rev/picker_2

This commit is contained in:
Oystein Kristoffer Tveit 2024-09-03 18:10:15 +02:00
parent 65205ac97c
commit 06a9be639c
Signed by: oysteikt
GPG Key ID: 9F2F7D8250F35146
3 changed files with 184 additions and 0 deletions

5
rev/picker_2/flag.txt Normal file
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# 0x70 0x69 0x63 0x6f 0x43 0x54 0x46 0x7b 0x66 0x31 0x6c 0x37 0x33 0x72 0x35 0x5f 0x66 0x34 0x31 0x6c 0x5f 0x63 0x30 0x64 0x33 0x5f 0x72 0x33 0x66 0x34 0x63 0x37 0x30 0x72 0x5f 0x6d 0x31 0x67 0x68 0x37 0x5f 0x35 0x75 0x63 0x63 0x33 0x33 0x64 0x5f 0x30 0x62 0x35 0x66 0x31 0x31 0x33 0x31 0x7d
#
# (hex to ascii)
picoCTF{f1l73r5_f41l_c0d3_r3f4c70r_m1gh7_5ucc33d_0b5f1131}

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rev/picker_2/output.txt Normal file
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$ nc saturn.picoctf.net 51639
==> globals()['wi' + 'n']
0x70 0x69 0x63 0x6f 0x43 0x54 0x46 0x7b 0x66 0x31 0x6c 0x37 0x33 0x72 0x35 0x5f 0x66 0x34 0x31 0x6c 0x5f 0x63 0x30 0x64 0x33 0x5f 0x72 0x33 0x66 0x34 0x63 0x37 0x30 0x72 0x5f 0x6d 0x31 0x67 0x68 0x37 0x5f 0x35 0x75 0x63 0x63 0x33 0x33 0x64 0x5f 0x30 0x62 0x35 0x66 0x31 0x31 0x33 0x31 0x7d

176
rev/picker_2/picker-II.py Normal file
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import sys
def getRandomNumber():
print(4) # Chosen by fair die roll.
# Guaranteed to be random.
# (See XKCD)
def exit():
sys.exit(0)
def esoteric1():
esoteric = \
'''
int query_apm_bios(void)
{
struct biosregs ireg, oreg;
/* APM BIOS installation check */
initregs(&ireg);
ireg.ah = 0x53;
intcall(0x15, &ireg, &oreg);
if (oreg.flags & X86_EFLAGS_CF)
return -1; /* No APM BIOS */
if (oreg.bx != 0x504d) /* "PM" signature */
return -1;
if (!(oreg.cx & 0x02)) /* 32 bits supported? */
return -1;
/* Disconnect first, just in case */
ireg.al = 0x04;
intcall(0x15, &ireg, NULL);
/* 32-bit connect */
ireg.al = 0x03;
intcall(0x15, &ireg, &oreg);
boot_params.apm_bios_info.cseg = oreg.ax;
boot_params.apm_bios_info.offset = oreg.ebx;
boot_params.apm_bios_info.cseg_16 = oreg.cx;
boot_params.apm_bios_info.dseg = oreg.dx;
boot_params.apm_bios_info.cseg_len = oreg.si;
boot_params.apm_bios_info.cseg_16_len = oreg.hsi;
boot_params.apm_bios_info.dseg_len = oreg.di;
if (oreg.flags & X86_EFLAGS_CF)
return -1;
/* Redo the installation check as the 32-bit connect;
some BIOSes return different flags this way... */
ireg.al = 0x00;
intcall(0x15, &ireg, &oreg);
if ((oreg.eflags & X86_EFLAGS_CF) || oreg.bx != 0x504d) {
/* Failure with 32-bit connect, try to disconnect and ignore */
ireg.al = 0x04;
intcall(0x15, &ireg, NULL);
return -1;
}
boot_params.apm_bios_info.version = oreg.ax;
boot_params.apm_bios_info.flags = oreg.cx;
return 0;
}
'''
print(esoteric)
def win():
# This line will not work locally unless you create your own 'flag.txt' in
# the same directory as this script
flag = open('flag.txt', 'r').read()
#flag = flag[:-1]
flag = flag.strip()
str_flag = ''
for c in flag:
str_flag += str(hex(ord(c))) + ' '
print(str_flag)
def esoteric2():
esoteric = \
'''
#include "boot.h"
#define MAX_8042_LOOPS 100000
#define MAX_8042_FF 32
static int empty_8042(void)
{
u8 status;
int loops = MAX_8042_LOOPS;
int ffs = MAX_8042_FF;
while (loops--) {
io_delay();
status = inb(0x64);
if (status == 0xff) {
/* FF is a plausible, but very unlikely status */
if (!--ffs)
return -1; /* Assume no KBC present */
}
if (status & 1) {
/* Read and discard input data */
io_delay();
(void)inb(0x60);
} else if (!(status & 2)) {
/* Buffers empty, finished! */
return 0;
}
}
return -1;
}
/* Returns nonzero if the A20 line is enabled. The memory address
used as a test is the int $0x80 vector, which should be safe. */
#define A20_TEST_ADDR (4*0x80)
#define A20_TEST_SHORT 32
#define A20_TEST_LONG 2097152 /* 2^21 */
static int a20_test(int loops)
{
int ok = 0;
int saved, ctr;
set_fs(0x0000);
set_gs(0xffff);
saved = ctr = rdfs32(A20_TEST_ADDR);
while (loops--) {
wrfs32(++ctr, A20_TEST_ADDR);
io_delay(); /* Serialize and make delay constant */
ok = rdgs32(A20_TEST_ADDR+0x10) ^ ctr;
if (ok)
break;
}
wrfs32(saved, A20_TEST_ADDR);
return ok;
}
/* Quick test to see if A20 is already enabled */
static int a20_test_short(void)
{
return a20_test(A20_TEST_SHORT);
}
'''
print(esoteric)
def filter(user_input):
if 'win' in user_input:
return False
return True
while(True):
try:
user_input = input('==> ')
if( filter(user_input) ):
eval(user_input + '()')
else:
print('Illegal input')
except Exception as e:
print(e)
break