Re: [PATCH v4 2/3] VT: Add KDFONTINFO ioctl

From: Jiri Slaby
Date: Wed Apr 03 2024 - 01:05:31 EST


First, there was no need to send this v4 so quickly. Provided we have not settled in v3... This makes the review process painful.

And then:

On 02. 04. 24, 19:50, Alexey Gladkov wrote:
Each driver has its own restrictions on font size. There is currently no
way to understand what the requirements are. The new ioctl allows
userspace to get the minimum and maximum font size values.

Acked-by: Helge Deller <deller@xxxxxx>
Signed-off-by: Alexey Gladkov <legion@xxxxxxxxxx>
..
--- a/drivers/tty/vt/vt_ioctl.c
+++ b/drivers/tty/vt/vt_ioctl.c
@@ -479,6 +479,17 @@ static int vt_k_ioctl(struct tty_struct *tty, unsigned int cmd,
break;
}
+ case KDFONTINFO: {
+ struct console_font_info fnt_info;
+
+ ret = con_font_info(vc, &fnt_info);
+ if (ret)
+ return ret;
+ if (copy_to_user(up, &fnt_info, sizeof(fnt_info)))

sizeof, I already commented.

Now you leak info to userspace unless everyone sets everything in fnt_info. IOW, do memset() above.

+ return -EFAULT;
+ break;
+ }
+
default:
return -ENOIOCTLCMD;
}

thanks,
--
js
suse labs