| Message ID | 20220629200024.187187-2-deller@gmx.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | fbcon: Fixes for screen resolution changes - round 2 | expand |
Hi Helge, On Wed, Jun 29, 2022 at 10:00 PM Helge Deller <deller@gmx.de> wrote: > Prevent that users set a font size which is bigger than the physical screen. > It's unlikely this may happen (because screens are usually much larger than the > fonts and each font char is limited to 32x32 pixels), but it may happen on > smaller screens/LCD displays. > > Signed-off-by: Helge Deller <deller@gmx.de> > Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Thanks for your patch! Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org> > --- a/drivers/video/fbdev/core/fbcon.c > +++ b/drivers/video/fbdev/core/fbcon.c > @@ -2469,6 +2469,11 @@ static int fbcon_set_font(struct vc_data *vc, struct console_font *font, > if (charcount != 256 && charcount != 512) > return -EINVAL; > > + /* font bigger than screen resolution ? */ > + if (font->width > FBCON_SWAP(info->var.rotate, info->var.xres, info->var.yres) || > + font->height > FBCON_SWAP(info->var.rotate, info->var.yres, info->var.xres)) Note that we already have local vars w and h, albeit with the wrong signedness. > + return -EINVAL; > + > /* Make sure drawing engine can handle the font */ > if (!(info->pixmap.blit_x & (1 << (font->width - 1))) || > !(info->pixmap.blit_y & (1 << (font->height - 1)))) There were already more opportunities for using w and h before... Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
On 6/30/22 20:51, Geert Uytterhoeven wrote: > Hi Helge, > > On Wed, Jun 29, 2022 at 10:00 PM Helge Deller <deller@gmx.de> wrote: >> Prevent that users set a font size which is bigger than the physical screen. >> It's unlikely this may happen (because screens are usually much larger than the >> fonts and each font char is limited to 32x32 pixels), but it may happen on >> smaller screens/LCD displays. >> >> Signed-off-by: Helge Deller <deller@gmx.de> >> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> > > Thanks for your patch! > > Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org> > >> --- a/drivers/video/fbdev/core/fbcon.c >> +++ b/drivers/video/fbdev/core/fbcon.c >> @@ -2469,6 +2469,11 @@ static int fbcon_set_font(struct vc_data *vc, struct console_font *font, >> if (charcount != 256 && charcount != 512) >> return -EINVAL; >> >> + /* font bigger than screen resolution ? */ >> + if (font->width > FBCON_SWAP(info->var.rotate, info->var.xres, info->var.yres) || >> + font->height > FBCON_SWAP(info->var.rotate, info->var.yres, info->var.xres)) > > Note that we already have local vars w and h, albeit with the wrong > signedness. I don't like the "h" and "w" variables. Maybe something like "fh" for "font-heigth" would have been better explaining which kind of "h" is meant. I assume that's why the patch below didn't used it either. That said, I'd like to keep it as is (at least for now). Helge >> + return -EINVAL; >> + >> /* Make sure drawing engine can handle the font */ >> if (!(info->pixmap.blit_x & (1 << (font->width - 1))) || >> !(info->pixmap.blit_y & (1 << (font->height - 1)))) > > There were already more opportunities for using w and h before... > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org > > In personal conversations with technical people, I call myself a hacker. But > when I'm talking to journalists I just say "programmer" or something like that. > -- Linus Torvalds
diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c index c4e91715ef00..e162d5e753e5 100644 --- a/drivers/video/fbdev/core/fbcon.c +++ b/drivers/video/fbdev/core/fbcon.c @@ -2469,6 +2469,11 @@ static int fbcon_set_font(struct vc_data *vc, struct console_font *font, if (charcount != 256 && charcount != 512) return -EINVAL; + /* font bigger than screen resolution ? */ + if (font->width > FBCON_SWAP(info->var.rotate, info->var.xres, info->var.yres) || + font->height > FBCON_SWAP(info->var.rotate, info->var.yres, info->var.xres)) + return -EINVAL; + /* Make sure drawing engine can handle the font */ if (!(info->pixmap.blit_x & (1 << (font->width - 1))) || !(info->pixmap.blit_y & (1 << (font->height - 1))))