This is a note to let you know that I've just added the patch titled
fbmem: Reject FB_ACTIVATE_KD_TEXT from userspace
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
fbmem-reject-fb_activate_kd_text-from-userspace.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <sta...@vger.kernel.org> know about it.
>From 6fd33a3333c7916689b8f051a185defe4dd515b0 Mon Sep 17 00:00:00 2001
From: Daniel Vetter <daniel.vet...@ffwll.ch>
Date: Tue, 4 Apr 2023 21:39:34 +0200
Subject: fbmem: Reject FB_ACTIVATE_KD_TEXT from userspace
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From: Daniel Vetter <daniel.vet...@ffwll.ch>
commit 6fd33a3333c7916689b8f051a185defe4dd515b0 upstream.
This is an oversight from dc5bdb68b5b3 ("drm/fb-helper: Fix vt
restore") - I failed to realize that nasty userspace could set this.
It's not pretty to mix up kernel-internal and userspace uapi flags
like this, but since the entire fb_var_screeninfo structure is uapi
we'd need to either add a new parameter to the ->fb_set_par callback
and fb_set_par() function, which has a _lot_ of users. Or some other
fairly ugly side-channel int fb_info. Neither is a pretty prospect.
Instead just correct the issue at hand by filtering out this
kernel-internal flag in the ioctl handling code.
Reviewed-by: Javier Martinez Canillas <javi...@redhat.com>
Acked-by: Maarten Lankhorst <maarten.lankho...@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vet...@intel.com>
Fixes: dc5bdb68b5b3 ("drm/fb-helper: Fix vt restore")
Cc: Alex Deucher <alexander.deuc...@amd.com>
Cc: shl...@fastmail.com
Cc: Michel Dänzer <mic...@daenzer.net>
Cc: Noralf Trønnes <nor...@tronnes.org>
Cc: Thomas Zimmermann <tzimmerm...@suse.de>
Cc: Daniel Vetter <daniel.vet...@intel.com>
Cc: Maarten Lankhorst <maarten.lankho...@linux.intel.com>
Cc: Maxime Ripard <mrip...@kernel.org>
Cc: David Airlie <airl...@linux.ie>
Cc: Daniel Vetter <dan...@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Cc: <sta...@vger.kernel.org> # v5.7+
Cc: Bartlomiej Zolnierkiewicz <b.zolnier...@samsung.com>
Cc: Geert Uytterhoeven <ge...@linux-m68k.org>
Cc: Nathan Chancellor <natechancel...@gmail.com>
Cc: Qiujun Huang <hqjag...@gmail.com>
Cc: Peter Rosin <p...@axentia.se>
Cc: linux-fb...@vger.kernel.org
Cc: Helge Deller <del...@gmx.de>
Cc: Sam Ravnborg <s...@ravnborg.org>
Cc: Geert Uytterhoeven <geert+rene...@glider.be>
Cc: Samuel Thibault <samuel.thiba...@ens-lyon.org>
Cc: Tetsuo Handa <penguin-ker...@i-love.sakura.ne.jp>
Cc: Shigeru Yoshida <syosh...@redhat.com>
Link:
https://patchwork.freedesktop.org/patch/msgid/20230404193934.472457-1-daniel.vet...@ffwll.ch
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/video/fbdev/core/fbmem.c | 2 ++
1 file changed, 2 insertions(+)
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1117,6 +1117,8 @@ static long do_fb_ioctl(struct fb_info *
case FBIOPUT_VSCREENINFO:
if (copy_from_user(&var, argp, sizeof(var)))
return -EFAULT;
+ /* only for kernel-internal use */
+ var.activate &= ~FB_ACTIVATE_KD_TEXT;
console_lock();
lock_fb_info(info);
ret = fbcon_modechange_possible(info, &var);
Patches currently in stable-queue which might be from daniel.vet...@ffwll.ch are
queue-5.10/fbmem-reject-fb_activate_kd_text-from-userspace.patch
