CVE-2025-38213

Description

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:
<TASK>
__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
...
</TASK>

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---