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 lists.trustedfirmware.org (lists.trustedfirmware.org [18.214.241.189]) (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 83008CD5BA4 for ; Thu, 21 May 2026 08:28:57 +0000 (UTC) Received: from lists.trustedfirmware.org (localhost [127.0.0.1]) by lists.trustedfirmware.org (Postfix) with ESMTP id BC9C544409 for ; Thu, 21 May 2026 08:28:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=lists.trustedfirmware.org; s=2024; t=1779352136; bh=K03Hlau5euY6gYBleQCs9QJdLkV+rr4sRlhVnlv6hAE=; h=Date:To:Subject:In-Reply-To:References:CC:List-Id:List-Archive: List-Help:List-Owner:List-Post:List-Subscribe:List-Unsubscribe: From:Reply-To:From; b=JCphcMdRWGsb9fEx6Q3ZSu7qr81Vljh8Jgci+pSn9MypFwE3azY8rp4O2HcNfsit5 0ePWyPWNkl6TyeFftUvIzrMf/6JNORDLYDuM2I6ia20B6ldqwJJzHSD5/vT49G6uMU qpT+eIbG4qWA/UVxblLXzcztArOUgEuifKgfxuuXVmyQnZpeZxVe0KpTwekH/S9+LN Lxk6n3+5wKrwf191DDz50zlD2HjCLL7ERyrGXwGckKE/JcMxzzwFDfg30Fbz7yLlGl IMBE7mVvq89+eTmGFSCqy75KFObd3BGB5FGX0ajCn0o7Zpws0gDoqlVNll0zvx5rlZ KeGEyG0d2S8Ww== Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by lists.trustedfirmware.org (Postfix) with ESMTPS id 6C425432A9 for ; Thu, 21 May 2026 08:28:49 +0000 (UTC) Authentication-Results: lists.trustedfirmware.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=NZPvq/pe; dkim-atps=neutral Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 1987A60172; Thu, 21 May 2026 08:28:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C25181F000E9; Thu, 21 May 2026 08:28:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779352128; bh=IbrqkoxuIfuNzeQcrLxNqThPnsSnqR3/o+5bhGiZKOI=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=NZPvq/peiYfTyDVIp3F+Aljz//iv56RDcCaX/tAgq0lzSLauBGyLngblpRNUydbd6 kY1dCkdgp7Kwr904Q0XAvSR3lEP8dFaHVkB6druHeRG5iL51dHVzsbtu+ok8HXQK0J qxS0ZTqeC8Ofa2PJxGiMXYSR/y3kU0Gfadpz+8AFzF5h+cOGllkxCMp9xfnBY1PqkV sMXYgl8kHOAmyVWlFNf8TiZW2G8+jsytBf+B0HrcU+/p+QrBzl7BGw8I+s/Ap1dbVf nEYn/iuOeCVLKw3L6h2tkHYU7woRjNwH0zRD9uf6PUpCoc3N9XarG4XimB59LNIpw+ GmSIV0Gp0lfrQ== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1wPylq-00000004j0s-2duA; Thu, 21 May 2026 08:28:46 +0000 Date: Thu, 21 May 2026 09:28:46 +0100 Message-ID: <86ldddw4ht.wl-maz@kernel.org> To: Mostafa Saleh Subject: Re: [PATCH v4 4/5] KVM: arm64: Fix bounds checking in do_ffa_mem_reclaim() In-Reply-To: <20260520204948.2440882-5-smostafa@google.com> References: <20260520204948.2440882-1-smostafa@google.com> <20260520204948.2440882-5-smostafa@google.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: smostafa@google.com, op-tee@lists.trustedfirmware.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, oupton@kernel.org, joey.gouly@arm.com, suzuki.poulose@arm.com, catalin.marinas@arm.com, jens.wiklander@linaro.org, sumit.garg@kernel.org, sebastianene@google.com, vdonnefort@google.com, sudeep.holla@kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-Rspamd-Action: no action X-Spamd-Result: default: False [-4.00 / 15.00]; BAYES_HAM(-3.00)[99.99%]; DWL_DNSWL_LOW(-1.00)[kernel.org:dkim]; MID_CONTAINS_FROM(1.00)[]; DMARC_POLICY_ALLOW(-0.50)[kernel.org,quarantine]; R_DKIM_ALLOW(-0.20)[kernel.org:s=k20260515]; R_SPF_ALLOW(-0.20)[+ip4:172.105.4.254]; MIME_GOOD(-0.10)[text/plain]; MIME_TRACE(0.00)[0:+]; TO_DN_SOME(0.00)[]; ASN(0.00)[asn:63949, ipnet:172.105.0.0/19, country:SG]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCPT_COUNT_TWELVE(0.00)[14]; ARC_NA(0.00)[]; NEURAL_HAM(-0.00)[-1.000]; RCVD_TLS_LAST(0.00)[]; FROM_HAS_DN(0.00)[]; RCVD_COUNT_THREE(0.00)[3]; FROM_EQ_ENVFROM(0.00)[]; DNSWL_BLOCKED(0.00)[172.105.4.254:from,185.219.108.64:received]; TO_MATCH_ENVRCPT_SOME(0.00)[]; DKIM_TRACE(0.00)[kernel.org:+] X-Rspamd-Server: lists.trustedfirmware.org X-Rspamd-Queue-Id: 6C425432A9 X-Spamd-Bar: --- Message-ID-Hash: 3IFKBA7NSVUDIXJT4N2KNISPTFZOFDNZ X-Message-ID-Hash: 3IFKBA7NSVUDIXJT4N2KNISPTFZOFDNZ X-MailFrom: maz@kernel.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-op-tee.lists.trustedfirmware.org-0; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: op-tee@lists.trustedfirmware.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, oupton@kernel.org, joey.gouly@arm.com, suzuki.poulose@arm.com, catalin.marinas@arm.com, sumit.garg@kernel.org, sebastianene@google.com, vdonnefort@google.com, sudeep.holla@kernel.org X-Mailman-Version: 3.3.5 Precedence: list List-Id: Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: From: Marc Zyngier via OP-TEE Reply-To: Marc Zyngier On Wed, 20 May 2026 21:49:47 +0100, Mostafa Saleh wrote: > > Sashiko (locally) reports out of bound write possiblity if SPMD > returns an invalid data. > > While SPMD is considered trusted, pKVM does some basic checks, > for offset to be less than or equal len. > > However, that is incorrect as even if the offset is smaller than > len pKVM can still access out of bound memory in the next > ffa_host_unshare_ranges(). > > Split this check into 2: > 1- Check that the fixed portion of the descriptor fits. > 2- After getting reg, check the variable array size addr_range_cnt > fits. > > Signed-off-by: Mostafa Saleh > --- > arch/arm64/kvm/hyp/nvhe/ffa.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c > index 1af722771178..e6aa2bfa63b1 100644 > --- a/arch/arm64/kvm/hyp/nvhe/ffa.c > +++ b/arch/arm64/kvm/hyp/nvhe/ffa.c > @@ -607,7 +607,7 @@ static void do_ffa_mem_reclaim(struct arm_smccc_1_2_regs *res, > * check that we end up with something that doesn't look _completely_ > * bogus. > */ > - if (WARN_ON(offset > len || > + if (WARN_ON(offset + CONSTITUENTS_OFFSET(0) > len || > fraglen > KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE)) { Do you really want to keep this a WARN_ON(), given that this results in a panic in most pKVM configurations? Thanks, M. -- Without deviation from the norm, progress is not possible. From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5A7A1261B91; Thu, 21 May 2026 08:28:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779352131; cv=none; b=RJtcoJRoBab8Ye4Bxu3767uOnfBDcoImHahqVzKyrmW2/8x3rfBrOuLP6icNrFGGTIHBWih/mBOTbbnkUnrdsq6MgL9C40JIAd2X9B7UydEn+/fwmUPmTFmfOwnsEW24+V8tv4EJL5tqI/tHSDIOfRaR62AHPueV/t1zSJaspcQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779352131; c=relaxed/simple; bh=K03Hlau5euY6gYBleQCs9QJdLkV+rr4sRlhVnlv6hAE=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=CmvVFKSRhCeA5lCJZaH2BvOyp6P9nE/vBD+MfXucj29MM5LNpQQusUExzVNQXx13qowmoyqeaVqyKg86hGz8umUx2a7RCOhkLTZykaSQIu8VbhpLIHeNIFSBu105f5HwLlkoe0/iSbL+LEAhG2nhF/A7WStFqn1SXAVkVPr75jg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=NZPvq/pe; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="NZPvq/pe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C25181F000E9; Thu, 21 May 2026 08:28:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779352128; bh=IbrqkoxuIfuNzeQcrLxNqThPnsSnqR3/o+5bhGiZKOI=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=NZPvq/peiYfTyDVIp3F+Aljz//iv56RDcCaX/tAgq0lzSLauBGyLngblpRNUydbd6 kY1dCkdgp7Kwr904Q0XAvSR3lEP8dFaHVkB6druHeRG5iL51dHVzsbtu+ok8HXQK0J qxS0ZTqeC8Ofa2PJxGiMXYSR/y3kU0Gfadpz+8AFzF5h+cOGllkxCMp9xfnBY1PqkV sMXYgl8kHOAmyVWlFNf8TiZW2G8+jsytBf+B0HrcU+/p+QrBzl7BGw8I+s/Ap1dbVf nEYn/iuOeCVLKw3L6h2tkHYU7woRjNwH0zRD9uf6PUpCoc3N9XarG4XimB59LNIpw+ GmSIV0Gp0lfrQ== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1wPylq-00000004j0s-2duA; Thu, 21 May 2026 08:28:46 +0000 Date: Thu, 21 May 2026 09:28:46 +0100 Message-ID: <86ldddw4ht.wl-maz@kernel.org> From: Marc Zyngier To: Mostafa Saleh Cc: op-tee@lists.trustedfirmware.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, oupton@kernel.org, joey.gouly@arm.com, suzuki.poulose@arm.com, catalin.marinas@arm.com, jens.wiklander@linaro.org, sumit.garg@kernel.org, sebastianene@google.com, vdonnefort@google.com, sudeep.holla@kernel.org Subject: Re: [PATCH v4 4/5] KVM: arm64: Fix bounds checking in do_ffa_mem_reclaim() In-Reply-To: <20260520204948.2440882-5-smostafa@google.com> References: <20260520204948.2440882-1-smostafa@google.com> <20260520204948.2440882-5-smostafa@google.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: smostafa@google.com, op-tee@lists.trustedfirmware.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, oupton@kernel.org, joey.gouly@arm.com, suzuki.poulose@arm.com, catalin.marinas@arm.com, jens.wiklander@linaro.org, sumit.garg@kernel.org, sebastianene@google.com, vdonnefort@google.com, sudeep.holla@kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Wed, 20 May 2026 21:49:47 +0100, Mostafa Saleh wrote: > > Sashiko (locally) reports out of bound write possiblity if SPMD > returns an invalid data. > > While SPMD is considered trusted, pKVM does some basic checks, > for offset to be less than or equal len. > > However, that is incorrect as even if the offset is smaller than > len pKVM can still access out of bound memory in the next > ffa_host_unshare_ranges(). > > Split this check into 2: > 1- Check that the fixed portion of the descriptor fits. > 2- After getting reg, check the variable array size addr_range_cnt > fits. > > Signed-off-by: Mostafa Saleh > --- > arch/arm64/kvm/hyp/nvhe/ffa.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c > index 1af722771178..e6aa2bfa63b1 100644 > --- a/arch/arm64/kvm/hyp/nvhe/ffa.c > +++ b/arch/arm64/kvm/hyp/nvhe/ffa.c > @@ -607,7 +607,7 @@ static void do_ffa_mem_reclaim(struct arm_smccc_1_2_regs *res, > * check that we end up with something that doesn't look _completely_ > * bogus. > */ > - if (WARN_ON(offset > len || > + if (WARN_ON(offset + CONSTITUENTS_OFFSET(0) > len || > fraglen > KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE)) { Do you really want to keep this a WARN_ON(), given that this results in a panic in most pKVM configurations? Thanks, M. -- Without deviation from the norm, progress is not possible.