lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite for Android: free password hash cracker in your pocket
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Fri, 27 Nov 2009 07:17:06 +0100
From:	Eric Dumazet <>
To:	David Miller <>
	Trond Myklebust <>
Subject: Re: [Bug 14470] New: freez in TCP stack

David Miller a écrit :

> I must be getting old and senile, but I specifically remembered that
> we prevented a socket from ever being bound again once it has been
> bound one time specifically so we didn't have to deal with issues
> like this.
> I really don't think it's valid for NFS to reuse the socket structure
> like this over and over again.  And that's why only NFS can reproduce
> this, the interfaces provided userland can't actually go through this
> sequence after a socket goes down one time all the way to close.
> Do we really want to audit each and every odd member of the socket
> structure from the generic portion all the way down to INET and
> TCP specifics to figure out what needs to get zero'd out?

An audit is always welcomed, we might find bugs :)

> So much relies upon the one-time full zero out during sock allocation.
> Let's fix NFS instead.

bugzilla reference :

Trond said :
  NFS MUST reuse the same port because on most servers, the replay cache is keyed
  to the port number. In other words, when we replay an RPC call, the server will
  only recognise it as a replay if it originates from the same port.

Please note the socket stays bound to a given local port.

We want to connect() it to a possible other target, that's all.

In NFS case 'other target' is in fact the same target, but this
is a special case of a more general one.

Hmm... if an application wants to keep a local port for itself (not
allowing another one to get this (ephemeral ?) port during the 
close()/socket()/bind() window), this is the only way.
TCP state machine allows this IMHO.

google for "tcp AF_UNSPEC connect" to find many references and man pages
for this stuff.

How other Unixes / OS handle this ?
How many applications use this trick ?

To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to
More majordomo info at

Powered by blists - more mailing lists