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 BDF113D9531; Wed, 30 Sep 2026 19:09:04 +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=1790795346; cv=none; b=bLGhiZ2KBy6TO3blg5OHHHlhTRd64Y74+Fx/XS0/BWSbd2N+AaR8qj55J2OYC9XgMU8twTEwi6IjWtaLuJ6IM+69XrEhpxW945bG3iNsPTIHWnwj/bsC6avc2iJL46hwTjnasOZxZI4PTPxisbSRMfJu4IoirSZ6mMxTZ3RsDAk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790795346; c=relaxed/simple; bh=1Sf9UWrhcCMe4N4NTx3lyDIQ+DF7qct5jWc8FAaFwCg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=erbWXd66F5z7+F875M90Aav+JrR55Rbqcm5o/C6ddafnH6lBwS93GZm1mOy++ZFiizjGfhxloyYX7YCjbWhMvV6++YRQ7N9MFJ9I1MpWvhtow5mhLvN3P75U0WVUjaW7B8cEDQDMQ0GAfXHDX29gdzyYeaRPHVU4f+aOuqlzo5w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=SLPevY6T; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="SLPevY6T" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 197A31F000FF; Wed, 30 Sep 2026 19:09:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790795344; bh=davvcgcip31UI0GTtkzAiYzb8TbnzGlbNZQwv4bn1ys=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=SLPevY6TtYhLeHtV5shqoKPP+eL1+NuC6lnG1DtIxMS3LxQlF3EEa5m+gNBgJipPU 5P5ujeKPqXTTHKHMqy1Soj/eHrZf2DfvqXMXZucYKL//CJBi9jfKHS1dDmdZ8q8vHM Uy8bYhuE/j11L7RZ0QcAa8lOn2+0iWL+10AKBJ2c= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jia Jia , "Michael S. Tsirkin" , Sasha Levin Subject: [PATCH 6.6 0530/1193] vhost/vdpa: reject VRING_NUM larger than device max Date: Wed, 30 Sep 2026 17:20:14 +0200 Message-ID: <20260930152445.977295810@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152434.301151190@linuxfoundation.org> References: <20260930152434.301151190@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jia Jia [ Upstream commit ccb1dc7c527f8c925925cf92afc76ae590dac311 ] vhost_vring_set_num() accepts any non-zero power-of-two queue size that fits in 16 bits. vhost-vdpa then passes that value to set_vq_num() without comparing it with get_vq_num_max(). A process with access to /dev/vhost-vdpa-* can therefore configure a queue larger than the device advertises. With vdpa_sim, the worker can walk descriptors beyond the mapped descriptor ring. KASAN reports a 16-byte out-of-bounds read, corresponding to one vring_desc, in the vringh IOTLB path: BUG: KASAN: out-of-bounds in _copy_from_iter Read of size 16 copy_from_iotlb copydesc_iotlb vringh_getdesc_iotlb vdpasim_net_work Cache get_vq_num_max() immediately after reset. Some backends derive it from writable queue-size state, so querying it after SET_NUM may return the current size instead of the device capability. Invalidate the cached value before reset so a failed reset leaves SET_NUM disabled. For VHOST_SET_VRING_NUM, copy the complete vring state once and use the same index and size for validation, vq->num, and set_vq_num(). This ensures that validation and use operate on the same copied values. Fixes: 4c8cf31885f6 ("vhost: introduce vDPA-based backend") Signed-off-by: Jia Jia Signed-off-by: Michael S. Tsirkin Message-ID: <20260810010300.132959-1-physicalmtea@gmail.com> Signed-off-by: Sasha Levin --- drivers/vhost/vdpa.c | 44 +++++++++++++++++++++++++++++++++++++------- 1 file changed, 37 insertions(+), 7 deletions(-) diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c index 61ba04a6b707c..a85e79ddf082c 100644 --- a/drivers/vhost/vdpa.c +++ b/drivers/vhost/vdpa.c @@ -53,6 +53,7 @@ struct vhost_vdpa { struct cdev cdev; atomic_t opened; u32 nvqs; + u16 vq_num_max; int virtio_id; int minor; struct eventfd_ctx *config_ctx; @@ -211,7 +212,9 @@ static void vhost_vdpa_unsetup_vq_irq(struct vhost_vdpa *v, u16 qid) static int _compat_vdpa_reset(struct vhost_vdpa *v) { struct vdpa_device *vdpa = v->vdpa; + const struct vdpa_config_ops *ops = vdpa->config; u32 flags = 0; + int ret; if (v->vdev.vqs) { flags |= !vhost_backend_has_feature(v->vdev.vqs[0], @@ -219,7 +222,14 @@ static int _compat_vdpa_reset(struct vhost_vdpa *v) VDPA_RESET_F_CLEAN_MAP : 0; } - return vdpa_reset(vdpa, flags); + v->vq_num_max = 0; + ret = vdpa_reset(vdpa, flags); + if (!ret) { + /* Some backends derive the max from mutable queue state. */ + v->vq_num_max = ops->get_vq_num_max(vdpa); + } + + return ret; } static int vhost_vdpa_reset(struct vhost_vdpa *v) @@ -605,9 +615,15 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd, u32 idx; long r; - r = get_user(idx, (u32 __user *)argp); - if (r < 0) - return r; + if (cmd == VHOST_SET_VRING_NUM) { + if (copy_from_user(&s, argp, sizeof(s))) + return -EFAULT; + idx = s.index; + } else { + r = get_user(idx, (u32 __user *)argp); + if (r < 0) + return r; + } if (idx >= v->nvqs) return -ENOBUFS; @@ -616,6 +632,23 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd, vq = &v->vqs[idx]; switch (cmd) { + case VHOST_SET_VRING_NUM: + mutex_lock(&vq->mutex); + if (vq->private_data) { + r = -EBUSY; + } else if (!s.num || s.num > 0xffff || + s.num > v->vq_num_max || + (s.num & (s.num - 1))) { + r = -EINVAL; + } else { + vq->num = s.num; + r = 0; + } + mutex_unlock(&vq->mutex); + if (r) + return r; + ops->set_vq_num(vdpa, idx, s.num); + return 0; case VHOST_VDPA_SET_VRING_ENABLE: if (copy_from_user(&s, argp, sizeof(s))) return -EFAULT; @@ -705,9 +738,6 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd, ops->set_vq_cb(vdpa, idx, &cb); break; - case VHOST_SET_VRING_NUM: - ops->set_vq_num(vdpa, idx, vq->num); - break; } return r; -- 2.53.0