From f453f32f13320137f2317c0ad7ae1c20508effca Mon Sep 17 00:00:00 2001 From: Helge Deller Date: Thu, 29 Aug 2024 18:14:04 +0200 Subject: [PATCH] fbmem: Check virtual screen sizes in fb_set_var() commit 6c11df58fd1ac0aefcb3b227f72769272b939e56 upstream. 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+ Signed-off-by: Hugo SIMELIERE Signed-off-by: Greg Kroah-Hartman --- drivers/video/fbdev/core/fbmem.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c index 4449c1fa9f76..114a8c534406 100644 --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -1006,6 +1006,17 @@ fb_set_var(struct fb_info *info, struct fb_var_screeninfo *var) if (ret) goto done; + /* 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); + ret = -EINVAL; + goto done; + } + if ((var->activate & FB_ACTIVATE_MASK) == FB_ACTIVATE_NOW) { struct fb_var_screeninfo old_var; struct fb_videomode mode;