Merge: dnsfilter: prevent recursion when both parental control and safebrowsing are enabled

Close #732

* commit 'c4e67690f4fcceb055cbea73610b5974855db96f':
  * dnsfilter: don't use global variable for custom resolver function
  - dnsfilter: prevent recursion when both parental control and safebrowsing are enabled
This commit is contained in:
Simon Zolin 2019-04-24 12:52:16 +03:00
commit e1bb89c393
1 changed files with 43 additions and 46 deletions

View File

@ -162,8 +162,6 @@ var (
safeSearchCache gcache.Cache
)
var resolverAddr string // DNS server address
// Result holds state of hostname check
type Result struct {
IsFiltered bool `json:",omitempty"` // True if the host name is filtered
@ -185,6 +183,10 @@ func (d *Dnsfilter) CheckHost(host string) (Result, error) {
return Result{Reason: NotFilteredNotFound}, nil
}
host = strings.ToLower(host)
// prevent recursion
if host == d.parentalServer || host == d.safeBrowsingServer {
return Result{}, nil
}
// try filter lists first
result, err := d.matchHost(host)
@ -674,10 +676,6 @@ func (d *Dnsfilter) checkSafeBrowsing(host string) (Result, error) {
defer timer.LogElapsed("SafeBrowsing HTTP lookup for %s", host)
}
// prevent recursion -- checking the host of safebrowsing server makes no sense
if host == d.safeBrowsingServer {
return Result{}, nil
}
format := func(hashparam string) string {
url := fmt.Sprintf(defaultSafebrowsingURL, d.safeBrowsingServer, hashparam)
return url
@ -720,10 +718,6 @@ func (d *Dnsfilter) checkParental(host string) (Result, error) {
defer timer.LogElapsed("Parental HTTP lookup for %s", host)
}
// prevent recursion -- checking the host of parental safety server makes no sense
if host == d.parentalServer {
return Result{}, nil
}
format := func(hashparam string) string {
url := fmt.Sprintf(defaultParentalURL, d.parentalServer, hashparam, d.ParentalSensitivity)
return url
@ -978,45 +972,49 @@ func (d *Dnsfilter) matchHost(host string) (Result, error) {
// lifecycle helper functions
//
type dialFunctionType func(ctx context.Context, network, addr string) (net.Conn, error)
// Connect to a remote server resolving hostname using our own DNS server
func customDialContext(ctx context.Context, network, addr string) (net.Conn, error) {
log.Tracef("network:%v addr:%v", network, addr)
func createCustomDialContext(resolverAddr string) dialFunctionType {
return func(ctx context.Context, network, addr string) (net.Conn, error) {
log.Tracef("network:%v addr:%v", network, addr)
host, port, err := net.SplitHostPort(addr)
if err != nil {
return nil, err
}
dialer := &net.Dialer{
Timeout: time.Minute * 5,
}
if net.ParseIP(host) != nil {
con, err := dialer.DialContext(ctx, network, addr)
return con, err
}
r := upstream.NewResolver(resolverAddr, 30*time.Second)
addrs, e := r.LookupIPAddr(ctx, host)
log.Tracef("LookupIPAddr: %s: %v", host, addrs)
if e != nil {
return nil, e
}
var firstErr error
firstErr = nil
for _, a := range addrs {
addr = fmt.Sprintf("%s:%s", a.String(), port)
con, err := dialer.DialContext(ctx, network, addr)
host, port, err := net.SplitHostPort(addr)
if err != nil {
if firstErr == nil {
firstErr = err
}
continue
return nil, err
}
return con, err
dialer := &net.Dialer{
Timeout: time.Minute * 5,
}
if net.ParseIP(host) != nil {
con, err := dialer.DialContext(ctx, network, addr)
return con, err
}
r := upstream.NewResolver(resolverAddr, 30*time.Second)
addrs, e := r.LookupIPAddr(ctx, host)
log.Tracef("LookupIPAddr: %s: %v", host, addrs)
if e != nil {
return nil, e
}
var firstErr error
firstErr = nil
for _, a := range addrs {
addr = fmt.Sprintf("%s:%s", a.String(), port)
con, err := dialer.DialContext(ctx, network, addr)
if err != nil {
if firstErr == nil {
firstErr = err
}
continue
}
return con, err
}
return nil, firstErr
}
return nil, firstErr
}
// New creates properly initialized DNS Filter that is ready to be used
@ -1039,8 +1037,7 @@ func New(c *Config) *Dnsfilter {
ExpectContinueTimeout: 1 * time.Second,
}
if c != nil && len(c.ResolverAddress) != 0 {
resolverAddr = c.ResolverAddress
d.transport.DialContext = customDialContext
d.transport.DialContext = createCustomDialContext(c.ResolverAddress)
}
d.client = http.Client{
Transport: d.transport,