From 68648f8fe23dd30cffec1ec05e3de42e434e1f31 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Karel=20Ko=C4=8D=C3=AD?= <cynerd@email.cz>
Date: Sun, 2 Dec 2018 21:09:06 +0100
Subject: Update to working version

Still way off from something usable by someone else but it already works
for me.
---
 main.c | 103 ++++++++++++++++++++++++++++++++++-------------------------------
 1 file changed, 54 insertions(+), 49 deletions(-)

(limited to 'main.c')

diff --git a/main.c b/main.c
index a20f6ff..7957be3 100644
--- a/main.c
+++ b/main.c
@@ -1,58 +1,63 @@
+/* uroot - User's root
+ *   main.c Source file with main function
+ *
+ * Copyright (C) 2018 Karel Kočí
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ 
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
 #define _GNU_SOURCE
 #include <stdio.h>
-#include <stdlib.h>
-#include <stdbool.h>
-#include <unistd.h>
 #include <sys/types.h>
-#include <sched.h>
-#include <errno.h>
-#include <assert.h>
-#include <string.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-#include <sys/mount.h>
 #include <sys/wait.h>
+#include <sched.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include "child.h"
 #include "utils.h"
+#include "sigpipe.h"
+#include "conf.h"
 
-void sigint_handler(int sig) { }
 
 int main(int argc, char **argv) {
-	pid_t ppid = getpid();
-
-	if (!fork()) {
-		system(aprintf("newuidmap %d 0 %d 1 1 65537 65536", ppid, getuid()));
-		system(aprintf("newgidmap %d 0 %d 1 1 65537 65536", ppid, getgid()));
-		kill(ppid, SIGINT);
-		return 0;
-	}
-
-	unshare(CLONE_NEWNS | CLONE_NEWUSER | CLONE_NEWPID);
-
-	signal(SIGINT, sigint_handler);
-	pause();
-	errno = 0; // Just clear error from pause()
-
-	pid_t chpid = fork();
-	if (chpid) {
-		int stat;
-		waitpid(chpid, &stat, 0);
-		return stat;
-	}
-
-	// mount /sys and /proc
-	mount("none", "/", NULL, MS_REC | MS_PRIVATE, NULL);
-	assert_perror(errno);
-	mount("none", "/proc", NULL, MS_REC | MS_PRIVATE, NULL);
-	assert_perror(errno);
-	mount("none", "/sys", NULL, MS_REC | MS_PRIVATE, NULL);
-	assert_perror(errno);
-	mount("proc", "/proc", "proc", MS_NOSUID|MS_NODEV|MS_NOEXEC, NULL);
-	assert_perror(errno);
-
-	// mount proc to root
-	// rbind mount dev and sys to root
-
-	// TODO verify that all upper directories have +rx rights
-	// TODO chroot
-	execv("/bin/sh", NULL);
+	// TODO arguments parsing
+
+	struct child_args chargs = (struct child_args) {
+		.ppid = getpid(),
+		.argc = argc,
+		.argv = argv,
+		.sigpipe = sigpipe_new()
+	};
+
+	uint8_t stack[STACK_SIZE];
+	pid_t chpid = clone(child_main, stack + STACK_SIZE,
+			SIGCHLD | CLONE_NEWNS | CLONE_NEWUSER | CLONE_NEWPID,
+			&chargs);
+
+#define FAIL(MSG) do { fputs(MSG, stderr); kill(chpid, SIGKILL); return 1; } while (false);
+	if (new_map_id("uid", chpid, getuid()))
+		FAIL("Mapping of uid failed!\n");
+	if (new_map_id("gid", chpid, getgid()))
+		FAIL("Mapping of gid failed!\n");
+
+	sigpipe_signal(chargs.sigpipe);
+
+	int stat;
+	waitpid(chpid, &stat, 0);
+	if (WIFEXITED(stat))
+		return WEXITSTATUS(stat);
+	else
+		return WIFSIGNALED(stat) || WCOREDUMP(stat);
 }
-- 
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