linux-kernel - Re: [syzbot] BUG: unable to handle kernel NULL pointer dereference in fbcon

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <0000000000004c2375062231e807@google.com>
Date: Sun, 15 Sep 2024 17:46:46 -0700
From: syzbot <syzbot+3d613ae53c031502687a@...kaller.appspotmail.com>
To: linux-kernel@...r.kernel.org
Subject: Re: [syzbot] BUG: unable to handle kernel NULL pointer dereference in fbcon_putcs

For archival purposes, forwarding an incoming command email to
linux-kernel@...r.kernel.org.

***

Subject: BUG: unable to handle kernel NULL pointer dereference in fbcon_putcs
Author: qianqiang.liu@....com

#syz test

diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index 3f7333dca508..96c1262cc981 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -1284,7 +1284,7 @@ static void fbcon_putcs(struct vc_data *vc, const u16 *s, unsigned int count,
 	struct fbcon_display *p = &fb_display[vc->vc_num];
 	struct fbcon_ops *ops = info->fbcon_par;
 
-	if (!fbcon_is_inactive(vc, info))
+	if (!fbcon_is_inactive(vc, info) && ops->putcs)
 		ops->putcs(vc, info, s, count, real_y(p, ypos), xpos,
 			   get_color(vc, info, scr_readw(s), 1),
 			   get_color(vc, info, scr_readw(s), 0));

-- 
Best,
Qianqiang Liu