Without actual debugging, it appears that kvm_vcpu_ioctl_x86_set_vcpu_events does not check the events data-structure before copying it to vcpu->arch.exception and vcpu->arch.interrupt. It therefore does not check that the exception number is correct (x<31 && x!=2) among other missing checks. Regards, Nadav Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > > > On 15/01/2016 18:11, Dmitry Vyukov wrote: >> 2016-01-08 16:42 GMT+01:00 Dmitry Vyukov <dvyukov@xxxxxxxxxx>: >>> Hello, >>> The following program triggers WARNING in exception_type: >>> >>> // autogenerated by syzkaller (http://github.com/google/syzkaller) >>> #include <unistd.h> >>> #include <sys/syscall.h> >>> #include <string.h> >>> #include <stdint.h> >>> >>> long r[31]; >>> >>> int main() >>> { >>> memset(r, -1, sizeof(r)); >>> r[0] = syscall(SYS_mmap, 0x20000000ul, 0x20000ul, 0x3ul, >>> 0x32ul, 0xfffffffffffffffful, 0x0ul); >>> memcpy((void*)0x20004000, "\x2f\x64\x65\x76\x2f\x6b\x76\x6d", 8); >>> r[2] = syscall(SYS_open, 0x20004000ul, 0x0ul, 0x0ul, 0, 0, 0); >>> r[3] = syscall(SYS_ioctl, r[2], 0xae01ul, 0x0ul, 0, 0, 0); >>> *(uint32_t*)0x2000fff8 = (uint32_t)0x8; >>> *(uint32_t*)0x2000fffc = (uint32_t)0xae84; >>> r[6] = syscall(SYS_ioctl, r[3], 0x4008ae61ul, 0x2000fff8ul, 0, 0, 0); >>> r[7] = syscall(SYS_ioctl, r[3], 0xae41ul, 0x0ul, 0, 0, 0); >>> *(uint8_t*)0x20011e0f = (uint8_t)0x9; >>> *(uint8_t*)0x20011e10 = (uint8_t)0x9d4; >>> *(uint8_t*)0x20011e11 = (uint8_t)0x9; >>> *(uint8_t*)0x20011e12 = (uint8_t)0x8; >>> *(uint32_t*)0x20011e13 = (uint32_t)0x1; >>> *(uint8_t*)0x20011e17 = (uint8_t)0x5; >>> *(uint8_t*)0x20011e18 = (uint8_t)0x482; >>> *(uint8_t*)0x20011e19 = (uint8_t)0x0; >>> *(uint8_t*)0x20011e1a = (uint8_t)0x5; >>> *(uint8_t*)0x20011e1b = (uint8_t)0x6; >>> *(uint8_t*)0x20011e1c = (uint8_t)0x1; >>> *(uint8_t*)0x20011e1d = (uint8_t)0xf382; >>> *(uint8_t*)0x20011e1e = (uint8_t)0x1b5; >>> *(uint32_t*)0x20011e1f = (uint32_t)0x9; >>> *(uint32_t*)0x20011e23 = (uint32_t)0x3; >>> *(uint8_t*)0x20011e27 = (uint8_t)0x1; >>> *(uint8_t*)0x20011e28 = (uint8_t)0x5; >>> *(uint8_t*)0x20011e29 = (uint8_t)0x6; >>> *(uint8_t*)0x20011e2a = (uint8_t)0x0; >>> r[27] = syscall(SYS_ioctl, r[7], 0x4040aea0ul, 0x20011e0ful, 0, 0, 0); >>> memcpy((void*)0x20012f83, >>> "\x29\xac\x42\x56\xbf\x67\x61\x4f\x07\xb8\xde\x10\x83\x05\x7b\x55\x68\x42\xcb\x36\x97\x84\xff\x6a\x69\x10\x05\x63\xb0\x27\xa5\xbf\xe8\x7b\xe2\xe8\x73\x5d\x7a\x1f\x9f\x48\x9a\xc6\xdf\x4e\x6f\xdd\xb2\xbe\x06\x5c\x2c\x3f\xa7\xf7\x6c\xb7\x02\x9e\x7c\x27\x47\x53\xc0\x4f\xe3\xcd\x7e\xe0\xcb\xe2\x57\xbb\x54\x99\xb0\xac\x01\x6a\x99\xd5\x3d\x95\x3f\x78\x07\xa8\xf2\xf1\x57\x1e\x02\x85\x52\xbb\x53\x8e\x63\x45\x86\x23\xf5\xcb\x04\x40\x5b\xe8\x4b\x22\x1e\xbe\xff\x01\xe6\x1c\x95\x15\xb5\x4a\x37\xa7\x4c\xf4\x3e", >>> 125); >>> r[29] = syscall(SYS_ioctl, r[7], 0x4138ae84ul, 0x20012f83ul, 0, 0, 0); >>> r[30] = syscall(SYS_ioctl, r[7], 0xae80ul, 0, 0, 0, 0); >>> return 0; >>> } >>> >>> >>> ------------[ cut here ]------------ >>> WARNING: CPU: 1 PID: 10173 at arch/x86/kvm/x86.c:345 exception_type+0x73/0x80() >>> Modules linked in: >>> CPU: 1 PID: 10173 Comm: a.out Tainted: G W 4.4.0-rc8+ #211 >>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 >>> 00000000ffffffff ffff880035347a08 ffffffff82907ccd 0000000000000000 >>> ffff880033f82f00 ffffffff85ed4540 ffff880035347a48 ffffffff8133f979 >>> ffffffff81036893 ffffffff85ed4540 0000000000000159 ffff880034138030 >>> Call Trace: >>> [< inline >] __dump_stack lib/dump_stack.c:15 >>> [<ffffffff82907ccd>] dump_stack+0x6f/0xa2 lib/dump_stack.c:50 >>> [<ffffffff8133f979>] warn_slowpath_common+0xd9/0x140 kernel/panic.c:460 >>> [<ffffffff8133fba9>] warn_slowpath_null+0x29/0x30 kernel/panic.c:493 >>> [<ffffffff81036893>] exception_type+0x73/0x80 arch/x86/kvm/x86.c:345 >>> [< inline >] inject_pending_event arch/x86/kvm/x86.c:5990 >>> [< inline >] vcpu_enter_guest arch/x86/kvm/x86.c:6471 >>> [< inline >] vcpu_run arch/x86/kvm/x86.c:6660 >>> [<ffffffff8106b1c4>] kvm_arch_vcpu_ioctl_run+0x3554/0x5800 >>> arch/x86/kvm/x86.c:6818 >>> [<ffffffff8101cf61>] kvm_vcpu_ioctl+0x5f1/0xd00 >>> arch/x86/kvm/../../../virt/kvm/kvm_main.c:2375 >>> [< inline >] vfs_ioctl fs/ioctl.c:43 >>> [<ffffffff817b66f1>] do_vfs_ioctl+0x681/0xe40 fs/ioctl.c:607 >>> [< inline >] SYSC_ioctl fs/ioctl.c:622 >>> [<ffffffff817b6f3f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:613 >>> [<ffffffff85e77af6>] entry_SYSCALL_64_fastpath+0x16/0x7a >>> arch/x86/entry/entry_64.S:185 >>> ---[ end trace 6d1cb7e02f8364e9 ]--- >>> >>> >>> On commit b06f3a168cdcd80026276898fd1fee443ef25743 (Jan 6). >> >> + more kvm people > > No need for. It's just that I'm busy and, while I appreciate your > reports, they take a considerable time to process. > > Paolo > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
