From mboxrd@z Thu Jan 1 00:00:00 1970 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 030C9C43334 for ; Tue, 5 Jul 2022 10:02:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231750AbiGEKCp (ORCPT ); Tue, 5 Jul 2022 06:02:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56342 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231264AbiGEKCk (ORCPT ); Tue, 5 Jul 2022 06:02:40 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id CDFE613E96 for ; Tue, 5 Jul 2022 03:02:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1657015358; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Sq1P6bjPwZGpMS6ut0qkpzOv+ePOi9aPiP7nYH2z6s0=; b=GVyZe242t9JoBVDlPdIJQIZ940fSpUQzr+AsY4kaYsRS8/7VQPbIc4GAexEj/haNwA5RSr Czf6hNSiJpncOvPxBC6cWOktAK0Bv2tl7PRYe5oheLaRR8t33sSSX2cZ5ANAFcZTMNyD4M tasPaFRXq348bGMVLqRJBcPE/1wjU0s= Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-672-3X3HCh6WO72H_DFVkzdeGQ-1; Tue, 05 Jul 2022 06:02:37 -0400 X-MC-Unique: 3X3HCh6WO72H_DFVkzdeGQ-1 Received: by mail-wr1-f72.google.com with SMTP id o1-20020adfba01000000b0021b90bd28d2so1806427wrg.14 for ; Tue, 05 Jul 2022 03:02:37 -0700 (PDT) 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:in-reply-to :references:mime-version:content-transfer-encoding; bh=Sq1P6bjPwZGpMS6ut0qkpzOv+ePOi9aPiP7nYH2z6s0=; b=iIdiqS51J59YXb5umrLxQnO8pEfUjmtKxQqwU04nl4+PhiOtuYcSuhUGAQsflYhiFb 2xLnqB+tskEGoI22k79+XyQ46ZVjUcEnq1OMC6qmAb/YVRnRFQb2f9ehoJG7FiGldOYQ PDpA1P5AYITFndlyk24TxZb7W4XHAxQzi1X+NsTS8mpHqhnLj9yp5LoDAQZXFkd8WEws bbywCFnM6m+OH/t7DlEzStWAjabk4MmESrU0rDlFq7xPHfEWSy6vozE4QtIiTWnfiKJM 4rZlEJsZfClFAUjofxNi62g3JKilKarKEPvULTx5gx5fAuQvUzwsiQOjtmjWkwtnzeth e3XA== X-Gm-Message-State: AJIora93xgef22LgjwEtA22qUR733QlGMl4xpITHtNLFKfqGt7DGOMDz JIBg5ZnFgHDGIM1L4cyeSQGR8WL/vbeaDOMRBRriQskVLovgiPcnzWYMXL9bnIhqUtHNqoPyaTs 8gJ8RL3jJtuAhmg1+OqcBrsKQWzk1QbG1zK1CA1V4HNUoI/FDNbD9EKt9LjXkQB/oyrtbJHqaRZ Y= X-Received: by 2002:adf:e889:0:b0:21d:6510:b750 with SMTP id d9-20020adfe889000000b0021d6510b750mr13203117wrm.498.1657015356468; Tue, 05 Jul 2022 03:02:36 -0700 (PDT) X-Google-Smtp-Source: AGRyM1u8SE6G4/Be28Rs7e4q8Eg7G3RpZqKHzTQ9mDJPsqfzMfDXb7eIz1ukYB668iijCdejuSh1Mw== X-Received: by 2002:adf:e889:0:b0:21d:6510:b750 with SMTP id d9-20020adfe889000000b0021d6510b750mr13203083wrm.498.1657015356198; Tue, 05 Jul 2022 03:02:36 -0700 (PDT) Received: from minerva.home (205.pool92-176-231.dynamic.orange.es. [92.176.231.205]) by smtp.gmail.com with ESMTPSA id f7-20020a0560001b0700b0021d68e1fd42sm6255192wrz.89.2022.07.05.03.02.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 Jul 2022 03:02:35 -0700 (PDT) From: Javier Martinez Canillas To: linux-kernel@vger.kernel.org Cc: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= , Peter Robinson , Thomas Zimmermann , Javier Martinez Canillas , Daniel Vetter , David Airlie , Maarten Lankhorst , Maxime Ripard , dri-devel@lists.freedesktop.org Subject: [PATCH v2 1/2] drm: Use size_t type for len variable in drm_copy_field() Date: Tue, 5 Jul 2022 12:02:13 +0200 Message-Id: <20220705100215.572498-2-javierm@redhat.com> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220705100215.572498-1-javierm@redhat.com> References: <20220705100215.572498-1-javierm@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The strlen() function returns a size_t which is an unsigned int on 32-bit arches and an unsigned long on 64-bit arches. But in the drm_copy_field() function, the strlen() return value is assigned to an 'int len' variable. Later, the len variable is passed as copy_from_user() third argument that is an unsigned long parameter as well. In theory, this can lead to an integer overflow via type conversion. Since the assignment happens to a signed int lvalue instead of a size_t lvalue. In practice though, that's unlikely since the values copied are set by DRM drivers and not controlled by userspace. But using a size_t for len is the correct thing to do anyways. Signed-off-by: Javier Martinez Canillas Tested-by: Peter Robinson Reviewed-by: Thomas Zimmermann --- Changes in v2: - Add Peter Robinson Tested-by and Thomas Zimmermann Reviewed-by tags. drivers/gpu/drm/drm_ioctl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c index 8faad23dc1d8..e1b9a03e619c 100644 --- a/drivers/gpu/drm/drm_ioctl.c +++ b/drivers/gpu/drm/drm_ioctl.c @@ -472,7 +472,7 @@ EXPORT_SYMBOL(drm_invalid_op); */ static int drm_copy_field(char __user *buf, size_t *buf_len, const char *value) { - int len; + size_t len; /* don't overflow userbuf */ len = strlen(value); -- 2.36.1