Re: net/9p/mux.c: use-after-free

[Eric Van Hensbergen]

On 7/22/07, Adrian Bunk <bunk@xxxxxxxxx> wrote:
> The Coverity checker spotted the following use-after-free
> in net/9p/mux.c:
>
> <--  snip  -->
>
> ...
> struct p9_conn *p9_conn_create(struct p9_transport *trans, int msize,
>                                     unsigned char *extended)
> {
> ...
>         if (!m->tagpool) {
>                 kfree(m);
>                 return ERR_PTR(PTR_ERR(m->tagpool));
>         }
> ...
>
> <--  snip  -->

I've got a fix for this one:
       if (!m->tagpool) {
               mtmp = ERR_PTR(PTR_ERR(m->tagpool));
               kfree(m);
               return mtmp;
       }

but I was wondering about one of the other returns further down the function:

...
       memset(&m->poll_waddr, 0, sizeof(m->poll_waddr));
       m->poll_task = NULL;
       n = p9_mux_poll_start(m);
       if (n)
               return ERR_PTR(n);

       n = trans->poll(trans, &m->pt);
...

lucho: doesn't that constitute a leak?  Shouldn't we be doing:

       if (n) {
               kfree(m);
               return ERR_PTR(n);
       }

        -eric
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