First commit

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 180 insertions, 0 deletions

diff --git a/asroot.c b/asroot.c
new file mode 100644
index 0000000..5f03b42
--- /dev/null
+++ b/asroot.c
@@ -0,0 +1,180 @@
+#include <errno.h>
+#include <pwd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "arg.h"
+
+
+char *argv0;
+
+extern char **environ;
+
+static const char *env_whitelist[] = {
+	"DISPLAY=",
+	"WAYLAND_DISPLAY=",
+	"PATH=",
+	"TERM=",
+	"COLORTERM=",
+	"XAUTHORITY=",
+	"LANG=",
+	"LANGUAGE=",
+	"LOCALE=",
+	"LC_CTYPE=",
+	"LC_NUMERIC=",
+	"LC_TIME=",
+	"LC_COLLATE=",
+	"LC_MONETARY=",
+	"LC_MESSAGES=",
+	"LC_PAPER=",
+	"LC_NAME=",
+	"LC_ADDRESS=",
+	"LC_TELEPHONE=",
+	"LC_MEASUREMENT=",
+	"LC_IDENTIFICATION=",
+	"LC_ALL=",
+	"LOCPATH=",
+	"NLSPATH=",
+	"TZ=",
+	"TZDIR=",
+	"SDL_VIDEO_FULLSCREEN_DISPLAY=",
+	"EDITOR=",
+	"VISUAL=",
+	"BROWSER=",
+	"DESKTOP_SESSION=",
+	"LS_COLORS=",
+	"GTK_THEME=",
+	"QT_STYLE_OVERRIDE=",
+	"PWD=",
+	"OLDPWD=",
+	"JAVA_HOME=",
+	"_JAVA_AWT_WM_NONREPARENTING=",
+	"_JAVA_OPTIONS=",
+	"MAIN_ALSA_MIXER=",
+	"MAIN_ALSA_CARD=",
+	"XDG_SEAT=",
+	"XDG_SESSION_TYPE=",
+	"XDG_SESSION_CLASS=",
+	"XDG_VTNR=",
+	"XDG_SESSION_ID=",
+	"XDG_DATA_DIRS=",
+	"XDG_CONFIG_DIRS=",
+	"MANPATH=",
+	"INFODIR=",
+	"PAGER=",
+	"ftp_proxy=",
+	"http_proxy=",
+	NULL
+};
+
+
+static void
+usage(void)
+{
+	fprintf(stderr, "usage: %s [-e] command [argument] ...\n", argv0);
+	exit(125);
+}
+
+
+int
+main(int argc, char *argv[])
+{
+	int keep_env = 0;
+	char **new_environ = NULL;
+	size_t i, j, n, len;
+	struct passwd *pw;
+
+	ARGBEGIN {
+	case 'e':
+		keep_env = 1;
+		break;
+	default:
+		usage();
+	} ARGEND;
+
+	if (!argc)
+		usage();
+
+	/* TODO check password */
+
+	if (setgid(0)) {
+		fprintf(stderr, "%s: setgid 0: %s\n", argv0, strerror(errno));
+		return 125;
+	}
+	if (setuid(0)) {
+		fprintf(stderr, "%s: setuid 0: %s\n", argv0, strerror(errno));
+		return 125;
+	}
+
+	if (!keep_env) {
+		new_environ = calloc(sizeof(env_whitelist) / sizeof(*env_whitelist) + 5, sizeof(*env_whitelist));
+		if (!new_environ) {
+			fprintf(stderr, "%s: calloc %zu %zu: %s\n",
+			        argv0, sizeof(env_whitelist) / sizeof(*env_whitelist) + 5, sizeof(*env_whitelist), strerror(errno));
+			return errno == ENOENT ? 127 : 126;
+		}
+		for (i = 0, n = 0; env_whitelist[i]; i++) {
+			len = strlen(env_whitelist[i]);
+			for (j = 0; environ[j]; j++) {
+				if (!strncmp(environ[j], env_whitelist[i], len)) {
+					new_environ[n++] = environ[j];
+					break;
+				}
+			}
+		}
+		errno = 0;
+		pw = getpwuid(0);
+		if (!pw) {
+			if (errno)
+				fprintf(stderr, "%s: getpwuid 0: %s\n", argv0, strerror(errno));
+			else
+				fprintf(stderr, "%s: cannot find root user\n", argv0);
+			exit(125);
+		}
+		if (pw->pw_dir && *pw->pw_dir) {
+			len = strlen(pw->pw_dir);
+			len += sizeof("HOME=");
+			new_environ[n] = malloc(len);
+			if (!new_environ[n])
+				fprintf(stderr, "%s: malloc %zu: %s\n", argv0, len, strerror(errno));
+			stpcpy(stpcpy(new_environ[n++], "HOME="), pw->pw_dir);
+		}
+		if (pw->pw_name && *pw->pw_name) {
+			len = strlen(pw->pw_name);
+			len += sizeof("LOGNAME=");
+			new_environ[n] = malloc(len);
+			if (!new_environ[n])
+				fprintf(stderr, "%s: malloc %zu: %s\n", argv0, len, strerror(errno));
+			stpcpy(stpcpy(new_environ[n++], "LOGNAME="), pw->pw_name);
+
+			len -= sizeof("LOGNAME=");
+			len += sizeof("USER=");
+			new_environ[n] = malloc(len);
+			if (!new_environ[n])
+				fprintf(stderr, "%s: malloc %zu: %s\n", argv0, len, strerror(errno));
+			stpcpy(stpcpy(new_environ[n++], "USER="), pw->pw_name);
+
+			len -= sizeof("USER=");
+			len += sizeof("MAIL=/var/spool/mail/");
+			new_environ[n] = malloc(len);
+			if (!new_environ[n])
+				fprintf(stderr, "%s: malloc %zu: %s\n", argv0, len, strerror(errno));
+			stpcpy(stpcpy(new_environ[n++], "MAIL=/var/spool/mail/"), pw->pw_name);
+		}
+		if (pw->pw_shell && *pw->pw_shell) {
+			len = strlen(pw->pw_dir);
+			len += sizeof("SHELL=");
+			new_environ[n] = malloc(len);
+			if (!new_environ[n])
+				fprintf(stderr, "%s: malloc %zu: %s\n", argv0, len, strerror(errno));
+			stpcpy(stpcpy(new_environ[n++], "SHELL="), pw->pw_dir);
+		}
+		new_environ[n] = NULL;
+	}
+
+	execvpe(argv[0], argv, new_environ ? new_environ : environ);
+	fprintf(stderr, "%s: execvpe %s: %s\n", argv0, argv[0], strerror(errno));
+	return errno == ENOENT ? 127 : 126;
+}