netdev - [PATCH 3/4] PPPOE: memory leak when socket is release()d before PPPIOCGCHAN has been called on it

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Date:	Tue, 13 Mar 2007 09:09:34 -0500
From:	Michal Ostrowski <mostrows@...thlink.net>
To:	mostrows@...son.ibm.com, davem@...emloft.net,
	netdev@...r.kernel.org
Cc:	Florian Zumbiehl <florz@...rz.de>
Subject: [PATCH 3/4] PPPOE: memory leak when socket is release()d before PPPIOCGCHAN has been called on it

below you find a patch that fixes a memory leak when a PPPoE socket is
release()d after it has been connect()ed, but before the PPPIOCGCHAN ioctl
ever has been called on it.

This is somewhat of a security problem, too, since PPPoE sockets can be
created by any user, so any user can easily allocate all the machine's
RAM to non-swappable address space and thus DoS the system.

Is there any specific reason for PPPoE sockets being available to any
unprivileged process, BTW? After all, you need a packet socket for the
discovery stage anyway, so it's unlikely that any unprivileged process
will ever need to create a PPPoE socket, no? Allocating all session IDs
for a known AC is a kind of DoS, too, after all - with Juniper ERXes,
this is really easy, actually, since they don't ever assign session ids
above 8000 ...

Signed-off-by: Florian Zumbiehl <florz@...rz.de>
Acked-by: Michal Ostrowski <mostrows@...thlink.net>
---
 drivers/net/pppox.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/net/pppox.c b/drivers/net/pppox.c
index 9315046..3f8115d 100644
--- a/drivers/net/pppox.c
+++ b/drivers/net/pppox.c
@@ -58,7 +58,7 @@ void pppox_unbind_sock(struct sock *sk)
 {
 	/* Clear connection to ppp device, if attached. */

-	if (sk->sk_state & (PPPOX_BOUND | PPPOX_ZOMBIE)) {
+	if (sk->sk_state & (PPPOX_BOUND | PPPOX_CONNECTED | PPPOX_ZOMBIE)) {
 		ppp_unregister_channel(&pppox_sk(sk)->chan);
 		sk->sk_state = PPPOX_DEAD;
 	}
-- 
1.5.0.g78e90

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