netdev - Re: [PATCH v2 2/2] NETWORKING: avoid use IPCB in cipso_v4

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Date:   Mon, 25 Feb 2019 17:06:44 -0500
From:   Paul Moore <paul@...l-moore.com>
To:     Nazarov Sergey <s-nazarov@...dex.ru>
Cc:     David Miller <davem@...emloft.net>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-security-module@...r.kernel.org" 
        <linux-security-module@...r.kernel.org>,
        "kuznet@....inr.ac.ru" <kuznet@....inr.ac.ru>,
        "yoshfuji@...ux-ipv6.org" <yoshfuji@...ux-ipv6.org>
Subject: Re: [PATCH v2 2/2] NETWORKING: avoid use IPCB in cipso_v4_error

On Mon, Feb 25, 2019 at 11:27 AM Nazarov Sergey <s-nazarov@...dex.ru> wrote:
>
> Extract IP options in cipso_v4_error and use __icmp_send.
>
> Signed-off-by: Sergey Nazarov <s-nazarov@...dex.ru>
> ---
>  include/net/ip.h      |    2 ++
>  net/ipv4/cipso_ipv4.c |   17 +++++++++++++++--
>  net/ipv4/ip_options.c |   22 +++++++++++++++++-----
>  3 files changed, 34 insertions(+), 7 deletions(-)

Thanks Sergey.

Acked-by: Paul Moore <paul@...l-moore.com>

> diff --git a/include/net/ip.h b/include/net/ip.h
> index 8866bfc..f0e8d06 100644
> --- a/include/net/ip.h
> +++ b/include/net/ip.h
> @@ -667,6 +667,8 @@ static inline int ip_options_echo(struct net *net, struct ip_options *dopt,
>  }
>
>  void ip_options_fragment(struct sk_buff *skb);
> +int __ip_options_compile(struct net *net, struct ip_options *opt,
> +                        struct sk_buff *skb, __be32 *info);
>  int ip_options_compile(struct net *net, struct ip_options *opt,
>                        struct sk_buff *skb);
>  int ip_options_get(struct net *net, struct ip_options_rcu **optp,
> diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
> index 777fa3b..eff86a7 100644
> --- a/net/ipv4/cipso_ipv4.c
> +++ b/net/ipv4/cipso_ipv4.c
> @@ -1735,13 +1735,26 @@ int cipso_v4_validate(const struct sk_buff *skb, unsigned char **option)
>   */
>  void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway)
>  {
> +       unsigned char optbuf[sizeof(struct ip_options) + 40];
> +       struct ip_options *opt = (struct ip_options *)optbuf;
> +
>         if (ip_hdr(skb)->protocol == IPPROTO_ICMP || error != -EACCES)
>                 return;
>
> +       /*
> +        * We might be called above the IP layer,
> +        * so we can not use icmp_send and IPCB here.
> +        */
> +
> +       memset(opt, 0, sizeof(struct ip_options));
> +       opt->optlen = ip_hdr(skb)->ihl*4 - sizeof(struct iphdr);
> +       if (__ip_options_compile(dev_net(skb->dev), opt, skb, NULL))
> +               return;
> +
>         if (gateway)
> -               icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0);
> +               __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0, opt);
>         else
> -               icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0);
> +               __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0, opt);
>  }
>
>  /**
> diff --git a/net/ipv4/ip_options.c b/net/ipv4/ip_options.c
> index ed194d4..32a3504 100644
> --- a/net/ipv4/ip_options.c
> +++ b/net/ipv4/ip_options.c
> @@ -251,8 +251,9 @@ static void spec_dst_fill(__be32 *spec_dst, struct sk_buff *skb)
>   * If opt == NULL, then skb->data should point to IP header.
>   */
>
> -int ip_options_compile(struct net *net,
> -                      struct ip_options *opt, struct sk_buff *skb)
> +int __ip_options_compile(struct net *net,
> +                        struct ip_options *opt, struct sk_buff *skb,
> +                        __be32 *info)
>  {
>         __be32 spec_dst = htonl(INADDR_ANY);
>         unsigned char *pp_ptr = NULL;
> @@ -468,11 +469,22 @@ int ip_options_compile(struct net *net,
>                 return 0;
>
>  error:
> -       if (skb) {
> -               icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((pp_ptr-iph)<<24));
> -       }
> +       if (info)
> +               *info = htonl((pp_ptr-iph)<<24);
>         return -EINVAL;
>  }
> +
> +int ip_options_compile(struct net *net,
> +                      struct ip_options *opt, struct sk_buff *skb)
> +{
> +       int ret;
> +       __be32 info;
> +
> +       ret = __ip_options_compile(net, opt, skb, &info);
> +       if (ret != 0 && skb)
> +               icmp_send(skb, ICMP_PARAMETERPROB, 0, info);
> +       return ret;
> +}
>  EXPORT_SYMBOL(ip_options_compile);
>
>  /*
> ---
>


-- 
paul moore
www.paul-moore.com