CVE-2025-38213

In the Linux kernel, the following vulnerability has been resolved:

vgacon: Add check for vc_origin address range in vgacon_scroll()

Our in-house Syzkaller reported the following BUG (twice), which we believed was the same issue with [1]:

================================================================== BUG: KASAN: slab-out-of-bounds in vcs_scr_readw+0xc2/0xd0 drivers/tty/vt/vt.c:4740 Read of size 2 at addr ffff88800f5bef60 by task syz.7.2620/12393 … Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x72/0xa0 lib/dump_stack.c:106 print_address_description.constprop.0+0x6b/0x3d0 mm/kasan/report.c:364 print_report+0xba/0x280 mm/kasan/report.c:475 kasan_report+0xa9/0xe0 mm/kasan/report.c:588 vcs_scr_readw+0xc2/0xd0 drivers/tty/vt/vt.c:4740 vcs_write_buf_noattr drivers/tty/vt/vc_screen.c:493 [inline] vcs_write+0x586/0x840 drivers/tty/vt/vc_screen.c:690 vfs_write+0x219/0x960 fs/read_write.c:584 ksys_write+0x12e/0x260 fs/read_write.c:639 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x59/0x110 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x78/0xe2 …

Allocated by task 5614: kasan_save_stack+0x20/0x40 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 ____kasan_kmalloc mm/kasan/common.c:374 [inline] __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:383 kasan_kmalloc include/linux/kasan.h:201 [inline] __do_kmalloc_node mm/slab_common.c:1007 [inline] __kmalloc+0x62/0x140 mm/slab_common.c:1020 kmalloc include/linux/slab.h:604 [inline] kzalloc include/linux/slab.h:721 [inline] vc_do_resize+0x235/0xf40 drivers/tty/vt/vt.c:1193 vgacon_adjust_height+0x2d4/0x350 drivers/video/console/vgacon.c:1007 vgacon_font_set+0x1f7/0x240 drivers/video/console/vgacon.c:1031 con_font_set drivers/tty/vt/vt.c:4628 [inline] con_font_op+0x4da/0xa20 drivers/tty/vt/vt.c:4675 vt_k_ioctl+0xa10/0xb30 drivers/tty/vt/vt_ioctl.c:474 vt_ioctl+0x14c/0x1870 drivers/tty/vt/vt_ioctl.c:752 tty_ioctl+0x655/0x1510 drivers/tty/tty_io.c:2779 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl+0x12d/0x190 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x59/0x110 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x78/0xe2

Last potentially related work creation: kasan_save_stack+0x20/0x40 mm/kasan/common.c:45 __kasan_record_aux_stack+0x94/0xa0 mm/kasan/generic.c:492 __call_rcu_common.constprop.0+0xc3/0xa10 kernel/rcu/tree.c:2713 netlink_release+0x620/0xc20 net/netlink/af_netlink.c:802 __sock_release+0xb5/0x270 net/socket.c:663 sock_close+0x1e/0x30 net/socket.c:1425 __fput+0x408/0xab0 fs/file_table.c:384 __fput_sync+0x4c/0x60 fs/file_table.c:465 __do_sys_close fs/open.c:1580 [inline] __se_sys_close+0x68/0xd0 fs/open.c:1565 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x59/0x110 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x78/0xe2

Second to last potentially related work creation: kasan_save_stack+0x20/0x40 mm/kasan/common.c:45 __kasan_record_aux_stack+0x94/0xa0 mm/kasan/generic.c:492 __call_rcu_common.constprop.0+0xc3/0xa10 kernel/rcu/tree.c:2713 netlink_release+0x620/0xc20 net/netlink/af_netlink.c:802 __sock_release+0xb5/0x270 net/socket.c:663 sock_close+0x1e/0x30 net/socket.c:1425 __fput+0x408/0xab0 fs/file_table.c:384 task_work_run+0x154/0x240 kernel/task_work.c:239 exit_task_work include/linux/task_work.h:45 [inline] do_exit+0x8e5/0x1320 kernel/exit.c:874 do_group_exit+0xcd/0x280 kernel/exit.c:1023 get_signal+0x1675/0x1850 kernel/signal.c:2905 arch_do_signal_or_restart+0x80/0x3b0 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x1b3/0x1e0 kernel/entry/common.c:218 do_syscall_64+0x66/0x110 arch/x86/ent —truncated—

Affected Software

References

• https://git.kernel.org/stable/c/2f4040a5855a59e48296f1b5a7cc0fceea3195b1
• https://git.kernel.org/stable/c/499b77fa1416a85fee106e60b240e912bca10cb8
• https://git.kernel.org/stable/c/843de5fbfe277e30fb333a7fa033b684c37829ac
• https://git.kernel.org/stable/c/864f9963ec6b4b76d104d595ba28110b87158003
• https://git.kernel.org/stable/c/9928ba7de39793a1c7c77b8b9e6ecf6209110311
• https://git.kernel.org/stable/c/bf9c07864765864b968e59c7b72db91130d621ca
• https://git.kernel.org/stable/c/e44532b1c358bfd2c4c7dc28fd01d47fef09ac70
• https://git.kernel.org/stable/c/f20fd54af4e1077fdbca4dd98375a4d1d941e50d