Milestone 5: deliver embedded RDP sessions and lifecycle hardening

third_party/FreeRDP/winpr/libwinpr/utils/wlog/UdpAppender.c

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+/**
+ * WinPR: Windows Portable Runtime
+ * WinPR Logger
+ *
+ * Copyright © 2015 Thincast Technologies GmbH
+ * Copyright © 2015 David FORT <contact@hardening-consulting.com>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <winpr/config.h>
+
+#include <winpr/crt.h>
+#include <winpr/environment.h>
+#include <winpr/winsock.h>
+
+#include "wlog.h"
+
+typedef struct
+{
+	wLogAppender common;
+	char* host;
+	struct sockaddr targetAddr;
+	int targetAddrLen;
+	SOCKET sock;
+} wLogUdpAppender;
+
+static BOOL WLog_UdpAppender_Open(WINPR_ATTR_UNUSED wLog* log, wLogAppender* appender)
+{
+	wLogUdpAppender* udpAppender = nullptr;
+	char addressString[256] = WINPR_C_ARRAY_INIT;
+	struct addrinfo hints = WINPR_C_ARRAY_INIT;
+	struct addrinfo* result = WINPR_C_ARRAY_INIT;
+	int status = 0;
+	char* colonPos = nullptr;
+
+	if (!appender)
+		return FALSE;
+
+	udpAppender = (wLogUdpAppender*)appender;
+
+	if (udpAppender->targetAddrLen) /* already opened */
+		return TRUE;
+
+	colonPos = strchr(udpAppender->host, ':');
+
+	if (!colonPos)
+		return FALSE;
+
+	const size_t addrLen = WINPR_ASSERTING_INT_CAST(size_t, (colonPos - udpAppender->host));
+	memcpy(addressString, udpAppender->host, addrLen);
+	addressString[addrLen] = '\0';
+	hints.ai_family = AF_INET;
+	hints.ai_socktype = SOCK_DGRAM;
+	status = getaddrinfo(addressString, colonPos + 1, &hints, &result);
+
+	if (status != 0)
+		return FALSE;
+
+	if (result->ai_addrlen > sizeof(udpAppender->targetAddr))
+	{
+		freeaddrinfo(result);
+		return FALSE;
+	}
+
+	memcpy(&udpAppender->targetAddr, result->ai_addr, result->ai_addrlen);
+	udpAppender->targetAddrLen = (int)result->ai_addrlen;
+	freeaddrinfo(result);
+	return TRUE;
+}
+
+static BOOL WLog_UdpAppender_Close(wLog* log, wLogAppender* appender)
+{
+	return !(!log || !appender);
+}
+
+static BOOL WLog_UdpAppender_WriteMessage(wLog* log, wLogAppender* appender,
+                                          const wLogMessage* cmessage)
+{
+	if (!log || !appender || !cmessage)
+		return FALSE;
+
+	wLogUdpAppender* udpAppender = (wLogUdpAppender*)appender;
+
+	char prefix[WLOG_MAX_PREFIX_SIZE] = WINPR_C_ARRAY_INIT;
+	WLog_Layout_GetMessagePrefix(log, appender->Layout, cmessage, prefix, sizeof(prefix));
+
+	(void)_sendto(udpAppender->sock, prefix, (int)strnlen(prefix, ARRAYSIZE(prefix)), 0,
+	              &udpAppender->targetAddr, udpAppender->targetAddrLen);
+	(void)_sendto(udpAppender->sock, cmessage->TextString,
+	              (int)strnlen(cmessage->TextString, INT_MAX), 0, &udpAppender->targetAddr,
+	              udpAppender->targetAddrLen);
+	(void)_sendto(udpAppender->sock, "\n", 1, 0, &udpAppender->targetAddr,
+	              udpAppender->targetAddrLen);
+	return TRUE;
+}
+
+static BOOL WLog_UdpAppender_WriteDataMessage(wLog* log, wLogAppender* appender,
+                                              const wLogMessage* message)
+{
+	return !(!log || !appender || !message);
+}
+
+static BOOL WLog_UdpAppender_WriteImageMessage(wLog* log, wLogAppender* appender,
+                                               const wLogMessage* message)
+{
+	return !(!log || !appender || !message);
+}
+
+static BOOL WLog_UdpAppender_Set(wLogAppender* appender, const char* setting, void* value)
+{
+	const char target[] = "target";
+	wLogUdpAppender* udpAppender = (wLogUdpAppender*)appender;
+
+	/* Just check the value string is not empty */
+	if (!value || (strnlen(value, 2) == 0))
+		return FALSE;
+
+	if (strncmp(target, setting, sizeof(target)) != 0)
+		return FALSE;
+
+	udpAppender->targetAddrLen = 0;
+
+	if (udpAppender->host)
+		free(udpAppender->host);
+
+	udpAppender->host = _strdup((const char*)value);
+	return (udpAppender->host != nullptr) && WLog_UdpAppender_Open(nullptr, appender);
+}
+
+static void WLog_UdpAppender_Free(wLogAppender* appender)
+{
+	wLogUdpAppender* udpAppender = nullptr;
+
+	if (appender)
+	{
+		udpAppender = (wLogUdpAppender*)appender;
+
+		if (udpAppender->sock != INVALID_SOCKET)
+		{
+			closesocket(udpAppender->sock);
+			udpAppender->sock = INVALID_SOCKET;
+		}
+
+		free(udpAppender->host);
+		free(udpAppender);
+	}
+}
+
+wLogAppender* WLog_UdpAppender_New(wLog* log)
+{
+	DWORD nSize = 0;
+	LPCSTR name = nullptr;
+	wLogUdpAppender* appender = (wLogUdpAppender*)calloc(1, sizeof(wLogUdpAppender));
+
+	if (!appender)
+		return nullptr;
+
+	appender->common.Type = WLOG_APPENDER_UDP;
+	appender->common.Open = WLog_UdpAppender_Open;
+	appender->common.Close = WLog_UdpAppender_Close;
+	appender->common.WriteMessage = WLog_UdpAppender_WriteMessage;
+	appender->common.WriteDataMessage = WLog_UdpAppender_WriteDataMessage;
+	appender->common.WriteImageMessage = WLog_UdpAppender_WriteImageMessage;
+	appender->common.Free = WLog_UdpAppender_Free;
+	appender->common.Set = WLog_UdpAppender_Set;
+	appender->sock = _socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+
+	if (appender->sock == INVALID_SOCKET)
+		goto error_sock;
+
+	name = "WLOG_UDP_TARGET";
+	nSize = GetEnvironmentVariableA(name, nullptr, 0);
+
+	if (nSize)
+	{
+		appender->host = (LPSTR)malloc(nSize);
+
+		if (!appender->host)
+			goto error_open;
+
+		if (GetEnvironmentVariableA(name, appender->host, nSize) != nSize - 1)
+			goto error_open;
+
+		if (!WLog_UdpAppender_Open(log, (wLogAppender*)appender))
+			goto error_open;
+	}
+	else
+	{
+		appender->host = _strdup("127.0.0.1:20000");
+
+		if (!appender->host)
+			goto error_open;
+	}
+
+	return &appender->common;
+error_open:
+	free(appender->host);
+	closesocket(appender->sock);
+error_sock:
+	free(appender);
+	return nullptr;
+}