From nobody Sat Apr 18 02:49:49 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 32419C43334 for ; Tue, 19 Jul 2022 05:49:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236970AbiGSFt5 (ORCPT ); Tue, 19 Jul 2022 01:49:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50794 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236951AbiGSFtt (ORCPT ); Tue, 19 Jul 2022 01:49:49 -0400 Received: from www262.sakura.ne.jp (www262.sakura.ne.jp [202.181.97.72]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 76E173120B for ; Mon, 18 Jul 2022 22:49:47 -0700 (PDT) Received: from fsav117.sakura.ne.jp (fsav117.sakura.ne.jp [27.133.134.244]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 26J5nfBB028033; Tue, 19 Jul 2022 14:49:41 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav117.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav117.sakura.ne.jp); Tue, 19 Jul 2022 14:49:41 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav117.sakura.ne.jp) Received: from [192.168.1.9] (M106072142033.v4.enabler.ne.jp [106.72.142.33]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id 26J5neQA028024 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NO); Tue, 19 Jul 2022 14:49:41 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Message-ID: <4ef053cf-e796-fb5e-58b7-3ae58242a4ad@I-love.SAKURA.ne.jp> Date: Tue, 19 Jul 2022 14:49:39 +0900 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: [PATCH] tty: vt: initialize unicode screen buffer Content-Language: en-US To: Greg Kroah-Hartman , Jiri Slaby References: <000000000000eca3eb0598e26a3d@google.com> <0000000000000bd4d405ae9d32a4@google.com> Cc: LKML From: Tetsuo Handa In-Reply-To: <0000000000000bd4d405ae9d32a4@google.com> Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" syzbot reports kernel infoleak at vcs_read() [1], for buffer can be read immediately after resize operation. Initialize buffer using kzalloc(). ---------- #include #include #include #include int main(int argc, char *argv[]) { struct fb_var_screeninfo var =3D { }; const int fb_fd =3D open("/dev/fb0", 3); ioctl(fb_fd, FBIOGET_VSCREENINFO, &var); var.yres =3D 0x21; ioctl(fb_fd, FBIOPUT_VSCREENINFO, &var); return read(open("/dev/vcsu", O_RDONLY), &var, sizeof(var)) =3D=3D -1; } ---------- Link: https://syzkaller.appspot.com/bug?extid=3D31a641689d43387f05d3 [1] Reported-by: syzbot Signed-off-by: Tetsuo Handa Reviewed-by: Jiri Slaby --- drivers/tty/vt/vt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c index f8c87c4d7399..6968517d6f8b 100644 --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -344,7 +344,7 @@ static struct uni_screen *vc_uniscr_alloc(unsigned int = cols, unsigned int rows) /* allocate everything in one go */ memsize =3D cols * rows * sizeof(char32_t); memsize +=3D rows * sizeof(char32_t *); - p =3D vmalloc(memsize); + p =3D vzalloc(memsize); if (!p) return NULL; =20 --=20 2.34.1