_signo);
-                        break; }
-
                 case AUDIT_EXECVE: {
                         struct audit_aux_data_execve *axi = (void *)aux;
                         audit_log_execve_info(context, &ab, axi);
@@ -2274,38 +2269,19 @@ int __audit_mq_timedreceive(mqd_t mqdes, size_t msg_len,
  * @mqdes: MQ descriptor
  * @u_notification: Notification event
  *
- * Returns 0 for success or NULL context or < 0 on error.
  */
 
-int __audit_mq_notify(mqd_t mqdes, const struct sigevent __user *u_notification)
+void __audit_mq_notify(mqd_t mqdes, const struct sigevent *notification)
 {
-        struct audit_aux_data_mq_notify *ax;
         struct audit_context *context = current->audit_context;
 
-        if (!audit_enabled)
-                return 0;
-
-        if (likely(!context))
-                return 0;
-
-        ax = kmalloc(sizeof(*ax), GFP_ATOMIC);
-        if (!ax)
-                return -ENOMEM;
-
-        if (u_notification != NULL) {
-                if (copy_from_user(&ax->notification, u_notification, sizeof(ax->notification))) {
-                        kfree(ax);
-                        return -EFAULT;
-                }
-        } else
-                memset(&ax->notification, 0, sizeof(ax->notification));
-
-        ax->mqdes = mqdes;
+        if (notification)
+                context->mq_notify.sigev_signo = notification->sigev_signo;
+        else
+                context->mq_notify.sigev_signo = 0;
 
-        ax->d.type = AUDIT_MQ_NOTIFY;
-        ax->d.next = context->aux;
-        context->aux = (void *)ax;
-        return 0;
+        context->mq_notify.mqdes = mqdes;
+        context->type = AUDIT_MQ_NOTIFY;
 }
 
 /**