Re: [PATCH -next v2] unix stream: Fix use-after-free crashes

Le mercredi 07 septembre 2011 à 12:36 +0800, Yan, Zheng a écrit :

I guess you misunderstood this code. Set scm_ref to false means skb will inherit
sender's reference. Then we call unix_scm_to_skb() with parameter
'ref' == false.
So it doesn't get additional reference. I admit my patch is confusing,
but I think
Tim's new patch is OK. (even in the case of fail skb allocation or
user->kernel copy)

I want to be able to review the code now, and in two or three years too,
without spending hours and hours.

Could you _please_ guys send a patch, with :

1) A good changelog : In this confusing area, this is probably more
important than actual code.

2) right logic and right variable names

I am sorry, but this is not good :

+               /* encode scm in skb and use the scm ref */
+               ref_avail = false;
+               if (sent + size < len) { 
+                       /* Only send the fds in the first buffer */
+                       /* get additional ref if more skbs will be created */
+                       err = unix_scm_to_skb(siocb->scm, skb, !fds_sent, true);
+                       ref_avail = true;
+               } else
+                       err = unix_scm_to_skb(siocb->scm, skb, !fds_sent, false);