* tty, fbcon: use-after-free in fbcon_invert_region
@ 2016-09-03 19:20 Dmitry Vyukov
2016-10-07 19:59 ` Dmitry Vyukov
0 siblings, 1 reply; 7+ messages in thread
From: Dmitry Vyukov @ 2016-09-03 19:20 UTC (permalink / raw)
To: Greg Kroah-Hartman, Peter Hurley, Jiri Slaby, LKML, plagnioj,
tomi.valkeinen, jean-philippe.brucker, Scot Doyle, linux-fbdev,
Eric W. Biederman
Cc: syzkaller
Hello,
The following program causes use-after-free in fbcon_invert_region:
https://gist.githubusercontent.com/dvyukov/d657f9a9ca39f34c430dcf63ec1153ac/raw/04e1b94aef0fc9eb770d11373b568980ecaa7f34/gistfile1.txt
=================================
BUG: KASAN: use-after-free in fbcon_invert_region+0x1cc/0x1f0 at addr
ffff88006cc3f51e
Read of size 2 by task a.out/4240
CPU: 0 PID: 4240 Comm: a.out Not tainted 4.8.0-rc3-next-20160825+ #10
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
ffffffff886b6fe0 ffff88003699f790 ffffffff82db3759 ffffffff8a0ae640
fffffbfff10d6dfc ffff88003e800100 ffff88006cc3f500 ffff88006cc3f520
0000000000000000 ffff88006cc3f51e ffff88003699f7b8 ffffffff81809e7c
Call Trace:
[<ffffffff8180a474>] __asan_report_load2_noabort+0x14/0x20
mm/kasan/report.c:325
[<ffffffff82fdbc8c>] fbcon_invert_region+0x1cc/0x1f0
drivers/video/console/fbcon.c:2750
[<ffffffff8327ce72>] invert_screen+0x192/0x630 drivers/tty/vt/vt.c:470
[< inline >] highlight drivers/tty/vt/selection.c:50
[<ffffffff8326037c>] clear_selection+0x4c/0x60 drivers/tty/vt/selection.c:76
[<ffffffff8327374e>] hide_cursor+0x24e/0x2d0 drivers/tty/vt/vt.c:599
[<ffffffff83276207>] redraw_screen+0x2e7/0x840 drivers/tty/vt/vt.c:682
[<ffffffff83278b0c>] vc_do_resize+0xebc/0x1160 drivers/tty/vt/vt.c:952
[<ffffffff83278eba>] vt_resize+0xaa/0xe0 drivers/tty/vt/vt.c:992
[< inline >] tiocswinsz drivers/tty/tty_io.c:2378
[<ffffffff83224e71>] tty_ioctl+0x10c1/0x21e0 drivers/tty/tty_io.c:2892
[< inline >] vfs_ioctl fs/ioctl.c:43
[<ffffffff818a1c6c>] do_vfs_ioctl+0x18c/0x1080 fs/ioctl.c:675
[< inline >] SYSC_ioctl fs/ioctl.c:690
[<ffffffff818a2bef>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:681
[<ffffffff86e10480>] entry_SYSCALL_64_fastpath+0x23/0xc1
arch/x86/entry/entry_64.S:208
Object at ffff88006cc3f500, in cache kmalloc-32 size: 32
Allocated:
PID = 3233
[< inline >] kmalloc ./include/linux/slab.h:490
[< inline >] kzalloc ./include/linux/slab.h:636
[<ffffffff82b85834>] aa_alloc_task_context+0x54/0x90
security/apparmor/context.c:40
[<ffffffff82b99e3d>] apparmor_cred_prepare+0x1d/0xb0 security/apparmor/lsm.c:76
[<ffffffff82acf12d>] security_prepare_creds+0x7d/0xb0 security/security.c:912
[<ffffffff813fb355>] prepare_kernel_cred+0x375/0x650 kernel/cred.c:630
[<ffffffff813cded9>] call_usermodehelper_exec_async+0xb9/0x460
kernel/kmod.c:232
[<ffffffff86e1070a>] ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431
Freed:
PID = 1693
[< inline >] __cache_free mm/slab.c:3520
[<ffffffff81807813>] kfree+0xc3/0x2a0 mm/slab.c:3837
[<ffffffff8175f108>] kzfree+0x28/0x30 mm/slab_common.c:1323
[<ffffffff82b85991>] aa_free_task_context+0x121/0x1d0
security/apparmor/context.c:54
[<ffffffff82b99f79>] apparmor_cred_free+0x39/0x80 security/apparmor/lsm.c:51
[<ffffffff82acf078>] security_cred_free+0x48/0x80 security/security.c:907
[<ffffffff813f8224>] put_cred_rcu+0xe4/0x3e0 kernel/cred.c:116
[< inline >] __rcu_reclaim kernel/rcu/rcu.h:118
[< inline >] rcu_do_batch kernel/rcu/tree.c:2777
[< inline >] invoke_rcu_callbacks kernel/rcu/tree.c:3041
[< inline >] __rcu_process_callbacks kernel/rcu/tree.c:3008
[<ffffffff814e7e3b>] rcu_process_callbacks+0xdbb/0x1560 kernel/rcu/tree.c:3025
[<ffffffff86e1358c>] __do_softirq+0x25c/0xa3e kernel/softirq.c:273
Memory state around the buggy address:
ffff88006cc3f400: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
ffff88006cc3f480: 00 00 fc fc fc fc fc fc fb fb fb fb fc fc fc fc
>ffff88006cc3f500: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
^
ffff88006cc3f580: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
ffff88006cc3f600: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
=================================
I am also hitting similar bugs all over fbcon:
BUG: KASAN: slab-out-of-bounds in fbcon_putcs+0x444/0x4b0 at addr
ffff8800384e58a8
https://gist.githubusercontent.com/dvyukov/645a5f48b735fb384de7ea35fe1748ea/raw/3690a8b2c82a3b8fd7d07f4602a166f5756c3749/gistfile1.txt
BUG: KASAN: slab-out-of-bounds in bit_putcs+0xcd6/0xd70 at addr ffff88006abad8e6
https://gist.githubusercontent.com/dvyukov/2d909f2673eafbc35f7f17f95c395217/raw/83f4eb0193226d51c546015cddee4b6a697015b3/gistfile1.txt
BUG: KASAN: use-after-free in fbcon_putcs+0x444/0x4b0 at addr ffff8800644bd820
https://gist.githubusercontent.com/dvyukov/286cdf2d3f9c6956ec9055dad0cf7a2a/raw/f7e0a380be364afd0c2c4c54ff5661e451fb143d/gistfile1.txt
BUG: KASAN: slab-out-of-bounds in do_update_region+0x642/0x670 at addr
ffff8800661c56ac
https://gist.githubusercontent.com/dvyukov/7fd9d858ea38e8131e21a0377435c32c/raw/5d59989e05b4e39bb5ee90f49658674fa9db89ad/gistfile1.txt
On 0f98f121e1670eaa2a2fbb675e07d6ba7f0e146f of linux-next.
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: tty, fbcon: use-after-free in fbcon_invert_region 2016-09-03 19:20 tty, fbcon: use-after-free in fbcon_invert_region Dmitry Vyukov @ 2016-10-07 19:59 ` Dmitry Vyukov 2016-10-11 1:43 ` Scot Doyle 2016-10-11 22:48 ` Scot Doyle 0 siblings, 2 replies; 7+ messages in thread From: Dmitry Vyukov @ 2016-10-07 19:59 UTC (permalink / raw) To: Greg Kroah-Hartman, Peter Hurley, Jiri Slaby, LKML, plagnioj, tomi.valkeinen, jean-philippe.brucker, Scot Doyle, linux-fbdev, Eric W. Biederman Cc: syzkaller On Sat, Sep 3, 2016 at 9:20 PM, Dmitry Vyukov <dvyukov@google.com> wrote: > Hello, > > The following program causes use-after-free in fbcon_invert_region: > > https://gist.githubusercontent.com/dvyukov/d657f9a9ca39f34c430dcf63ec1153ac/raw/04e1b94aef0fc9eb770d11373b568980ecaa7f34/gistfile1.txt > > ================================= > BUG: KASAN: use-after-free in fbcon_invert_region+0x1cc/0x1f0 at addr > ffff88006cc3f51e > Read of size 2 by task a.out/4240 > CPU: 0 PID: 4240 Comm: a.out Not tainted 4.8.0-rc3-next-20160825+ #10 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > ffffffff886b6fe0 ffff88003699f790 ffffffff82db3759 ffffffff8a0ae640 > fffffbfff10d6dfc ffff88003e800100 ffff88006cc3f500 ffff88006cc3f520 > 0000000000000000 ffff88006cc3f51e ffff88003699f7b8 ffffffff81809e7c > > Call Trace: > [<ffffffff8180a474>] __asan_report_load2_noabort+0x14/0x20 > mm/kasan/report.c:325 > [<ffffffff82fdbc8c>] fbcon_invert_region+0x1cc/0x1f0 > drivers/video/console/fbcon.c:2750 > [<ffffffff8327ce72>] invert_screen+0x192/0x630 drivers/tty/vt/vt.c:470 > [< inline >] highlight drivers/tty/vt/selection.c:50 > [<ffffffff8326037c>] clear_selection+0x4c/0x60 drivers/tty/vt/selection.c:76 > [<ffffffff8327374e>] hide_cursor+0x24e/0x2d0 drivers/tty/vt/vt.c:599 > [<ffffffff83276207>] redraw_screen+0x2e7/0x840 drivers/tty/vt/vt.c:682 > [<ffffffff83278b0c>] vc_do_resize+0xebc/0x1160 drivers/tty/vt/vt.c:952 > [<ffffffff83278eba>] vt_resize+0xaa/0xe0 drivers/tty/vt/vt.c:992 > [< inline >] tiocswinsz drivers/tty/tty_io.c:2378 > [<ffffffff83224e71>] tty_ioctl+0x10c1/0x21e0 drivers/tty/tty_io.c:2892 > [< inline >] vfs_ioctl fs/ioctl.c:43 > [<ffffffff818a1c6c>] do_vfs_ioctl+0x18c/0x1080 fs/ioctl.c:675 > [< inline >] SYSC_ioctl fs/ioctl.c:690 > [<ffffffff818a2bef>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:681 > [<ffffffff86e10480>] entry_SYSCALL_64_fastpath+0x23/0xc1 > arch/x86/entry/entry_64.S:208 > Object at ffff88006cc3f500, in cache kmalloc-32 size: 32 > > Allocated: > PID = 3233 > [< inline >] kmalloc ./include/linux/slab.h:490 > [< inline >] kzalloc ./include/linux/slab.h:636 > [<ffffffff82b85834>] aa_alloc_task_context+0x54/0x90 > security/apparmor/context.c:40 > [<ffffffff82b99e3d>] apparmor_cred_prepare+0x1d/0xb0 security/apparmor/lsm.c:76 > [<ffffffff82acf12d>] security_prepare_creds+0x7d/0xb0 security/security.c:912 > [<ffffffff813fb355>] prepare_kernel_cred+0x375/0x650 kernel/cred.c:630 > [<ffffffff813cded9>] call_usermodehelper_exec_async+0xb9/0x460 > kernel/kmod.c:232 > [<ffffffff86e1070a>] ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 > > Freed: > PID = 1693 > [< inline >] __cache_free mm/slab.c:3520 > [<ffffffff81807813>] kfree+0xc3/0x2a0 mm/slab.c:3837 > [<ffffffff8175f108>] kzfree+0x28/0x30 mm/slab_common.c:1323 > [<ffffffff82b85991>] aa_free_task_context+0x121/0x1d0 > security/apparmor/context.c:54 > [<ffffffff82b99f79>] apparmor_cred_free+0x39/0x80 security/apparmor/lsm.c:51 > [<ffffffff82acf078>] security_cred_free+0x48/0x80 security/security.c:907 > [<ffffffff813f8224>] put_cred_rcu+0xe4/0x3e0 kernel/cred.c:116 > [< inline >] __rcu_reclaim kernel/rcu/rcu.h:118 > [< inline >] rcu_do_batch kernel/rcu/tree.c:2777 > [< inline >] invoke_rcu_callbacks kernel/rcu/tree.c:3041 > [< inline >] __rcu_process_callbacks kernel/rcu/tree.c:3008 > [<ffffffff814e7e3b>] rcu_process_callbacks+0xdbb/0x1560 kernel/rcu/tree.c:3025 > [<ffffffff86e1358c>] __do_softirq+0x25c/0xa3e kernel/softirq.c:273 > Memory state around the buggy address: > ffff88006cc3f400: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc > ffff88006cc3f480: 00 00 fc fc fc fc fc fc fb fb fb fb fc fc fc fc >>ffff88006cc3f500: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc > ^ > ffff88006cc3f580: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc > ffff88006cc3f600: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc > ================================= > > > I am also hitting similar bugs all over fbcon: > > BUG: KASAN: slab-out-of-bounds in fbcon_putcs+0x444/0x4b0 at addr > ffff8800384e58a8 > > https://gist.githubusercontent.com/dvyukov/645a5f48b735fb384de7ea35fe1748ea/raw/3690a8b2c82a3b8fd7d07f4602a166f5756c3749/gistfile1.txt > > BUG: KASAN: slab-out-of-bounds in bit_putcs+0xcd6/0xd70 at addr ffff88006abad8e6 > > https://gist.githubusercontent.com/dvyukov/2d909f2673eafbc35f7f17f95c395217/raw/83f4eb0193226d51c546015cddee4b6a697015b3/gistfile1.txt > > BUG: KASAN: use-after-free in fbcon_putcs+0x444/0x4b0 at addr ffff8800644bd820 > > https://gist.githubusercontent.com/dvyukov/286cdf2d3f9c6956ec9055dad0cf7a2a/raw/f7e0a380be364afd0c2c4c54ff5661e451fb143d/gistfile1.txt > > BUG: KASAN: slab-out-of-bounds in do_update_region+0x642/0x670 at addr > ffff8800661c56ac > > https://gist.githubusercontent.com/dvyukov/7fd9d858ea38e8131e21a0377435c32c/raw/5d59989e05b4e39bb5ee90f49658674fa9db89ad/gistfile1.txt > > On 0f98f121e1670eaa2a2fbb675e07d6ba7f0e146f of linux-next. A friendly ping. This still happens at insane rate on a6930aaee06755d1bdcfd943fbf614e4d92bb0c7 (Oct 5). ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: tty, fbcon: use-after-free in fbcon_invert_region 2016-10-07 19:59 ` Dmitry Vyukov @ 2016-10-11 1:43 ` Scot Doyle 2016-10-11 13:31 ` Dmitry Vyukov 2016-10-11 22:48 ` Scot Doyle 1 sibling, 1 reply; 7+ messages in thread From: Scot Doyle @ 2016-10-11 1:43 UTC (permalink / raw) To: Dmitry Vyukov Cc: Greg Kroah-Hartman, Peter Hurley, Jiri Slaby, LKML, plagnioj, tomi.valkeinen, jean-philippe.brucker, linux-fbdev, Eric W. Biederman, syzkaller On Fri, 7 Oct 2016, Dmitry Vyukov wrote: > On Sat, Sep 3, 2016 at 9:20 PM, Dmitry Vyukov <dvyukov@google.com> wrote: > > Hello, > > > > The following program causes use-after-free in fbcon_invert_region: > > > > https://gist.githubusercontent.com/dvyukov/d657f9a9ca39f34c430dcf63ec1153ac/raw/04e1b94aef0fc9eb770d11373b568980ecaa7f34/gistfile1.txt > > > > ================================= > > BUG: KASAN: use-after-free in fbcon_invert_region+0x1cc/0x1f0 at addr > > ffff88006cc3f51e > > Read of size 2 by task a.out/4240 > > CPU: 0 PID: 4240 Comm: a.out Not tainted 4.8.0-rc3-next-20160825+ #10 > > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > > ffffffff886b6fe0 ffff88003699f790 ffffffff82db3759 ffffffff8a0ae640 > > fffffbfff10d6dfc ffff88003e800100 ffff88006cc3f500 ffff88006cc3f520 > > 0000000000000000 ffff88006cc3f51e ffff88003699f7b8 ffffffff81809e7c > > > > Call Trace: > > [<ffffffff8180a474>] __asan_report_load2_noabort+0x14/0x20 > > mm/kasan/report.c:325 > > [<ffffffff82fdbc8c>] fbcon_invert_region+0x1cc/0x1f0 > > drivers/video/console/fbcon.c:2750 > > [<ffffffff8327ce72>] invert_screen+0x192/0x630 drivers/tty/vt/vt.c:470 > > [< inline >] highlight drivers/tty/vt/selection.c:50 > > [<ffffffff8326037c>] clear_selection+0x4c/0x60 drivers/tty/vt/selection.c:76 > > [<ffffffff8327374e>] hide_cursor+0x24e/0x2d0 drivers/tty/vt/vt.c:599 > > [<ffffffff83276207>] redraw_screen+0x2e7/0x840 drivers/tty/vt/vt.c:682 > > [<ffffffff83278b0c>] vc_do_resize+0xebc/0x1160 drivers/tty/vt/vt.c:952 > > [<ffffffff83278eba>] vt_resize+0xaa/0xe0 drivers/tty/vt/vt.c:992 > > [< inline >] tiocswinsz drivers/tty/tty_io.c:2378 > > [<ffffffff83224e71>] tty_ioctl+0x10c1/0x21e0 drivers/tty/tty_io.c:2892 > > [< inline >] vfs_ioctl fs/ioctl.c:43 > > [<ffffffff818a1c6c>] do_vfs_ioctl+0x18c/0x1080 fs/ioctl.c:675 > > [< inline >] SYSC_ioctl fs/ioctl.c:690 > > [<ffffffff818a2bef>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:681 > > [<ffffffff86e10480>] entry_SYSCALL_64_fastpath+0x23/0xc1 I wonder if the text selection is outside the newly resized vc? Does this patch help? --- vt.c 2016-10-11 00:32:43.079605599 -0000 +++ vt.c.new 2016-10-11 00:36:12.744650759 -0000 @@ -874,6 +874,9 @@ if (!newscreen) return -ENOMEM; + if (vc = sel_cons) + clear_selection(); + old_rows = vc->vc_rows; old_row_size = vc->vc_size_row; ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: tty, fbcon: use-after-free in fbcon_invert_region 2016-10-11 1:43 ` Scot Doyle @ 2016-10-11 13:31 ` Dmitry Vyukov 0 siblings, 0 replies; 7+ messages in thread From: Dmitry Vyukov @ 2016-10-11 13:31 UTC (permalink / raw) To: syzkaller Cc: Greg Kroah-Hartman, Peter Hurley, Jiri Slaby, LKML, plagnioj, tomi.valkeinen, jean-philippe.brucker, linux-fbdev, Eric W. Biederman On Tue, Oct 11, 2016 at 3:43 AM, Scot Doyle <lkml14@scotdoyle.com> wrote: > On Fri, 7 Oct 2016, Dmitry Vyukov wrote: >> On Sat, Sep 3, 2016 at 9:20 PM, Dmitry Vyukov <dvyukov@google.com> wrote: >> > Hello, >> > >> > The following program causes use-after-free in fbcon_invert_region: >> > >> > https://gist.githubusercontent.com/dvyukov/d657f9a9ca39f34c430dcf63ec1153ac/raw/04e1b94aef0fc9eb770d11373b568980ecaa7f34/gistfile1.txt >> > >> > ================================= >> > BUG: KASAN: use-after-free in fbcon_invert_region+0x1cc/0x1f0 at addr >> > ffff88006cc3f51e >> > Read of size 2 by task a.out/4240 >> > CPU: 0 PID: 4240 Comm: a.out Not tainted 4.8.0-rc3-next-20160825+ #10 >> > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 >> > ffffffff886b6fe0 ffff88003699f790 ffffffff82db3759 ffffffff8a0ae640 >> > fffffbfff10d6dfc ffff88003e800100 ffff88006cc3f500 ffff88006cc3f520 >> > 0000000000000000 ffff88006cc3f51e ffff88003699f7b8 ffffffff81809e7c >> > >> > Call Trace: >> > [<ffffffff8180a474>] __asan_report_load2_noabort+0x14/0x20 >> > mm/kasan/report.c:325 >> > [<ffffffff82fdbc8c>] fbcon_invert_region+0x1cc/0x1f0 >> > drivers/video/console/fbcon.c:2750 >> > [<ffffffff8327ce72>] invert_screen+0x192/0x630 drivers/tty/vt/vt.c:470 >> > [< inline >] highlight drivers/tty/vt/selection.c:50 >> > [<ffffffff8326037c>] clear_selection+0x4c/0x60 drivers/tty/vt/selection.c:76 >> > [<ffffffff8327374e>] hide_cursor+0x24e/0x2d0 drivers/tty/vt/vt.c:599 >> > [<ffffffff83276207>] redraw_screen+0x2e7/0x840 drivers/tty/vt/vt.c:682 >> > [<ffffffff83278b0c>] vc_do_resize+0xebc/0x1160 drivers/tty/vt/vt.c:952 >> > [<ffffffff83278eba>] vt_resize+0xaa/0xe0 drivers/tty/vt/vt.c:992 >> > [< inline >] tiocswinsz drivers/tty/tty_io.c:2378 >> > [<ffffffff83224e71>] tty_ioctl+0x10c1/0x21e0 drivers/tty/tty_io.c:2892 >> > [< inline >] vfs_ioctl fs/ioctl.c:43 >> > [<ffffffff818a1c6c>] do_vfs_ioctl+0x18c/0x1080 fs/ioctl.c:675 >> > [< inline >] SYSC_ioctl fs/ioctl.c:690 >> > [<ffffffff818a2bef>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:681 >> > [<ffffffff86e10480>] entry_SYSCALL_64_fastpath+0x23/0xc1 > > I wonder if the text selection is outside the newly resized vc? > Does this patch help? > > --- vt.c 2016-10-11 00:32:43.079605599 -0000 > +++ vt.c.new 2016-10-11 00:36:12.744650759 -0000 > @@ -874,6 +874,9 @@ > if (!newscreen) > return -ENOMEM; > > + if (vc = sel_cons) > + clear_selection(); > + > old_rows = vc->vc_rows; > old_row_size = vc->vc_size_row; This helped with the use-after-frees and out-of-bounds. Tested-by: Dmitry Vyukov <dvyukov@google.com> However, now the test program hanged in D unkillable stack on some kind of kernel deadlock. Don't know if it's induced by your patch, or just another bug. At least there are no vc_do_resize in stacks. # ps afxu | grep a.out root 6163 6.5 0.0 0 0 pts/0 Zl 13:25 0:00 | \_ [a.out] <defunct> # ls /proc/6163/task/ 6163 6191 6193 6194 6201 # cat /proc/6163/task/*/stack [< inline >] down_read_failed drivers/tty/tty_ldsem.c:241 [<ffffffff831b8da6>] __ldsem_down_read_nested+0x2a6/0x5b0 drivers/tty/tty_ldsem.c:332 [<ffffffff831b23f5>] tty_ldisc_ref_wait+0x35/0xb0 drivers/tty/tty_ldisc.c:274 [<ffffffff831962b7>] tty_write+0x177/0x840 drivers/tty/tty_io.c:1250 [<ffffffff8182c700>] __vfs_write+0x110/0x620 fs/read_write.c:510 [<ffffffff8182dc05>] vfs_write+0x175/0x4e0 fs/read_write.c:560 [< inline >] SYSC_write fs/read_write.c:607 [<ffffffff818314c9>] SyS_write+0xd9/0x1b0 fs/read_write.c:599 [<ffffffff86daf545>] entry_SYSCALL_64_fastpath+0x23/0xc6 arch/x86/entry/entry_64.S:208 [<ffffffffffffffff>] 0xffffffffffffffff [< inline >] down_read_failed drivers/tty/tty_ldsem.c:241 [<ffffffff831b8da6>] __ldsem_down_read_nested+0x2a6/0x5b0 drivers/tty/tty_ldsem.c:332 [<ffffffff831b23f5>] tty_ldisc_ref_wait+0x35/0xb0 drivers/tty/tty_ldisc.c:274 [<ffffffff831962b7>] tty_write+0x177/0x840 drivers/tty/tty_io.c:1250 [<ffffffff8182c700>] __vfs_write+0x110/0x620 fs/read_write.c:510 [<ffffffff8182dc05>] vfs_write+0x175/0x4e0 fs/read_write.c:560 [< inline >] SYSC_write fs/read_write.c:607 [<ffffffff818314c9>] SyS_write+0xd9/0x1b0 fs/read_write.c:599 [<ffffffff86daf545>] entry_SYSCALL_64_fastpath+0x23/0xc6 arch/x86/entry/entry_64.S:208 [<ffffffffffffffff>] 0xffffffffffffffff [< inline >] down_read_failed drivers/tty/tty_ldsem.c:241 [<ffffffff831b8da6>] __ldsem_down_read_nested+0x2a6/0x5b0 drivers/tty/tty_ldsem.c:332 [<ffffffff831b23f5>] tty_ldisc_ref_wait+0x35/0xb0 drivers/tty/tty_ldisc.c:274 [<ffffffff831962b7>] tty_write+0x177/0x840 drivers/tty/tty_io.c:1250 [<ffffffff8182c700>] __vfs_write+0x110/0x620 fs/read_write.c:510 [<ffffffff8182dc05>] vfs_write+0x175/0x4e0 fs/read_write.c:560 [< inline >] SYSC_write fs/read_write.c:607 [<ffffffff818314c9>] SyS_write+0xd9/0x1b0 fs/read_write.c:599 [<ffffffff86daf545>] entry_SYSCALL_64_fastpath+0x23/0xc6 arch/x86/entry/entry_64.S:208 [<ffffffffffffffff>] 0xffffffffffffffff [< inline >] down_read_failed drivers/tty/tty_ldsem.c:241 [<ffffffff831b8da6>] __ldsem_down_read_nested+0x2a6/0x5b0 drivers/tty/tty_ldsem.c:332 [<ffffffff831b23f5>] tty_ldisc_ref_wait+0x35/0xb0 drivers/tty/tty_ldisc.c:274 [<ffffffff8319def3>] tty_ioctl+0xc53/0x2180 drivers/tty/tty_io.c:2987 [< inline >] vfs_ioctl fs/ioctl.c:43 [<ffffffff8186bc31>] do_vfs_ioctl+0x191/0x1050 fs/ioctl.c:679 [< inline >] SYSC_ioctl fs/ioctl.c:694 [<ffffffff8186cb84>] SyS_ioctl+0x94/0xc0 fs/ioctl.c:685 [<ffffffff86daf545>] entry_SYSCALL_64_fastpath+0x23/0xc6 arch/x86/entry/entry_64.S:208 [<ffffffffffffffff>] 0xffffffffffffffff # cat /proc/6191/status Name: a.out Umask: 0022 State: D (disk sleep) Tgid: 6163 Ngid: 0 Pid: 6191 PPid: 6154 TracerPid: 0 Uid: 0 0 0 0 Gid: 0 0 0 0 FDSize: 256 Groups: 0 NStgid: 6163 NSpid: 6191 NSpgid: 6163 NSsid: 6154 VmPeak: 402244 kB VmSize: 402244 kB VmLck: 0 kB VmPin: 0 kB VmHWM: 3140 kB VmRSS: 3140 kB RssAnon: 2508 kB RssFile: 632 kB RssShmem: 0 kB VmData: 401072 kB VmStk: 136 kB VmExe: 832 kB VmLib: 8 kB VmPTE: 212 kB VmPMD: 12 kB VmSwap: 0 kB HugetlbPages: 0 kB Threads: 5 SigQ: 1/3150 SigPnd: 0000000000000100 ShdPnd: 0000000000000100 SigBlk: 0000000000000000 SigIgn: 0000000000000000 SigCgt: 0000000180000440 CapInh: 0000000000000000 CapPrm: 0000003fffffffff CapEff: 0000003fffffffff CapBnd: 0000003fffffffff CapAmb: 0000000000000000 Seccomp: 0 Cpus_allowed: f Cpus_allowed_list: 0-3 Mems_allowed: 00000000,00000003 Mems_allowed_list: 0-1 voluntary_ctxt_switches: 1 nonvoluntary_ctxt_switches: 0 ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: tty, fbcon: use-after-free in fbcon_invert_region 2016-10-07 19:59 ` Dmitry Vyukov 2016-10-11 1:43 ` Scot Doyle @ 2016-10-11 22:48 ` Scot Doyle 2016-10-13 11:08 ` Dmitry Vyukov 1 sibling, 1 reply; 7+ messages in thread From: Scot Doyle @ 2016-10-11 22:48 UTC (permalink / raw) To: Dmitry Vyukov Cc: Greg Kroah-Hartman, Peter Hurley, Jiri Slaby, linux-kernel, plagnioj, tomi.valkeinen, jean-philippe.brucker, linux-fbdev, Eric W. Biederman, syzkaller > On Tue, Oct 11, 2016 at 3:43 AM, Scot Doyle <lkml14@scotdoyle.com> wrote: > > I wonder if the text selection is outside the newly resized vc? > > Does this patch help? > > > > --- vt.c 2016-10-11 00:32:43.079605599 -0000 > > +++ vt.c.new 2016-10-11 00:36:12.744650759 -0000 > > @@ -874,6 +874,9 @@ > > if (!newscreen) > > return -ENOMEM; > > > > + if (vc = sel_cons) > > + clear_selection(); > > + > > old_rows = vc->vc_rows; > > old_row_size = vc->vc_size_row; > > This helped with the use-after-frees and out-of-bounds. > Tested-by: Dmitry Vyukov <dvyukov@google.com> > > However, now the test program hanged in D unkillable stack on some > kind of kernel deadlock. Don't know if it's induced by your patch, or > just another bug. At least there are no vc_do_resize in stacks. > > # ps afxu | grep a.out > root 6163 6.5 0.0 0 0 pts/0 Zl 13:25 0:00 | > \_ [a.out] <defunct> > > # ls /proc/6163/task/ > 6163 6191 6193 6194 6201 > > # cat /proc/6163/task/*/stack > [< inline >] down_read_failed drivers/tty/tty_ldsem.c:241 > [<ffffffff831b8da6>] __ldsem_down_read_nested+0x2a6/0x5b0 drivers/tty/tty_ldsem.c:332 > [<ffffffff831b23f5>] tty_ldisc_ref_wait+0x35/0xb0 drivers/tty/tty_ldisc.c:274 > [<ffffffff831962b7>] tty_write+0x177/0x840 drivers/tty/tty_io.c:1250 > [<ffffffff8182c700>] __vfs_write+0x110/0x620 fs/read_write.c:510 > [<ffffffff8182dc05>] vfs_write+0x175/0x4e0 fs/read_write.c:560 > [< inline >] SYSC_write fs/read_write.c:607 > [<ffffffff818314c9>] SyS_write+0xd9/0x1b0 fs/read_write.c:599 > [<ffffffff86daf545>] entry_SYSCALL_64_fastpath+0x23/0xc6 > arch/x86/entry/entry_64.S:208 The patch below removes the resize ioctl's from the first test program. Are there any use-after-free/out-of-bounds errors when running the patched test program on the unpatched kernel? If not, but there are still deadlocks, then perhaps they aren't caused by the proposed kernel patch? --- test.c +++ test.c.new @@ -141,8 +141,6 @@ NONFAILING(*(uint16_t*)0x20f77ff9 = (uint16_t)0x6); NONFAILING(*(uint16_t*)0x20f77ffb = (uint16_t)0x3f); NONFAILING(*(uint16_t*)0x20f77ffd = (uint16_t)0x0); - r[17] = execute_syscall(__NR_ioctl, r[8], 0x541cul, 0x20f77ff4ul, 0, - 0, 0, 0, 0, 0); break; case 8: NONFAILING(*(uint32_t*)0x20f6dffc = (uint32_t)0x5); @@ -212,8 +210,6 @@ NONFAILING(*(uint16_t*)0x20f78ffa = (uint16_t)0xeb8); NONFAILING(*(uint16_t*)0x20f78ffc = (uint16_t)0x9); NONFAILING(*(uint16_t*)0x20f78ffe = (uint16_t)0x7); - r2[17] = execute_syscall(__NR_ioctl, r2[5], 0x5609ul, 0x20f78ffaul, 0, - 0, 0, 0, 0, 0); break; case 8: r2[18] @@ -273,8 +269,6 @@ NONFAILING(*(uint16_t*)0x20f70002 = (uint16_t)0x2); NONFAILING(*(uint16_t*)0x20f70004 = (uint16_t)0xd1e); NONFAILING(*(uint16_t*)0x20f70006 = (uint16_t)0x7); - r2[34] = execute_syscall(__NR_ioctl, r2[5], 0x5414ul, 0x20f70000ul, 0, - 0, 0, 0, 0, 0); break; } return 0; ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: tty, fbcon: use-after-free in fbcon_invert_region 2016-10-11 22:48 ` Scot Doyle @ 2016-10-13 11:08 ` Dmitry Vyukov 2016-10-13 17:12 ` [PATCH] vt: clear selection before resizing Scot Doyle 0 siblings, 1 reply; 7+ messages in thread From: Dmitry Vyukov @ 2016-10-13 11:08 UTC (permalink / raw) To: Scot Doyle Cc: Greg Kroah-Hartman, Peter Hurley, Jiri Slaby, LKML, plagnioj, tomi.valkeinen, jean-philippe.brucker, linux-fbdev, Eric W. Biederman, syzkaller On Wed, Oct 12, 2016 at 12:48 AM, Scot Doyle <lkml14@scotdoyle.com> wrote: >> On Tue, Oct 11, 2016 at 3:43 AM, Scot Doyle <lkml14@scotdoyle.com> wrote: >> > I wonder if the text selection is outside the newly resized vc? >> > Does this patch help? >> > >> > --- vt.c 2016-10-11 00:32:43.079605599 -0000 >> > +++ vt.c.new 2016-10-11 00:36:12.744650759 -0000 >> > @@ -874,6 +874,9 @@ >> > if (!newscreen) >> > return -ENOMEM; >> > >> > + if (vc = sel_cons) >> > + clear_selection(); >> > + >> > old_rows = vc->vc_rows; >> > old_row_size = vc->vc_size_row; >> >> This helped with the use-after-frees and out-of-bounds. >> Tested-by: Dmitry Vyukov <dvyukov@google.com> >> >> However, now the test program hanged in D unkillable stack on some >> kind of kernel deadlock. Don't know if it's induced by your patch, or >> just another bug. At least there are no vc_do_resize in stacks. >> >> # ps afxu | grep a.out >> root 6163 6.5 0.0 0 0 pts/0 Zl 13:25 0:00 | >> \_ [a.out] <defunct> >> >> # ls /proc/6163/task/ >> 6163 6191 6193 6194 6201 >> >> # cat /proc/6163/task/*/stack >> [< inline >] down_read_failed drivers/tty/tty_ldsem.c:241 >> [<ffffffff831b8da6>] __ldsem_down_read_nested+0x2a6/0x5b0 drivers/tty/tty_ldsem.c:332 >> [<ffffffff831b23f5>] tty_ldisc_ref_wait+0x35/0xb0 drivers/tty/tty_ldisc.c:274 >> [<ffffffff831962b7>] tty_write+0x177/0x840 drivers/tty/tty_io.c:1250 >> [<ffffffff8182c700>] __vfs_write+0x110/0x620 fs/read_write.c:510 >> [<ffffffff8182dc05>] vfs_write+0x175/0x4e0 fs/read_write.c:560 >> [< inline >] SYSC_write fs/read_write.c:607 >> [<ffffffff818314c9>] SyS_write+0xd9/0x1b0 fs/read_write.c:599 >> [<ffffffff86daf545>] entry_SYSCALL_64_fastpath+0x23/0xc6 >> arch/x86/entry/entry_64.S:208 > > The patch below removes the resize ioctl's from the first test program. > Are there any use-after-free/out-of-bounds errors when running the patched > test program on the unpatched kernel? If not, but there are still > deadlocks, then perhaps they aren't caused by the proposed kernel patch? Yes, I've removed these: ioctl(0, 0x5609ul, 0); // VT_RESIZE ioctl(0, 0x5414ul, 0); // TIOCSWINSZ It does not crash, but still deadlocks. So I guess your patch fixes the crashes. Please mail a patch with the fix. > --- test.c > +++ test.c.new > @@ -141,8 +141,6 @@ > NONFAILING(*(uint16_t*)0x20f77ff9 = (uint16_t)0x6); > NONFAILING(*(uint16_t*)0x20f77ffb = (uint16_t)0x3f); > NONFAILING(*(uint16_t*)0x20f77ffd = (uint16_t)0x0); > - r[17] = execute_syscall(__NR_ioctl, r[8], 0x541cul, 0x20f77ff4ul, 0, > - 0, 0, 0, 0, 0); > break; > case 8: > NONFAILING(*(uint32_t*)0x20f6dffc = (uint32_t)0x5); > @@ -212,8 +210,6 @@ > NONFAILING(*(uint16_t*)0x20f78ffa = (uint16_t)0xeb8); > NONFAILING(*(uint16_t*)0x20f78ffc = (uint16_t)0x9); > NONFAILING(*(uint16_t*)0x20f78ffe = (uint16_t)0x7); > - r2[17] = execute_syscall(__NR_ioctl, r2[5], 0x5609ul, 0x20f78ffaul, 0, > - 0, 0, 0, 0, 0); > break; > case 8: > r2[18] > @@ -273,8 +269,6 @@ > NONFAILING(*(uint16_t*)0x20f70002 = (uint16_t)0x2); > NONFAILING(*(uint16_t*)0x20f70004 = (uint16_t)0xd1e); > NONFAILING(*(uint16_t*)0x20f70006 = (uint16_t)0x7); > - r2[34] = execute_syscall(__NR_ioctl, r2[5], 0x5414ul, 0x20f70000ul, 0, > - 0, 0, 0, 0, 0); > break; > } > return 0; > ^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH] vt: clear selection before resizing 2016-10-13 11:08 ` Dmitry Vyukov @ 2016-10-13 17:12 ` Scot Doyle 0 siblings, 0 replies; 7+ messages in thread From: Scot Doyle @ 2016-10-13 17:12 UTC (permalink / raw) To: Greg Kroah-Hartman Cc: Jiri Slaby, Dmitry Vyukov, Peter Hurley, tomi.valkeinen, jean-philippe.brucker, Eric W. Biederman, linux-kernel, linux-fbdev When resizing a vt its selection may exceed the new size, resulting in an invalid memory access [1]. Clear the selection before resizing. [1] http://lkml.kernel.org/r/CACT4Y+acDTwy4umEvf5ROBGiRJNrxHN4Cn5szCXE5Jw-d1B=Xw@mail.gmail.com Reported-and-tested-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Scot Doyle <lkml14@scotdoyle.com> --- drivers/tty/vt/vt.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c index 06fb39c..5d6a549 100644 --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -874,6 +874,9 @@ static int vc_do_resize(struct tty_struct *tty, struct vc_data *vc, if (!newscreen) return -ENOMEM; + if (vc = sel_cons) + clear_selection(); + old_rows = vc->vc_rows; old_row_size = vc->vc_size_row; -- 2.7.4 ^ permalink raw reply related [flat|nested] 7+ messages in thread
end of thread, other threads:[~2016-10-13 17:12 UTC | newest] Thread overview: 7+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2016-09-03 19:20 tty, fbcon: use-after-free in fbcon_invert_region Dmitry Vyukov 2016-10-07 19:59 ` Dmitry Vyukov 2016-10-11 1:43 ` Scot Doyle 2016-10-11 13:31 ` Dmitry Vyukov 2016-10-11 22:48 ` Scot Doyle 2016-10-13 11:08 ` Dmitry Vyukov 2016-10-13 17:12 ` [PATCH] vt: clear selection before resizing Scot Doyle
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