9pfs: fix potential segfault during walk

If the call to fid_to_qid() returns an error, we will call v9fs_path_free()
on uninitialized paths.

It is a regression introduced by the following commit:

56f101ecce 9pfs: handle walk of ".." in the root directory

Let's fix this by initializing dpath and path before calling fid_to_qid().

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
[groug: updated the changelog to indicate this is regression and to provide
        the offending commit SHA1]
Signed-off-by: Greg Kurz <groug@kaod.org>
This commit is contained in:
Greg Kurz 2016-09-16 11:44:49 +02:00
parent 557a4cc04a
commit 13fd08e631

View File

@ -1333,13 +1333,14 @@ static void v9fs_walk(void *opaque)
goto out_nofid;
}
v9fs_path_init(&dpath);
v9fs_path_init(&path);
err = fid_to_qid(pdu, fidp, &qid);
if (err < 0) {
goto out;
}
v9fs_path_init(&dpath);
v9fs_path_init(&path);
/*
* Both dpath and path initially poin to fidp.
* Needed to handle request with nwnames == 0