比较2个文件中的子字符串

时间:2017-12-30 10:58:17

标签: c hash passwords substring strcmp

我有2个文件:shadow.txt和mytab2411.txt。 " shadow.txt"包含密码哈希,而#34; mytab2411.txt"是一个密码查找文件,包含密码及其相应的哈希值。我想要做的是使用" mytab2411.txt"找到" shadow.txt"的密码通过比较来自" shadow.txt"的哈希值和" mytab2411.txt"。

我有两个问题:

  1. 我不知道如何从mytab2411.txt获取密码文本。

  2. 我得到此输出而不是所需的输出:

  3. 用户ID:pyc 1 -password(未找到)

    用户ID:pyc 2 -password(未找到)

    用户ID:pyc 3 -password(未找到)

    用户ID:pyc 4 -password(未找到)

    用户ID:pyc 5 -password(未找到)

    用户ID:pyc 6 -password(未找到)

    shadow.txt

    pyc1:$1$$Tnq7a6/C1wwyKyt0V/.BP/:17482:0:99999:7:::
    pyc2:$6$$/xMg2/4CZwMUbah4IhNwCjqzZf0/OByfs6UHmq32jFbsdpbDw9bhLttC7n/bAVlM2NwJ7hBQ3d0H47leLXE6g1:17482:0:99999:7:::
    pyc3:$1$$zZQKNjRd94GHyYOwXuStf0:17482:0:99999:7:::
    pyc4:$6$iKYSRG68$STdY8TCgoCaNfSUcyCwSBlVekdjs0P3qXtwxSbgpQpMUnHJRRSHOT5amoR24IqZBTPNWuIfO.uhZEnGLuE4q/.:17482:0:99999:7:::
    pyc5:$6$$FDqvMBbQOCyKP9uBL8E6TAEupCh72v.3/ow4fZ5HpZ/0NS7LBifFS9nJdzc/u2OEhUnRF9yC4Lw23hHjD1EmD.:17482:0:99999:7:::
    pyc6:$6$$LfCuhKecDtIfX77LOTWD1PjhF1IC0hBzjxckEthmoT8mVbxKH3qJzFgEi/P9GN1mptR4WPiwuh69X/41M6pHW1:17482:0:99999:7:::
    

    mytab2411.txt (缩短版本,因为有超过200,000行)

    apple:$1$$Tnq7a6/C1wwyKyt0V/.BP/
    apple:$6$$vTqYXuMRNbK5N1xiTvUKcJuKVmEQyPtgUiyawaEBMwknJ3AQoOvPpr2RrANRxDTS.qo7rQuFvxZcUkT31W6uG/
    banana:$1$$zZQKNjRd94GHyYOwXuStf0
    banana:$6$$5iQBiKBv7vIGqC5iQJOVUpzgnSO0P.pMQ.Guwczcn9nQSu61IVKT9GU4IEYjb5WbsBLaIfZ3io59M4oac.W0/1
    orange:$1$$Ro.kDk5GNLNQbdJyDEovy1
    orange:$6$$/xMg2/4CZwMUbah4IhNwCjqzZf0/OByfs6UHmq32jFbsdpbDw9bhLttC7n/bAVlM2NwJ7hBQ3d0H47leLXE6g1
    

    所需的输出

    user id : pyc1 – password found => apple
    
    user id : pyc2 –  password found => orange
    
    user id : pyc3 – password found => banana
    
    Data Error: Invalid entry found in the shadow file. (skipped)
    
    user id : pyc5 – password (NOT FOUND)
    
    user id : pyc6 – password (NOT FOUND)
    

    主要代码

    #include <stdlib.h>
    #include <stdio.h>
    #include <string.h>
    #include <strings.h>
    int printDataError(){
    
      printf("Data error: Invalid entry found in the shadow file. (Skipped)\n");
    }
    
    int main(void)
    {
        {
    char buf[1024];
    char **arr1 = NULL;
    char **arr2 = NULL;
    int size1 = 0;
    int size2 = 0;
    FILE * f1, *f2;
    f1 = fopen("shadow.txt", "r");
    f2 = fopen("mytab2411.txt", "r");
    
    // Allocate memory for shadow.txt
    while(fgets(buf, 1024, f1))
    {
        size1++;
        arr1 = realloc(arr1, sizeof(char*) * size1);
        arr1[size1 - 1] = strdup(buf);
    }
    
    // Allocate memory for mytab2411.txt
    while(fgets(buf, 1024, f2))
    {
        size2++;
        arr2 = realloc(arr2, sizeof(char*) * size2);
        arr2[size2 - 1] = strdup(buf);
    }
    
    
    char line[1000]; //Allocate max number of characters in a line for shadow.txt
    char line2[1000]; //Allocate max number of characters in a line for mytab2411.txt
    
    char hash[1000]; //Allocate max number of characters in a hash (substring of a line) for shadow.txt
    char hash2[1000]; //Allocate max number of characters in a hash (substring of a line) for shadow.txt
    
    char md5[5]= "$1$$"; // Define string to be searched for md5
    char sha512[5]="$6$$"; //Define string to be searched for sha512
    char *ret; // Used for shadow.txt
    char *ret2; //Used for shadow.txt
    char * ret3; //Used for mytab2411.txt
    char * ret4; //Used for mytab2411.txt
    
    // Read shadow.txt line by line
    for(int i = 0; i < size1; i++) {
    
    memset(hash, '\0', sizeof(hash));
    strcpy(line, arr1[i]);
    
    //Search for md5 in shadow.txt
      md5[4]='\0';
      ret = strstr(line, md5);
    
    //Search for sha512 in shadow.txt
      sha512[4]='\0';
      ret2 = strstr(line, sha512);
    
    // Copies md5 hash to the variable hash if md5 is detected in shadow.txt
    if (ret){
       strncpy(hash, line+5, 26);
       hash[26] = '\0';
       //printf("pyc %d hash: %s\n", i+1,hash);
    
    }
    
    // Copies sha512 hash to the variable hash if sha512 is detected in shadow.txt
    else if (ret2){
    
      strncpy(hash, line+5, 90);
       hash[90] = '\0';
       //printf("pyc %d hash: %s\n", i+1,hash);
    
    
    }
    
    // Read mytab2411.txt line by line
    for(int j = 0; j < size2; j++){
    
    memset(hash2, '\0', sizeof(hash2));
    strcpy(line2, arr2[j]);
    
    //Search for md5 in mytab2411.txt
      md5[4]='\0';
      ret3 = strstr(line2, md5);
    
    //Search for sha512 in mytab2411.txt
      sha512[4]='\0';
      ret4 = strstr(line2, sha512);
    
    // Copies sha512 hash to the variable hash if md5 is detected in mytab2411.txt  
    if (ret3){
    
       strcpy(hash2, &line2[strlen(line2) - 27]);
    
       //printf("Line %d hash: %s\n", j+1,hash2);
    
    }
    
    // Copies sha512 hash to the variable hash if sha512 is detected in mytab2411.txt
    else if (ret4){
    
      strcpy(hash2, &line2[strlen(line2) - 91]);
    
       //printf("Line %d hash: %s\n", j+1,hash2);
    
    }
    
    }//End of "for(int j = 0; j < size2; j++)" loop
    
    // Compares the hash in shadow.txt (hash) and hash in mytab2411.txt (hash2).
    if(strcmp(hash,hash2) == 0)
                    printf("user id: pyc %d - password found =>  \n",i+1); 
    
    else if (strcmp(hash,hash2) != 0)
                    printf("user id: pyc %d -password <NOT FOUND>\n",i+1);
    
    
    else
    printDataError();
    
    }//End of "for (int i = 0; i < size1; i++)" loop
    
    
        return 0;
    } //End of main
    

1 个答案:

答案 0 :(得分:1)

已经的两个文件中的密码都是哈希。你不应该自己计算任何哈希值。相反,您应该将密码读作 text ,并将其简单地比较。