From: Helge Deller deller@gmx.de
stable inclusion from stable-v5.10.142 commit 989201bb8c00b222235aff04e6200230d29dc7bb category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I6CSFH
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit 566f9c9f89337792070b5a6062dff448b3e7977f upstream.
When changing the console font with ioctl(KDFONTOP) the new font size can be bigger than the previous font. A previous selection may thus now be outside of the new screen size and thus trigger out-of-bounds accesses to graphics memory if the selection is removed in vc_do_resize().
Prevent such out-of-memory accesses by dropping the selection before the various con_font_set() console handlers are called.
Reported-by: syzbot+14b0e8f3fd1612e35350@syzkaller.appspotmail.com Cc: stable stable@kernel.org Tested-by: Khalid Masum khalid.masum.92@gmail.com Signed-off-by: Helge Deller deller@gmx.de Link: https://lore.kernel.org/r/YuV9apZGNmGfjcor@p100 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Jialin Zhang zhangjialin11@huawei.com Reviewed-by: Zheng Zengkai zhengzengkai@huawei.com --- drivers/tty/vt/vt.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c index a4d005fa2569..0252c0562dbc 100644 --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -4671,9 +4671,11 @@ static int con_font_set(struct vc_data *vc, struct console_font_op *op) console_lock(); if (vc->vc_mode != KD_TEXT) rc = -EINVAL; - else if (vc->vc_sw->con_font_set) + else if (vc->vc_sw->con_font_set) { + if (vc_is_sel(vc)) + clear_selection(); rc = vc->vc_sw->con_font_set(vc, &font, op->flags); - else + } else rc = -ENOSYS; console_unlock(); kfree(font.data); @@ -4700,9 +4702,11 @@ static int con_font_default(struct vc_data *vc, struct console_font_op *op) console_unlock(); return -EINVAL; } - if (vc->vc_sw->con_font_default) + if (vc->vc_sw->con_font_default) { + if (vc_is_sel(vc)) + clear_selection(); rc = vc->vc_sw->con_font_default(vc, &font, s); - else + } else rc = -ENOSYS; console_unlock(); if (!rc) {