From nobody Sun Sep 28 15:58:44 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1756308129580298.30669083877865; Wed, 27 Aug 2025 08:22:09 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1urHnZ-0006VV-GX; Wed, 27 Aug 2025 11:10:53 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1urHlb-0000x9-G6; Wed, 27 Aug 2025 11:08:52 -0400 Received: from isrv.corpit.ru ([212.248.84.144]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1urHlZ-0005te-RD; Wed, 27 Aug 2025 11:08:51 -0400 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id 5006F14C561; Wed, 27 Aug 2025 18:03:00 +0300 (MSK) Received: from think4mjt.tls.msk.ru (mjtthink.wg.tls.msk.ru [192.168.177.146]) by tsrv.corpit.ru (Postfix) with ESMTP id 3D70D269868; Wed, 27 Aug 2025 18:03:27 +0300 (MSK) From: Michael Tokarev To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Mauro Matteo Cascella , ZDI , Gerd Hoffmann , Michael Tokarev Subject: [Stable-10.0.4 56/59] hw/uefi: clear uefi-vars buffer in uefi_vars_write callback Date: Wed, 27 Aug 2025 18:03:01 +0300 Message-ID: <20250827150323.2694101-56-mjt@tls.msk.ru> X-Mailer: git-send-email 2.47.2 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=212.248.84.144; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZM-MESSAGEID: 1756308130569116600 Content-Type: text/plain; charset="utf-8" From: Mauro Matteo Cascella When the guest writes to register UEFI_VARS_REG_BUFFER_SIZE, the .write callback `uefi_vars_write` is invoked. The function allocates a heap buffer without zeroing the memory, leaving the buffer filled with residual data from prior allocations. When the guest later reads from register UEFI_VARS_REG_PIO_BUFFER_TRANSFER, the .read callback `uefi_vars_read` returns leftover metadata or other sensitive process memory from the previously allocated buffer, leading to an information disclosure vulnerability. Fixes: CVE-2025-8860 Fixes: 90ca4e03c27d ("hw/uefi: add var-service-core.c") Reported-by: ZDI Suggested-by: Gerd Hoffmann Signed-off-by: Mauro Matteo Cascella Message-ID: <20250811101128.17661-1-mcascell@redhat.com> Signed-off-by: Gerd Hoffmann (cherry picked from commit f757d9d90d19b914d4023663bfc4da73bbbf007e) Signed-off-by: Michael Tokarev diff --git a/hw/uefi/var-service-core.c b/hw/uefi/var-service-core.c index 4836a0cb81..92fc121fe7 100644 --- a/hw/uefi/var-service-core.c +++ b/hw/uefi/var-service-core.c @@ -259,8 +259,8 @@ static void uefi_vars_write(void *opaque, hwaddr addr, = uint64_t val, unsigned si uv->buf_size =3D val; g_free(uv->buffer); g_free(uv->pio_xfer_buffer); - uv->buffer =3D g_malloc(uv->buf_size); - uv->pio_xfer_buffer =3D g_malloc(uv->buf_size); + uv->buffer =3D g_malloc0(uv->buf_size); + uv->pio_xfer_buffer =3D g_malloc0(uv->buf_size); break; case UEFI_VARS_REG_DMA_BUFFER_ADDR_LO: uv->buf_addr_lo =3D val; --=20 2.47.2