From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 B62DCBA4F for ; Tue, 7 Mar 2023 19:09:22 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 347C4C433D2; Tue, 7 Mar 2023 19:09:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1678216162; bh=kv61pPeZdtdgwx4Z+2SU5Ux9voCWAYw/Wef2lFVUXR4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EwHS15YgmZfC7nWEekBy0VWecv4ceSu2Ii+YrBjksnSmkqlZTxIbjFmHlqXAL6VSj niwYQeuQ9wk9cFjthClMYiqoJlN3ItsZZhYBwzfsR54bcJY/qIFrhF7KM2D5sXDPyk VFPK7qAVGsDMXsjPQCcbKS65dp/gXshuxE1gPkyQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Andy Nguyen , Thomas Lendacky , Peter Gonda , David Rientjes , Paolo Bonzini , Sean Christopherson , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 5.15 468/567] KVM: SVM: Fix potential overflow in SEVs send|receive_update_data() Date: Tue, 7 Mar 2023 18:03:24 +0100 Message-Id: <20230307165926.158959863@linuxfoundation.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230307165905.838066027@linuxfoundation.org> References: <20230307165905.838066027@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Peter Gonda commit f94f053aa3a5d6ff17951870483d9eb9e13de2e2 upstream. KVM_SEV_SEND_UPDATE_DATA and KVM_SEV_RECEIVE_UPDATE_DATA have an integer overflow issue. Params.guest_len and offset are both 32 bits wide, with a large params.guest_len the check to confirm a page boundary is not crossed can falsely pass: /* Check if we are crossing the page boundary * offset = params.guest_uaddr & (PAGE_SIZE - 1); if ((params.guest_len + offset > PAGE_SIZE)) Add an additional check to confirm that params.guest_len itself is not greater than PAGE_SIZE. Note, this isn't a security concern as overflow can happen if and only if params.guest_len is greater than 0xfffff000, and the FW spec says these commands fail with lengths greater than 16KB, i.e. the PSP will detect KVM's goof. Fixes: 15fb7de1a7f5 ("KVM: SVM: Add KVM_SEV_RECEIVE_UPDATE_DATA command") Fixes: d3d1af85e2c7 ("KVM: SVM: Add KVM_SEND_UPDATE_DATA command") Reported-by: Andy Nguyen Suggested-by: Thomas Lendacky Signed-off-by: Peter Gonda Cc: David Rientjes Cc: Paolo Bonzini Cc: Sean Christopherson Cc: kvm@vger.kernel.org Cc: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org Reviewed-by: Tom Lendacky Link: https://lore.kernel.org/r/20230207171354.4012821-1-pgonda@google.com Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/svm/sev.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -1277,7 +1277,7 @@ static int sev_send_update_data(struct k /* Check if we are crossing the page boundary */ offset = params.guest_uaddr & (PAGE_SIZE - 1); - if ((params.guest_len + offset > PAGE_SIZE)) + if (params.guest_len > PAGE_SIZE || (params.guest_len + offset) > PAGE_SIZE) return -EINVAL; /* Pin guest memory */ @@ -1457,7 +1457,7 @@ static int sev_receive_update_data(struc /* Check if we are crossing the page boundary */ offset = params.guest_uaddr & (PAGE_SIZE - 1); - if ((params.guest_len + offset > PAGE_SIZE)) + if (params.guest_len > PAGE_SIZE || (params.guest_len + offset) > PAGE_SIZE) return -EINVAL; hdr = psp_copy_user_blob(params.hdr_uaddr, params.hdr_len);