Re: [PATCH] net/9p: validate fds in p9_fd_open

[Doug Nazar]

On 2020-07-10 04:57, Christoph Hellwig wrote:

diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
index 13cd683a658ab6..1cd8ea0e493617 100644
--- a/net/9p/trans_fd.c
+++ b/net/9p/trans_fd.c
@@ -803,20 +803,28 @@ static int p9_fd_open(struct p9_client *client, int rfd, 
int wfd)
                return -ENOMEM;

ts->rd = fget(rfd);

+       if (!ts->rd)
+               goto out_free_ts;
+       if (!(ts->rd->f_mode & FMODE_READ))
+               goto out_put_wr;

                goto out_put_rd;

unless I'm mistaken.

        ts->wr = fget(wfd);
-       if (!ts->rd || !ts->wr) {
-               if (ts->rd)
-                       fput(ts->rd);
-               if (ts->wr)
-                       fput(ts->wr);
-               kfree(ts);
-               return -EIO;
-       }
+       if (!ts->wr)
+               goto out_put_rd;
+       if (!(ts->wr->f_mode & FMODE_WRITE))
+               goto out_put_wr;

client->trans = ts;

        client->status = Connected;

return 0;

+
+out_put_wr:
+       fput(ts->wr);
+out_put_rd:
+       fput(ts->rd);
+out_free_ts:
+       kfree(ts);
+       return -EIO;
  }

static int p9_socket_open(struct p9_client *client, struct socket *csocket)

Doug