Re: KMSAN: kernel-infoleak in compat_drm_wait_vblank
On Wed, Mar 03, 2021 at 04:37:18PM +0100, Michel Dänzer wrote: > On 2021-02-22 10:15 a.m., syzbot wrote: > > Hello, > > > > syzbot found the following issue on: > > > > HEAD commit:29ad81a1 arch/x86: add missing include to sparsemem.h > > git tree: https://github.com/google/kmsan.git master > > console output: https://syzkaller.appspot.com/x/log.txt?x=111e6312d0 > > kernel config: https://syzkaller.appspot.com/x/.config?x=c8e3b38ca92283e > > dashboard link: https://syzkaller.appspot.com/bug?extid=620cf21140fc7e772a5d > > compiler: Debian clang version 11.0.1-2 > > userspace arch: i386 > > > > Unfortunately, I don't have any reproducer for this issue yet. > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > Reported-by: syzbot+620cf21140fc7e772...@syzkaller.appspotmail.com > > > > = > > BUG: KMSAN: kernel-infoleak in kmsan_copy_to_user+0x9c/0xb0 > > mm/kmsan/kmsan_hooks.c:249 > > CPU: 1 PID: 26999 Comm: syz-executor.2 Not tainted 5.11.0-rc7-syzkaller #0 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > > Google 01/01/2011 > > Call Trace: > > __dump_stack lib/dump_stack.c:79 [inline] > > dump_stack+0x21c/0x280 lib/dump_stack.c:120 > > kmsan_report+0xfb/0x1e0 mm/kmsan/kmsan_report.c:118 > > kmsan_internal_check_memory+0x484/0x520 mm/kmsan/kmsan.c:437 > > kmsan_copy_to_user+0x9c/0xb0 mm/kmsan/kmsan_hooks.c:249 > > instrument_copy_to_user include/linux/instrumented.h:121 [inline] > > _copy_to_user+0x1ac/0x270 lib/usercopy.c:33 > > copy_to_user include/linux/uaccess.h:209 [inline] > > compat_drm_wait_vblank+0x36f/0x450 drivers/gpu/drm/drm_ioc32.c:866 > > drm_compat_ioctl+0x3f6/0x590 drivers/gpu/drm/drm_ioc32.c:995 > > __do_compat_sys_ioctl fs/ioctl.c:842 [inline] > > __se_compat_sys_ioctl+0x53d/0x1100 fs/ioctl.c:793 > > __ia32_compat_sys_ioctl+0x4a/0x70 fs/ioctl.c:793 > > do_syscall_32_irqs_on arch/x86/entry/common.c:79 [inline] > > __do_fast_syscall_32+0x102/0x160 arch/x86/entry/common.c:141 > > do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:166 > > do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:209 > > entry_SYSENTER_compat_after_hwframe+0x4d/0x5c > > RIP: 0023:0xf7f47549 > > Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 > > 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 > > 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 > > RSP: 002b:f55415fc EFLAGS: 0296 ORIG_RAX: 0036 > > RAX: ffda RBX: 0003 RCX: c018643a > > RDX: 2100 RSI: RDI: > > RBP: R08: R09: > > R10: R11: R12: > > R13: R14: R15: > > > > Uninit was stored to memory at: > > kmsan_save_stack_with_flags mm/kmsan/kmsan.c:121 [inline] > > kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:289 > > __msan_chain_origin+0x57/0xa0 mm/kmsan/kmsan_instr.c:147 > > compat_drm_wait_vblank+0x43c/0x450 drivers/gpu/drm/drm_ioc32.c:865 > > drm_compat_ioctl+0x3f6/0x590 drivers/gpu/drm/drm_ioc32.c:995 > > __do_compat_sys_ioctl fs/ioctl.c:842 [inline] > > __se_compat_sys_ioctl+0x53d/0x1100 fs/ioctl.c:793 > > __ia32_compat_sys_ioctl+0x4a/0x70 fs/ioctl.c:793 > > do_syscall_32_irqs_on arch/x86/entry/common.c:79 [inline] > > __do_fast_syscall_32+0x102/0x160 arch/x86/entry/common.c:141 > > do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:166 > > do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:209 > > entry_SYSENTER_compat_after_hwframe+0x4d/0x5c > > > > Local variable req@compat_drm_wait_vblank created at: > > compat_drm_wait_vblank+0x7b/0x450 drivers/gpu/drm/drm_ioc32.c:849 > > compat_drm_wait_vblank+0x7b/0x450 drivers/gpu/drm/drm_ioc32.c:849 > > > > Bytes 12-15 of 16 are uninitialized > > Memory access of size 16 starts at 88814ffe3c98 > > Data copied to user address 2100 > > = > > compat_drm_wait_vblank would need to initialize > > req.reply.tval_usec = req32.reply.tval_usec; > > before calling drm_ioctl_kernel, since it's not aliased by any > req.request.* member, and drm_wait_vblank_ioctl doesn't always write to > it. I've fixed this in commit e926c474ebee404441c838d18224cd6f246a71b7 Author: Daniel Vetter Date: Mon Feb 22 11:06:43 2021 +0100 drm/compat: Clear bounce structures Or at least tried to. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
Re: KMSAN: kernel-infoleak in compat_drm_wait_vblank
On 2021-02-22 10:15 a.m., syzbot wrote: Hello, syzbot found the following issue on: HEAD commit:29ad81a1 arch/x86: add missing include to sparsemem.h git tree: https://github.com/google/kmsan.git master console output: https://syzkaller.appspot.com/x/log.txt?x=111e6312d0 kernel config: https://syzkaller.appspot.com/x/.config?x=c8e3b38ca92283e dashboard link: https://syzkaller.appspot.com/bug?extid=620cf21140fc7e772a5d compiler: Debian clang version 11.0.1-2 userspace arch: i386 Unfortunately, I don't have any reproducer for this issue yet. IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+620cf21140fc7e772...@syzkaller.appspotmail.com = BUG: KMSAN: kernel-infoleak in kmsan_copy_to_user+0x9c/0xb0 mm/kmsan/kmsan_hooks.c:249 CPU: 1 PID: 26999 Comm: syz-executor.2 Not tainted 5.11.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x21c/0x280 lib/dump_stack.c:120 kmsan_report+0xfb/0x1e0 mm/kmsan/kmsan_report.c:118 kmsan_internal_check_memory+0x484/0x520 mm/kmsan/kmsan.c:437 kmsan_copy_to_user+0x9c/0xb0 mm/kmsan/kmsan_hooks.c:249 instrument_copy_to_user include/linux/instrumented.h:121 [inline] _copy_to_user+0x1ac/0x270 lib/usercopy.c:33 copy_to_user include/linux/uaccess.h:209 [inline] compat_drm_wait_vblank+0x36f/0x450 drivers/gpu/drm/drm_ioc32.c:866 drm_compat_ioctl+0x3f6/0x590 drivers/gpu/drm/drm_ioc32.c:995 __do_compat_sys_ioctl fs/ioctl.c:842 [inline] __se_compat_sys_ioctl+0x53d/0x1100 fs/ioctl.c:793 __ia32_compat_sys_ioctl+0x4a/0x70 fs/ioctl.c:793 do_syscall_32_irqs_on arch/x86/entry/common.c:79 [inline] __do_fast_syscall_32+0x102/0x160 arch/x86/entry/common.c:141 do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:166 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:209 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c RIP: 0023:0xf7f47549 Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:f55415fc EFLAGS: 0296 ORIG_RAX: 0036 RAX: ffda RBX: 0003 RCX: c018643a RDX: 2100 RSI: RDI: RBP: R08: R09: R10: R11: R12: R13: R14: R15: Uninit was stored to memory at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:121 [inline] kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:289 __msan_chain_origin+0x57/0xa0 mm/kmsan/kmsan_instr.c:147 compat_drm_wait_vblank+0x43c/0x450 drivers/gpu/drm/drm_ioc32.c:865 drm_compat_ioctl+0x3f6/0x590 drivers/gpu/drm/drm_ioc32.c:995 __do_compat_sys_ioctl fs/ioctl.c:842 [inline] __se_compat_sys_ioctl+0x53d/0x1100 fs/ioctl.c:793 __ia32_compat_sys_ioctl+0x4a/0x70 fs/ioctl.c:793 do_syscall_32_irqs_on arch/x86/entry/common.c:79 [inline] __do_fast_syscall_32+0x102/0x160 arch/x86/entry/common.c:141 do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:166 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:209 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c Local variable req@compat_drm_wait_vblank created at: compat_drm_wait_vblank+0x7b/0x450 drivers/gpu/drm/drm_ioc32.c:849 compat_drm_wait_vblank+0x7b/0x450 drivers/gpu/drm/drm_ioc32.c:849 Bytes 12-15 of 16 are uninitialized Memory access of size 16 starts at 88814ffe3c98 Data copied to user address 2100 = compat_drm_wait_vblank would need to initialize req.reply.tval_usec = req32.reply.tval_usec; before calling drm_ioctl_kernel, since it's not aliased by any req.request.* member, and drm_wait_vblank_ioctl doesn't always write to it. -- Earthling Michel Dänzer | https://redhat.com Libre software enthusiast | Mesa and X developer
KMSAN: kernel-infoleak in compat_drm_wait_vblank
Hello, syzbot found the following issue on: HEAD commit:29ad81a1 arch/x86: add missing include to sparsemem.h git tree: https://github.com/google/kmsan.git master console output: https://syzkaller.appspot.com/x/log.txt?x=111e6312d0 kernel config: https://syzkaller.appspot.com/x/.config?x=c8e3b38ca92283e dashboard link: https://syzkaller.appspot.com/bug?extid=620cf21140fc7e772a5d compiler: Debian clang version 11.0.1-2 userspace arch: i386 Unfortunately, I don't have any reproducer for this issue yet. IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+620cf21140fc7e772...@syzkaller.appspotmail.com = BUG: KMSAN: kernel-infoleak in kmsan_copy_to_user+0x9c/0xb0 mm/kmsan/kmsan_hooks.c:249 CPU: 1 PID: 26999 Comm: syz-executor.2 Not tainted 5.11.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x21c/0x280 lib/dump_stack.c:120 kmsan_report+0xfb/0x1e0 mm/kmsan/kmsan_report.c:118 kmsan_internal_check_memory+0x484/0x520 mm/kmsan/kmsan.c:437 kmsan_copy_to_user+0x9c/0xb0 mm/kmsan/kmsan_hooks.c:249 instrument_copy_to_user include/linux/instrumented.h:121 [inline] _copy_to_user+0x1ac/0x270 lib/usercopy.c:33 copy_to_user include/linux/uaccess.h:209 [inline] compat_drm_wait_vblank+0x36f/0x450 drivers/gpu/drm/drm_ioc32.c:866 drm_compat_ioctl+0x3f6/0x590 drivers/gpu/drm/drm_ioc32.c:995 __do_compat_sys_ioctl fs/ioctl.c:842 [inline] __se_compat_sys_ioctl+0x53d/0x1100 fs/ioctl.c:793 __ia32_compat_sys_ioctl+0x4a/0x70 fs/ioctl.c:793 do_syscall_32_irqs_on arch/x86/entry/common.c:79 [inline] __do_fast_syscall_32+0x102/0x160 arch/x86/entry/common.c:141 do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:166 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:209 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c RIP: 0023:0xf7f47549 Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:f55415fc EFLAGS: 0296 ORIG_RAX: 0036 RAX: ffda RBX: 0003 RCX: c018643a RDX: 2100 RSI: RDI: RBP: R08: R09: R10: R11: R12: R13: R14: R15: Uninit was stored to memory at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:121 [inline] kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:289 __msan_chain_origin+0x57/0xa0 mm/kmsan/kmsan_instr.c:147 compat_drm_wait_vblank+0x43c/0x450 drivers/gpu/drm/drm_ioc32.c:865 drm_compat_ioctl+0x3f6/0x590 drivers/gpu/drm/drm_ioc32.c:995 __do_compat_sys_ioctl fs/ioctl.c:842 [inline] __se_compat_sys_ioctl+0x53d/0x1100 fs/ioctl.c:793 __ia32_compat_sys_ioctl+0x4a/0x70 fs/ioctl.c:793 do_syscall_32_irqs_on arch/x86/entry/common.c:79 [inline] __do_fast_syscall_32+0x102/0x160 arch/x86/entry/common.c:141 do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:166 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:209 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c Local variable req@compat_drm_wait_vblank created at: compat_drm_wait_vblank+0x7b/0x450 drivers/gpu/drm/drm_ioc32.c:849 compat_drm_wait_vblank+0x7b/0x450 drivers/gpu/drm/drm_ioc32.c:849 Bytes 12-15 of 16 are uninitialized Memory access of size 16 starts at 88814ffe3c98 Data copied to user address 2100 = --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkal...@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
