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Tsirkin" , Stefano Garzarella , DARKNAVY Subject: [PATCH 1/2] libvhost-user: fix buffer overflow in virtqueue_read_indirect_desc() Date: Fri, 17 Apr 2026 15:26:44 +0200 Message-ID: <20260417132645.121192-2-sgarzare@redhat.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260417132645.121192-1-sgarzare@redhat.com> References: <20260417132645.121192-1-sgarzare@redhat.com> 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=lists1p.gnu.org; Received-SPF: pass client-ip=170.10.129.124; envelope-from=sgarzare@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -25 X-Spam_score: -2.6 X-Spam_bar: -- X-Spam_report: (-2.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.54, 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_H4=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=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development 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-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1776432446108158500 Content-Type: text/plain; charset="utf-8" From: Stefano Garzarella virtqueue_read_indirect_desc() copies an indirect descriptor table into a buffer in chunks when the table crosses a memory region boundary. The destination is a struct vring_desc pointer but is advanced by a byte count, so each increment moves the pointer by read_len elements instead of read_len bytes, writing beyond the buffer. Use a char pointer for the destination so that the arithmetic advances correctly. While at it, change the source from a struct vring_desc pointer to a void pointer: when the table is split across regions, vu_gpa_to_va() can return a pointer into the middle of a descriptor, so casting it to a struct vring_desc pointer is wrong. The pointer is only used as a memcpy() source, so a void pointer is fine. Fixes: CVE-2026-6425 Fixes: 293084a719 ("libvhost-user: Support across-memory-boundary access") Cc: qemu-stable@nongnu.org Reported-by: DARKNAVY Signed-off-by: Stefano Garzarella Reviewed-by: Daniel P. Berrang=C3=A9 --- subprojects/libvhost-user/libvhost-user.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/subprojects/libvhost-user/libvhost-user.c b/subprojects/libvho= st-user/libvhost-user.c index 9c630c2170..014d210748 100644 --- a/subprojects/libvhost-user/libvhost-user.c +++ b/subprojects/libvhost-user/libvhost-user.c @@ -2391,8 +2391,9 @@ static int virtqueue_read_indirect_desc(VuDev *dev, struct vring_desc *desc, uint64_t addr, size_t len) { - struct vring_desc *ori_desc; + char *dst_desc =3D (char *)desc; uint64_t read_len; + void *ori_desc; =20 if (len > (VIRTQUEUE_MAX_SIZE * sizeof(struct vring_desc))) { return -1; @@ -2409,10 +2410,10 @@ virtqueue_read_indirect_desc(VuDev *dev, struct vri= ng_desc *desc, return -1; } =20 - memcpy(desc, ori_desc, read_len); + memcpy(dst_desc, ori_desc, read_len); len -=3D read_len; addr +=3D read_len; - desc +=3D read_len; + dst_desc +=3D read_len; } =20 return 0; --=20 2.53.0 From nobody Sat May 30 20:11:40 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; 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; dmarc=pass(p=quarantine dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1776432461; cv=none; d=zohomail.com; s=zohoarc; b=m0XHlJtlFjj/FO8J64ip5trTKUfcOPXNOGiGU6c839h1nLNXNRZnGuCkSnw8fNA2uVVqyIF7H5IG7B2k72ocnm4awF2weGgFSvLhfwB9zjKL71/PmI9sJtPb7MF04RpDtL0/qfEmmH64GAJypQ8mQ1JB0ZTFlvw2BO1MQQDBZxg= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1776432461; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=TkKEtBNLy2N5J1c6O82yD0C+DpO7PoG1KTI1MijcaHc=; b=RiHZmV+DOI62JFZ5BXKiBD5kNTUAj0lIt0LTvcAFMilnTwMCMdmOx3+VsATCyayWRfSvnQjaQxjhKAmkFepLaxeIf9NbfSRDOFJ5ufKHTvI2ciyUy627/9+MXaGtxru434+UU3x8WbRYgREpcEmm4QWdMekaKnIyrA8ploF01Ns= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; 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; dmarc=pass header.from= (p=quarantine dis=none) Return-Path: Received: from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1776432461318718.413746879023; Fri, 17 Apr 2026 06:27:41 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wDjDu-0003xJ-4T; Fri, 17 Apr 2026 09:27:06 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wDjDr-0003wl-1l for qemu-devel@nongnu.org; Fri, 17 Apr 2026 09:27:03 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wDjDp-0008T7-Kl for qemu-devel@nongnu.org; Fri, 17 Apr 2026 09:27:02 -0400 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-561-Bp_rsrDeM8qFEL25jYRISA-1; Fri, 17 Apr 2026 09:26:59 -0400 Received: by mail-wm1-f69.google.com with SMTP id 5b1f17b1804b1-488d2cd2674so5688045e9.0 for ; Fri, 17 Apr 2026 06:26:59 -0700 (PDT) Received: from stex1.redhat.corp (host-87-16-204-83.retail.telecomitalia.it. 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Tsirkin" , Stefano Garzarella , DARKNAVY Subject: [PATCH 2/2] libvduse: fix buffer overflow in vduse_queue_read_indirect_desc() Date: Fri, 17 Apr 2026 15:26:45 +0200 Message-ID: <20260417132645.121192-3-sgarzare@redhat.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260417132645.121192-1-sgarzare@redhat.com> References: <20260417132645.121192-1-sgarzare@redhat.com> 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=lists1p.gnu.org; Received-SPF: pass client-ip=170.10.129.124; envelope-from=sgarzare@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -25 X-Spam_score: -2.6 X-Spam_bar: -- X-Spam_report: (-2.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.54, 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_H4=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=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development 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-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1776432463552154100 Content-Type: text/plain; charset="utf-8" From: Stefano Garzarella vduse_queue_read_indirect_desc() copies an indirect descriptor table into a buffer in chunks when the table crosses a memory region boundary. The destination is a struct vring_desc pointer but is advanced by a byte count, so each increment moves the pointer by read_len elements instead of read_len bytes, writing beyond the buffer. Use a char pointer for the destination so that the arithmetic advances correctly. While at it, change the source from a struct vring_desc pointer to a void pointer: when the table is split across regions, iova_to_va() can return a pointer into the middle of a descriptor, so casting it to a struct vring_desc pointer is wrong. The pointer is only used as a memcpy() source, so a void pointer is fine. Fixes: CVE-2026-6425 Fixes: a6caeee811 ("libvduse: Add VDUSE (vDPA Device in Userspace) library") Cc: qemu-stable@nongnu.org Reported-by: DARKNAVY Signed-off-by: Stefano Garzarella Reviewed-by: Daniel P. Berrang=C3=A9 --- subprojects/libvduse/libvduse.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/subprojects/libvduse/libvduse.c b/subprojects/libvduse/libvdus= e.c index 21ffbb5b8d..df9ca5e56f 100644 --- a/subprojects/libvduse/libvduse.c +++ b/subprojects/libvduse/libvduse.c @@ -465,8 +465,9 @@ static int vduse_queue_read_indirect_desc(VduseDev *dev, struct vring_desc *desc, uint64_t addr, size_t len) { - struct vring_desc *ori_desc; + char *dst_desc =3D (char *)desc; uint64_t read_len; + void *ori_desc; =20 if (len > (VIRTQUEUE_MAX_SIZE * sizeof(struct vring_desc))) { return -1; @@ -483,10 +484,10 @@ vduse_queue_read_indirect_desc(VduseDev *dev, struct = vring_desc *desc, return -1; } =20 - memcpy(desc, ori_desc, read_len); + memcpy(dst_desc, ori_desc, read_len); len -=3D read_len; addr +=3D read_len; - desc +=3D read_len; + dst_desc +=3D read_len; } =20 return 0; --=20 2.53.0