IMA: iint put in ima_counts_get and put

ima_counts_get() calls ima_iint_find_insert_get() which takes a reference
to the iint in question, but does not put that reference at the end of the
function.  This can lead to a nasty memory leak.  Easy enough to reproduce:

#include <sys/mman.h>
#include <stdio.h>

int main (void)
{
	int i;
	void *ptr;

	for (i=0; i < 100000; i++) {
		ptr = mmap(NULL, 4096, PROT_READ|PROT_WRITE,
			   MAP_SHARED|MAP_ANONYMOUS, -1, 0);
		if (ptr == MAP_FAILED)
			return 2;
		munmap(ptr, 4096);
	}

	return 0;
}

Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>

security/integrity/ima/ima_main.c

@@ -262,6 +262,8 @@ void ima_counts_put(struct path *path, int mask)
 	else if (mask & (MAY_READ | MAY_EXEC))
 		iint->readcount--;
 	mutex_unlock(&iint->mutex);
+
+	kref_put(&iint->refcount, iint_free);
 }
 
 /*
@@ -291,6 +293,8 @@ void ima_counts_get(struct file *file)
 	if (file->f_mode & FMODE_WRITE)
 		iint->writecount++;
 	mutex_unlock(&iint->mutex);
+
+	kref_put(&iint->refcount, iint_free);
 }
 EXPORT_SYMBOL_GPL(ima_counts_get);