From b0449734be8db1127c91cb3409bd31d0a5a72be9 Mon Sep 17 00:00:00 2001 From: Dominique Martinet Date: Fri, 18 Nov 2022 22:44:41 +0900 Subject: [PATCH] 9p/xen: check logical size for buffer size [ Upstream commit 35d92eb14cbf19824e87f3085f0e3a8a98e6c7e0 ] 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 Reviewed-by: Christian Schoenebeck Link: https://lkml.kernel.org/r/20221118135542.63400-1-asmadeus@codewreck.org Signed-off-by: Dominique Martinet Signed-off-by: Sasha Levin --- 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 2779ec1053a02..f043938ae782d 100644 --- a/net/9p/trans_xen.c +++ b/net/9p/trans_xen.c @@ -230,6 +230,14 @@ 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; @@ -239,6 +247,7 @@ static void p9_xen_response(struct work_struct *work) masked_prod, &masked_cons, XEN_9PFS_RING_SIZE); +recv_error: virt_mb(); cons += h.size; ring->intf->in_cons = cons; -- 2.39.5