From: George Kennedy Date: Fri, 31 Jul 2020 16:33:12 +0000 (-0400) Subject: vt_ioctl: change VT_RESIZEX ioctl to check for error return from vc_resize() X-Git-Tag: v5.9-rc3~29^2~9 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=bc5269ca765057a1b762e79a1cfd267cd7bf1c46;p=thirdparty%2Fkernel%2Flinux.git vt_ioctl: change VT_RESIZEX ioctl to check for error return from vc_resize() vc_resize() can return with an error after failure. Change VT_RESIZEX ioctl to save struct vc_data values that are modified and restore the original values in case of error. Signed-off-by: George Kennedy Cc: stable Reported-by: syzbot+38a3699c7eaf165b97a6@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/1596213192-6635-2-git-send-email-george.kennedy@oracle.com Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/tty/vt/vt_ioctl.c b/drivers/tty/vt/vt_ioctl.c index 91c3017750476..a4e520bdd521d 100644 --- a/drivers/tty/vt/vt_ioctl.c +++ b/drivers/tty/vt/vt_ioctl.c @@ -806,12 +806,22 @@ static int vt_resizex(struct vc_data *vc, struct vt_consize __user *cs) console_lock(); vcp = vc_cons[i].d; if (vcp) { + int ret; + int save_scan_lines = vcp->vc_scan_lines; + int save_font_height = vcp->vc_font.height; + if (v.v_vlin) vcp->vc_scan_lines = v.v_vlin; if (v.v_clin) vcp->vc_font.height = v.v_clin; vcp->vc_resize_user = 1; - vc_resize(vcp, v.v_cols, v.v_rows); + ret = vc_resize(vcp, v.v_cols, v.v_rows); + if (ret) { + vcp->vc_scan_lines = save_scan_lines; + vcp->vc_font.height = save_font_height; + console_unlock(); + return ret; + } } console_unlock(); }