rev/picker_1

rev/picker_1/flag.txt

@@ -0,0 +1,5 @@
+# 0x70 0x69 0x63 0x6f 0x43 0x54 0x46 0x7b 0x34 0x5f 0x64 0x31 0x34 0x6d 0x30 0x6e 0x64 0x5f 0x31 0x6e 0x5f 0x37 0x68 0x33 0x5f 0x72 0x30 0x75 0x67 0x68 0x5f 0x36 0x65 0x30 0x34 0x34 0x34 0x30 0x64 0x7d
+# 
+# (hex to ascii)
+
+picoCTF{4_d14m0nd_1n_7h3_r0ugh_6e04440d}

rev/picker_1/output.txt

@@ -0,0 +1,6 @@
+$ nc saturn.picoctf.net 63851
+Try entering "getRandomNumber" without the double quotes...
+==> win
+0x70 0x69 0x63 0x6f 0x43 0x54 0x46 0x7b 0x34 0x5f 0x64 0x31 0x34 0x6d 0x30 0x6e 0x64 0x5f 0x31 0x6e 0x5f 0x37 0x68 0x33 0x5f 0x72 0x30 0x75 0x67 0x68 0x5f 0x36 0x65 0x30 0x34 0x34 0x34 0x30 0x64 0x7d
+Try entering "getRandomNumber" without the double quotes...
+

rev/picker_1/picker-I.py

@@ -0,0 +1,168 @@
+
+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)
+
+
+while(True):
+  try:
+    print('Try entering "getRandomNumber" without the double quotes...')
+    user_input = input('==> ')
+    eval(user_input + '()')
+  except Exception as e:
+    print(e)
+    break