On Tue, Sep 28, 2021 at 09:08:26AM +0200, Jack Wang wrote:

Leon Romanovsky [off-list ref] 于2021年9月27日周一 下午2:23写道：

quoted

On Wed, Sep 22, 2021 at 02:53:32PM +0200, Md Haris Iqbal wrote:

quoted

Allowing these characters in sessname can lead to unexpected results,
particularly because / is used as a separator between files in a path,
and . points to the current directory.

Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Reviewed-by: Gioh Kim <redacted>
Reviewed-by: Aleksei Marov <redacted>
---
 drivers/infiniband/ulp/rtrs/rtrs-clt.c | 6 ++++++
 drivers/infiniband/ulp/rtrs/rtrs-srv.c | 5 +++++
 2 files changed, 11 insertions(+)

It will be safer if you check for only allowed symbols and disallow
everything else. Check for: a-Z, 0-9 and "-".

Hi Leon,

Thanks for your suggestions.
The reasons we choose to do disallow only '/' and '.':
1 more flexible, most UNIX filenames allow any 8-bit set, except '/' and null.

So you need to add all possible protections and checks that VFS has to allow "random" name.

2 matching for 2 characters is faster than checking all the allowed
symbols during session establishment.

Extra CPU cycles won't make any difference here.

3 we do use hostnameA@hostnameB for production usage right now, we
don't want to break the user space.

You can add "@" into the list of accepted symbols.

I hope this makes sense to you.

Regards!

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diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.c b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
index bc8824b4ee0d..15c0077dd27e 100644
--- a/drivers/infiniband/ulp/rtrs/rtrs-clt.c
+++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.c

@@ -2788,6 +2788,12 @@ struct rtrs_clt *rtrs_clt_open(struct rtrs_clt_ops *ops,
      struct rtrs_clt *clt;
      int err, i;

+     if (strchr(sessname, '/') || strchr(sessname, '.')) {
+             pr_err("sessname cannot contain / and .\n");
+             err = -EINVAL;
+             goto out;
+     }
+
      clt = alloc_clt(sessname, paths_num, port, pdu_sz, ops->priv,
                      ops->link_ev,
                      reconnect_delay_sec,

diff --git a/drivers/infiniband/ulp/rtrs/rtrs-srv.c b/drivers/infiniband/ulp/rtrs/rtrs-srv.c
index 078a1cbac90c..7df71f8cf149 100644
--- a/drivers/infiniband/ulp/rtrs/rtrs-srv.c
+++ b/drivers/infiniband/ulp/rtrs/rtrs-srv.c

@@ -803,6 +803,11 @@ static int process_info_req(struct rtrs_srv_con *con,
              return err;
      }

+     if (strchr(msg->sessname, '/') || strchr(msg->sessname, '.')) {
+             rtrs_err(s, "sessname cannot contain / and .\n");
+             return -EINVAL;
+     }
+
      if (exist_sessname(sess->srv->ctx,
                         msg->sessname, &sess->srv->paths_uuid)) {
              rtrs_err(s, "sessname is duplicated: %s\n", msg->sessname);
--

2.25.1