ksmbd: override fsids for smb2_query_info()

Sangsoo reported that a DAC denial error occurred when accessing
files through the ksmbd thread. This patch override fsids for
smb2_query_info().

Reported-by: Sangsoo Lee <constant.lee@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: namjaejeon

fs/smb/server/smb2pdu.c

@@ -5596,6 +5596,11 @@ int smb2_query_info(struct ksmbd_work *work)
 
 	ksmbd_debug(SMB, "GOT query info request\n");
 
+	if (ksmbd_override_fsids(work)) {
+		rc = -ENOMEM;
+		goto err_out;
+	}
+
 	switch (req->InfoType) {
 	case SMB2_O_INFO_FILE:
 		ksmbd_debug(SMB, "GOT SMB2_O_INFO_FILE\n");
@@ -5614,6 +5619,7 @@ int smb2_query_info(struct ksmbd_work *work)
 			    req->InfoType);
 		rc = -EOPNOTSUPP;
 	}
+	ksmbd_revert_fsids(work);
 
 	if (!rc) {
 		rsp->StructureSize = cpu_to_le16(9);
@@ -5623,6 +5629,7 @@ int smb2_query_info(struct ksmbd_work *work)
 					le32_to_cpu(rsp->OutputBufferLength));
 	}
 
+err_out:
 	if (rc < 0) {
 		if (rc == -EACCES)
 			rsp->hdr.Status = STATUS_ACCESS_DENIED;