From nobody Fri Sep 5 20:05:13 2025 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 A71DCC32772 for ; Tue, 23 Aug 2022 11:09:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357168AbiHWLJH (ORCPT ); Tue, 23 Aug 2022 07:09:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48696 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1357409AbiHWLGw (ORCPT ); Tue, 23 Aug 2022 07:06:52 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9374C6DAD3; Tue, 23 Aug 2022 02:16:10 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 7EBB8CE1B5A; Tue, 23 Aug 2022 09:16:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 92E8CC433D6; Tue, 23 Aug 2022 09:16:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1661246167; bh=7Jj2tH95KOIwaTxARlYh01f+IroJdOrakoNNAcv34J0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XeESJ5p6i2u20sxEKBWGtRtY8Z/4GnIvlukIFSke/eZq0ePD3KMVj9Ko8Szraz20G Zlydja07mSxT6wu8zoVRBitrr19Ax0fHZ8syMKzpSVBcef6zaC0g94FGXmuPSfQvxU JBZ/gtYtdVSVZiKjmypIBnGbjIXZa/McLYj4qrW0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot , Jiri Slaby , Tetsuo Handa Subject: [PATCH 5.4 022/389] tty: vt: initialize unicode screen buffer Date: Tue, 23 Aug 2022 10:21:40 +0200 Message-Id: <20220823080116.631573441@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220823080115.331990024@linuxfoundation.org> References: <20220823080115.331990024@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Tetsuo Handa commit af77c56aa35325daa2bc2bed5c2ebf169be61b86 upstream. 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] Cc: stable Reported-by: syzbot Reviewed-by: Jiri Slaby Signed-off-by: Tetsuo Handa Link: https://lore.kernel.org/r/4ef053cf-e796-fb5e-58b7-3ae58242a4ad@I-love= .SAKURA.ne.jp Signed-off-by: Greg Kroah-Hartman --- drivers/tty/vt/vt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -351,7 +351,7 @@ static struct uni_screen *vc_uniscr_allo /* 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;