netdev - Re: [PATCH net] netlabel: out of bound access in cipso_v4

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Date:   Fri, 3 Feb 2017 18:26:40 -0500
From:   Paul Moore <paul@...l-moore.com>
To:     Eric Dumazet <eric.dumazet@...il.com>,
        David Miller <davem@...emloft.net>,
        Dmitry Vyukov <dvyukov@...gle.com>
Cc:     netdev <netdev@...r.kernel.org>
Subject: Re: [PATCH net] netlabel: out of bound access in cipso_v4_validate()

On Fri, Feb 3, 2017 at 3:03 AM, Eric Dumazet <eric.dumazet@...il.com> wrote:
> From: Eric Dumazet <edumazet@...gle.com>
>
> syzkaller found another out of bound access in ip_options_compile(),
> or more exactly in cipso_v4_validate()
>
> Fixes: 20e2a8648596 ("cipso: handle CIPSO options correctly when NetLabel is disabled")
> Fixes: 446fda4f2682 ("[NetLabel]: CIPSOv4 engine")
> Signed-off-by: Eric Dumazet <edumazet@...gle.com>
> Reported-by: Dmitry Vyukov  <dvyukov@...gle.com>
> Cc: Paul Moore <paul@...l-moore.com>
> ---
>  include/net/cipso_ipv4.h |    4 ++++
>  net/ipv4/cipso_ipv4.c    |    4 ++++
>  2 files changed, 8 insertions(+)

Thanks guys.

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

> diff --git a/include/net/cipso_ipv4.h b/include/net/cipso_ipv4.h
> index 3ebb168b9afc68ad639b5d32f6182a845c83d759..a34b141f125f0032662f147b598c9fef4fb4bcef 100644
> --- a/include/net/cipso_ipv4.h
> +++ b/include/net/cipso_ipv4.h
> @@ -309,6 +309,10 @@ static inline int cipso_v4_validate(const struct sk_buff *skb,
>         }
>
>         for (opt_iter = 6; opt_iter < opt_len;) {
> +               if (opt_iter + 1 == opt_len) {
> +                       err_offset = opt_iter;
> +                       goto out;
> +               }
>                 tag_len = opt[opt_iter + 1];
>                 if ((tag_len == 0) || (tag_len > (opt_len - opt_iter))) {
>                         err_offset = opt_iter + 1;
> diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
> index 72d6f056d863603c959e1d04b9f863909a37c758..ae206163c273381ba6e8bd8a24fa050619a4a6ae 100644
> --- a/net/ipv4/cipso_ipv4.c
> +++ b/net/ipv4/cipso_ipv4.c
> @@ -1587,6 +1587,10 @@ int cipso_v4_validate(const struct sk_buff *skb, unsigned char **option)
>                                 goto validate_return_locked;
>                         }
>
> +               if (opt_iter + 1 == opt_len) {
> +                       err_offset = opt_iter;
> +                       goto validate_return_locked;
> +               }
>                 tag_len = tag[1];
>                 if (tag_len > (opt_len - opt_iter)) {
>                         err_offset = opt_iter + 1;
>
>



-- 
paul moore
www.paul-moore.com