From nobody Thu Jun 25 09:38:34 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 AF15DC433EF for ; Tue, 22 Feb 2022 08:11:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229617AbiBVILe (ORCPT ); Tue, 22 Feb 2022 03:11:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53176 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229604AbiBVILd (ORCPT ); Tue, 22 Feb 2022 03:11:33 -0500 Received: from mail-pg1-x532.google.com (mail-pg1-x532.google.com [IPv6:2607:f8b0:4864:20::532]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 319C6151D03 for ; Tue, 22 Feb 2022 00:11:08 -0800 (PST) Received: by mail-pg1-x532.google.com with SMTP id 12so12841061pgd.0 for ; Tue, 22 Feb 2022 00:11:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id; bh=1ewwsYJzbOlGrRg/5LtBaFSLY+YVPW6LvHzITLWMd+M=; b=a/XzAzT5Iy3cExR3bLhwAr9dB5ILxwEivpVpU0xEJzXgL71wwn1t5U/+Bhsfxz8URV XOUu0laoAJpZga5y2JZgFtY+YbZUU/WRsbhL2RIDkjD5zHob1Y/BhPNtA1g/kCbP0i7j TK0OBKV7zPTcV5Dj1wUNa72bYXn/m3V9h6sROKkRMLpQFGB46NopD1URys/3aBMtjNov Dbltds12jzJ5CAK6S16cv+Twc1Dwg7DjJXXL13Hqxwb2KcpVHeDtMWu2HWr4pSimxUeg JhBxFS9CBznZ2hN532lK2xk19GuyXc1dFtf/6o3JMv2RIcFfP/5+1eXp+OpCPhafV2Vj K9qQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=1ewwsYJzbOlGrRg/5LtBaFSLY+YVPW6LvHzITLWMd+M=; b=rYq3wnDTSIhQ33A4500og0cpuglrC8vf8KnC7f6y/LImUxE+cWK24wQZVNtTSkZ0me ANMqkwdg33btWU+ye3lnkyA/nBx3dVJN4aQL6MZWfzXMILXBYucBbmh77GiT1gitdYmo LD4nhVeDCKtvPe0tqAJ721UhlDTkQmqNKdal9ukbnHqzpJzWFfG29DeLVvRDrD9q24jK A2lMLaA2BRcxvimuDRibtyIcYvBCwxXjONVnzfkJ2AFfk+dHBiSjRTuMGfBvNZfInLI7 B7SIBxCBMbHZAi6sw4ktdQ08dOJrc3GfZvOWFs7tZLK/QIi/81fgNHpmNhx15vnVbTQ7 bSZA== X-Gm-Message-State: AOAM532tLj3OX6npVKJvn/v87YbVAyJ55KS2yaaufT5AZnXBOOuQVzuM mfOqdLOoyqngKWtCjcklXiQ= X-Google-Smtp-Source: ABdhPJw6OTUtX6GZj2IzCgZBLnhDm741qs5KZgxLmc3O/+HinVZu03+1uiPRVi0gdPIckuJtxHZ4YA== X-Received: by 2002:a63:de46:0:b0:364:cad7:bf3b with SMTP id y6-20020a63de46000000b00364cad7bf3bmr18961824pgi.491.1645517467680; Tue, 22 Feb 2022 00:11:07 -0800 (PST) Received: from ubuntu.huawei.com ([119.3.119.21]) by smtp.googlemail.com with ESMTPSA id w198sm16101185pff.96.2022.02.22.00.11.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 22 Feb 2022 00:11:07 -0800 (PST) From: Xiaomeng Tong To: gregkh@linuxfoundation.org, jirislaby@kernel.org Cc: linux-kernel@vger.kernel.org, Xiaomeng Tong Subject: [PATCH v2] vt_ioctl: fix potential spectre v1 in VT_DISALLOCATE Date: Tue, 22 Feb 2022 16:11:01 +0800 Message-Id: <20220222081101.21233-1-xiam0nd.tong@gmail.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" In VT_ACTIVATE an almost identical code path has been patched with array_index_nospec. In the VT_DISALLOCATE path, the arg is the user input from a system call argument and lately used as a index for vc_cons[index].d access, which can be reached through path like vt_disallocate->vc_busy or vt_disallocate->vc_deallocate. For consistency both code paths should have the same mitigations applied. Also, the code style is adjusted as suggested by Jiri. Signed-off-by: Xiaomeng Tong Reviewed-by: Jiri Slaby --- drivers/tty/vt/vt_ioctl.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/tty/vt/vt_ioctl.c b/drivers/tty/vt/vt_ioctl.c index 580136986..8c685b501 100644 --- a/drivers/tty/vt/vt_ioctl.c +++ b/drivers/tty/vt/vt_ioctl.c @@ -898,11 +898,13 @@ int vt_ioctl(struct tty_struct *tty, if (arg > MAX_NR_CONSOLES) return -ENXIO; =20 - if (arg =3D=3D 0) + if (arg =3D=3D 0) { vt_disallocate_all(); - else - return vt_disallocate(--arg); - break; + break; + } + + arg =3D array_index_nospec(arg - 1, MAX_NR_CONSOLES); + return vt_disallocate(arg); =20 case VT_RESIZE: { --=20 2.17.1