From: Namjae Jeon <linkinjeon@xxxxxxxxxx>
commit 9ca8581e79e51c57e60b3b8e3b89d816448f49fe upstream.
cifs client set 4 to DataLength of create_posix context, which mean
Mode variable of create_posix context is only available. So buffer
validation of ksmbd should check only the size of Mode except for
the size of Reserved variable.
Fixes: 8f77150c15f8 ("ksmbd: add buffer validation for SMB2_CREATE_CONTEXT")
Cc: stable@xxxxxxxxxxxxxxx # v5.15+
Reported-by: Steve French <smfrench@xxxxxxxxx>
Tested-by: Steve French <stfrench@xxxxxxxxxxxxx>
Signed-off-by: Namjae Jeon <linkinjeon@xxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ksmbd/smb2pdu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/ksmbd/smb2pdu.c
+++ b/fs/ksmbd/smb2pdu.c
@@ -2688,7 +2688,7 @@ int smb2_open(struct ksmbd_work *work)
(struct create_posix *)context;
if (le16_to_cpu(context->DataOffset) +
le32_to_cpu(context->DataLength) <
- sizeof(struct create_posix)) {
+ sizeof(struct create_posix) - 4) {
rc = -EINVAL;
goto err_out1;
}
