From 94e6a058b16820e02f25e1221a4c4e713ba23550 Mon Sep 17 00:00:00 2001 From: Helge Deller Date: Sat, 22 Aug 2026 12:03:15 +0200 Subject: [PATCH] fbcon: Fix KASAN slab-out-of-bounds Read in fbcon_prepare_logo Ensure the logo will not exceed the screen size, which then should fix a reported KASAN: slab-out-of-bounds Read in fbcon_prepare_logo. Reported-by: syzbot+0c815b25cdb3678e7083@syzkaller.appspotmail.com Signed-off-by: Helge Deller --- drivers/video/fbdev/core/fbcon.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c index 23b3c536d53d..01715873ea49 100644 --- a/drivers/video/fbdev/core/fbcon.c +++ b/drivers/video/fbdev/core/fbcon.c @@ -660,6 +660,13 @@ static void fbcon_prepare_logo(struct vc_data *vc, struct fb_info *info, erase &= ~0x400; logo_height = fb_prepare_logo(info, par->rotate); logo_lines = DIV_ROUND_UP(logo_height, vc->vc_font.height); + logo_lines = min(logo_lines, rows); + logo_lines = min(logo_lines, new_rows - 1); + if (logo_lines <= 0) { + logo_lines = 0; + logo_shown = FBCON_LOGO_DONTSHOW; + return; + } q = (unsigned short *) (vc->vc_origin + vc->vc_size_row * rows); step = logo_lines * cols;