github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-11-07 06:17:02 +01:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

fbcon: Avoid OOB font access if console rotation fails

Browse Source 
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 <tzimmermann@suse.de>
Fixes: 6cc50e1c5b ("[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 <deller@gmx.de>
This commit is contained in:
Thomas Zimmermann 2026-04-07 11:23:12 +02:00 committed by Helge Deller
parent a9cdba5c35
commit e4ef723d89
1 changed files with 4 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
drivers/video/fbdev/core/fbcon_rotate.c
View File

@ -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;
}