[libvirt PATCH] conf: network: remove hostname validation

[Laine Stump]

On 1/27/22 4:33 PM, Ján Tomko wrote:
> We used to validate that the first character of the hostname is a
> letter. Later, RFC1123 relaxed the requirements to allow a number
> as well.
> 
> Drop the validation completely, since we do not care about the
> following characters, and neither does dnsmasq (even if it's a comma,
> which is a delimiter in the hosts file).

Was there some discussion somewhere that prompted this patch (and thus 
invalidates the opinion I'm about to spout)? The only email I could find 
about it was the email of the "reverted" patch itself (sent by Peter on 
behalf of the author, with r-b given in the same email).

My opinion is that if a current RFC restricts the first letter of a 
hostname, then we should validate that too, *especially* if dnsmasq 
doesn't; who knows what entity beyond dnsmasq will barf on it in some 
way, and the closer to the source the non-compliance is reported, the 
easier it will be to fix. (Additionally, it's easy to remove extra 
validation, but much more difficult to add it back later if we decide it 
shouldn't have been removed)


> 
> Reverts: 673b74be5fda928da5e9f3c2cfbf6c1cb1eda0c6
> Signed-off-by: Ján Tomko <jtomko at redhat.com>
> ---
>   src/conf/network_conf.c | 6 ------
>   1 file changed, 6 deletions(-)
> 
> diff --git a/src/conf/network_conf.c b/src/conf/network_conf.c
> index c769bbaeb5..8f50e22be5 100644
> --- a/src/conf/network_conf.c
> +++ b/src/conf/network_conf.c
> @@ -548,12 +548,6 @@ virNetworkDHCPHostDefParseXML(const char *networkName,
>       }
>   
>       name = virXMLPropString(node, "name");
> -    if (name && !(g_ascii_isalpha(name[0]) || g_ascii_isdigit(name[0]))) {
> -        virReportError(VIR_ERR_XML_ERROR,
> -                       _("Cannot use host name '%s' in network '%s'"),
> -                       name, networkName);
> -        return -1;
> -    }
>   
>       ip = virXMLPropString(node, "ip");
>       if (ip && (virSocketAddrParse(&inaddr, ip, AF_UNSPEC) < 0)) {