syzbot


KMSAN: kernel-infoleak in con_font_op (2)

Status: upstream: reported on 2024/10/10 16:14
Subsystems: serial
[Documentation on labels]
Reported-by: syzbot+955da2d57931604ee691@syzkaller.appspotmail.com
Fix commit: f956052e00de vt: prevent kernel-infoleak in con_font_get()
Patched on: [ci-qemu-gce-upstream-auto ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-snapshot-upstream-root ci-upstream-bpf-kasan-gce ci-upstream-gce-arm64 ci-upstream-gce-leak ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root ci-upstream-linux-next-kasan-gce-root ci2-upstream-fs ci2-upstream-kcsan-gce ci2-upstream-usb], missing on: [ci-qemu-native-arm64-kvm ci-qemu2-riscv64 ci-upstream-bpf-next-kasan-gce ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce]
First crash: 16d, last: 3d03h
Discussions (2)
Title Replies (including bot) Last reply
[PATCH] vt: prevent kernel-infoleak in con_font_get() 1 (1) 2024/10/10 17:46
[syzbot] [serial?] KMSAN: kernel-infoleak in con_font_op (2) 0 (1) 2024/10/10 16:14
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KMSAN: kernel-infoleak in con_font_op serial 1 171d 167d 0/28 auto-obsoleted due to no activity on 2024/08/12 01:40

Sample crash report:
=====================================================
BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline]
BUG: KMSAN: kernel-infoleak in _inline_copy_to_user include/linux/uaccess.h:187 [inline]
BUG: KMSAN: kernel-infoleak in _copy_to_user+0xbc/0x110 lib/usercopy.c:26
 instrument_copy_to_user include/linux/instrumented.h:114 [inline]
 _inline_copy_to_user include/linux/uaccess.h:187 [inline]
 _copy_to_user+0xbc/0x110 lib/usercopy.c:26
 copy_to_user include/linux/uaccess.h:216 [inline]
 con_font_get drivers/tty/vt/vt.c:4760 [inline]
 con_font_op+0x14a2/0x1710 drivers/tty/vt/vt.c:4854
 vt_k_ioctl drivers/tty/vt/vt_ioctl.c:474 [inline]
 vt_ioctl+0x2b6e/0x2fe0 drivers/tty/vt/vt_ioctl.c:751
 tty_ioctl+0xd0c/0x1990 drivers/tty/tty_io.c:2803
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0x25e/0x450 fs/ioctl.c:893
 __x64_sys_ioctl+0x96/0xe0 fs/ioctl.c:893
 x64_sys_call+0x18bf/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:17
 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 created at:
 ___kmalloc_large_node+0x22c/0x370 mm/slub.c:4219
 __kmalloc_large_node_noprof+0x3f/0x1e0 mm/slub.c:4236
 __do_kmalloc_node mm/slub.c:4252 [inline]
 __kmalloc_node_noprof+0x9d6/0xf50 mm/slub.c:4270
 __kvmalloc_node_noprof+0xc0/0x2d0 mm/util.c:658
 con_font_get drivers/tty/vt/vt.c:4729 [inline]
 con_font_op+0x659/0x1710 drivers/tty/vt/vt.c:4854
 vt_k_ioctl drivers/tty/vt/vt_ioctl.c:474 [inline]
 vt_ioctl+0x2b6e/0x2fe0 drivers/tty/vt/vt_ioctl.c:751
 tty_ioctl+0xd0c/0x1990 drivers/tty/tty_io.c:2803
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0x25e/0x450 fs/ioctl.c:893
 __x64_sys_ioctl+0x96/0xe0 fs/ioctl.c:893
 x64_sys_call+0x18bf/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:17
 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

Bytes 61440-76799 of 76800 are uninitialized
Memory access of size 76800 starts at ffff8880b5c00000
Data copied to user address 0000000020000880

CPU: 0 UID: 0 PID: 7973 Comm: syz.2.4245 Tainted: G        W          6.12.0-rc1-syzkaller-00349-g8f602276d390 #0
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
=====================================================

Crashes (8):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/10/06 16:13 upstream 8f602276d390 d7906eff .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: kernel-infoleak in con_font_op
2024/10/19 17:26 upstream 9197b73fd7bb cd6fc0a3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: kernel-infoleak in con_font_op
2024/10/19 17:26 upstream 9197b73fd7bb cd6fc0a3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: kernel-infoleak in con_font_op
2024/10/17 21:37 upstream 6efbea77b390 666f77ed .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: kernel-infoleak in con_font_op
2024/10/15 10:08 upstream eca631b8fe80 14943bb8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: kernel-infoleak in con_font_op
2024/10/15 10:08 upstream eca631b8fe80 14943bb8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: kernel-infoleak in con_font_op
2024/10/14 22:58 upstream eca631b8fe80 b01b6661 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: kernel-infoleak in con_font_op
2024/10/14 22:57 upstream eca631b8fe80 b01b6661 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-386-root KMSAN: kernel-infoleak in con_font_op
* Struck through repros no longer work on HEAD.