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-rwxr-xr-xnxcomp/Auth.cpp628
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diff --git a/nxcomp/Auth.cpp b/nxcomp/Auth.cpp
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+/**************************************************************************/
+/* */
+/* Copyright (c) 2001, 2007 NoMachine, http://www.nomachine.com/. */
+/* */
+/* NXCOMP, NX protocol compression and NX extensions to this software */
+/* are copyright of NoMachine. Redistribution and use of the present */
+/* software is allowed according to terms specified in the file LICENSE */
+/* which comes in the source distribution. */
+/* */
+/* Check http://www.nomachine.com/licensing.html for applicability. */
+/* */
+/* NX and NoMachine are trademarks of NoMachine S.r.l. */
+/* */
+/* All rights reserved. */
+/* */
+/**************************************************************************/
+
+#include "Auth.h"
+
+#include "Misc.h"
+#include "Control.h"
+#include "Timestamp.h"
+#include "Pipe.h"
+
+#define DEFAULT_STRING_LIMIT 512
+
+//
+// Set the verbosity level.
+//
+
+#define PANIC
+#define WARNING
+#undef TEST
+#undef DEBUG
+
+//
+// Store the provided cookie as our 'fake' cookie, then
+// read the 'real' cookie from the current X authority
+// file.
+//
+
+Auth::Auth(char *display, char *cookie)
+{
+ display_ = NULL;
+
+ file_ = NULL;
+
+ last_ = nullTimestamp();
+
+ fakeCookie_ = NULL;
+ realCookie_ = NULL;
+
+ fakeData_ = NULL;
+ realData_ = NULL;
+
+ dataSize_ = 0;
+
+ if (display == NULL || *display == '\0' || cookie == NULL ||
+ *cookie == '\0' || strlen(cookie) != 32)
+ {
+ #ifdef PANIC
+ *logofs << "Auth: PANIC! Can't create the X authorization data "
+ << "with cookie '" << cookie << "' and display '"
+ << display << "'.\n" << logofs_flush;
+ #endif
+
+ cerr << "Error" << ": Can't create the X authorization data "
+ << "with cookie '" << cookie << "' and display '"
+ << display << "'.\n";
+
+ return;
+ }
+
+ #ifdef TEST
+ *logofs << "Auth: Creating X authorization data with cookie '"
+ << cookie << "' and display '" << display << "'.\n"
+ << logofs_flush;
+ #endif
+
+ //
+ // Get a local copy of all parameters.
+ //
+
+ display_ = new char[strlen(display) + 1];
+ file_ = new char[DEFAULT_STRING_LIMIT];
+
+ fakeCookie_ = new char[strlen(cookie) + 1];
+ realCookie_ = new char[DEFAULT_STRING_LIMIT];
+
+ if (display_ == NULL || file_ == NULL ||
+ fakeCookie_ == NULL || realCookie_ == NULL)
+ {
+ #ifdef PANIC
+ *logofs << "Auth: PANIC! Cannot allocate memory for the X "
+ << "authorization data.\n" << logofs_flush;
+ #endif
+
+ cerr << "Error" << ": Cannot allocate memory for the X "
+ << "authorization data.\n";
+
+ return;
+ }
+
+ strcpy(display_, display);
+
+ *file_ = '\0';
+
+ strcpy(fakeCookie_, cookie);
+
+ *realCookie_ = '\0';
+
+ //
+ // Get the real cookie from the authorization file.
+ //
+
+ updateCookie();
+}
+
+Auth::~Auth()
+{
+ delete [] display_;
+ delete [] file_;
+
+ delete [] fakeCookie_;
+ delete [] realCookie_;
+
+ delete [] fakeData_;
+ delete [] realData_;
+}
+
+//
+// At the present moment the cookie is read only once,
+// at the time the instance is initialized. If the auth
+// file changes along the life of the session, the old
+// cookie will be used. This works with X servers beca-
+// use of an undocumented "feature". See nx-X11.
+//
+
+int Auth::updateCookie()
+{
+ if (isTimestamp(last_) == 0)
+ {
+ #ifdef TEST
+ *logofs << "Auth: Reading the X authorization file "
+ << "with last update at " << strMsTimestamp(last_)
+ << ".\n" << logofs_flush;
+ #endif
+
+ if (getCookie() == 1 && validateCookie() == 1)
+ {
+ //
+ // It should rather be the modification time
+ // the auth file, so we can read it again if
+ // the file is changed.
+ //
+
+ #ifdef TEST
+ *logofs << "Auth: Setting last X authorization file "
+ << "update at " << strMsTimestamp() << ".\n"
+ << logofs_flush;
+ #endif
+
+ last_ = getTimestamp();
+
+ return 1;
+ }
+
+ #ifdef PANIC
+ *logofs << "Auth: PANIC! Cannot read the cookie from the X "
+ << "authorization file.\n" << logofs_flush;
+ #endif
+
+ cerr << "Error" << ": Cannot read the cookie from the X "
+ << "authorization file.\n";
+
+ return -1;
+ }
+
+ #ifdef TEST
+ *logofs << "Auth: WARNING! Skipping check on the X "
+ << "authorization file.\n" << logofs_flush;
+ #endif
+
+ return 0;
+}
+
+int Auth::getCookie()
+{
+ //
+ // Check the name of the auth file that we are going to use.
+ // It can be either the value of the XAUTHORITY environment
+ // or the default .Xauthority file in the user's home.
+ //
+
+ char *environment;
+
+ environment = getenv("XAUTHORITY");
+
+ if (environment != NULL && *environment != '\0')
+ {
+ strncpy(file_, environment, DEFAULT_STRING_LIMIT - 1);
+ }
+ else
+ {
+ snprintf(file_, DEFAULT_STRING_LIMIT - 1, "%s/.Xauthority",
+ control -> HomePath);
+ }
+
+ *(file_ + DEFAULT_STRING_LIMIT - 1) = '\0';
+
+ #ifdef TEST
+ *logofs << "Auth: Using X authorization file '" << file_
+ << "'.\n" << logofs_flush;
+ #endif
+
+ //
+ // Use the nxauth command on Windows and the Mac, xauth
+ // on all the other platforms. On Windows and on the Mac
+ // we assume that the nxauth command is located under
+ // bin in the client installation directory. On all the
+ // other platforms we use the default xauth command that
+ // is in our path.
+ //
+
+ char command[DEFAULT_STRING_LIMIT];
+
+ #if defined(__CYGWIN32__) || defined(__APPLE__)
+
+ snprintf(command, DEFAULT_STRING_LIMIT - 1,
+ "%s/bin/nxauth", control -> SystemPath);
+
+ *(command + DEFAULT_STRING_LIMIT - 1) = '\0';
+
+ #else
+
+ strcpy(command, "xauth");
+
+ #endif
+
+ #ifdef TEST
+ *logofs << "Auth: Using X auth command '" << command
+ << "'.\n" << logofs_flush;
+ #endif
+
+ //
+ // The SSH code forces using the unix:n port when passing localhost:n.
+ // This is probably because localhost:n can fail to return a valid
+ // entry on machines where the hostname for localhost doesn't match
+ // exactly the 'localhost' string. For example, on a freshly installed
+ // Fedora Core 3 I get a 'localhost.localdomain/unix:0' entry. Query-
+ // ing 'xauth list localhost:0' results in an empty result, while the
+ // query 'xauth list unix:0' works as expected. Note anyway that if
+ // the cookie for the TCP connection on 'localhost' is set to a dif-
+ // ferent cookie than the one for the Unix connections, both SSH and
+ // NX will match the wrong cookie and session will fail.
+ //
+
+ char line[DEFAULT_STRING_LIMIT];
+
+ if (strncmp(display_, "localhost:", 10) == 0)
+ {
+ snprintf(line, DEFAULT_STRING_LIMIT, "unix:%s", display_ + 10);
+ }
+ else
+ {
+ snprintf(line, DEFAULT_STRING_LIMIT, "%.200s", display_);
+ }
+
+ char *parameters[256];
+
+ parameters[0] = command;
+ parameters[1] = command;
+ parameters[2] = "-f";
+ parameters[3] = file_;
+ parameters[4] = "list";
+ parameters[5] = line;
+ parameters[6] = NULL;
+
+ #ifdef TEST
+ *logofs << "Auth: Executing command ";
+
+ for (int i = 0; i < 256 && parameters[i] != NULL; i++)
+ {
+ *logofs << "[" << parameters[i] << "]";
+ }
+
+ *logofs << ".\n" << logofs_flush;
+ #endif
+
+ //
+ // Use the popen() function to read the result
+ // of the command. We would better use our own
+ // implementation.
+ //
+
+ FILE *data = Popen(parameters, "r");
+
+ int result = -1;
+
+ if (data == NULL)
+ {
+ #ifdef PANIC
+ *logofs << "Auth: PANIC! Failed to execute the X auth command.\n"
+ << logofs_flush;
+ #endif
+
+ cerr << "Error" << ": Failed to execute the X auth command.\n";
+
+ goto AuthGetCookieResult;
+ }
+
+ if (fgets(line, DEFAULT_STRING_LIMIT, data) == NULL)
+ {
+ #ifdef WARNING
+ *logofs << "Auth: WARNING! Failed to read data from the X "
+ << "auth command.\n" << logofs_flush;
+ #endif
+
+ cerr << "Warning" << ": Failed to read data from the X "
+ << "auth command.\n";
+
+ #ifdef PANIC
+ *logofs << "Auth: WARNING! Generating a fake cookie for "
+ << "X authentication.\n" << logofs_flush;
+ #endif
+
+ cerr << "Warning" << ": Generating a fake cookie for "
+ << "X authentication.\n";
+
+ generateCookie(realCookie_);
+ }
+ else
+ {
+ #ifdef TEST
+ *logofs << "Auth: Checking cookie in string '" << line
+ << "'.\n" << logofs_flush;
+ #endif
+
+ if (sscanf(line, "%*s %*s %511s", realCookie_) != 1)
+ {
+ #ifdef PANIC
+ *logofs << "Auth: PANIC! Failed to identify the cookie "
+ << "in string '" << line << "'.\n"
+ << logofs_flush;
+ #endif
+
+ cerr << "Error" << ": Failed to identify the cookie "
+ << "in string '" << line << "'.\n";
+
+ goto AuthGetCookieResult;
+ }
+
+ #ifdef TEST
+ *logofs << "Auth: Got cookie '" << realCookie_
+ << "' from file '" << file_ << "'.\n"
+ << logofs_flush;
+ #endif
+ }
+
+ result = 1;
+
+AuthGetCookieResult:
+
+ if (data != NULL)
+ {
+ Pclose(data);
+ }
+
+ return result;
+}
+
+int Auth::validateCookie()
+{
+ unsigned int length = strlen(realCookie_);
+
+ if (length > DEFAULT_STRING_LIMIT / 2 - 1 ||
+ strlen(fakeCookie_) != length)
+ {
+ #ifdef PANIC
+ *logofs << "Auth: PANIC! Size mismatch between cookies '"
+ << realCookie_ << "' and '" << fakeCookie_ << "'.\n"
+ << logofs_flush;
+ #endif
+
+ cerr << "Error" << ": Size mismatch between cookies '"
+ << realCookie_ << "' and '" << fakeCookie_ << "'.\n";
+
+ goto AuthValidateCookieError;
+ }
+
+ //
+ // The length of the resulting data will be
+ // half the size of the Hex cookie.
+ //
+
+ length = length / 2;
+
+ fakeData_ = new char[length];
+ realData_ = new char[length];
+
+ if (fakeData_ == NULL || realData_ == NULL)
+ {
+ #ifdef PANIC
+ *logofs << "Auth: PANIC! Cannot allocate memory for the binary X "
+ << "authorization data.\n" << logofs_flush;
+ #endif
+
+ cerr << "Error" << ": Cannot allocate memory for the binary X "
+ << "authorization data.\n";
+
+ goto AuthValidateCookieError;
+ }
+
+ //
+ // Translate the real cookie from Hex data
+ // to its binary representation.
+ //
+
+ unsigned int value;
+
+ for (unsigned int i = 0; i < length; i++)
+ {
+ if (sscanf(realCookie_ + 2 * i, "%2x", &value) != 1)
+ {
+ #ifdef PANIC
+ *logofs << "Auth: PANIC! Bad X authorization data in real "
+ << "cookie '" << realCookie_ << "'.\n" << logofs_flush;
+ #endif
+
+ cerr << "Error" << ": Bad X authorization data in real cookie '"
+ << realCookie_ << "'.\n";
+
+ goto AuthValidateCookieError;
+ }
+
+ realData_[i] = value;
+
+ if (sscanf(fakeCookie_ + 2 * i, "%2x", &value) != 1)
+ {
+ #ifdef PANIC
+ *logofs << "Auth: PANIC! Bad X authorization data in fake "
+ << "cookie '" << fakeCookie_ << "'.\n" << logofs_flush;
+ #endif
+
+ cerr << "Error" << ": Bad X authorization data in fake cookie '"
+ << fakeCookie_ << "'.\n";
+
+ goto AuthValidateCookieError;
+ }
+
+ fakeData_[i] = value;
+ }
+
+ dataSize_ = length;
+
+ #ifdef TEST
+ *logofs << "Auth: Validated real cookie '"
+ << realCookie_ << "' and fake cookie '" << fakeCookie_
+ << "' with data with size " << dataSize_ << ".\n"
+ << logofs_flush;
+
+ *logofs << "Auth: Ready to accept incoming connections.\n"
+ << logofs_flush;
+ #endif
+
+ return 1;
+
+AuthValidateCookieError:
+
+ delete [] fakeData_;
+ delete [] realData_;
+
+ fakeData_ = NULL;
+ realData_ = NULL;
+
+ dataSize_ = 0;
+
+ return -1;
+}
+
+int Auth::checkCookie(unsigned char *buffer)
+{
+ if (isValid() != 1)
+ {
+ #ifdef PANIC
+ *logofs << "Auth: PANIC! Attempt to check the X cookie with "
+ << "invalid authorization data.\n" << logofs_flush;
+ #endif
+
+ cerr << "Error" << ": Attempt to check the X cookie with "
+ << "invalid authorization data.\n";
+
+ return -1;
+ }
+
+ char *protoName = "MIT-MAGIC-COOKIE-1";
+ int protoSize = strlen(protoName);
+
+ int matchedProtoSize;
+ int matchedDataSize;
+
+ if (buffer[0] == 0x42)
+ {
+ //
+ // Byte order is MSB first.
+ //
+
+ matchedProtoSize = 256 * buffer[6] + buffer[7];
+ matchedDataSize = 256 * buffer[8] + buffer[9];
+ }
+ else if (buffer[0] == 0x6c)
+ {
+ //
+ // Byte order is LSB first.
+ //
+
+ matchedProtoSize = buffer[6] + 256 * buffer[7];
+ matchedDataSize = buffer[8] + 256 * buffer[9];
+ }
+ else
+ {
+ #ifdef WARNING
+ *logofs << "Auth: WARNING! Bad X connection data in the buffer.\n"
+ << logofs_flush;
+ #endif
+
+ cerr << "Warning" << ": Bad X connection data in the buffer.\n";
+
+ return -1;
+ }
+
+ //
+ // Check if both the authentication protocol
+ // and the fake cookie match our data.
+ //
+
+ int protoOffset = 12;
+
+ #ifdef TEST
+ *logofs << "Auth: Received a protocol size of "
+ << matchedProtoSize << " bytes.\n"
+ << logofs_flush;
+ #endif
+
+ if (matchedProtoSize != protoSize ||
+ memcmp(buffer + protoOffset, protoName, protoSize) != 0)
+ {
+ #ifdef WARNING
+ *logofs << "Auth: WARNING! Protocol mismatch or no X "
+ << "authentication data.\n" << logofs_flush;
+ #endif
+
+ cerr << "Warning" << ": Protocol mismatch or no X "
+ << "authentication data.\n";
+
+ return -1;
+ }
+
+ int dataOffset = protoOffset + ((matchedProtoSize + 3) & ~3);
+
+ #ifdef TEST
+ *logofs << "Auth: Received a data size of "
+ << matchedDataSize << " bytes.\n"
+ << logofs_flush;
+ #endif
+
+ if (matchedDataSize != dataSize_ ||
+ memcmp(buffer + dataOffset, fakeData_, dataSize_) != 0)
+ {
+ #ifdef WARNING
+ *logofs << "Auth: WARNING! Cookie mismatch in the X "
+ << "authentication data.\n" << logofs_flush;
+ #endif
+
+ cerr << "Warning" << ": Cookie mismatch in the X "
+ << "authentication data.\n";
+
+ return -1;
+ }
+
+ //
+ // Everything is OK. Replace the fake data.
+ //
+
+ #ifdef TEST
+ *logofs << "Auth: Replacing fake X authentication data "
+ << "with the real data.\n" << logofs_flush;
+ #endif
+
+ memcpy(buffer + dataOffset, realData_, dataSize_);
+
+ return 1;
+}
+
+void Auth::generateCookie(char *cookie)
+{
+ //
+ // Code is from the SSH implementation, except that
+ // we use a much weaker random number generator.
+ // This is not critical, anyway, as this is just a
+ // fake cookie. The X server doesn't have a cookie
+ // for the display, so it will ignore the value we
+ // feed to it.
+ //
+
+ T_timestamp timer = getTimestamp();
+
+ srand((unsigned int) timer.tv_usec);
+
+ unsigned int data = rand();
+
+ for (int i = 0; i < 16; i++)
+ {
+ if (i % 4 == 0)
+ {
+ data = rand();
+ }
+
+ snprintf(cookie + 2 * i, 3, "%02x", data & 0xff);
+
+ data >>= 8;
+ }
+
+ #ifdef TEST
+ *logofs << "Auth: Generated X cookie string '"
+ << cookie << "'.\n" << logofs_flush;
+ #endif
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-05 17:46:32 +0000