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Re: [Qemu-devel] [PATCH v4 3/4] virtio-9p: break device if buffers are m
From: |
Stefano Stabellini |
Subject: |
Re: [Qemu-devel] [PATCH v4 3/4] virtio-9p: break device if buffers are misconfigured |
Date: |
Mon, 26 Jun 2017 16:22:23 -0700 (PDT) |
User-agent: |
Alpine 2.10 (DEB 1266 2009-07-14) |
On Fri, 23 Jun 2017, Greg Kurz wrote:
> The 9P protocol is transport agnostic: if the guest misconfigured the
> buffers, the best we can do is to set the broken flag on the device.
>
> Since virtio_pdu_vmarshal() may be called by several active PDUs, we
> check if the transport isn't broken already to avoid printing extra
> error messages.
>
> Signed-off-by: Greg Kurz <address@hidden>
> ---
> v4: - update changelog and add comment to explain why we check vdev->broken
> in virtio_pdu_vmarshal()
> - dropped uneeded vdev->broken check in virtio_pdu_vunmarshal()
> ---
> hw/9pfs/9p.c | 2 +-
> hw/9pfs/9p.h | 2 +-
> hw/9pfs/virtio-9p-device.c | 48
> +++++++++++++++++++++++++++++++++++++++-----
> hw/9pfs/xen-9p-backend.c | 3 ++-
> 4 files changed, 47 insertions(+), 8 deletions(-)
>
> diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
> index a0ae98f7ca6f..8e5cac71eb60 100644
> --- a/hw/9pfs/9p.c
> +++ b/hw/9pfs/9p.c
> @@ -1664,7 +1664,7 @@ static void v9fs_init_qiov_from_pdu(QEMUIOVector *qiov,
> V9fsPDU *pdu,
> unsigned int niov;
>
> if (is_write) {
> - pdu->s->transport->init_out_iov_from_pdu(pdu, &iov, &niov);
> + pdu->s->transport->init_out_iov_from_pdu(pdu, &iov, &niov, size +
> skip);
> } else {
> pdu->s->transport->init_in_iov_from_pdu(pdu, &iov, &niov, size +
> skip);
> }
> diff --git a/hw/9pfs/9p.h b/hw/9pfs/9p.h
> index aac1b0b2ce3d..d1cfeaf10e4f 100644
> --- a/hw/9pfs/9p.h
> +++ b/hw/9pfs/9p.h
> @@ -363,7 +363,7 @@ struct V9fsTransport {
> void (*init_in_iov_from_pdu)(V9fsPDU *pdu, struct iovec **piov,
> unsigned int *pniov, size_t size);
> void (*init_out_iov_from_pdu)(V9fsPDU *pdu, struct iovec **piov,
> - unsigned int *pniov);
> + unsigned int *pniov, size_t size);
> void (*push_and_notify)(V9fsPDU *pdu);
> };
>
> diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c
> index 1a68c1622d3a..ed9e4817a26c 100644
> --- a/hw/9pfs/virtio-9p-device.c
> +++ b/hw/9pfs/virtio-9p-device.c
> @@ -146,8 +146,22 @@ static ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t
> offset,
> V9fsState *s = pdu->s;
> V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
> VirtQueueElement *elem = v->elems[pdu->idx];
> -
> - return v9fs_iov_vmarshal(elem->in_sg, elem->in_num, offset, 1, fmt, ap);
> + int ret;
I think ret should be ssize_t
> + ret = v9fs_iov_vmarshal(elem->in_sg, elem->in_num, offset, 1, fmt, ap);
> + if (ret < 0) {
> + VirtIODevice *vdev = VIRTIO_DEVICE(v);
> +
> + /* Any active PDU may try to send something back to the client
> without
> + * knowing if the transport is broken or not. This could result in
> + * MAX_REQ - 1 (ie, 127) extra error messages being printed.
> + */
> + if (!vdev->broken) {
> + virtio_error(vdev, "Failed to encode VirtFS reply type %d",
> + pdu->id + 1);
> + }
> + }
> + return ret;
> }
>
> static ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
> @@ -156,28 +170,52 @@ static ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu,
> size_t offset,
> V9fsState *s = pdu->s;
> V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
> VirtQueueElement *elem = v->elems[pdu->idx];
> + int ret;
same here
> - return v9fs_iov_vunmarshal(elem->out_sg, elem->out_num, offset, 1, fmt,
> ap);
> + ret = v9fs_iov_vunmarshal(elem->out_sg, elem->out_num, offset, 1, fmt,
> ap);
> + if (ret < 0) {
> + VirtIODevice *vdev = VIRTIO_DEVICE(v);
> +
> + virtio_error(vdev, "Failed to decode VirtFS request type %d",
> pdu->id);
> + }
> + return ret;
> }
>
> -/* The size parameter is used by other transports. Do not drop it. */
> static void virtio_init_in_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
> unsigned int *pniov, size_t size)
> {
> V9fsState *s = pdu->s;
> V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
> VirtQueueElement *elem = v->elems[pdu->idx];
> + size_t buf_size = iov_size(elem->in_sg, elem->in_num);
> +
> + if (buf_size < size) {
> + VirtIODevice *vdev = VIRTIO_DEVICE(v);
> +
> + virtio_error(vdev,
> + "VirtFS reply type %d needs %zu bytes, buffer has %zu",
> + pdu->id + 1, size, buf_size);
> + }
>
> *piov = elem->in_sg;
> *pniov = elem->in_num;
> }
>
> static void virtio_init_out_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
> - unsigned int *pniov)
> + unsigned int *pniov, size_t size)
> {
> V9fsState *s = pdu->s;
> V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
> VirtQueueElement *elem = v->elems[pdu->idx];
> + size_t buf_size = iov_size(elem->out_sg, elem->out_num);
> +
> + if (buf_size < size) {
> + VirtIODevice *vdev = VIRTIO_DEVICE(v);
> +
> + virtio_error(vdev,
> + "VirtFS request type %d needs %zu bytes, buffer has
> %zu",
> + pdu->id, size, buf_size);
> + }
>
> *piov = elem->out_sg;
> *pniov = elem->out_num;
> diff --git a/hw/9pfs/xen-9p-backend.c b/hw/9pfs/xen-9p-backend.c
> index 922cc967be63..a82cf817fe45 100644
> --- a/hw/9pfs/xen-9p-backend.c
> +++ b/hw/9pfs/xen-9p-backend.c
> @@ -147,7 +147,8 @@ static ssize_t xen_9pfs_pdu_vunmarshal(V9fsPDU *pdu,
>
> static void xen_9pfs_init_out_iov_from_pdu(V9fsPDU *pdu,
> struct iovec **piov,
> - unsigned int *pniov)
> + unsigned int *pniov,
> + size_t size)
> {
> Xen9pfsDev *xen_9pfs = container_of(pdu->s, Xen9pfsDev, state);
> Xen9pfsRing *ring = &xen_9pfs->rings[pdu->tag % xen_9pfs->num_rings];
Maybe you could include the same changes you made for xen, see below
diff --git a/hw/9pfs/xen-9p-backend.c b/hw/9pfs/xen-9p-backend.c
index a82cf81..83a2bfe 100644
--- a/hw/9pfs/xen-9p-backend.c
+++ b/hw/9pfs/xen-9p-backend.c
@@ -125,10 +125,17 @@ static ssize_t xen_9pfs_pdu_vmarshal(V9fsPDU *pdu,
Xen9pfsDev *xen_9pfs = container_of(pdu->s, Xen9pfsDev, state);
struct iovec in_sg[2];
int num;
+ ssize_t ret;
xen_9pfs_in_sg(&xen_9pfs->rings[pdu->tag % xen_9pfs->num_rings],
in_sg, &num, pdu->idx, ROUND_UP(offset + 128, 512));
- return v9fs_iov_vmarshal(in_sg, num, offset, 0, fmt, ap);
+
+ ret = v9fs_iov_vmarshal(in_sg, num, offset, 0, fmt, ap);
+ if (ret < 0) {
+ xen_pv_printf(&xen_9pfs->xendev, 0,
+ "Failed to encode VirtFS request type %d", pdu->id + 1);
+ }
+ return ret;
}
static ssize_t xen_9pfs_pdu_vunmarshal(V9fsPDU *pdu,
@@ -139,10 +146,17 @@ static ssize_t xen_9pfs_pdu_vunmarshal(V9fsPDU *pdu,
Xen9pfsDev *xen_9pfs = container_of(pdu->s, Xen9pfsDev, state);
struct iovec out_sg[2];
int num;
+ ssize_t ret;
xen_9pfs_out_sg(&xen_9pfs->rings[pdu->tag % xen_9pfs->num_rings],
out_sg, &num, pdu->idx);
- return v9fs_iov_vunmarshal(out_sg, num, offset, 0, fmt, ap);
+
+ ret = v9fs_iov_vunmarshal(out_sg, num, offset, 0, fmt, ap);
+ if (ret < 0) {
+ xen_pv_printf(&xen_9pfs->xendev, 0,
+ "Failed to decode VirtFS request type %d", pdu->id);
+ }
+ return ret;
}
static void xen_9pfs_init_out_iov_from_pdu(V9fsPDU *pdu,
@@ -153,11 +167,20 @@ static void xen_9pfs_init_out_iov_from_pdu(V9fsPDU *pdu,
Xen9pfsDev *xen_9pfs = container_of(pdu->s, Xen9pfsDev, state);
Xen9pfsRing *ring = &xen_9pfs->rings[pdu->tag % xen_9pfs->num_rings];
int num;
+ size_t buf_size;
g_free(ring->sg);
ring->sg = g_malloc0(sizeof(*ring->sg) * 2);
xen_9pfs_out_sg(ring, ring->sg, &num, pdu->idx);
+
+ buf_size = iov_size(ring->sg, num);
+ if (buf_size < size) {
+ xen_pv_printf(&xen_9pfs->xendev, 0, "Xen 9pfs request type %d"
+ "needs %zu bytes, buffer has %zu", pdu->id, size,
+ buf_size);
+ }
+
*piov = ring->sg;
*pniov = num;
}
@@ -170,11 +193,20 @@ static void xen_9pfs_init_in_iov_from_pdu(V9fsPDU *pdu,
Xen9pfsDev *xen_9pfs = container_of(pdu->s, Xen9pfsDev, state);
Xen9pfsRing *ring = &xen_9pfs->rings[pdu->tag % xen_9pfs->num_rings];
int num;
+ size_t buf_size;
g_free(ring->sg);
ring->sg = g_malloc0(sizeof(*ring->sg) * 2);
xen_9pfs_in_sg(ring, ring->sg, &num, pdu->idx, size);
+
+ buf_size = iov_size(ring->sg, num);
+ if (buf_size < size) {
+ xen_pv_printf(&xen_9pfs->xendev, 0, "Xen 9pfs request type %d"
+ "needs %zu bytes, buffer has %zu", pdu->id, size,
+ buf_size);
+ }
+
*piov = ring->sg;
*pniov = num;
}
- [Qemu-devel] [PATCH v4 0/4] 9pfs: handle transport errors, Greg Kurz, 2017/06/23
- [Qemu-devel] [PATCH v4 1/4] virtio-9p: record element after sanity checks, Greg Kurz, 2017/06/23
- [Qemu-devel] [PATCH v4 2/4] virtio-9p: message header is 7-byte long, Greg Kurz, 2017/06/23
- [Qemu-devel] [PATCH v4 3/4] virtio-9p: break device if buffers are misconfigured, Greg Kurz, 2017/06/23
- Re: [Qemu-devel] [PATCH v4 3/4] virtio-9p: break device if buffers are misconfigured,
Stefano Stabellini <=
- Re: [Qemu-devel] [PATCH v4 3/4] virtio-9p: break device if buffers are misconfigured, Greg Kurz, 2017/06/27
- Re: [Qemu-devel] [PATCH v4 3/4] virtio-9p: break device if buffers are misconfigured, Stefano Stabellini, 2017/06/27
- Re: [Qemu-devel] [PATCH v4 3/4] virtio-9p: break device if buffers are misconfigured, Greg Kurz, 2017/06/28
- Re: [Qemu-devel] [PATCH v4 3/4] virtio-9p: break device if buffers are misconfigured, Stefano Stabellini, 2017/06/28
- Re: [Qemu-devel] [PATCH v4 3/4] virtio-9p: break device if buffers are misconfigured, Greg Kurz, 2017/06/28
- Re: [Qemu-devel] [PATCH v4 3/4] virtio-9p: break device if buffers are misconfigured, Stefano Stabellini, 2017/06/28
[Qemu-devel] [PATCH v4 4/4] 9pfs: handle transport errors in pdu_complete(), Greg Kurz, 2017/06/23