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Date: Mon, 05 Dec 2016 13:19:32 -0500 (EST)
Message-Id: <20161205.131932.1911368739049813377.davem@davemloft.net>
To: keescook@chromium.org
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Subject: Re: [PATCH] net: ping: check minimum size on ICMP header length
From: David Miller <davem@davemloft.net>
In-Reply-To: <20161203005853.GA117599@beast>
References: <20161203005853.GA117599@beast>
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From: Kees Cook <keescook@chromium.org>
Date: Fri, 2 Dec 2016 16:58:53 -0800

> diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
> index 205e2000d395..8257be3f032c 100644
> --- a/net/ipv4/ping.c
> +++ b/net/ipv4/ping.c
> @@ -654,7 +654,7 @@ int ping_common_sendmsg(int family, struct msghdr *msg, size_t len,
>  			void *user_icmph, size_t icmph_len) {
>  	u8 type, code;
>  
> -	if (len > 0xFFFF)
> +	if (len > 0xFFFF || len < icmph_len)
>  		return -EMSGSIZE;

As suggested by Lorenzo, please use -EINVAL here.

Thanks.