From: Thomas Zimmermann Date: Tue, 7 Apr 2026 09:23:12 +0000 (+0200) Subject: fbcon: Avoid OOB font access if console rotation fails X-Git-Tag: v7.1-rc1~168^2~13 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=e4ef723d8975a2694cc90733a6b888a5e2841842;p=thirdparty%2Flinux.git fbcon: Avoid OOB font access if console rotation fails Clear the font buffer if the reallocation during console rotation fails in fbcon_rotate_font(). The putcs implementations for the rotated buffer will return early in this case. See [1] for an example. Currently, fbcon_rotate_font() keeps the old buffer, which is too small for the rotated font. Printing to the rotated console with a high-enough character code will overflow the font buffer. v2: - fix typos in commit message Signed-off-by: Thomas Zimmermann Fixes: 6cc50e1c5b57 ("[PATCH] fbcon: Console Rotation - Add support to rotate font bitmap") Cc: stable@vger.kernel.org # v2.6.15+ Link: https://elixir.bootlin.com/linux/v6.19/source/drivers/video/fbdev/core/fbcon_ccw.c#L144 # [1] Signed-off-by: Helge Deller --- diff --git a/drivers/video/fbdev/core/fbcon_rotate.c b/drivers/video/fbdev/core/fbcon_rotate.c index 1562a8f20b4f5..5348f6c6f57c7 100644 --- a/drivers/video/fbdev/core/fbcon_rotate.c +++ b/drivers/video/fbdev/core/fbcon_rotate.c @@ -46,6 +46,10 @@ int fbcon_rotate_font(struct fb_info *info, struct vc_data *vc) info->fbops->fb_sync(info); if (par->fd_size < d_cellsize * len) { + kfree(par->fontbuffer); + par->fontbuffer = NULL; + par->fd_size = 0; + dst = kmalloc_array(len, d_cellsize, GFP_KERNEL); if (dst == NULL) { @@ -54,7 +58,6 @@ int fbcon_rotate_font(struct fb_info *info, struct vc_data *vc) } par->fd_size = d_cellsize * len; - kfree(par->fontbuffer); par->fontbuffer = dst; }