Add gosprintfhostport linter

The Go linter go-sprintf-host-port checks that sprintf is not used to
construct a host:port combination in a URL. A frequent pattern is for a
developer to construct a URL like this:

```go
fmt.Sprintf("http://%s:%d/foo", host, port)
```

However, if "host" is an IPv6 address like 2001:4860:4860::8888, the URL
constructed will be invalid. IPv6 addresses must be bracketed, like
this:

```
http://[2001:4860:4860::8888]:9443
```

The linter is naive, and really only looks for the most obvious cases,
but where it's possible to infer that a URL is being constructed with
Sprintf containing a :, this informs the user to use net.JoinHostPort
instead.

Running it against some real world code bases like OpenShift and
Kubernetes has found a number of cases that would break in IPv6
environments.

Author: stbenjam

go.mod

@@ -153,6 +153,7 @@ require (
 	github.com/spf13/afero v1.6.0 // indirect
 	github.com/spf13/cast v1.4.1 // indirect
 	github.com/spf13/jwalterweatherman v1.1.0 // indirect
+	github.com/stbenjam/go-sprintf-host-port v0.0.0-20220406232701-e6c52ffc7e9c // indirect
 	github.com/stretchr/objx v0.1.1 // indirect
 	github.com/subosito/gotenv v1.2.0 // indirect
 	github.com/tklauser/go-sysconf v0.3.10 // indirect

go.sum

@@ -0,0 +1,19 @@
+package golinters
+
+import (
+	"github.com/stbenjam/go-sprintf-host-port/pkg/analyzer"
+	"golang.org/x/tools/go/analysis"
+
+	"github.com/golangci/golangci-lint/pkg/golinters/goanalysis"
+)
+
+func NewGoSprintfHostPort() *goanalysis.Linter {
+	a := analyzer.Analyzer
+
+	return goanalysis.NewLinter(
+		a.Name,
+		a.Doc,
+		[]*analysis.Analyzer{a},
+		nil,
+	).WithLoadMode(goanalysis.LoadModeSyntax)
+}

pkg/golinters/gosprintfhostport.go

@@ -407,6 +407,11 @@ func (m Manager) GetAllSupportedLinterConfigs() []*linter.Config {
 			WithPresets(linter.PresetStyle).
 			WithURL("https://github.com/jirfag/go-printf-func-name"),
 
+		linter.NewConfig(golinters.NewGoSprintfHostPort()).
+			WithSince("v1.46.0").
+			WithPresets(linter.PresetStyle).
+			WithURL("https://github.com/stbenjam/go-sprintf-host-port"),
+
 		linter.NewConfig(golinters.NewGosec(gosecCfg)).
 			WithSince("v1.0.0").
 			WithLoadForGoAnalysis().

pkg/lint/lintersdb/manager.go

@@ -0,0 +1,42 @@
+//args: -Egosprintfhostport
+package testdata
+
+import (
+	"fmt"
+	"net"
+)
+
+func _() {
+	_ = fmt.Sprintf("gopher://%s/foo", net.JoinHostPort("foo", "80"))
+
+	_ = fmt.Sprintf("postgres://%s:%[email protected]/%s", "foo", "bar", "baz")
+
+	_ = fmt.Sprintf("http://%s/foo", net.JoinHostPort("foo", "80"))
+
+	_ = fmt.Sprintf("http://api.%s:6443/foo", "example.com")
+
+	_ = fmt.Sprintf("http://api.%s/foo", "example.com")
+
+	_ = fmt.Sprintf("telnet+ssl://%s/foo", net.JoinHostPort("foo", "80"))
+
+	_ = fmt.Sprintf("http://%s/foo:bar", net.JoinHostPort("foo", "80"))
+
+	_ = fmt.Sprintf("http://user:password@%s/foo:bar", net.JoinHostPort("foo", "80"))
+
+	_ = fmt.Sprintf("http://example.com:9211")
+
+	_ = fmt.Sprintf("gopher://%s:%d", "myHost", 70) // ERROR "host:port in url should be constructed with net.JoinHostPort and not directly with fmt.Sprintf"
+
+	_ = fmt.Sprintf("telnet+ssl://%s:%d", "myHost", 23) // ERROR "host:port in url should be constructed with net.JoinHostPort and not directly with fmt.Sprintf"
+
+	_ = fmt.Sprintf("https://user@%s:%d", "myHost", 8443) // ERROR "host:port in url should be constructed with net.JoinHostPort and not directly with fmt.Sprintf"
+
+	_ = fmt.Sprintf("postgres://%s:%s@%s:5050/%s", "foo", "bar", "baz", "qux") // ERROR "host:port in url should be constructed with net.JoinHostPort and not directly with fmt.Sprintf"
+
+	_ = fmt.Sprintf("https://%s:%d", "myHost", 8443) // ERROR "host:port in url should be constructed with net.JoinHostPort and not directly with fmt.Sprintf"
+
+	_ = fmt.Sprintf("https://%s:9211", "myHost") // ERROR "host:port in url should be constructed with net.JoinHostPort and not directly with fmt.Sprintf"
+
+	ip := "fd00::1"
+	_ = fmt.Sprintf("http://%s:1936/healthz", ip) // ERROR "host:port in url should be constructed with net.JoinHostPort and not directly with fmt.Sprintf"
+}