[PATCH 5.2 307/313] CIFS: fix max ea value size

From: Greg Kroah-Hartman
Date: Thu Oct 03 2019 - 12:37:55 EST


From: Murphy Zhou <jencce.kernel@xxxxxxxxx>

commit 63d37fb4ce5ae7bf1e58f906d1bf25f036fe79b2 upstream.

It should not be larger then the slab max buf size. If user
specifies a larger size, it passes this check and goes
straightly to SMB2_set_info_init performing an insecure memcpy.

Signed-off-by: Murphy Zhou <jencce.kernel@xxxxxxxxx>
Reviewed-by: Aurelien Aptel <aaptel@xxxxxxxx>
CC: Stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
fs/cifs/xattr.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/cifs/xattr.c
+++ b/fs/cifs/xattr.c
@@ -31,7 +31,7 @@
#include "cifs_fs_sb.h"
#include "cifs_unicode.h"

-#define MAX_EA_VALUE_SIZE 65535
+#define MAX_EA_VALUE_SIZE CIFSMaxBufSize
#define CIFS_XATTR_CIFS_ACL "system.cifs_acl"
#define CIFS_XATTR_ATTRIB "cifs.dosattrib" /* full name: user.cifs.dosattrib */
#define CIFS_XATTR_CREATETIME "cifs.creationtime" /* user.cifs.creationtime */