From: Dominique Martinet <asmadeus@xxxxxxxxxxxxx> [ Upstream commit 391c18cf776eb4569ecda1f7794f360fe0a45a26 ] trans_xen did not check the data fits into the buffer before copying from the xen ring, but we probably should. Add a check that just skips the request and return an error to userspace if it did not fit Tested-by: Stefano Stabellini <sstabellini@xxxxxxxxxx> Reviewed-by: Christian Schoenebeck <linux_oss@xxxxxxxxxxxxx> Link: https://lkml.kernel.org/r/20221118135542.63400-1-asmadeus@xxxxxxxxxxxxx Signed-off-by: Dominique Martinet <asmadeus@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- net/9p/trans_xen.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c index 227f89cc7237..0f862d5a5960 100644 --- a/net/9p/trans_xen.c +++ b/net/9p/trans_xen.c @@ -208,6 +208,14 @@ static void p9_xen_response(struct work_struct *work) continue; } + if (h.size > req->rc.capacity) { + dev_warn(&priv->dev->dev, + "requested packet size too big: %d for tag %d with capacity %zd\n", + h.size, h.tag, req->rc.capacity); + req->status = REQ_STATUS_ERROR; + goto recv_error; + } + memcpy(&req->rc, &h, sizeof(h)); req->rc.offset = 0; @@ -217,6 +225,7 @@ static void p9_xen_response(struct work_struct *work) masked_prod, &masked_cons, XEN_9PFS_RING_SIZE(ring)); +recv_error: virt_mb(); cons += h.size; ring->intf->in_cons = cons; -- 2.35.1
