[Ph4nt0m] 一道漏洞发掘的作业题 大家帮忙看 看

Sun, 28 Sep 2008 23:38:59 -0700 

以下是源代码，至少有一个security问题 可以导致溢出 得到rootshell
平台式Linux 标准C函数库

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

int main(int argc, char **argv)
{
    int max;
    char *composites;
    int curprime = 0, curcomp = 0;

    if (argc < 2) {
        fprintf(stderr, "Usage: %s max\nOutputs the primes from 2 to max\n",
            argv[0]);
        return 1;
    }

    max = atoi(argv[1]);
    printf("%ld\n",max);
    if (max == 0 && strcmp(argv[1], "0")) {
        /* argv[1] wasn't a number */
        fprintf(stderr, "Supplied argument not a number: ");
        fprintf(stderr, argv[1]);
        fprintf(stderr, "\n");
        return 1;
    }
    if (max < 2 || max > 1000000) {
        fprintf(stderr, "Supplied argument out of range.\n");
        return 1;
    }
    composites = calloc(1,max+1);
    /* 0 and 1 are not prime */
    composites[0] = composites[1] = 1;

    while(1) {
        /* Find the smallest number not yet marked as composite */
        do {
            ++curprime;
        } while (curprime <= max && composites[curprime]);

        if (curprime > max) {
            /* We're done */
            return 0;
        }

        printf("%d\n", curprime);
        /* Mark all multiples of curprime as composite */
        curcomp = 2*curprime;
        while (curcomp <= max) {
            composites[curcomp] = 1;
            curcomp += curprime;
        }
    }
}

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