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[149.14.88.26]) by smtp.gmail.com with ESMTPSA id b16-20020a05600010d000b0031aef72a021sm11830334wrx.86.2023.09.18.02.13.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 18 Sep 2023 02:13:49 -0700 (PDT) Message-ID: <72a444cd42629f5bdd56647e7aa24588d6964bec.camel@redhat.com> Subject: Re: [PATCH v2 1/5] string.h: add array-wrappers for (v)memdup_user() From: Philipp Stanner To: Dan Carpenter Cc: Kees Cook , Andy Shevchenko , Eric Biederman , Christian Brauner , David Disseldorp , Luis Chamberlain , Siddh Raman Pant , Nick Alcock , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , Zack Rusin , VMware Graphics Reviewers , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-hardening@vger.kernel.org, David Airlie Date: Mon, 18 Sep 2023 11:13:48 +0200 In-Reply-To: References: <93001a9f3f101be0f374080090f9c32df73ca773.1694202430.git.pstanner@redhat.com> User-Agent: Evolution 3.48.4 (3.48.4-1.fc38) MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org On Sat, 2023-09-16 at 17:32 +0300, Dan Carpenter wrote: > On Fri, Sep 08, 2023 at 09:59:40PM +0200, Philipp Stanner wrote: > > +static inline void *memdup_array_user(const void __user *src, > > size_t n, size_t size) > > +{ > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0size_t nbytes; > > + > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0if (unlikely(check_mul_overf= low(n, size, &nbytes))) > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0return ERR_PTR(-EOVERFLOW); >=20 > No need for an unlikely() because check_mul_overflow() already has > one > inside. ACK. I overlooked that as it was hidden in the callstack. > =C2=A0 I feel like -ENOMEM is more traditional but I doubt > anyone/userspace > cares. I agree with Andy here. We're not allocating, so -ENOMEM makes no sense IMO. P. >=20 > > + > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0return memdup_user(src, nbyt= es); > > +} >=20 > regards, > dan carpenter >=20 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0360FC46CA1 for ; Mon, 18 Sep 2023 09:14:08 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 40FE010E23B; Mon, 18 Sep 2023 09:14:06 +0000 (UTC) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by gabe.freedesktop.org (Postfix) with ESMTPS id 3402D10E237 for ; Mon, 18 Sep 2023 09:13:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1695028434; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ySETEWMBBYemMdp3jyvFHrMDlDasjAvK3U0xoCA3NQU=; b=cd42VR+RzlMdxl2zq5h68JxAWA8yz9ZBAJOKiUVT3dhi3Lh3XLe7PsYjrzdRkGYwBOj9Zg RQ5B9x9uDHJvs+J7Ose05SKJ2WJjpmWVxfvQlBQ2QwXTknFhm9r27dysILszFa1kVglnSs Lg2Q1OKi5RFTi1boQdgEFkBDB2qbXMY= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-19-Pse6RQ-xMTmWHBkcDjThyg-1; Mon, 18 Sep 2023 05:13:51 -0400 X-MC-Unique: Pse6RQ-xMTmWHBkcDjThyg-1 Received: by mail-wm1-f69.google.com with SMTP id 5b1f17b1804b1-404daa4f5a7so7379575e9.1 for ; Mon, 18 Sep 2023 02:13:51 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1695028430; x=1695633230; h=mime-version:user-agent:content-transfer-encoding:references :in-reply-to:date:cc:to:from:subject:message-id:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=ySETEWMBBYemMdp3jyvFHrMDlDasjAvK3U0xoCA3NQU=; b=r8jyv/0Ff9jVE6fc6GACfLf6Orax/FNplZ6ywIR9LMFTje0udNZ4rWZEPtEixAzmlE /ZqCUWSxIkxQoMQtIKe8OmWoTqS4HUlph5QGkb2g1/vHOPQM/Dj8Jg7S5/fhPNgDm1/2 pJHTGTcZFJmSmshA48gCUFNi2tvFP/1jAepoh61iR3jjLwKVavspdK53aoauECWTk2Gh LTxEypEt9NdTPKCHRQEMB4pTVtOjJcShMjay/Pe2NCWs0UYtKyPZ3KeVGoQuJNvBwtBy PZmYiO9O5p69sLP4Vsle4jBazWiB1kYjfBZtZI7nf7BEONC3LqWK6yVNJ5z5fn6TPLy+ iPSA== X-Gm-Message-State: AOJu0Yzq/PtenL6bnShXMIV5sr2bjY499HgIK0EWZGim7OVK9YOIDXxz i8gfBiyloFmYW6fV9xtPyoyynkutrM24HxL+RCkC25NUGwhaB2SF3+39CfTAMa4Dn1Odbh6hcds qlHGWgtIdWPedx+zUS2AxdkOVavmp X-Received: by 2002:a5d:508e:0:b0:317:73e3:cf41 with SMTP id a14-20020a5d508e000000b0031773e3cf41mr6416391wrt.1.1695028430603; Mon, 18 Sep 2023 02:13:50 -0700 (PDT) X-Google-Smtp-Source: AGHT+IGB8VnbhuBBqYU4diZ/ky5juLhWgDDI8ddqsgXauCCvjjTxBkK6OXa7bUUeWyDSF9cThUqM3g== X-Received: by 2002:a5d:508e:0:b0:317:73e3:cf41 with SMTP id a14-20020a5d508e000000b0031773e3cf41mr6416363wrt.1.1695028430263; Mon, 18 Sep 2023 02:13:50 -0700 (PDT) Received: from [10.32.64.2] (nat-pool-muc-t.redhat.com. [149.14.88.26]) by smtp.gmail.com with ESMTPSA id b16-20020a05600010d000b0031aef72a021sm11830334wrx.86.2023.09.18.02.13.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 18 Sep 2023 02:13:49 -0700 (PDT) Message-ID: <72a444cd42629f5bdd56647e7aa24588d6964bec.camel@redhat.com> Subject: Re: [PATCH v2 1/5] string.h: add array-wrappers for (v)memdup_user() From: Philipp Stanner To: Dan Carpenter Date: Mon, 18 Sep 2023 11:13:48 +0200 In-Reply-To: References: <93001a9f3f101be0f374080090f9c32df73ca773.1694202430.git.pstanner@redhat.com> User-Agent: Evolution 3.48.4 (3.48.4-1.fc38) MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Andy Shevchenko , Christian Brauner , Siddh Raman Pant , Kees Cook , kexec@lists.infradead.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Maxime Ripard , linux-hardening@vger.kernel.org, Luis Chamberlain , VMware Graphics Reviewers , Eric Biederman , Thomas Zimmermann , David Airlie , David Disseldorp , Nick Alcock Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Sat, 2023-09-16 at 17:32 +0300, Dan Carpenter wrote: > On Fri, Sep 08, 2023 at 09:59:40PM +0200, Philipp Stanner wrote: > > +static inline void *memdup_array_user(const void __user *src, > > size_t n, size_t size) > > +{ > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0size_t nbytes; > > + > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0if (unlikely(check_mul_overf= low(n, size, &nbytes))) > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0return ERR_PTR(-EOVERFLOW); >=20 > No need for an unlikely() because check_mul_overflow() already has > one > inside. ACK. I overlooked that as it was hidden in the callstack. > =C2=A0 I feel like -ENOMEM is more traditional but I doubt > anyone/userspace > cares. I agree with Andy here. We're not allocating, so -ENOMEM makes no sense IMO. P. >=20 > > + > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0return memdup_user(src, nbyt= es); > > +} >=20 > regards, > dan carpenter >=20