| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <CACT4Y+biOxV9RwryH4w-DGYJUrzVmPfa54ywyqs7t7zq2eOAMw@mail.gmail.com>
Date: Sun, 28 Aug 2016 20:58:45 +0200
From: Dmitry Vyukov <dvyukov@...gle.com>
To: airlied@...ux.ie, dri-devel@...ts.freedesktop.org,
LKML <linux-kernel@...r.kernel.org>
Cc: Alexander Potapenko <glider@...gle.com>,
Kostya Serebryany <kcc@...gle.com>,
syzkaller <syzkaller@...glegroups.com>
Subject: drm: GPF in drm_context_switch_complete
Hello,
The following program triggers GPF in drm_context_switch_complete:
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN
Dumping ftrace buffer:
(ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 1965 Comm: syz-executor Not tainted 4.8.0-rc3+ #33
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
task: ffff88003c87a480 task.stack: ffff88002e540000
RIP: 0010:[<ffffffff83408ca0>]
[< inline >] drm_context_switch_complete
drivers/gpu/drm/drm_context.c:303
[<ffffffff83408ca0>] drm_legacy_newctx+0x190/0x290
drivers/gpu/drm/drm_context.c:467
RSP: 0018:ffff88002e547c50 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffff88006af60000 RCX: ffffc90001780000
RDX: 0000000000000000 RSI: ffff88002e547cf8 RDI: ffff88003d15b640
RBP: ffff88002e547c70 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff880032b6f6c0 R14: 0000000000000000 R15: 0000000000000000
FS: 00007f14ed4f2700(0000) GS:ffff88003ed00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000002000a000 CR3: 0000000038762000 CR4: 00000000000006e0
Stack:
ffff88002e547cf8 ffff88006af60000 ffffffff8739efd8 ffffffff88ae13c0
ffff88002e547dc0 ffffffff83410a5c ffff880000000000 ffffffff8739efdc
ffffffff83408b10 ffff880032b6f6e8 000000002000a000 ffff88002e547cf8
Call Trace:
[<ffffffff83410a5c>] drm_ioctl+0x7bc/0xc60 drivers/gpu/drm/drm_ioctl.c:724
[< inline >] vfs_ioctl fs/ioctl.c:43
[<ffffffff8186f1fc>] do_vfs_ioctl+0x18c/0x1080 fs/ioctl.c:675
[< inline >] SYSC_ioctl fs/ioctl.c:690
[<ffffffff8187017f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:681
[<ffffffff86c25480>] entry_SYSCALL_64_fastpath+0x23/0xc1
arch/x86/entry/entry_64.S:207
Code: 00 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 02 01 00 00 4d 8b a4
24 80 00 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 e2 48 c1 ea 03 <0f>
b6 14 02 4c 89 e0 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85
RIP [< inline >] drm_context_switch_complete
drivers/gpu/drm/drm_context.c:303
RIP [<ffffffff83408ca0>] drm_legacy_newctx+0x190/0x290
drivers/gpu/drm/drm_context.c:467
RSP <ffff88002e547c50>
---[ end trace f61dcca66bdbbe88 ]---
On commit 61c04572de404e52a655a36752e696bbcb483cf5 (Aug 25).
// autogenerated by syzkaller (http://github.com/google/syzkaller)
#ifndef __NR_ioctl
#define __NR_ioctl 16
#endif
#ifndef __NR_syz_fuse_mount
#define __NR_syz_fuse_mount 1000003
#endif
#ifndef __NR_syz_fuseblk_mount
#define __NR_syz_fuseblk_mount 1000004
#endif
#ifndef __NR_syz_open_pts
#define __NR_syz_open_pts 1000002
#endif
#ifndef __NR_mmap
#define __NR_mmap 9
#endif
#ifndef __NR_syz_open_dev
#define __NR_syz_open_dev 1000001
#endif
#include <fcntl.h>
#include <pthread.h>
#include <setjmp.h>
#include <signal.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <unistd.h>
__thread int skip_segv;
__thread jmp_buf segv_env;
static void segv_handler(int sig, siginfo_t* info, void* uctx)
{
if (__atomic_load_n(&skip_segv, __ATOMIC_RELAXED))
_longjmp(segv_env, 1);
exit(sig);
}
static void install_segv_handler()
{
struct sigaction sa;
memset(&sa, 0, sizeof(sa));
sa.sa_sigaction = segv_handler;
sa.sa_flags = SA_NODEFER | SA_SIGINFO;
sigaction(SIGSEGV, &sa, NULL);
sigaction(SIGBUS, &sa, NULL);
}
#define NONFAILING(...) \
{ \
__atomic_fetch_add(&skip_segv, 1, __ATOMIC_SEQ_CST); \
if (_setjmp(segv_env) == 0) { \
__VA_ARGS__; \
} \
__atomic_fetch_sub(&skip_segv, 1, __ATOMIC_SEQ_CST); \
}
static uintptr_t syz_open_dev(uintptr_t a0, uintptr_t a1, uintptr_t a2)
{
if (a0 == 0xc || a0 == 0xb) {
char buf[128];
sprintf(buf, "/dev/%s/%d:%d", a0 == 0xc ? "char" : "block",
(uint8_t)a1, (uint8_t)a2);
return open(buf, O_RDWR, 0);
} else {
char buf[1024];
char* hash;
strncpy(buf, (char*)a0, sizeof(buf));
buf[sizeof(buf) - 1] = 0;
while ((hash = strchr(buf, '#'))) {
*hash = '0' + (char)(a1 % 10);
a1 /= 10;
}
return open(buf, a2, 0);
}
}
static uintptr_t syz_open_pts(uintptr_t a0, uintptr_t a1)
{
int ptyno = 0;
if (ioctl(a0, TIOCGPTN, &ptyno))
return -1;
char buf[128];
sprintf(buf, "/dev/pts/%d", ptyno);
return open(buf, a1, 0);
}
static uintptr_t syz_fuse_mount(uintptr_t a0, uintptr_t a1,
uintptr_t a2, uintptr_t a3,
uintptr_t a4, uintptr_t a5)
{
uint64_t target = a0;
uint64_t mode = a1;
uint64_t uid = a2;
uint64_t gid = a3;
uint64_t maxread = a4;
uint64_t flags = a5;
int fd = open("/dev/fuse", O_RDWR);
if (fd == -1)
return fd;
char buf[1024];
sprintf(buf, "fd=%d,user_id=%ld,group_id=%ld,rootmode=0%o", fd,
(long)uid, (long)gid, (unsigned)mode & ~3u);
if (maxread != 0)
sprintf(buf + strlen(buf), ",max_read=%ld", (long)maxread);
if (mode & 1)
strcat(buf, ",default_permissions");
if (mode & 2)
strcat(buf, ",allow_other");
syscall(SYS_mount, "", target, "fuse", flags, buf);
return fd;
}
static uintptr_t syz_fuseblk_mount(uintptr_t a0, uintptr_t a1,
uintptr_t a2, uintptr_t a3,
uintptr_t a4, uintptr_t a5,
uintptr_t a6, uintptr_t a7)
{
uint64_t target = a0;
uint64_t blkdev = a1;
uint64_t mode = a2;
uint64_t uid = a3;
uint64_t gid = a4;
uint64_t maxread = a5;
uint64_t blksize = a6;
uint64_t flags = a7;
int fd = open("/dev/fuse", O_RDWR);
if (fd == -1)
return fd;
if (syscall(SYS_mknodat, AT_FDCWD, blkdev, S_IFBLK, makedev(7, 199)))
return fd;
char buf[256];
sprintf(buf, "fd=%d,user_id=%ld,group_id=%ld,rootmode=0%o", fd,
(long)uid, (long)gid, (unsigned)mode & ~3u);
if (maxread != 0)
sprintf(buf + strlen(buf), ",max_read=%ld", (long)maxread);
if (blksize != 0)
sprintf(buf + strlen(buf), ",blksize=%ld", (long)blksize);
if (mode & 1)
strcat(buf, ",default_permissions");
if (mode & 2)
strcat(buf, ",allow_other");
syscall(SYS_mount, blkdev, target, "fuseblk", flags, buf);
return fd;
}
static uintptr_t execute_syscall(int nr, uintptr_t a0, uintptr_t a1,
uintptr_t a2, uintptr_t a3,
uintptr_t a4, uintptr_t a5,
uintptr_t a6, uintptr_t a7,
uintptr_t a8)
{
switch (nr) {
default:
return syscall(nr, a0, a1, a2, a3, a4, a5);
case __NR_syz_open_dev:
return syz_open_dev(a0, a1, a2);
case __NR_syz_open_pts:
return syz_open_pts(a0, a1);
case __NR_syz_fuse_mount:
return syz_fuse_mount(a0, a1, a2, a3, a4, a5);
case __NR_syz_fuseblk_mount:
return syz_fuseblk_mount(a0, a1, a2, a3, a4, a5, a6, a7);
}
}
long r[6];
int main()
{
install_segv_handler();
memset(r, -1, sizeof(r));
r[0] = execute_syscall(__NR_mmap, 0x20000000ul, 0xc000ul, 0x3ul,
0x32ul, 0xfffffffffffffffful, 0x0ul, 0, 0, 0);
NONFAILING(memcpy(
(void*)0x20002000,
"\x2f\x64\x65\x76\x2f\x64\x72\x69\x2f\x63\x61\x72\x64\x23\x00",
15));
r[2] = execute_syscall(__NR_syz_open_dev, 0x20002000ul, 0x0ul,
0x100ul, 0, 0, 0, 0, 0, 0);
NONFAILING(*(uint32_t*)0x2000a000 = (uint32_t)0x0);
NONFAILING(*(uint32_t*)0x2000a004 = (uint32_t)0x2);
r[5] = execute_syscall(__NR_ioctl, r[2], 0x40086425ul, 0x2000a000ul,
0, 0, 0, 0, 0, 0);
return 0;
}
Powered by blists - more mailing lists