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.gnu.org (lists.gnu.org [209.51.188.17]) (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 C18BBCA0EDC for ; Tue, 12 Aug 2025 10:02:37 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ullp5-0002FJ-4W; Tue, 12 Aug 2025 06:01:39 -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 1ullp2-0002EW-1k for qemu-devel@nongnu.org; Tue, 12 Aug 2025 06:01:36 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ullos-0004vu-H6 for qemu-devel@nongnu.org; Tue, 12 Aug 2025 06:01:31 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1754992879; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=jN2ij8af1dnCmSc1kGgSBlKEEnJ3MJUar/jrXC2tiMQ=; b=Rw3O+TJaAjbsuB2i4lVQaDiFlxtJ0gpzGadOmKwPLFhah+djLCUla+S80sxPvAekmdRLV4 cEP4zwPuoK2AmOhgSDmo8wSpQxXgZ7+QzbAWXpXKRQEjR0fi7Qsgph4l5PpjPRELeZ1LGd +yC2L28PaGIjkjFr6YGQiHGDL0y5FdY= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-454-R4sqTIZPP7u2e0ubHNXNdw-1; Tue, 12 Aug 2025 06:01:15 -0400 X-MC-Unique: R4sqTIZPP7u2e0ubHNXNdw-1 X-Mimecast-MFC-AGG-ID: R4sqTIZPP7u2e0ubHNXNdw_1754992874 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 893511800292; Tue, 12 Aug 2025 10:01:14 +0000 (UTC) Received: from sirius.home.kraxel.org (unknown [10.45.224.64]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id EC5C7180028A; Tue, 12 Aug 2025 10:01:13 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id 47B9F18000B4; Tue, 12 Aug 2025 12:01:11 +0200 (CEST) From: Gerd Hoffmann To: qemu-devel@nongnu.org Cc: Gerd Hoffmann , Mauro Matteo Cascella , ZDI Subject: [PULL 1/4] hw/uefi: clear uefi-vars buffer in uefi_vars_write callback Date: Tue, 12 Aug 2025 12:01:07 +0200 Message-ID: <20250812100111.1520917-2-kraxel@redhat.com> In-Reply-To: <20250812100111.1520917-1-kraxel@redhat.com> References: <20250812100111.1520917-1-kraxel@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Received-SPF: pass client-ip=170.10.133.124; envelope-from=kraxel@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-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+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org 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 --- hw/uefi/var-service-core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/hw/uefi/var-service-core.c b/hw/uefi/var-service-core.c index feec5a59583b..6ab8df091aaf 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 = val; g_free(uv->buffer); g_free(uv->pio_xfer_buffer); - uv->buffer = g_malloc(uv->buf_size); - uv->pio_xfer_buffer = g_malloc(uv->buf_size); + uv->buffer = g_malloc0(uv->buf_size); + uv->pio_xfer_buffer = g_malloc0(uv->buf_size); break; case UEFI_VARS_REG_DMA_BUFFER_ADDR_LO: uv->buf_addr_lo = val; -- 2.50.1