77 lines
1.8 KiB
C
77 lines
1.8 KiB
C
#define MAX_SIZE 32
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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unsigned int a = 1103515245;
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unsigned int c = 12345;
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unsigned int m = 2147483647;
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unsigned int seed = 1337;
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unsigned char user_input[MAX_SIZE];
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const unsigned int STATE[4] = {0x1e48add6, 0xaaa7550c, 0x18df53bf, 0xe6af1116};
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unsigned int start[] = {0x0, 0x0, 0x0, 0x0};
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unsigned int gen_random(void) {
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seed = (unsigned int)(((unsigned int)a * (unsigned int)seed + (unsigned int)c) % m);
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return (unsigned int)seed;
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}
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void setup() {
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printf("==================================================");
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printf("= SECURE LOCK - v0.5 =");
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printf("==================================================");
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}
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int check_pass(unsigned int start[]) {
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printf("checking\n");
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unsigned int temp = 0;
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for (int i = 0; i < 4; ++i) {
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temp = start[i];
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temp *= (unsigned int)0xcafebeef;
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temp += (unsigned int)gen_random();
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temp *= (unsigned int)0xfacefeed;
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temp ^= (unsigned int)gen_random();
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if ((unsigned int)temp != (unsigned int)STATE[i]) {
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return 0;
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}
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}
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return 1;
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}
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void main(){
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memset(user_input,0,MAX_SIZE);
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memset(start, 0, 16);
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read(0, user_input, MAX_SIZE);
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for (int i = 0; i < 4; i++) {
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start[i] |= ((unsigned int)user_input[(i * 4)] << 24);
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start[i] |= ((unsigned int)user_input[(i * 4)+1] << 16);
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start[i] |= ((unsigned int)user_input[(i * 4)+2] << 8);
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start[i] |= ((unsigned int)user_input[(i * 4)+3] << 0);
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printf("%X ",start[i]);
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}
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printf("\n");
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if (check_pass(start) == 1) {
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printf("Thats it!\r\nSubmit in the format FLAG{");
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for (int i = 0; i < 4; i++) {
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printf("%X",start[i]);
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}
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printf("}\n");
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}
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// Failed, just spin
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printf("Incorrect password!");
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}
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