apparmor: add kvzalloc to handle zeroing for kvmalloc

Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Steve Beattie <sbeattie@ubuntu.com>

security/apparmor/include/apparmor.h

@@ -15,6 +15,7 @@
 #ifndef __APPARMOR_H
 #define __APPARMOR_H
 
+#include <linux/slab.h>
 #include <linux/fs.h>
 
 #include "match.h"
@@ -64,9 +65,18 @@ extern int apparmor_initialized __initdata;
 /* fn's in lib */
 char *aa_split_fqname(char *args, char **ns_name);
 void aa_info_message(const char *str);
-void *kvmalloc(size_t size);
+void *__aa_kvmalloc(size_t size, gfp_t flags);
 void kvfree(void *buffer);
 
+static inline void *kvmalloc(size_t size)
+{
+	return __aa_kvmalloc(size, 0);
+}
+
+static inline void *kvzalloc(size_t size)
+{
+	return __aa_kvmalloc(size, __GFP_ZERO);
+}
 
 /**
  * aa_strneq - compare null terminated @str to a non null terminated substring

security/apparmor/lib.c

@@ -75,15 +75,16 @@ void aa_info_message(const char *str)
 }
 
 /**
- * kvmalloc - do allocation preferring kmalloc but falling back to vmalloc
- * @size: size of allocation
+ * __aa_kvmalloc - do allocation preferring kmalloc but falling back to vmalloc
+ * @size: how many bytes of memory are required
+ * @flags: the type of memory to allocate (see kmalloc).
  *
  * Return: allocated buffer or NULL if failed
  *
  * It is possible that policy being loaded from the user is larger than
  * what can be allocated by kmalloc, in those cases fall back to vmalloc.
  */
-void *kvmalloc(size_t size)
+void *__aa_kvmalloc(size_t size, gfp_t flags)
 {
 	void *buffer = NULL;
 
@@ -92,14 +93,17 @@ void *kvmalloc(size_t size)
 
 	/* do not attempt kmalloc if we need more than 16 pages at once */
 	if (size <= (16*PAGE_SIZE))
-		buffer = kmalloc(size, GFP_NOIO | __GFP_NOWARN);
+		buffer = kmalloc(size, flags | GFP_NOIO | __GFP_NOWARN);
 	if (!buffer) {
 		/* see kvfree for why size must be at least work_struct size
 		 * when allocated via vmalloc
 		 */
 		if (size < sizeof(struct work_struct))
 			size = sizeof(struct work_struct);
-		buffer = vmalloc(size);
+		if (flags & __GFP_ZERO)
+			buffer = vzalloc(size);
+		else
+			buffer = vmalloc(size);
 	}
 	return buffer;
 }

security/apparmor/match.c

@@ -30,7 +30,7 @@
  *
  * Returns: pointer to table else NULL on failure
  *
- * NOTE: must be freed by kvfree (not kmalloc)
+ * NOTE: must be freed by kvfree (not kfree)
  */
 static struct table_header *unpack_table(char *blob, size_t bsize)
 {
@@ -57,7 +57,7 @@ static struct table_header *unpack_table(char *blob, size_t bsize)
 	if (bsize < tsize)
 		goto out;
 
-	table = kvmalloc(tsize);
+	table = kvzalloc(tsize);
 	if (table) {
 		*table = th;
 		if (th.td_flags == YYTD_DATA8)