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Merge pull request #11288 from estesp/warn-on-localhost-dns

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Add warning for --dns flag set to localhost addresses.
This commit is contained in:
Jessie Frazelle 2015-03-10 12:03:46 -07:00
commit c7bac5a484
1 changed files with 14 additions and 5 deletions
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13
networkfs/resolvconf/resolvconf.go
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@ -23,8 +23,10 @@ var (
// For readability and sufficiency for Docker purposes this seemed more reasonable than a
// 1000+ character regexp with exact and complete IPv6 validation
ipv6Address = `([0-9A-Fa-f]{0,4}:){2,7}([0-9A-Fa-f]{0,4})`
ipLocalhost = `((127\.([0-9]{1,3}.){2}[0-9]{1,3})|(::1))`
localhostRegexp = regexp.MustCompile(`(?m)^nameserver\s+((127\.([0-9]{1,3}.){2}[0-9]{1,3})|(::1))\s*\n*`)
localhostIPRegexp = regexp.MustCompile(ipLocalhost)
localhostNSRegexp = regexp.MustCompile(`(?m)^nameserver\s+` + ipLocalhost + `\s*\n*`)
nsIPv6Regexp = regexp.MustCompile(`(?m)^nameserver\s+` + ipv6Address + `\s*\n*`)
nsRegexp = regexp.MustCompile(`^\s*nameserver\s*((` + ipv4Address + `)|(` + ipv6Address + `))\s*$`)
searchRegexp = regexp.MustCompile(`^\s*search\s*(([^\s]+\s*)*)$`)
@ -87,7 +89,7 @@ func GetLastModified() ([]byte, string) {
// It also returns a boolean to notify the caller if changes were made at all
func FilterResolvDns(resolvConf []byte, ipv6Enabled bool) ([]byte, bool) {
changed := false
cleanedResolvConf := localhostRegexp.ReplaceAll(resolvConf, []byte{})
cleanedResolvConf := localhostNSRegexp.ReplaceAll(resolvConf, []byte{})
// if IPv6 is not enabled, also clean out any IPv6 address nameserver
if !ipv6Enabled {
cleanedResolvConf = nsIPv6Regexp.ReplaceAll(cleanedResolvConf, []byte{})
@ -124,6 +126,13 @@ func getLines(input []byte, commentMarker []byte) [][]byte {
return output
}
// returns true if the IP string matches the localhost IP regular expression.
// Used for determining if nameserver settings are being passed which are
// localhost addresses
func IsLocalhost(ip string) bool {
return localhostIPRegexp.MatchString(ip)
}
// GetNameservers returns nameservers (if any) listed in /etc/resolv.conf
func GetNameservers(resolvConf []byte) []string {
nameservers := []string{}