From nobody Fri Dec 19 18:52:08 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 B0C56ECAAA1 for ; Mon, 24 Oct 2022 16:17:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231802AbiJXQR1 (ORCPT ); Mon, 24 Oct 2022 12:17:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36746 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234981AbiJXQPg (ORCPT ); Mon, 24 Oct 2022 12:15:36 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DE0374A818; Mon, 24 Oct 2022 08:03:23 -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 ams.source.kernel.org (Postfix) with ESMTPS id 38871B81613; Mon, 24 Oct 2022 12:13:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 97506C433D6; Mon, 24 Oct 2022 12:13:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666613635; bh=ymqqx1RvVFDAG+2fiPlsdd2DsdhocIdcqP2p+8HU/t0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yWsN/mXIaeV8SHdzv4jK7c2MMb8lgdj6oCFES+LIdWkyo0dtL+TPDOg7RXNWIfyCa qyGzLZnTQmV92YXEeO2Ny+O5mQpZRG+iP2rHYXoOvcbuSyWp6PxzeXv39paAd7PQpE yZNUils4idcw+0Z049K89P+dLNIiwUxYfy6anV7c= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Javier Martinez Canillas , Peter Robinson , Thomas Zimmermann , Sasha Levin Subject: [PATCH 5.4 211/255] drm: Use size_t type for len variable in drm_copy_field() Date: Mon, 24 Oct 2022 13:32:01 +0200 Message-Id: <20221024113010.055053979@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221024113002.471093005@linuxfoundation.org> References: <20221024113002.471093005@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: Javier Martinez Canillas [ Upstream commit 94dc3471d1b2b58b3728558d0e3f264e9ce6ff59 ] 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 Link: https://patchwork.freedesktop.org/patch/msgid/20220705100215.572498-2= -javierm@redhat.com Signed-off-by: Sasha Levin --- 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 76b6676b0106..bde71aa67784 100644 --- a/drivers/gpu/drm/drm_ioctl.c +++ b/drivers/gpu/drm/drm_ioctl.c @@ -473,7 +473,7 @@ EXPORT_SYMBOL(drm_invalid_op); */ static int drm_copy_field(char __user *buf, size_t *buf_len, const char *v= alue) { - int len; + size_t len; =20 /* don't overflow userbuf */ len =3D strlen(value); --=20 2.35.1