linux-kernel - Re: [PATCH net-next v3 3/5] netconsole: add support for strings with new line in netpoll_parse_ip

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Message-ID: <20250725134224.0a2da8e7@kernel.org>
Date: Fri, 25 Jul 2025 13:42:24 -0700
From: Jakub Kicinski <kuba@...nel.org>
To: Breno Leitao <leitao@...ian.org>
Cc: "David S. Miller" <davem@...emloft.net>, Eric Dumazet
 <edumazet@...gle.com>, Paolo Abeni <pabeni@...hat.com>, Simon Horman
 <horms@...nel.org>, Andrew Lunn <andrew+netdev@...n.ch>,
 netdev@...r.kernel.org, linux-kernel@...r.kernel.org, kernel-team@...a.com
Subject: Re: [PATCH net-next v3 3/5] netconsole: add support for strings
 with new line in netpoll_parse_ip_addr

On Wed, 23 Jul 2025 10:20:31 -0700 Breno Leitao wrote:
>  	const char *end;
> +	int len;
>  
> -	if (!strchr(str, ':') &&
> -	    in4_pton(str, -1, (void *)addr, -1, &end) > 0) {
> -		if (!*end)
> -			return 0;
> -	}
> -	if (in6_pton(str, -1, addr->in6.s6_addr, -1, &end) > 0) {
> -#if IS_ENABLED(CONFIG_IPV6)
> -		if (!*end)
> -			return 1;
> -#else
> +	len = strlen(str);
> +	if (!len)
>  		return -1;
> -#endif
> -	}
> +
> +	if (str[len - 1] == '\n')
> +		len -= 1;
> +
> +	if (in4_pton(str, len, (void *)addr, -1, &end) > 0)
> +		return 0;
> +	if (IS_ENABLED(CONFIG_IPV6) &&
> +	    in6_pton(str, len, addr->in6.s6_addr, -1, &end) > 0)
> +		return 1;
>  	return -1;

Looks like we're removing the validation for reaching the end of 
the buffer? This should at least be explained in the commit message.
AFAICT for IPv4 for example 1.2.3.4:xyz would have been rejected,
now it's accepted. Personally I find the

	if (*end && *end != '\n')

removed by subsequent patch cleaner than modifying the input string.

I'll apply the first patch of the series..