fix: small security fixes (#1651)

This is based on private evaluation of a prerelease security product.
I cannot comment further other than I am impressed by its output.

This commit is a squash of several commits. The impactful commits
have details underneath markdown heading twos.

## fix(metrics): don't expose pprof by default

pprof[1] is the Go standard library profiling toolkit. It is invaluable
for diagnosing how Go programs perform in the wild. However it also is
able to expose secret data set with command line flags. This is not
ideal and should be mitigated by correctly configured firewall rules. We
don't live in a world where people correctly configure firewall rules,
so we have to fix things for people. Welcome to 2026.

[1]: https://pkg.go.dev/runtime/pprof

Ref: AWOO-001

## fix(honeypot/naive): cap r9k delay to one second

Otherwise this can get unbounded, which can cause problems with lesser
HTTP proxies such as Apache.

Ref: AWOO-002

## fix(policy): mend an edge case with subrequest auth and query strings

This fixes an unlikely edge case where using subrequest auth and query
strings with path based filtering can cause reality to differ from
administrator intent. This effectively strips the query string from
subrequest auth checks. This deficiency should be fixed in the future.

Ref: AWOO-004

## fix(expressions): mend possible nil pointer deref edge case

If Anubis just started up, load averages may not be set in memory. This
can cause a nil pointer dereference which could fail requests with weird
errors until the async thread sets the load averages.

Ref: AWOO-005

## fix(lib): mend case where domainless redirects could allow cross-domain redirects

Ref: AWOO-009

## fix(expressions): validate randInt bounds before rand.IntN

Non-positive or platform-overflowing arguments to the CEL randInt
helper used to reach rand.IntN unchecked, surfacing a CEL evaluator
error during request processing when policies passed
attacker-influenced values (e.g. contentLength). Reject non-positive
bounds and detect int narrowing explicitly, returning a typed CEL
error in both cases.

Ref: AWOO-010

Signed-off-by: Xe Iaso <xe.iaso@techaro.lol>

lib/policy/expressions/environment.go

@@ -222,7 +222,16 @@ func New(opts ...cel.EnvOption) (*cel.Env, error) {
 						return types.ValOrErr(val, "value is not an integer, but is %T", val)
 					}
 
-					return types.Int(rand.IntN(int(n)))
+					if n <= 0 {
+						return types.NewErr("randInt bound must be positive, got %d", int64(n))
+					}
+
+					bound := int(n)
+					if types.Int(bound) != n {
+						return types.NewErr("randInt bound %d overflows platform int", int64(n))
+					}
+
+					return types.Int(rand.IntN(bound))
 				}),
 			),
 		),

lib/policy/expressions/environment_test.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/TecharoHQ/anubis/internal/dns"
 	"github.com/TecharoHQ/anubis/lib/store/memory"
+	"github.com/google/cel-go/cel"
 	"github.com/google/cel-go/common/types"
 	"github.com/google/cel-go/common/types/ref"
 )
@@ -688,6 +689,14 @@ func TestNewEnvironment(t *testing.T) {
 			description:   "should return values in correct range",
 			shouldCompile: true,
 		},
+		{
+			name:          "randInt-large-bound",
+			expression:    `randInt(2147483647) >= 0`,
+			variables:     map[string]any{},
+			expectBool:    boolPtr(true),
+			description:   "should accept int32-max bounds without overflow",
+			shouldCompile: true,
+		},
 		{
 			name:          "strings-extension-size",
 			expression:    `"hello".size() == 5`,
@@ -750,3 +759,65 @@ func TestNewEnvironment(t *testing.T) {
 func boolPtr(b bool) *bool {
 	return &b
 }
+
+func TestRandIntInvalidBounds(t *testing.T) {
+	env, err := New(cel.Variable("contentLength", cel.IntType))
+	if err != nil {
+		t.Fatalf("failed to create environment: %v", err)
+	}
+
+	tests := []struct {
+		name        string
+		expression  string
+		variables   map[string]any
+		wantErrText string
+		description string
+	}{
+		{
+			name:        "zero-bound-literal",
+			expression:  `randInt(0)`,
+			variables:   map[string]any{},
+			wantErrText: "randInt bound must be positive",
+			description: "randInt(0) should return a CEL error, not panic",
+		},
+		{
+			name:        "negative-bound-literal",
+			expression:  `randInt(-5)`,
+			variables:   map[string]any{},
+			wantErrText: "randInt bound must be positive",
+			description: "randInt(-5) should return a CEL error, not panic",
+		},
+		{
+			name:        "zero-bound-from-variable",
+			expression:  `randInt(contentLength)`,
+			variables:   map[string]any{"contentLength": 0},
+			wantErrText: "randInt bound must be positive",
+			description: "attacker-controlled zero contentLength should error gracefully",
+		},
+		{
+			name:        "negative-bound-from-variable",
+			expression:  `randInt(contentLength)`,
+			variables:   map[string]any{"contentLength": -1},
+			wantErrText: "randInt bound must be positive",
+			description: "attacker-controlled negative contentLength should error gracefully",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			prog, err := Compile(env, tt.expression)
+			if err != nil {
+				t.Fatalf("failed to compile expression %q: %v", tt.expression, err)
+			}
+
+			result, _, err := prog.Eval(tt.variables)
+			if err == nil {
+				t.Fatalf("%s: expected an evaluation error, got result %v", tt.description, result)
+			}
+
+			if !strings.Contains(err.Error(), tt.wantErrText) {
+				t.Errorf("%s: expected error containing %q, got %q", tt.description, tt.wantErrText, err.Error())
+			}
+		})
+	}
+}

lib/policy/expressions/loadavg.go

@@ -46,7 +46,7 @@ var (
 )
 
 func init() {
-	globalLoadAvg = &loadAvg{}
+	globalLoadAvg = &loadAvg{data: &load.AvgStat{}}
 	go globalLoadAvg.updateThread(context.Background())
 }