Re: Non-superuser subscription owners

Hi,

On 2023-01-20 11:08:54 -0500, Robert Haas wrote:
>  /*
> - * Validate connection info string (just try to parse it)
> + * Validate connection info string, and determine whether it might cause
> + * local filesystem access to be attempted.
> + *
> + * If the connection string can't be parsed, this function will raise
> + * an error and will not return. If it can, it will return true if local
> + * filesystem access may be attempted and false otherwise.
>   */
> -static void
> +static bool
>  libpqrcv_check_conninfo(const char *conninfo)
>  {
>  	PQconninfoOption *opts = NULL;
> +	PQconninfoOption *opt;
>  	char	   *err = NULL;
> +	bool		result = false;
>  
>  	opts = PQconninfoParse(conninfo, &err);
>  	if (opts == NULL)
> @@ -267,7 +274,40 @@ libpqrcv_check_conninfo(const char *conninfo)
>  				 errmsg("invalid connection string syntax: %s", errcopy)));
>  	}
>  
> +	for (opt = opts; opt->keyword != NULL; ++opt)
> +	{
> +		/* Ignore connection options that are not present. */
> +		if (opt->val == NULL)
> +			continue;
> +
> +		/* For all these parameters, the value is a local filename. */
> +		if (strcmp(opt->keyword, "passfile") == 0 ||
> +			strcmp(opt->keyword, "sslcert") == 0 ||
> +			strcmp(opt->keyword, "sslkey") == 0 ||
> +			strcmp(opt->keyword, "sslrootcert") == 0 ||
> +			strcmp(opt->keyword, "sslcrl") == 0 ||
> +			strcmp(opt->keyword, "sslcrldir") == 0 ||
> +			strcmp(opt->keyword, "service") == 0)
> +		{
> +			result = true;
> +			break;
> +		}

Do we need to think about 'options' allowing anything bad? I don't
immediately* see a problem, but ...


> +
> +		/*
> +		 * For the host parameter, the value might be a local filename.
> +		 * It might also be a reference to the local host's abstract UNIX
> +		 * socket namespace, which we consider equivalent to a local pathname
> +		 * for security purporses.
> +		 */
> +		if (strcmp(opt->keyword, "host") == 0 && is_unixsock_path(opt->val))
> +		{
> +			result = true;
> +			break;
> +		}
> +	}

Hm, what about kerberos / gss / SSPI? Aren't those essentially also tied to
the local filesystem / user?

Greetings,

Andres Freund