diff options
Diffstat (limited to 'src/net/lookup.go')
| -rw-r--r-- | src/net/lookup.go | 111 |
1 files changed, 98 insertions, 13 deletions
diff --git a/src/net/lookup.go b/src/net/lookup.go index 5f7119872a4..0660268249b 100644 --- a/src/net/lookup.go +++ b/src/net/lookup.go @@ -389,8 +389,11 @@ func (r *Resolver) LookupPort(ctx context.Context, network, service string) (por // LookupCNAME does not return an error if host does not // contain DNS "CNAME" records, as long as host resolves to // address records. +// +// The returned canonical name is validated to be a properly +// formatted presentation-format domain name. func LookupCNAME(host string) (cname string, err error) { - return DefaultResolver.lookupCNAME(context.Background(), host) + return DefaultResolver.LookupCNAME(context.Background(), host) } // LookupCNAME returns the canonical name for the given host. @@ -403,8 +406,18 @@ func LookupCNAME(host string) (cname string, err error) { // LookupCNAME does not return an error if host does not // contain DNS "CNAME" records, as long as host resolves to // address records. -func (r *Resolver) LookupCNAME(ctx context.Context, host string) (cname string, err error) { - return r.lookupCNAME(ctx, host) +// +// The returned canonical name is validated to be a properly +// formatted presentation-format domain name. +func (r *Resolver) LookupCNAME(ctx context.Context, host string) (string, error) { + cname, err := r.lookupCNAME(ctx, host) + if err != nil { + return "", err + } + if !isDomainName(cname) { + return "", &DNSError{Err: "CNAME target is invalid", Name: host} + } + return cname, nil } // LookupSRV tries to resolve an SRV query of the given service, @@ -416,8 +429,11 @@ func (r *Resolver) LookupCNAME(ctx context.Context, host string) (cname string, // That is, it looks up _service._proto.name. To accommodate services // publishing SRV records under non-standard names, if both service // and proto are empty strings, LookupSRV looks up name directly. +// +// The returned service names are validated to be properly +// formatted presentation-format domain names. func LookupSRV(service, proto, name string) (cname string, addrs []*SRV, err error) { - return DefaultResolver.lookupSRV(context.Background(), service, proto, name) + return DefaultResolver.LookupSRV(context.Background(), service, proto, name) } // LookupSRV tries to resolve an SRV query of the given service, @@ -429,28 +445,82 @@ func LookupSRV(service, proto, name string) (cname string, addrs []*SRV, err err // That is, it looks up _service._proto.name. To accommodate services // publishing SRV records under non-standard names, if both service // and proto are empty strings, LookupSRV looks up name directly. -func (r *Resolver) LookupSRV(ctx context.Context, service, proto, name string) (cname string, addrs []*SRV, err error) { - return r.lookupSRV(ctx, service, proto, name) +// +// The returned service names are validated to be properly +// formatted presentation-format domain names. +func (r *Resolver) LookupSRV(ctx context.Context, service, proto, name string) (string, []*SRV, error) { + cname, addrs, err := r.lookupSRV(ctx, service, proto, name) + if err != nil { + return "", nil, err + } + if cname != "" && !isDomainName(cname) { + return "", nil, &DNSError{Err: "SRV header name is invalid", Name: name} + } + for _, addr := range addrs { + if addr == nil { + continue + } + if !isDomainName(addr.Target) { + return "", nil, &DNSError{Err: "SRV target is invalid", Name: name} + } + } + return cname, addrs, nil } // LookupMX returns the DNS MX records for the given domain name sorted by preference. +// +// The returned mail server names are validated to be properly +// formatted presentation-format domain names. func LookupMX(name string) ([]*MX, error) { - return DefaultResolver.lookupMX(context.Background(), name) + return DefaultResolver.LookupMX(context.Background(), name) } // LookupMX returns the DNS MX records for the given domain name sorted by preference. +// +// The returned mail server names are validated to be properly +// formatted presentation-format domain names. func (r *Resolver) LookupMX(ctx context.Context, name string) ([]*MX, error) { - return r.lookupMX(ctx, name) + records, err := r.lookupMX(ctx, name) + if err != nil { + return nil, err + } + for _, mx := range records { + if mx == nil { + continue + } + if !isDomainName(mx.Host) { + return nil, &DNSError{Err: "MX target is invalid", Name: name} + } + } + return records, nil } // LookupNS returns the DNS NS records for the given domain name. +// +// The returned name server names are validated to be properly +// formatted presentation-format domain names. func LookupNS(name string) ([]*NS, error) { - return DefaultResolver.lookupNS(context.Background(), name) + return DefaultResolver.LookupNS(context.Background(), name) } // LookupNS returns the DNS NS records for the given domain name. +// +// The returned name server names are validated to be properly +// formatted presentation-format domain names. func (r *Resolver) LookupNS(ctx context.Context, name string) ([]*NS, error) { - return r.lookupNS(ctx, name) + records, err := r.lookupNS(ctx, name) + if err != nil { + return nil, err + } + for _, ns := range records { + if ns == nil { + continue + } + if !isDomainName(ns.Host) { + return nil, &DNSError{Err: "NS target is invalid", Name: name} + } + } + return records, nil } // LookupTXT returns the DNS TXT records for the given domain name. @@ -466,14 +536,29 @@ func (r *Resolver) LookupTXT(ctx context.Context, name string) ([]string, error) // LookupAddr performs a reverse lookup for the given address, returning a list // of names mapping to that address. // +// The returned names are validated to be properly formatted presentation-format +// domain names. +// // When using the host C library resolver, at most one result will be // returned. To bypass the host resolver, use a custom Resolver. func LookupAddr(addr string) (names []string, err error) { - return DefaultResolver.lookupAddr(context.Background(), addr) + return DefaultResolver.LookupAddr(context.Background(), addr) } // LookupAddr performs a reverse lookup for the given address, returning a list // of names mapping to that address. -func (r *Resolver) LookupAddr(ctx context.Context, addr string) (names []string, err error) { - return r.lookupAddr(ctx, addr) +// +// The returned names are validated to be properly formatted presentation-format +// domain names. +func (r *Resolver) LookupAddr(ctx context.Context, addr string) ([]string, error) { + names, err := r.lookupAddr(ctx, addr) + if err != nil { + return nil, err + } + for _, name := range names { + if !isDomainName(name) { + return nil, &DNSError{Err: "PTR target is invalid", Name: addr} + } + } + return names, nil } |