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

Le mercredi 07 septembre 2011 à 23:26 +0200, Eric Dumazet a écrit :

Le mercredi 07 septembre 2011 à 05:01 -0700, Tim Chen a écrit :

quoted

Eric, are you planning to do a fast path patch that doesn't do pid ref
for the case where CONFIG_PID_NS is not set?

Yes, I'll try to cook a patch.

Thinking a bit more on this issue, I really believe we should not stick
pid/cred in skbs sent from a write() system call.

That would break following use case :

An application uses a write(fd) and expects a receiver using recvmsg()
to get process credentials (SCM_CREDENTIALS)

This is currently working, but not documented (man unix says ancillary
data are sent with sendmsg())

If everybody agrees, I can send a patch for this : This would speedup
write()/read() af_unix by an order of magnitude.