Re: [syzbot]

syzbot <[email protected]> Mon, 07 Apr 2025 07:17:12 -0700

Newsgroups	org.kernel.vger.linux-ppp,org.kernel.vger.linux-kernel,org.kernel.vger.netdev
Message-ID	<[email protected]>

> Author: [email protected]
>
> #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

want either no args or 2 args (repo, branch), got 5

>
> diff --git a/drivers/net/ppp/ppp_synctty.c b/drivers/net/ppp/ppp_synctty.c
> index 644e99fc3623..520d895acc60 100644
> --- a/drivers/net/ppp/ppp_synctty.c
> +++ b/drivers/net/ppp/ppp_synctty.c
> @@ -506,6 +506,11 @@ ppp_sync_txmunge(struct syncppp *ap, struct sk_buff *skb)
>  	unsigned char *data;
>  	int islcp;
>  
> +	/* Ensure we can safely access protocol field and LCP code */
> +	if (!skb || !pskb_may_pull(skb, 3)) {
> +		kfree_skb(skb);
> +		return NULL;
> +	}
>  	data  = skb->data;
>  	proto = get_unaligned_be16(data);