From 6c11df58fd1ac0aefcb3b227f72769272b939e56 Mon Sep 17 00:00:00 2001 From: Helge Deller Date: Wed, 29 Jun 2022 15:53:55 +0200 Subject: fbmem: Check virtual screen sizes in fb_set_var() Verify that the fbdev or drm driver correctly adjusted the virtual screen sizes. On failure report the failing driver and reject the screen size change. Signed-off-by: Helge Deller Reviewed-by: Geert Uytterhoeven Cc: stable@vger.kernel.org # v5.4+ --- drivers/video/fbdev/core/fbmem.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c index 7dc6848a96bb..7ee6eb2fa715 100644 --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -1017,6 +1017,16 @@ fb_set_var(struct fb_info *info, struct fb_var_screeninfo *var) if (ret) return ret; + /* verify that virtual resolution >= physical resolution */ + if (var->xres_virtual < var->xres || + var->yres_virtual < var->yres) { + pr_warn("WARNING: fbcon: Driver '%s' missed to adjust virtual screen size (%ux%u vs. %ux%u)\n", + info->fix.id, + var->xres_virtual, var->yres_virtual, + var->xres, var->yres); + return -EINVAL; + } + if ((var->activate & FB_ACTIVATE_MASK) != FB_ACTIVATE_NOW) return 0; -- cgit v1.2.3