9p: fix use after free

On 7/22/07, Adrian Bunk <bunk@stusta.de> 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  -->

Also spotted was a leak of the same structure further down in the function.

Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/net/9p/mux.c b/net/9p/mux.c
index acb038810f39..5d70558c4c61 100644
--- a/net/9p/mux.c
+++ b/net/9p/mux.c
@@ -288,9 +288,10 @@ struct p9_conn *p9_conn_create(struct p9_transport *trans, int msize,
         m->extended = extended;
         m->trans = trans;
         m->tagpool = p9_idpool_create();
-        if (!m->tagpool) {
+        if (IS_ERR(m->tagpool)) {
+                mtmp = ERR_PTR(-ENOMEM);
                 kfree(m);
-                return ERR_PTR(PTR_ERR(m->tagpool));
+                return mtmp;
         }
 
         m->err = 0;
@@ -308,8 +309,10 @@ struct p9_conn *p9_conn_create(struct p9_transport *trans, int msize,
         memset(&m->poll_waddr, 0, sizeof(m->poll_waddr));
         m->poll_task = NULL;
         n = p9_mux_poll_start(m);
-        if (n)
+        if (n) {
+                kfree(m);
                 return ERR_PTR(n);
+        }
 
         n = trans->poll(trans, &m->pt);
         if (n & POLLIN) {