Fix IP redaction: assign ReplaceAllString return values (#79)

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: NickMillerUK

results/telemetry.go

@@ -44,7 +44,7 @@ var fontMediumBytes []byte
 var fontLightBytes []byte
 
 var (
-	ipv4Regex     = regexp.MustCompile(`(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)`)
+	ipv4Regex     = regexp.MustCompile(`(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)`)
 	ipv6Regex     = regexp.MustCompile(`(([0-9a-fA-F]{1,4}:){7}[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,7}:|([0-9a-fA-F]{1,4}:){1,6}:[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,5}(:[0-9a-fA-F]{1,4}){1,2}|([0-9a-fA-F]{1,4}:){1,4}(:[0-9a-fA-F]{1,4}){1,3}|([0-9a-fA-F]{1,4}:){1,3}(:[0-9a-fA-F]{1,4}){1,4}|([0-9a-fA-F]{1,4}:){1,2}(:[0-9a-fA-F]{1,4}){1,5}|[0-9a-fA-F]{1,4}:((:[0-9a-fA-F]{1,4}){1,6})|:((:[0-9a-fA-F]{1,4}){1,7}|:)|fe80:(:[0-9a-fA-F]{0,4}){0,4}%[0-9a-zA-Z]{1,}|::(ffff(:0{1,4})?:)?((25[0-5]|(2[0-4]|1?[0-9])?[0-9])\.){3}(25[0-5]|(2[0-4]|1?[0-9])?[0-9])|([0-9a-fA-F]{1,4}:){1,4}:((25[0-5]|(2[0-4]|1?[0-9])?[0-9])\.){3}(25[0-5]|(2[0-4]|1?[0-9])?[0-9]))`)
 	hostnameRegex = regexp.MustCompile(`"hostname":"([^\\\\"]|\\\\")*"`)
 
@@ -164,13 +164,13 @@ func Record(w http.ResponseWriter, r *http.Request) {
 	extra := r.FormValue("extra")
 
 	if config.LoadedConfig().RedactIP {
-		ipAddr = "0.0.0.0"
-		ipv4Regex.ReplaceAllString(ispInfo, "0.0.0.0")
-		ipv4Regex.ReplaceAllString(logs, "0.0.0.0")
-		ipv6Regex.ReplaceAllString(ispInfo, "0.0.0.0")
-		ipv6Regex.ReplaceAllString(logs, "0.0.0.0")
-		hostnameRegex.ReplaceAllString(ispInfo, `"hostname":"REDACTED"`)
-		hostnameRegex.ReplaceAllString(logs, `"hostname":"REDACTED"`)
+		ipAddr  = "0.0.0.0"
+		ispInfo = ipv4Regex.ReplaceAllString(ispInfo, "0.0.0.0")
+		logs    = ipv4Regex.ReplaceAllString(logs, "0.0.0.0")
+		ispInfo = ipv6Regex.ReplaceAllString(ispInfo, "::")
+		logs    = ipv6Regex.ReplaceAllString(logs, "::")
+		ispInfo = hostnameRegex.ReplaceAllString(ispInfo, `"hostname":"REDACTED"`)
+		logs    = hostnameRegex.ReplaceAllString(logs, `"hostname":"REDACTED"`)
 	}
 
 	var record schema.TelemetryData

results/telemetry_test.go

@@ -0,0 +1,121 @@
+package results
+
+import (
+	"testing"
+)
+
+func TestIPRedaction(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		wantOut  string
+		regex    func(string, string) string
+		redactTo string
+	}{
+		{
+			name:     "IPv4 in ispInfo is redacted",
+			input:    `{"ip":"203.0.113.42","org":"AS12345 Example ISP"}`,
+			wantOut:  `{"ip":"0.0.0.0","org":"AS12345 Example ISP"}`,
+			regex:    ipv4Regex.ReplaceAllString,
+			redactTo: "0.0.0.0",
+		},
+		{
+			name:     "multiple IPv4 addresses in logs are all redacted",
+			input:    `connected from 203.0.113.42, forwarded for 198.51.100.7`,
+			wantOut:  `connected from 0.0.0.0, forwarded for 0.0.0.0`,
+			regex:    ipv4Regex.ReplaceAllString,
+			redactTo: "0.0.0.0",
+		},
+		{
+			name:     "empty string is handled safely by IPv4 regex",
+			input:    "",
+			wantOut:  "",
+			regex:    ipv4Regex.ReplaceAllString,
+			redactTo: "0.0.0.0",
+		},
+		{
+			name:     "IPv6 in ispInfo is redacted",
+			input:    `{"ip":"2001:0db8:85a3:0000:0000:8a2e:0370:7334","org":"AS12345 Example ISP"}`,
+			wantOut:  `{"ip":"::","org":"AS12345 Example ISP"}`,
+			regex:    ipv6Regex.ReplaceAllString,
+			redactTo: "::",
+		},
+		{
+			name:     "empty string is handled safely by IPv6 regex",
+			input:    "",
+			wantOut:  "",
+			regex:    ipv6Regex.ReplaceAllString,
+			redactTo: "::",
+		},
+		{
+			name:     "hostname in ispInfo is redacted",
+			input:    `{"ip":"0.0.0.0","hostname":"client.example.com","org":"AS12345 Example ISP"}`,
+			wantOut:  `{"ip":"0.0.0.0","hostname":"REDACTED","org":"AS12345 Example ISP"}`,
+			regex:    hostnameRegex.ReplaceAllString,
+			redactTo: `"hostname":"REDACTED"`,
+		},
+		{
+			name:     "empty string is handled safely by hostname regex",
+			input:    "",
+			wantOut:  "",
+			regex:    hostnameRegex.ReplaceAllString,
+			redactTo: `"hostname":"REDACTED"`,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := tt.regex(tt.input, tt.redactTo)
+			if got != tt.wantOut {
+				t.Errorf("\ngot:  %s\nwant: %s", got, tt.wantOut)
+			}
+		})
+	}
+}
+
+func TestIPRedactionChain(t *testing.T) {
+	tests := []struct {
+		name      string
+		ispInfo   string
+		logs      string
+		wantISP   string
+		wantLogs  string
+	}{
+		{
+			name:     "IPv4 client: addresses and hostname redacted",
+			ispInfo:  `{"ip":"203.0.113.42","hostname":"client.example.com","org":"AS12345 Example ISP"}`,
+			logs:     `connected from 203.0.113.42 and 198.51.100.7`,
+			wantISP:  `{"ip":"0.0.0.0","hostname":"REDACTED","org":"AS12345 Example ISP"}`,
+			wantLogs: `connected from 0.0.0.0 and 0.0.0.0`,
+		},
+		{
+			name:     "IPv6 client: redacted as :: to preserve address family for debugging",
+			ispInfo:  `{"ip":"2001:0db8:85a3:0000:0000:8a2e:0370:7334","hostname":"client.example.com","org":"AS12345 Example ISP"}`,
+			logs:     `connected from 2001:0db8:85a3:0000:0000:8a2e:0370:7334`,
+			wantISP:  `{"ip":"::","hostname":"REDACTED","org":"AS12345 Example ISP"}`,
+			wantLogs: `connected from ::`,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			ispInfo := tt.ispInfo
+			logs := tt.logs
+
+			// Mirror the full redaction block in Record()
+			ispInfo = ipv4Regex.ReplaceAllString(ispInfo, "0.0.0.0")
+			logs = ipv4Regex.ReplaceAllString(logs, "0.0.0.0")
+			ispInfo = ipv6Regex.ReplaceAllString(ispInfo, "::")
+			logs = ipv6Regex.ReplaceAllString(logs, "::")
+			ispInfo = hostnameRegex.ReplaceAllString(ispInfo, `"hostname":"REDACTED"`)
+			logs = hostnameRegex.ReplaceAllString(logs, `"hostname":"REDACTED"`)
+
+			if ispInfo != tt.wantISP {
+				t.Errorf("ispInfo\ngot:  %s\nwant: %s", ispInfo, tt.wantISP)
+			}
+			if logs != tt.wantLogs {
+				t.Errorf("logs\ngot:  %s\nwant: %s", logs, tt.wantLogs)
+			}
+		})
+	}
+}