syzbot


KMSAN: kernel-infoleak in tty_read

Status: upstream: reported on 2024/08/12 09:45
Subsystems: serial
[Documentation on labels]
Reported-by: syzbot+aa7ddf2352c316bb08d0@syzkaller.appspotmail.com
First crash: 116d, last: 82d
Discussions (2)
Title Replies (including bot) Last reply
[syzbot] Monthly serial report (Sep 2024) 0 (1) 2024/09/14 10:58
[syzbot] [serial?] KMSAN: kernel-infoleak in tty_read 0 (1) 2024/08/12 09:45
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KMSAN: kernel-infoleak-after-free in tty_read serial 1 397d 397d 0/28 auto-obsoleted due to no activity on 2024/01/30 12:05

Sample crash report:
=====================================================
BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline]
BUG: KMSAN: kernel-infoleak in copy_to_user_iter lib/iov_iter.c:24 [inline]
BUG: KMSAN: kernel-infoleak in iterate_ubuf include/linux/iov_iter.h:29 [inline]
BUG: KMSAN: kernel-infoleak in iterate_and_advance2 include/linux/iov_iter.h:245 [inline]
BUG: KMSAN: kernel-infoleak in iterate_and_advance include/linux/iov_iter.h:271 [inline]
BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x366/0x24a0 lib/iov_iter.c:185
 instrument_copy_to_user include/linux/instrumented.h:114 [inline]
 copy_to_user_iter lib/iov_iter.c:24 [inline]
 iterate_ubuf include/linux/iov_iter.h:29 [inline]
 iterate_and_advance2 include/linux/iov_iter.h:245 [inline]
 iterate_and_advance include/linux/iov_iter.h:271 [inline]
 _copy_to_iter+0x366/0x24a0 lib/iov_iter.c:185
 copy_to_iter include/linux/uio.h:196 [inline]
 iterate_tty_read drivers/tty/tty_io.c:882 [inline]
 tty_read+0x42c/0xe10 drivers/tty/tty_io.c:937
 new_sync_read fs/read_write.c:395 [inline]
 vfs_read+0x8c0/0xf60 fs/read_write.c:476
 ksys_read+0x20f/0x4c0 fs/read_write.c:619
 __do_sys_read fs/read_write.c:629 [inline]
 __se_sys_read fs/read_write.c:627 [inline]
 __x64_sys_read+0x93/0xe0 fs/read_write.c:627
 x64_sys_call+0x3055/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:1
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
 copy_from_read_buf drivers/tty/n_tty.c:1978 [inline]
 n_tty_read+0x7f8/0x3260 drivers/tty/n_tty.c:2187
 iterate_tty_read drivers/tty/tty_io.c:862 [inline]
 tty_read+0x327/0xe10 drivers/tty/tty_io.c:937
 new_sync_read fs/read_write.c:395 [inline]
 vfs_read+0x8c0/0xf60 fs/read_write.c:476
 ksys_read+0x20f/0x4c0 fs/read_write.c:619
 __do_sys_read fs/read_write.c:629 [inline]
 __se_sys_read fs/read_write.c:627 [inline]
 __x64_sys_read+0x93/0xe0 fs/read_write.c:627
 x64_sys_call+0x3055/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:1
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
 n_tty_receive_buf_real_raw drivers/tty/n_tty.c:1532 [inline]
 __receive_buf drivers/tty/n_tty.c:1618 [inline]
 n_tty_receive_buf_common+0xe6e/0x2490 drivers/tty/n_tty.c:1739
 n_tty_receive_buf2+0x4c/0x60 drivers/tty/n_tty.c:1785
 tty_ldisc_receive_buf+0xd0/0x290 drivers/tty/tty_buffer.c:387
 tty_port_default_receive_buf+0xdf/0x190 drivers/tty/tty_port.c:37
 receive_buf drivers/tty/tty_buffer.c:445 [inline]
 flush_to_ldisc+0x473/0xdb0 drivers/tty/tty_buffer.c:495
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0xae0/0x1c40 kernel/workqueue.c:3312
 worker_thread+0xea7/0x14d0 kernel/workqueue.c:3389
 kthread+0x3e2/0x540 kernel/kthread.c:389
 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:3998 [inline]
 slab_alloc_node mm/slub.c:4041 [inline]
 __do_kmalloc_node mm/slub.c:4161 [inline]
 __kmalloc_noprof+0x661/0xf30 mm/slub.c:4174
 kmalloc_noprof include/linux/slab.h:685 [inline]
 tty_buffer_alloc drivers/tty/tty_buffer.c:180 [inline]
 __tty_buffer_request_room+0x36e/0x6d0 drivers/tty/tty_buffer.c:273
 __tty_insert_flip_string_flags+0x140/0x570 drivers/tty/tty_buffer.c:309
 kbd_keycode drivers/tty/vt/keyboard.c:1424 [inline]
 kbd_event+0x3b1b/0x6010 drivers/tty/vt/keyboard.c:1541
 input_handler_events_default+0x128/0x1f0 drivers/input/input.c:2552
 input_pass_values+0x216/0x990 drivers/input/input.c:126
 input_event_dispose+0x552/0x6e0 drivers/input/input.c:352
 input_handle_event+0xf3c/0x1430 drivers/input/input.c:369
 input_event+0xe2/0x120 drivers/input/input.c:398
 hidinput_hid_event+0x256d/0x2960 drivers/hid/hid-input.c:1746
 hid_process_event+0x766/0x930 drivers/hid/hid-core.c:1540
 hid_process_report drivers/hid/hid-core.c:1688 [inline]
 hid_report_raw_event+0x1e77/0x2820 drivers/hid/hid-core.c:2015
 __hid_input_report drivers/hid/hid-core.c:2085 [inline]
 hid_input_report+0x5a2/0x610 drivers/hid/hid-core.c:2107
 hid_irq_in+0x737/0xd00 drivers/hid/usbhid/hid-core.c:285
 __usb_hcd_giveback_urb+0x572/0x840 drivers/usb/core/hcd.c:1650
 usb_hcd_giveback_urb+0x157/0x720 drivers/usb/core/hcd.c:1734
 dummy_timer+0xd3f/0x6aa0 drivers/usb/gadget/udc/dummy_hcd.c:1987
 __run_hrtimer kernel/time/hrtimer.c:1689 [inline]
 __hrtimer_run_queues+0x564/0xe40 kernel/time/hrtimer.c:1753
 hrtimer_interrupt+0x3ab/0x1490 kernel/time/hrtimer.c:1815
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1032 [inline]
 __sysvec_apic_timer_interrupt+0xa6/0x3a0 arch/x86/kernel/apic/apic.c:1049
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
 sysvec_apic_timer_interrupt+0x7e/0x90 arch/x86/kernel/apic/apic.c:1043
 asm_sysvec_apic_timer_interrupt+0x1f/0x30 arch/x86/include/asm/idtentry.h:702

Bytes 0-6 of 22 are uninitialized
Memory access of size 22 starts at ffff88811e987c70
Data copied to user address 0000000020002480

CPU: 0 UID: 0 PID: 14578 Comm: syz.3.1164 Not tainted 6.11.0-rc7-syzkaller-00021-g7c6a3a65ace7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
=====================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/09/12 01:31 upstream 7c6a3a65ace7 d94c83d8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: kernel-infoleak in tty_read
2024/09/07 12:30 upstream b31c44928842 9750182a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: kernel-infoleak in tty_read
2024/08/08 09:42 upstream 6a0e38264012 de12cf65 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: kernel-infoleak in tty_read
* Struck through repros no longer work on HEAD.