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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <signal.h>
int32_t clz(uint32_t i)
{
int32_t ret = 0;
uint32_t temp = ~i;
while (temp & 0x80000000)
{
temp <<= 1;
ret++;
}
return ret;
}
int32_t sub_11DC(int32_t i, int32_t len)
{
char v2; // r2
uint32_t v3; // r1
uint32_t v4; // r3
uint32_t v5; // r2
int32_t v6; // zf
if (len != 1)
{
if (len)
{
if (i <= len)
{
i = i == len;
}
else if ((len & (len - 1)) != 0)
{
v2 = clz((uint32_t)len) - clz((uint32_t)i);
v3 = len << v2;
v4 = 1 << v2;
v5 = 0;
while (1)
{
if (i >= v3)
{
i -= v3;
v5 |= v4;
}
if (i >= v3 >> 1)
{
i -= v3 >> 1;
v5 |= v4 >> 1;
}
if (i >= v3 >> 2)
{
i -= v3 >> 2;
v5 |= v4 >> 2;
}
if (i >= v3 >> 3)
{
i -= v3 >> 3;
v5 |= v4 >> 3;
}
v6 = i == 0;
if (i)
{
v4 >>= 4;
v6 = v4 == 0;
}
if (v6)
break;
v3 >>= 4;
}
i = v5;
}
else
{
i >>= 31 - clz((uint32_t)len);
}
}
else
{
i = raise(8);
}
}
return i;
}
int32_t sub_126C(int32_t i, int32_t len)
{
int32_t r1 = i, r2 = len;
int32_t r0 = sub_11DC(i, len);
int32_t r3 = r2 * r0;
r1 = r1 - r3;
return r1;
}
void subFFC(char *str1, char *str2, int32_t len)
{
char v12[256];
memset(v12, 0, 0x100);
int32_t i;
int32_t v7, v8;
for (i = 0; i != 256; ++i)
{
str1[i] = i;
v7 = sub_126C(i, len);
v12[i] = str2[v7];
}
v8 = 0;
int32_t v9 = 0;
int32_t v10;
while (v8 != 256)
{
v10 = (unsigned char)str1[v8];
v9 = (v9 + v10 + (unsigned char)v12[v8]) % 256;
str1[v8++] = str1[v9];
str1[v9] = v10;
}
}
void sub1088(char *str1, char *str2, int32_t len)
{
int32_t v3, v4, v5;
v3 = 0, v4 = 0;
while (len)
{
--len;
v4 = (v4 + 1) % 256;
v5 = (unsigned char)str1[v4];
v3 = (v3 + v5) % 256;
str1[v4] = str1[v3];
str1[v3] = v5;
*str2++ ^= str1[(unsigned char)(v5 + str1[v4])];
}
}
void sub_10D4(char *str1, int32_t len1, char *str2, int32_t len2)
{
int32_t i; // r4
char *v5; // r6
char v6; // r5
char v7; // lr
char v8; // r12
int32_t j; // lr
int32_t k; // r6
for (i = 0; i < len1; i += 3)
{
v5 = &str1[i];
v6 = str1[i + 2];
v7 = str1[i + 1];
v8 = str1[i] ^ v6;
str1[i] = v8;
v5[2] = v6 ^ v7;
v5[1] = v7 ^ v8;
}
for (j = 0; j < len1; j += len2)
{
for (k = 0; (len2 & ~(len2 >> 31)) != k && j + k < len1; ++k)
str1[k] ^= str2[k];
str1 += len2;
}
}
void checkFlag(char *flag)
{
char str_12345678[256];
char empty_str[256];
memset(empty_str, 0, 0x100);
// qmemcpy(str_12345678, "12345678", sizeof(str_12345678));
memcpy(str_12345678, "12345678", sizeof(str_12345678));
int32_t len256 = strlen(str_12345678);
subFFC(empty_str, str_12345678, len256);
sub1088(empty_str, flag, 39);
sub_10D4(flag, 39, str_12345678, len256);
}
char tocmp[] = {0xA3, 0x1A, 0xE3, 0x69, 0x2F, 0xBB, 0x1A, 0x84, 0x65, 0xC2, 0xAD, 0xAD, 0x9E, 0x96, 0x5, 0x2, 0x1F, 0x8E, 0x36, 0x4F, 0xE1, 0xEB, 0xAF, 0xF0, 0xEA, 0xC4, 0xA8, 0x2D, 0x42, 0xC7, 0x6E, 0x3F, 0xB0, 0xD3, 0xCC, 0x78, 0xF9, 0x98, 0x3F, 0x00};
int main()
{
// char flag[40] = "CISCN{AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA}";
char flag[40] = "CISCN{B6AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\0";
char flag_cpy[40];
int32_t i = 0;
char j;
int32_t k;
int a, b, c;
while (1)
{
printf("[+] %d\n", i);
for (a = 0x2d; a < 0x7E; ++a)
{
for (b = 0x2d; b < 0x7E; ++b)
{
for (c = 0x2d; c < 0x7E; ++c)
{
for (k = 0; k < 40; ++k)
{
printf("%x ", (unsigned char)flag_cpy[k]);
}
strcpy(flag_cpy, flag);
flag_cpy[i] = a;
flag_cpy[i + 1] = b;
flag_cpy[i + 2] = c;
checkFlag(flag_cpy);
if (flag_cpy[i] == tocmp[i] && flag_cpy[i + 1] == tocmp[i + 1] && flag_cpy[i + 2] == tocmp[i + 2])
{
for (k = 0; k < 40; ++k)
{
printf("%x ", (unsigned char)flag_cpy[k]);
}
putchar('\n');
printf("flag[%d]=%c\n", i, a);
printf("flag[%d]=%c\n", i + 1, b);
printf("flag[%d]=%c\n", i + 2, c);
flag[i] = a;
flag[i + 1] = b;
flag[i + 2] = c;
printf("%s\n", flag);
// exit(0);
goto label;
}
}
}
}
label:
i += 3;
}
return 0;
}
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