linux-kernel - Re: [PATCH] Re: WAN: new PPP code for generic HDLC

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Message-ID: <m33aqvsnyg.fsf@maximus.localdomain>
Date:	Wed, 12 Mar 2008 21:10:31 +0100
From:	Krzysztof Halasa <khc@...waw.pl>
To:	Jan Engelhardt <jengelh@...putergmbh.de>
Cc:	Jeff Garzik <jeff@...zik.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, netdev@...r.kernel.org
Subject: Re: [PATCH] Re: WAN: new PPP code for generic HDLC

Jan Engelhardt <jengelh@...putergmbh.de> writes:

>>+	/* LCP only */
>>+	if (pid == PID_LCP)
>>+		switch (cp->code) {
>>+		case LCP_PROTO_REJ:
>>+			pid = ntohs(*(__be16*)skb->data);
>
> What if skb->data happens to be unaligned (can that even happen?)

It can't if the hdlc header is 32-bit aligned... however, I can now
see the above is buggy, skb->data doesn't point to the protocol
field. Unused code paths :-(

> -static const char *code_names[CP_CODES] = {"0", "ConfReq", "ConfAck",
> +static const char *const code_names[] = {"0", "ConfReq", "ConfAck",
>  					   "ConfNak", "ConfRej", "TermReq",
>  					   "TermAck", "CodeRej", "ProtoRej",
>  					   "EchoReq", "EchoReply", "Discard"};

The explicit sizes are there as a prevention.
Thanks.
-- 
Krzysztof Halasa
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