From: Florian Zumbiehl Date: Fri, 20 Apr 2007 23:58:14 +0000 (-0700) Subject: [PPPOE]: memory leak when socket is release()d before PPPIOCGCHAN has been called ... X-Git-Tag: v2.6.22-rc1~1128^2~92 X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=202a03acf9994076055df40ae093a5c5474ad0bd [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 Acked-by: Michal Ostrowski Signed-off-by: David S. Miller --- 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; }