SET 017 0x13

eZine lover (@eZine)

Published in 

Saqueadores Edicion Tecnica

 · 5 years ago

  

-[ 0x13 ]-------------------------------------------------------------------- 
-[ SET-EXT ]----------------------------------------------------------------- 
-[ by SET Staff ]-----------------------------------------------------SET-17- 

Hasta el momento os hemos venido ofrecion una version modificada del programa 
de extraccion de ficheros desarrollado originariamente por Route, y como no, 
publicado en la Phrack. 

En este numero vamos a dar un peque~o giro, publicando la version original 
del programa en C. En la Phrack 53 podeis conseguir versiones en PERL, Awk, 
Shell script e incluso Python. 

Se que muchos os estareis preguntando porque si llevamos dando tanto tiempo 
la version modificada ahora os damos el original. La respuesta, en SET 18 ;> 

 
<++> utils/extract2.c 
/*  extract.c by Phrack Staff and sirsyko  
 * 
 *  (c) Phrack Magazine, 1997  
 *      1.8.98 rewritten by route: 
 *          - aesthetics 
 *          - now accepts file globs 
 *      todo: 
 *          - more info in tag header (file mode, checksum) 
 *  Extracts textfiles from a specially tagged flatfile into a hierarchical  
 *  directory strcuture.  Use to extract source code from any of the articles  
 *  in Phrack Magazine (first appeared in Phrack 50). 
 * 
 *  gcc -o extract extract.c 
 *   
 *  ./extract file1 file2 file3 ... 
 */ 

  
#include <stdio.h> 
#include <stdlib.h> 
#include <sys/stat.h> 
#include <string.h> 
#include <dirent.h> 

#define BEGIN_TAG   "<++> " 
#define END_TAG     "<-->" 
#define BT_SIZE     strlen(BEGIN_TAG) 
#define ET_SIZE     strlen(END_TAG) 

struct f_name 
{ 
    u_char name[256]; 
    struct f_name *next; 
}; 

int 
main(int argc, char **argv) 
{  
    u_char b[256], *bp, *fn; 
    int i, j = 0; 
    FILE *in_p, *out_p = NULL;  
    struct f_name *fn_p = NULL, *head = NULL;  

    if (argc < 2) 
    { 
        printf("Usage: %s file1 file2 ... filen\n", argv[0]); 
        exit(0);  
    } 

    /* 
     *  Fill the f_name list with all the files on the commandline (ignoring 
     *  argv[0] which is this executable).  This includes globs. 
     */ 
    for (i = 1; (fn = argv[i++]); ) 
    { 
        if (!head) 
        { 
            if (!(head = (struct f_name *)malloc(sizeof(struct f_name)))) 
            { 
                perror("malloc"); 
                exit(1); 
            } 
            strncpy(head->name, fn, sizeof(head->name)); 
            head->next = NULL; 
            fn_p = head; 
        } 
        else 
        { 
            if (!(fn_p->next = (struct f_name *)malloc(sizeof(struct f_name)))) 
            { 
                perror("malloc"); 
                exit(1); 
            } 
            fn_p = fn_p->next; 
            strncpy(fn_p->name, fn, sizeof(fn_p->name)); 
            fn_p->next = NULL; 
        } 
    } 
    /* 
     *  Sentry node. 
     */ 
    if (!(fn_p->next = (struct f_name *)malloc(sizeof(struct f_name)))) 
    { 
        perror("malloc"); 
        exit(1); 
     } 
    fn_p = fn_p->next; 
    fn_p->next = NULL; 

    /* 
     *  Check each file in the f_name list for extraction tags. 
     */ 
    for (fn_p = head; fn_p->next; fn_p = fn_p->next) 
    { 
        if (!(in_p = fopen(fn_p->name, "r"))) 
        { 
            fprintf(stderr, "Could not open input file %s.\n", fn_p->name); 
	    continue; 
        } 
        else fprintf(stderr, "Opened %s\n", fn_p->name); 
        while (fgets(b, 256, in_p)) 
        {  
            if (!strncmp (b, BEGIN_TAG, BT_SIZE)) 
            {  
	        b[strlen(b) - 1] = 0;           /* Now we have a string. */ 
                j++; 

                if ((bp = strchr(b + BT_SIZE + 1, '/'))) 
                { 
                    while (bp) 
                    { 
		        *bp = 0; 
		        mkdir(b + BT_SIZE, 0700);  
		        *bp = '/'; 
		        bp = strchr(bp + 1, '/');  
		    } 
                } 
                if ((out_p = fopen(b + BT_SIZE, "w"))) 
                { 
                    printf("- Extracting %s\n", b + BT_SIZE); 
                } 
                else 
                { 
		    printf("Could not extract '%s'.\n", b + BT_SIZE); 
		    continue; 
	        } 
	    }  
            else if (!strncmp (b, END_TAG, ET_SIZE)) 
            { 
	        if (out_p) fclose(out_p); 
	        else 
                { 
	            fprintf(stderr, "Error closing file %s.\n", fn_p->name); 
		    continue; 
	        } 
            }  
            else if (out_p) 
            { 
                fputs(b, out_p); 
            } 
        } 
    } 
    if (!j) printf("No extraction tags found in list.\n"); 
    else printf("Extracted %d file(s).\n", j); 
    return (0); 
} 

/* EOF */ 
<-->