On Fri, Jan 27, 2017 at 10:26 PM, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: > Hello, > > The following program triggers use-after-free in irq_bypass_register_consumer: > https://bit.googleplex.com/raw/5875575541465088/5629499534213120/ > > BUG: KASAN: use-after-free in irq_bypass_register_consumer+0x48c/0x4c0 > virt/lib/irqbypass.c:198 at addr ffff88006b74b438 > Read of size 8 by task a.out/24723 > CPU: 1 PID: 24723 Comm: a.out Not tainted 4.10.0-rc5+ #201 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:15 [inline] > dump_stack+0x2ee/0x3ef lib/dump_stack.c:51 > kasan_object_err+0x1c/0x70 mm/kasan/report.c:165 > print_address_description mm/kasan/report.c:203 [inline] > kasan_report_error+0x17b/0x430 mm/kasan/report.c:287 > kasan_report mm/kasan/report.c:307 [inline] > __asan_report_load8_noabort+0x3e/0x40 mm/kasan/report.c:328 > irq_bypass_register_consumer+0x48c/0x4c0 virt/lib/irqbypass.c:198 > kvm_irqfd_assign arch/x86/kvm/../../../virt/kvm/eventfd.c:417 [inline] > kvm_irqfd+0x130e/0x1e30 arch/x86/kvm/../../../virt/kvm/eventfd.c:578 > kvm_vm_ioctl+0x107a/0x1d10 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3007 > vfs_ioctl fs/ioctl.c:43 [inline] > do_vfs_ioctl+0x1bf/0x1790 fs/ioctl.c:683 > SYSC_ioctl fs/ioctl.c:698 [inline] > SyS_ioctl+0x8f/0xc0 fs/ioctl.c:689 > entry_SYSCALL_64_fastpath+0x1f/0xc2 > RIP: 0033:0x4402b9 > RSP: 002b:00007f7f07514d98 EFLAGS: 00000297 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004402b9 > RDX: 0000000020ae3000 RSI: 000000004020ae76 RDI: 0000000000000007 > RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000297 R12: 0000000000000000 > R13: 0000000000000000 R14: 00007f7f075159c0 R15: 00007f7f07515700 > Object at ffff88006b74b2c0, in cache kmalloc-512 size: 512 > Allocated: > PID = 24723 > [<ffffffff812b1506>] save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 > [<ffffffff81a0cdd3>] save_stack+0x43/0xd0 mm/kasan/kasan.c:502 > [<ffffffff81a0d09a>] set_track mm/kasan/kasan.c:514 [inline] > [<ffffffff81a0d09a>] kasan_kmalloc+0xaa/0xd0 mm/kasan/kasan.c:605 > [<ffffffff81a098eb>] kmem_cache_alloc_trace+0x10b/0x670 mm/slab.c:3629 > [<ffffffff8108b95f>] kmalloc include/linux/slab.h:490 [inline] > [<ffffffff8108b95f>] kzalloc include/linux/slab.h:636 [inline] > [<ffffffff8108b95f>] kvm_irqfd_assign > arch/x86/kvm/../../../virt/kvm/eventfd.c:296 [inline] > [<ffffffff8108b95f>] kvm_irqfd+0x16f/0x1e30 > arch/x86/kvm/../../../virt/kvm/eventfd.c:578 > [<ffffffff81081b4a>] kvm_vm_ioctl+0x107a/0x1d10 > arch/x86/kvm/../../../virt/kvm/kvm_main.c:3007 > [<ffffffff81aa41cf>] vfs_ioctl fs/ioctl.c:43 [inline] > [<ffffffff81aa41cf>] do_vfs_ioctl+0x1bf/0x1790 fs/ioctl.c:683 > [<ffffffff81aa582f>] SYSC_ioctl fs/ioctl.c:698 [inline] > [<ffffffff81aa582f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:689 > [<ffffffff841c9c81>] entry_SYSCALL_64_fastpath+0x1f/0xc2 > Freed: > PID = 1556 > [<ffffffff812b1506>] save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 > [<ffffffff81a0cdd3>] save_stack+0x43/0xd0 mm/kasan/kasan.c:502 > [<ffffffff81a0d70f>] set_track mm/kasan/kasan.c:514 [inline] > [<ffffffff81a0d70f>] kasan_slab_free+0x6f/0xb0 mm/kasan/kasan.c:578 > [<ffffffff81a0b5c3>] __cache_free mm/slab.c:3505 [inline] > [<ffffffff81a0b5c3>] kfree+0xd3/0x250 mm/slab.c:3822 > [<ffffffff8108b4f0>] irqfd_shutdown+0x150/0x1c0 > arch/x86/kvm/../../../virt/kvm/eventfd.c:148 > [<ffffffff814b4920>] process_one_work+0xbd0/0x1c10 kernel/workqueue.c:2098 > [<ffffffff814b5b83>] worker_thread+0x223/0x1990 kernel/workqueue.c:2232 > [<ffffffff814ce546>] kthread+0x326/0x3f0 kernel/kthread.c:227 > [<ffffffff841c9ef1>] ret_from_fork+0x31/0x40 arch/x86/entry/entry_64.S:430 > > On commit fd694aaa46c7ed811b72eb47d5eb11ce7ab3f7f1. Still happens on commit 0710f3ff91ecc4a715db6e4d0690472b13c4dac6: BUG: KASAN: use-after-free in irq_bypass_register_consumer+0x4cb/0x4e0 virt/lib/irqbypass.c:198 at addr ffff88006777ddf8 Read of size 8 by task a.out/15766 CPU: 2 PID: 15766 Comm: a.out Not tainted 4.10.0+ #285 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x2fb/0x3fd lib/dump_stack.c:52 kasan_object_err+0x1c/0x70 mm/kasan/report.c:166 print_address_description mm/kasan/report.c:204 [inline] kasan_report_error mm/kasan/report.c:288 [inline] kasan_report.part.2+0x1b0/0x460 mm/kasan/report.c:310 kasan_report mm/kasan/report.c:331 [inline] __asan_report_load8_noabort+0x29/0x30 mm/kasan/report.c:331 irq_bypass_register_consumer+0x4cb/0x4e0 virt/lib/irqbypass.c:198 kvm_irqfd_assign arch/x86/kvm/../../../virt/kvm/eventfd.c:417 [inline] kvm_irqfd+0x137d/0x1e20 arch/x86/kvm/../../../virt/kvm/eventfd.c:578 kvm_vm_ioctl+0x108c/0x1d70 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3011 vfs_ioctl fs/ioctl.c:45 [inline] do_vfs_ioctl+0x1bf/0x1790 fs/ioctl.c:685 SYSC_ioctl fs/ioctl.c:700 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:691 entry_SYSCALL_64_fastpath+0x1f/0xc2 RIP: 0033:0x4402b9 RSP: 002b:00007fb73c4f9d98 EFLAGS: 00000297 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004402b9 RDX: 0000000020ae3000 RSI: 000000004020ae76 RDI: 0000000000000008 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000297 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fb73c4fa9c0 R15: 00007fb73c4fa700 Object at ffff88006777dc80, in cache kmalloc-512 size: 512 Allocated: PID = 15766 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x43/0xd0 mm/kasan/kasan.c:513 set_track mm/kasan/kasan.c:525 [inline] kasan_kmalloc+0xaa/0xd0 mm/kasan/kasan.c:616 kmem_cache_alloc_trace+0x10b/0x6e0 mm/slab.c:3638 kmalloc include/linux/slab.h:490 [inline] kzalloc include/linux/slab.h:663 [inline] kvm_irqfd_assign arch/x86/kvm/../../../virt/kvm/eventfd.c:296 [inline] kvm_irqfd+0x16f/0x1e20 arch/x86/kvm/../../../virt/kvm/eventfd.c:578 kvm_vm_ioctl+0x108c/0x1d70 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3011 vfs_ioctl fs/ioctl.c:45 [inline] do_vfs_ioctl+0x1bf/0x1790 fs/ioctl.c:685 SYSC_ioctl fs/ioctl.c:700 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:691 entry_SYSCALL_64_fastpath+0x1f/0xc2 Freed: PID = 670 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x43/0xd0 mm/kasan/kasan.c:513 set_track mm/kasan/kasan.c:525 [inline] kasan_slab_free+0x6f/0xb0 mm/kasan/kasan.c:589 __cache_free mm/slab.c:3514 [inline] kfree+0xd3/0x250 mm/slab.c:3831 irqfd_shutdown+0x150/0x1c0 arch/x86/kvm/../../../virt/kvm/eventfd.c:148 process_one_work+0xc06/0x1c40 kernel/workqueue.c:2096 worker_thread+0x223/0x19f0 kernel/workqueue.c:2230 kthread+0x334/0x400 kernel/kthread.c:229 ret_from_fork+0x31/0x40 arch/x86/entry/entry_64.S:430 Memory state around the buggy address: ffff88006777dc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88006777dd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88006777dd80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88006777de00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88006777de80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== Here is correct link for reproducer program: https://gist.githubusercontent.com/dvyukov/34114444518fa22baff19ae204cc46a6/raw/7826cbcd1cbc472dfa4972fe56371df3c94b70c7/gistfile1.txt
