This is a note to let you know that I've just added the patch titled
9p/xen: check logical size for buffer size
to the 6.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
9p-xen-check-logical-size-for-buffer-size.patch
and it can be found in the queue-6.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 4b875faf4dbc160cdade3b01f5050b91a942a919
Author: Dominique Martinet <asmadeus@xxxxxxxxxxxxx>
Date: Fri Nov 18 22:44:41 2022 +0900
9p/xen: check logical size for buffer size
[ 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>
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;
