--- /dev/null
+/*
+ * X server wrapper.
+ *
+ * This wrapper makes some sanity checks on the command line arguments
+ * and environment variables when run with euid == 0 && euid != uid.
+ * If the checks fail, the wrapper exits with a message.
+ * If they succeed, it exec's the Xserver.
+ */
+
+/*
+ * Copyright (c) 1998 by The XFree86 Project, Inc. All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject
+ * to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE XFREE86 PROJECT BE LIABLE FOR ANY CLAIM, DAMAGES
+ * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
+ * OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Except as contained in this notice, the name of the XFree86 Project
+ * shall not be used in advertising or otherwise to promote the sale,
+ * use or other dealings in this Software without prior written
+ * authorization from the XFree86 Project.
+ */
+
+/* $XFree86: xc/programs/Xserver/os/wrapper.c,v 1.1.2.5 1998/02/27 15:28:59 dawes Exp $ */
+
+/* This is normally set in the Imakefile */
+#ifndef XSERVER_PATH
+#define XSERVER_PATH "/usr/X11R6/bin/X"
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+
+/* Neither of these should be required for XFree86 3.3.2 */
+#ifndef REJECT_CONFIG
+#define REJECT_CONFIG 0
+#endif
+#ifndef REJECT_XKBDIR
+#define REJECT_XKBDIR 0
+#endif
+
+/* Consider LD* variables insecure ? */
+#ifndef REMOVE_ENV_LD
+#define REMOVE_ENV_LD 1
+#endif
+
+/* Remove long environment variables? */
+#ifndef REMOVE_LONG_ENV
+#define REMOVE_LONG_ENV 1
+#endif
+
+/* Check args and env only if running setuid (euid == 0 && euid != uid) ? */
+#ifndef CHECK_EUID
+#define CHECK_EUID 1
+#endif
+
+/*
+ * Maybe the locale can be faked to make isprint(3) report that everything
+ * is printable? Avoid it by default.
+ */
+#ifndef USE_ISPRINT
+#define USE_ISPRINT 0
+#endif
+
+#define MAX_ARG_LENGTH 128
+#define MAX_ENV_LENGTH 256
+#define MAX_ENV_PATH_LENGTH 2048
+
+#if USE_ISPRINT
+#include <ctype.h>
+#define checkPrintable(c) isprint(c)
+#else
+#define checkPrintable(c) (((c) & 0x7f) >= 0x20 && ((c) & 0x7f) != 0x7f)
+#endif
+
+enum BadCode {
+ NotBad = 0,
+ UnsafeArg,
+ ArgTooLong,
+ UnprintableArg,
+ EnvTooLong,
+ InternalError
+};
+
+#define ARGMSG \
+ "\nIf the arguments used are valid, and have been rejected incorrectly\n" \
+ "please send details of the arguments and why they are valid to\n" \
+ "XFree86@XFree86.org. In the meantime, you can start the Xserver as\n" \
+ "the \"super user\" (root).\n"
+
+#define ENVMSG \
+ "\nIf the environment is valid, and have been rejected incorrectly\n" \
+ "please send details of the environment and why it is valid to\n" \
+ "XFree86@XFree86.org. In the meantime, you can start the Xserver as\n" \
+ "the \"super user\" (root).\n"
+
+int
+main(int argc, char **argv, char **envp)
+{
+ enum BadCode bad = NotBad;
+ int i, j;
+ char *a, *e;
+
+#if CHECK_EUID
+ if (geteuid() == 0 && getuid() != geteuid()) {
+#endif
+ /* Check each argv[] */
+ for (i = 1; i < argc; i++) {
+
+ /* Check for known bad arguments */
+#if REJECT_CONFIG
+ if (strcmp(argv[i], "-config") == 0) {
+ bad = UnsafeArg;
+ break;
+ }
+#endif
+#if REJECT_XKBDIR
+ if (strcmp(argv[i], "-xkbdir") == 0) {
+ bad = UnsafeArg;
+ break;
+ }
+#endif
+ if (strlen(argv[i]) > MAX_ARG_LENGTH) {
+ bad = ArgTooLong;
+ break;
+ }
+ a = argv[i];
+ while (*a) {
+ if (checkPrintable(*a) == 0) {
+ bad = UnprintableArg;
+ break;
+ }
+ a++;
+ }
+ if (bad)
+ break;
+ }
+ /* Check each envp[] */
+ if (!bad)
+ for (i = 0; envp[i]; i++) {
+
+ /* Check for bad environment variables and values */
+#if REMOVE_ENV_LD
+ while (envp[i] && (strncmp(envp[i], "LD", 2) == 0)) {
+ for (j = i; envp[j]; j++) {
+ envp[j] = envp[j+1];
+ }
+ }
+#endif
+ if (envp[i] && (strlen(envp[i]) > MAX_ENV_LENGTH)) {
+#if REMOVE_LONG_ENV
+ for (j = i; envp[j]; j++) {
+ envp[j] = envp[j+1];
+ }
+ i--;
+#else
+ char *eq;
+ int len;
+
+ eq = strchr(envp[i], '=');
+ if (!eq)
+ continue;
+ len = eq - envp[i];
+ e = malloc(len + 1);
+ if (!e) {
+ bad = InternalError;
+ break;
+ }
+ strncpy(e, envp[i], len);
+ e[len] = 0;
+ if (len >= 4 &&
+ (strcmp(e + len - 4, "PATH") == 0 ||
+ strcmp(e, "TERMCAP") == 0)) {
+ if (strlen(envp[i]) > MAX_ENV_PATH_LENGTH) {
+ bad = EnvTooLong;
+ break;
+ } else {
+ free(e);
+ }
+ } else {
+ bad = EnvTooLong;
+ break;
+ }
+#endif
+ }
+ }
+#if CHECK_EUID
+ }
+#endif
+ switch (bad) {
+ case NotBad:
+ execve(XSERVER_PATH, argv, envp);
+ fprintf(stderr, "execve failed for %s (errno %d)\n", XSERVER_PATH,
+ errno);
+ break;
+ case UnsafeArg:
+ fprintf(stderr, "Command line argument number %d is unsafe\n", i);
+ fprintf(stderr, ARGMSG);
+ break;
+ case ArgTooLong:
+ fprintf(stderr, "Command line argument number %d is too long\n", i);
+ fprintf(stderr, ARGMSG);
+ break;
+ case UnprintableArg:
+ fprintf(stderr, "Command line argument number %d contains unprintable"
+ " characters\n", i);
+ fprintf(stderr, ARGMSG);
+ break;
+ case EnvTooLong:
+ fprintf(stderr, "Environment variable `%s' is too long\n", e);
+ fprintf(stderr, ENVMSG);
+ break;
+ case InternalError:
+ fprintf(stderr, "Internal Error\n");
+ break;
+ default:
+ fprintf(stderr, "Unknown error\n");
+ fprintf(stderr, ARGMSG);
+ fprintf(stderr, ENVMSG);
+ break;
+ }
+ exit(1);
+}
+
projects / rdpsrv / blobdiff