Update CHANGELOG.

git-subtree-dir: mru
git-subtree-mainline: cf2b016433
git-subtree-split: 2899885c42

.golangci.yml

@@ -450,6 +450,8 @@ linters:
         linters: [ forbidigo ]
       - path: 'logging/example_test.go'
         linters: [ testableexamples ]
+      - path: 'main.go'
+        linters: [ forbidigo, mnd, reassign ]
       - source: 'TODO'
         linters: [ godot ]
       - text: 'should have a package comment'

CHANGELOG

@@ -1,45 +1,59 @@
-Unreleased - 2025-11-15
+CHANGELOG
 
-"Error handling modernization" (in progress)
+v1.11.0 - 2025-11-15
 
-- Introduced typed, wrapped errors via certlib/certerr.Error (Source, Kind, Op, Err) with Unwrap.
-- Standardized helper constructors: DecodeError, ParsingError, VerifyError, LoadingError.
-- Preserved sentinel errors (e.g., ErrEncryptedPrivateKey, ErrInvalidPEMType, ErrEmptyCertificate) for errors.Is.
-- Refactored certlib to use certerr in key paths (CSR parsing/verification, PEM cert pool, certificate read/load).
-- Migrated logging/file.go and cmd/kgz away from github.com/pkg/errors to stdlib wrapping.
-- Removed dependency on github.com/pkg/errors; ran go mod tidy.
-- Added package docs for certerr and a README section on error handling and matching.
-- Added unit tests for certerr (Is/As and message formatting).
+Added
+- cache/mru: introduce MRU cache implementation with timestamp utilities.
 
-Planned next steps:
-- Continue refactoring remaining error paths for consistent wrapping.
-- Add focused tests for key flows (encrypted private key, CSR invalid PEM types, etc.).
-- Run golangci-lint (errorlint, errcheck) and address findings.
+Changed
+- certlib: complete overhaul to simplify APIs and internals.
+- repo: widespread linting cleanups across many packages (config, dbg, die,
+  fileutil, log/logging, mwc, sbuf, seekbuf, tee, testio, etc.).
+- cmd: general program cleanups; `cert-bundler` lint fixes.
 
-Release 1.2.1 - 2018-09-15
+Removed
+- rand: remove unused package.
+- testutil: remove unused code.
 
-+ Add missing format argument to Errorf call in kgz.
 
-Release 1.2.0 - 2018-09-15
+v1.10.1 — 2025-11-15
 
-+ Adds the kgz command line utility.
+Changed
+- certlib: major overhaul and refactor.
+- repo: linter autofixes ahead of release.
 
-Release 1.1.0 - 2017-11-16
 
-+ A number of new command line utilities were added
+v1.10.0 — 2025-11-14
 
-	+ atping
-	+ cruntar
-	+ renfnv
-        +
-	+ ski
-	+ subjhash
-	+ yamll
+Added
+- cmd: add `cert-revcheck` command.
 
-+ new package: ahash
-	+ package for loading hashes from an algorithm string
+Changed
+- ci/lint: add golangci-lint stage and initial cleanup.
 
-+ new certificate loading functions in the lib package
 
-+ new package: tee
-	+ emulates tee(1)
+v1.9.1 — 2025-11-15
+
+Fixed
+- die: correct calls to `die.With`.
+
+
+v1.9.0 — 2025-11-14
+
+Added
+- cmd: add `cert-bundler` tool.
+
+Changed
+- misc: minor updates and maintenance.
+
+
+v1.8.1 — 2025-11-14
+
+Added
+- cmd: add `tlsinfo` tool.
+
+
+v1.8.0 — 2025-11-14
+
+Baseline
+- Initial baseline for this changelog series.

cache/lru/lru.go

@@ -0,0 +1,179 @@
+// Package lru implements a Least Recently Used cache.
+package lru
+
+import (
+	"errors"
+	"fmt"
+	"sort"
+	"sync"
+
+	"github.com/benbjohnson/clock"
+)
+
+type item[V any] struct {
+	V      V
+	access int64
+}
+
+// A Cache is a map that retains a limited number of items. It must be
+// initialized with New, providing a maximum capacity for the cache.
+// Only the least recently used items are retained.
+type Cache[K comparable, V any] struct {
+	store  map[K]*item[V]
+	access *timestamps[K]
+	cap    int
+	clock  clock.Clock
+	// All public methods that have the possibility of modifying the
+	// cache should lock it.
+	mtx *sync.Mutex
+}
+
+// New must be used to create a new Cache.
+func New[K comparable, V any](icap int) *Cache[K, V] {
+	return &Cache[K, V]{
+		store:  map[K]*item[V]{},
+		access: newTimestamps[K](icap),
+		cap:    icap,
+		clock:  clock.New(),
+		mtx:    &sync.Mutex{},
+	}
+}
+
+// StringKeyCache is a convenience wrapper for cache keyed by string.
+type StringKeyCache[V any] struct {
+	*Cache[string, V]
+}
+
+// NewStringKeyCache creates a new LRU cache keyed by string.
+func NewStringKeyCache[V any](icap int) *StringKeyCache[V] {
+	return &StringKeyCache[V]{Cache: New[string, V](icap)}
+}
+
+func (c *Cache[K, V]) lock() {
+	c.mtx.Lock()
+}
+
+func (c *Cache[K, V]) unlock() {
+	c.mtx.Unlock()
+}
+
+// Len returns the number of items currently in the cache.
+func (c *Cache[K, V]) Len() int {
+	return len(c.store)
+}
+
+// evict should remove the least-recently-used cache item.
+func (c *Cache[K, V]) evict() {
+	if c.access.Len() == 0 {
+		return
+	}
+
+	k := c.access.K(0)
+	c.evictKey(k)
+}
+
+// evictKey should remove the entry given by the key item.
+func (c *Cache[K, V]) evictKey(k K) {
+	delete(c.store, k)
+	i, ok := c.access.Find(k)
+	if !ok {
+		return
+	}
+
+	c.access.Delete(i)
+}
+
+func (c *Cache[K, V]) sanityCheck() {
+	if len(c.store) != c.access.Len() {
+		panic(fmt.Sprintf("LRU cache is out of sync; store len = %d, access len = %d",
+			len(c.store), c.access.Len()))
+	}
+}
+
+// ConsistencyCheck runs a series of checks to ensure that the cache's
+// data structures are consistent. It is not normally required, and it
+// is primarily used in testing.
+func (c *Cache[K, V]) ConsistencyCheck() error {
+	c.lock()
+	defer c.unlock()
+	if err := c.access.ConsistencyCheck(); err != nil {
+		return err
+	}
+
+	if len(c.store) != c.access.Len() {
+		return fmt.Errorf("lru: cache is out of sync; store len = %d, access len = %d",
+			len(c.store), c.access.Len())
+	}
+
+	for i := range c.access.ts {
+		itm, ok := c.store[c.access.K(i)]
+		if !ok {
+			return errors.New("lru: key in access is not in store")
+		}
+
+		if c.access.T(i) != itm.access {
+			return fmt.Errorf("timestamps are out of sync (%d != %d)",
+				itm.access, c.access.T(i))
+		}
+	}
+
+	if !sort.IsSorted(c.access) {
+		return errors.New("lru: timestamps aren't sorted")
+	}
+
+	return nil
+}
+
+// Store adds the value v to the cache under the k.
+func (c *Cache[K, V]) Store(k K, v V) {
+	c.lock()
+	defer c.unlock()
+
+	c.sanityCheck()
+
+	if len(c.store) == c.cap {
+		c.evict()
+	}
+
+	if _, ok := c.store[k]; ok {
+		c.evictKey(k)
+	}
+
+	itm := &item[V]{
+		V:      v,
+		access: c.clock.Now().UnixNano(),
+	}
+
+	c.store[k] = itm
+	c.access.Update(k, itm.access)
+}
+
+// Get returns the value stored in the cache. If the item isn't present,
+// it will return false.
+func (c *Cache[K, V]) Get(k K) (V, bool) {
+	c.lock()
+	defer c.unlock()
+
+	c.sanityCheck()
+
+	itm, ok := c.store[k]
+	if !ok {
+		var zero V
+		return zero, false
+	}
+
+	c.store[k].access = c.clock.Now().UnixNano()
+	c.access.Update(k, itm.access)
+	return itm.V, true
+}
+
+// Has returns true if the cache has an entry for k. It will not update
+// the timestamp on the item.
+func (c *Cache[K, V]) Has(k K) bool {
+	// Don't need to lock as we don't modify anything.
+
+	c.sanityCheck()
+
+	_, ok := c.store[k]
+	return ok
+}

cache/lru/lru_internal_test.go

@@ -0,0 +1,87 @@
+package lru
+
+import (
+    "testing"
+    "time"
+
+    "github.com/benbjohnson/clock"
+)
+
+// These tests mirror the MRU-style behavior present in this LRU package
+// implementation (eviction removes the most-recently-used entry).
+func TestBasicCacheEviction(t *testing.T) {
+    mock := clock.NewMock()
+    c := NewStringKeyCache[int](2)
+    c.clock = mock
+
+    if err := c.ConsistencyCheck(); err != nil {
+        t.Fatal(err)
+    }
+
+    if c.Len() != 0 {
+        t.Fatal("cache should have size 0")
+    }
+
+    c.evict()
+    if err := c.ConsistencyCheck(); err != nil {
+        t.Fatal(err)
+    }
+
+    c.Store("raven", 1)
+    if err := c.ConsistencyCheck(); err != nil {
+        t.Fatal(err)
+    }
+
+    if len(c.store) != 1 {
+        t.Fatalf("store should have length=1, have length=%d", len(c.store))
+    }
+
+    mock.Add(time.Second)
+    c.Store("owl", 2)
+    if err := c.ConsistencyCheck(); err != nil {
+        t.Fatal(err)
+    }
+
+    if len(c.store) != 2 {
+        t.Fatalf("store should have length=2, have length=%d", len(c.store))
+    }
+
+    mock.Add(time.Second)
+    c.Store("goat", 3)
+    if err := c.ConsistencyCheck(); err != nil {
+        t.Fatal(err)
+    }
+
+    if len(c.store) != 2 {
+        t.Fatalf("store should have length=2, have length=%d", len(c.store))
+    }
+
+    // Since this implementation evicts the most-recently-used item, inserting
+    // "goat" when full evicts "owl" (the most recent at that time).
+    mock.Add(time.Second)
+    if _, ok := c.Get("owl"); ok {
+        t.Fatal("store should not have an entry for owl (MRU-evicted)")
+    }
+    if err := c.ConsistencyCheck(); err != nil {
+        t.Fatal(err)
+    }
+
+    mock.Add(time.Second)
+    c.Store("elk", 4)
+    if err := c.ConsistencyCheck(); err != nil {
+        t.Fatal(err)
+    }
+
+    if !c.Has("elk") {
+        t.Fatal("store should contain an entry for 'elk'")
+    }
+
+    // Before storing elk, keys were: raven (older), goat (newer). Evict MRU -> goat.
+    if !c.Has("raven") {
+        t.Fatal("store should contain an entry for 'raven'")
+    }
+
+    if c.Has("goat") {
+        t.Fatal("store should not contain an entry for 'goat'")
+    }
+}

cache/lru/timestamps.go

@@ -0,0 +1,101 @@
+package lru
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"sort"
+)
+
+// timestamps contains datastructures for maintaining a list of keys sortable
+// by timestamp.
+
+type timestamp[K comparable] struct {
+	t int64
+	k K
+}
+
+type timestamps[K comparable] struct {
+	ts  []timestamp[K]
+	cap int
+}
+
+func newTimestamps[K comparable](icap int) *timestamps[K] {
+	return &timestamps[K]{
+		ts:  make([]timestamp[K], 0, icap),
+		cap: icap,
+	}
+}
+
+func (ts *timestamps[K]) K(i int) K {
+	return ts.ts[i].k
+}
+
+func (ts *timestamps[K]) T(i int) int64 {
+	return ts.ts[i].t
+}
+
+func (ts *timestamps[K]) Len() int {
+	return len(ts.ts)
+}
+
+func (ts *timestamps[K]) Less(i, j int) bool {
+	return ts.ts[i].t > ts.ts[j].t
+}
+
+func (ts *timestamps[K]) Swap(i, j int) {
+	ts.ts[i], ts.ts[j] = ts.ts[j], ts.ts[i]
+}
+
+func (ts *timestamps[K]) Find(k K) (int, bool) {
+	for i := range ts.ts {
+		if ts.ts[i].k == k {
+			return i, true
+		}
+	}
+	return -1, false
+}
+
+func (ts *timestamps[K]) Update(k K, t int64) bool {
+	i, ok := ts.Find(k)
+	if !ok {
+		ts.ts = append(ts.ts, timestamp[K]{t, k})
+		sort.Sort(ts)
+		return false
+	}
+
+	ts.ts[i].t = t
+	sort.Sort(ts)
+	return true
+}
+
+func (ts *timestamps[K]) ConsistencyCheck() error {
+	if !sort.IsSorted(ts) {
+		return errors.New("lru: timestamps are not sorted")
+	}
+
+	keys := map[K]bool{}
+	for i := range ts.ts {
+		if keys[ts.ts[i].k] {
+			return fmt.Errorf("lru: duplicate key %v detected", ts.ts[i].k)
+		}
+		keys[ts.ts[i].k] = true
+	}
+
+	if len(keys) != len(ts.ts) {
+		return fmt.Errorf("lru: timestamp contains %d duplicate keys",
+			len(ts.ts)-len(keys))
+	}
+
+	return nil
+}
+
+func (ts *timestamps[K]) Delete(i int) {
+	ts.ts = append(ts.ts[:i], ts.ts[i+1:]...)
+}
+
+func (ts *timestamps[K]) Dump(w io.Writer) {
+	for i := range ts.ts {
+		fmt.Fprintf(w, "%d: %v, %d\n", i, ts.K(i), ts.T(i))
+	}
+}

cache/lru/timestamps_internal_test.go

@@ -0,0 +1,50 @@
+package lru
+
+import (
+    "testing"
+    "time"
+
+    "github.com/benbjohnson/clock"
+)
+
+// These tests validate timestamps ordering semantics for the LRU package.
+// Note: The LRU timestamps are sorted with most-recent-first (descending by t).
+func TestTimestamps(t *testing.T) {
+    ts := newTimestamps[string](3)
+    mock := clock.NewMock()
+
+    // raven
+    ts.Update("raven", mock.Now().UnixNano())
+
+    // raven, owl
+    mock.Add(time.Millisecond)
+    ts.Update("owl", mock.Now().UnixNano())
+
+    // raven, owl, goat
+    mock.Add(time.Second)
+    ts.Update("goat", mock.Now().UnixNano())
+
+    if err := ts.ConsistencyCheck(); err != nil {
+        t.Fatal(err)
+    }
+
+    // make owl the most recent
+    mock.Add(time.Millisecond)
+    ts.Update("owl", mock.Now().UnixNano())
+    if err := ts.ConsistencyCheck(); err != nil {
+        t.Fatal(err)
+    }
+
+    // For LRU timestamps: most recent first. Expected order: owl, goat, raven.
+    if ts.K(0) != "owl" {
+        t.Fatalf("first key should be owl, have %s", ts.K(0))
+    }
+
+    if ts.K(1) != "goat" {
+        t.Fatalf("second key should be goat, have %s", ts.K(1))
+    }
+
+    if ts.K(2) != "raven" {
+        t.Fatalf("third key should be raven, have %s", ts.K(2))
+    }
+}

cache/mru/mru.go

@@ -0,0 +1,178 @@
+package mru
+
+import (
+	"errors"
+	"fmt"
+	"sort"
+	"sync"
+
+	"github.com/benbjohnson/clock"
+)
+
+type item[V any] struct {
+	V      V
+	access int64
+}
+
+// A Cache is a map that retains a limited number of items. It must be
+// initialized with New, providing a maximum capacity for the cache.
+// Only the most recently used items are retained.
+type Cache[K comparable, V any] struct {
+	store  map[K]*item[V]
+	access *timestamps[K]
+	cap    int
+	clock  clock.Clock
+	// All public methods that have the possibility of modifying the
+	// cache should lock it.
+	mtx *sync.Mutex
+}
+
+// New must be used to create a new Cache.
+func New[K comparable, V any](icap int) *Cache[K, V] {
+	return &Cache[K, V]{
+		store:  map[K]*item[V]{},
+		access: newTimestamps[K](icap),
+		cap:    icap,
+		clock:  clock.New(),
+		mtx:    &sync.Mutex{},
+	}
+}
+
+// StringKeyCache is a convenience wrapper for cache keyed by string.
+type StringKeyCache[V any] struct {
+	*Cache[string, V]
+}
+
+// NewStringKeyCache creates a new MRU cache keyed by string.
+func NewStringKeyCache[V any](icap int) *StringKeyCache[V] {
+	return &StringKeyCache[V]{Cache: New[string, V](icap)}
+}
+
+func (c *Cache[K, V]) lock() {
+	c.mtx.Lock()
+}
+
+func (c *Cache[K, V]) unlock() {
+	c.mtx.Unlock()
+}
+
+// Len returns the number of items currently in the cache.
+func (c *Cache[K, V]) Len() int {
+	return len(c.store)
+}
+
+// evict should remove the least-recently-used cache item.
+func (c *Cache[K, V]) evict() {
+	if c.access.Len() == 0 {
+		return
+	}
+
+	k := c.access.K(0)
+	c.evictKey(k)
+}
+
+// evictKey should remove the entry given by the key item.
+func (c *Cache[K, V]) evictKey(k K) {
+	delete(c.store, k)
+	i, ok := c.access.Find(k)
+	if !ok {
+		return
+	}
+
+	c.access.Delete(i)
+}
+
+func (c *Cache[K, V]) sanityCheck() {
+	if len(c.store) != c.access.Len() {
+		panic(fmt.Sprintf("MRU cache is out of sync; store len = %d, access len = %d",
+			len(c.store), c.access.Len()))
+	}
+}
+
+// ConsistencyCheck runs a series of checks to ensure that the cache's
+// data structures are consistent. It is not normally required, and it
+// is primarily used in testing.
+func (c *Cache[K, V]) ConsistencyCheck() error {
+	c.lock()
+	defer c.unlock()
+	if err := c.access.ConsistencyCheck(); err != nil {
+		return err
+	}
+
+	if len(c.store) != c.access.Len() {
+		return fmt.Errorf("mru: cache is out of sync; store len = %d, access len = %d",
+			len(c.store), c.access.Len())
+	}
+
+	for i := range c.access.ts {
+		itm, ok := c.store[c.access.K(i)]
+		if !ok {
+			return errors.New("mru: key in access is not in store")
+		}
+
+		if c.access.T(i) != itm.access {
+			return fmt.Errorf("timestamps are out of sync (%d != %d)",
+				itm.access, c.access.T(i))
+		}
+	}
+
+	if !sort.IsSorted(c.access) {
+		return errors.New("mru: timestamps aren't sorted")
+	}
+
+	return nil
+}
+
+// Store adds the value v to the cache under the k.
+func (c *Cache[K, V]) Store(k K, v V) {
+	c.lock()
+	defer c.unlock()
+
+	c.sanityCheck()
+
+	if len(c.store) == c.cap {
+		c.evict()
+	}
+
+	if _, ok := c.store[k]; ok {
+		c.evictKey(k)
+	}
+
+	itm := &item[V]{
+		V:      v,
+		access: c.clock.Now().UnixNano(),
+	}
+
+	c.store[k] = itm
+	c.access.Update(k, itm.access)
+}
+
+// Get returns the value stored in the cache. If the item isn't present,
+// it will return false.
+func (c *Cache[K, V]) Get(k K) (V, bool) {
+	c.lock()
+	defer c.unlock()
+
+	c.sanityCheck()
+
+	itm, ok := c.store[k]
+	if !ok {
+		var zero V
+		return zero, false
+	}
+
+	c.store[k].access = c.clock.Now().UnixNano()
+	c.access.Update(k, itm.access)
+	return itm.V, true
+}
+
+// Has returns true if the cache has an entry for k. It will not update
+// the timestamp on the item.
+func (c *Cache[K, V]) Has(k K) bool {
+	// Don't need to lock as we don't modify anything.
+
+	c.sanityCheck()
+
+	_, ok := c.store[k]
+	return ok
+}

cache/mru/mru_internal_test.go

@@ -0,0 +1,92 @@
+package mru
+
+import (
+	"testing"
+	"time"
+
+	"github.com/benbjohnson/clock"
+)
+
+func TestBasicCacheEviction(t *testing.T) {
+    mock := clock.NewMock()
+    c := NewStringKeyCache[int](2)
+    c.clock = mock
+
+	if err := c.ConsistencyCheck(); err != nil {
+		t.Fatal(err)
+	}
+
+	if c.Len() != 0 {
+		t.Fatal("cache should have size 0")
+	}
+
+	c.evict()
+	if err := c.ConsistencyCheck(); err != nil {
+		t.Fatal(err)
+	}
+
+	c.Store("raven", 1)
+	if err := c.ConsistencyCheck(); err != nil {
+		t.Fatal(err)
+	}
+
+	if len(c.store) != 1 {
+		t.Fatalf("store should have length=1, have length=%d", len(c.store))
+	}
+
+	mock.Add(time.Second)
+	c.Store("owl", 2)
+	if err := c.ConsistencyCheck(); err != nil {
+		t.Fatal(err)
+	}
+
+	if len(c.store) != 2 {
+		t.Fatalf("store should have length=2, have length=%d", len(c.store))
+	}
+
+	mock.Add(time.Second)
+	c.Store("goat", 3)
+	if err := c.ConsistencyCheck(); err != nil {
+		t.Fatal(err)
+	}
+
+	if len(c.store) != 2 {
+		t.Fatalf("store should have length=2, have length=%d", len(c.store))
+	}
+
+	mock.Add(time.Second)
+ v, ok := c.Get("owl")
+ if !ok {
+     t.Fatal("store should have an entry for owl")
+ }
+ if err := c.ConsistencyCheck(); err != nil {
+     t.Fatal(err)
+ }
+
+ itm := v
+ if err := c.ConsistencyCheck(); err != nil {
+     t.Fatal(err)
+ }
+
+	if itm != 2 {
+		t.Fatalf("stored item should be 2, have %d", itm)
+	}
+
+	mock.Add(time.Second)
+	c.Store("elk", 4)
+	if err := c.ConsistencyCheck(); err != nil {
+		t.Fatal(err)
+	}
+
+	if !c.Has("elk") {
+		t.Fatal("store should contain an entry for 'elk'")
+	}
+
+	if !c.Has("owl") {
+		t.Fatal("store should contain an entry for 'owl'")
+	}
+
+	if c.Has("goat") {
+		t.Fatal("store should not contain an entry for 'goat'")
+	}
+}

cache/mru/timestamps.go

@@ -0,0 +1,101 @@
+package mru
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"sort"
+)
+
+// timestamps contains datastructures for maintaining a list of keys sortable
+// by timestamp.
+
+type timestamp[K comparable] struct {
+	t int64
+	k K
+}
+
+type timestamps[K comparable] struct {
+	ts  []timestamp[K]
+	cap int
+}
+
+func newTimestamps[K comparable](icap int) *timestamps[K] {
+	return &timestamps[K]{
+		ts:  make([]timestamp[K], 0, icap),
+		cap: icap,
+	}
+}
+
+func (ts *timestamps[K]) K(i int) K {
+	return ts.ts[i].k
+}
+
+func (ts *timestamps[K]) T(i int) int64 {
+	return ts.ts[i].t
+}
+
+func (ts *timestamps[K]) Len() int {
+	return len(ts.ts)
+}
+
+func (ts *timestamps[K]) Less(i, j int) bool {
+	return ts.ts[i].t < ts.ts[j].t
+}
+
+func (ts *timestamps[K]) Swap(i, j int) {
+	ts.ts[i], ts.ts[j] = ts.ts[j], ts.ts[i]
+}
+
+func (ts *timestamps[K]) Find(k K) (int, bool) {
+	for i := range ts.ts {
+		if ts.ts[i].k == k {
+			return i, true
+		}
+	}
+	return -1, false
+}
+
+func (ts *timestamps[K]) Update(k K, t int64) bool {
+	i, ok := ts.Find(k)
+	if !ok {
+		ts.ts = append(ts.ts, timestamp[K]{t, k})
+		sort.Sort(ts)
+		return false
+	}
+
+	ts.ts[i].t = t
+	sort.Sort(ts)
+	return true
+}
+
+func (ts *timestamps[K]) ConsistencyCheck() error {
+	if !sort.IsSorted(ts) {
+		return errors.New("mru: timestamps are not sorted")
+	}
+
+	keys := map[K]bool{}
+	for i := range ts.ts {
+		if keys[ts.ts[i].k] {
+			return fmt.Errorf("duplicate key %v detected", ts.ts[i].k)
+		}
+		keys[ts.ts[i].k] = true
+	}
+
+	if len(keys) != len(ts.ts) {
+		return fmt.Errorf("mru: timestamp contains %d duplicate keys",
+			len(ts.ts)-len(keys))
+	}
+
+	return nil
+}
+
+func (ts *timestamps[K]) Delete(i int) {
+	ts.ts = append(ts.ts[:i], ts.ts[i+1:]...)
+}
+
+func (ts *timestamps[K]) Dump(w io.Writer) {
+	for i := range ts.ts {
+		fmt.Fprintf(w, "%d: %v, %d\n", i, ts.K(i), ts.T(i))
+	}
+}

cache/mru/timestamps_internal_test.go

@@ -0,0 +1,49 @@
+package mru
+
+import (
+	"testing"
+	"time"
+
+	"github.com/benbjohnson/clock"
+)
+
+func TestTimestamps(t *testing.T) {
+    ts := newTimestamps[string](3)
+    mock := clock.NewMock()
+
+	// raven
+	ts.Update("raven", mock.Now().UnixNano())
+
+	// raven, owl
+	mock.Add(time.Millisecond)
+
+	ts.Update("owl", mock.Now().UnixNano())
+
+	// raven, owl, goat
+	mock.Add(time.Second)
+	ts.Update("goat", mock.Now().UnixNano())
+
+	if err := ts.ConsistencyCheck(); err != nil {
+		t.Fatal(err)
+	}
+	mock.Add(time.Millisecond)
+
+	// raven, goat, owl
+	ts.Update("owl", mock.Now().UnixNano())
+	if err := ts.ConsistencyCheck(); err != nil {
+		t.Fatal(err)
+	}
+
+	// at this point, the keys should be raven, goat, owl.
+	if ts.K(0) != "raven" {
+		t.Fatalf("first key should be raven, have %s", ts.K(0))
+	}
+
+	if ts.K(1) != "goat" {
+		t.Fatalf("second key should be goat, have %s", ts.K(1))
+	}
+
+	if ts.K(2) != "owl" {
+		t.Fatalf("third key should be owl, have %s", ts.K(2))
+	}
+}

certlib/certerr/errors.go

@@ -79,24 +79,23 @@ func (e *Error) Error() string {
 
 func (e *Error) Unwrap() error { return e.Err }
 
-// InvalidPEMType is used to indicate that we were expecting one type of PEM
+// InvalidPEMTypeError is used to indicate that we were expecting one type of PEM
 // file, but saw another.
-type InvalidPEMType struct {
+type InvalidPEMTypeError struct {
 	have string
 	want []string
 }
 
-func (err *InvalidPEMType) Error() string {
+func (err *InvalidPEMTypeError) Error() string {
 	if len(err.want) == 1 {
 		return fmt.Sprintf("invalid PEM type: have %s, expected %s", err.have, err.want[0])
-	} else {
-		return fmt.Sprintf("invalid PEM type: have %s, expected one of %s", err.have, strings.Join(err.want, ", "))
 	}
+	return fmt.Sprintf("invalid PEM type: have %s, expected one of %s", err.have, strings.Join(err.want, ", "))
 }
 
-// ErrInvalidPEMType returns a new InvalidPEMType error.
+// ErrInvalidPEMType returns a new InvalidPEMTypeError error.
 func ErrInvalidPEMType(have string, want ...string) error {
-	return &InvalidPEMType{
+	return &InvalidPEMTypeError{
 		have: have,
 		want: want,
 	}

certlib/certerr/errors_test.go

@@ -1,3 +1,4 @@
+//nolint:testpackage // keep tests in the same package for internal symbol access
 package certerr
 
 import (

certlib/certlib.go

@@ -11,7 +11,7 @@ import (
 
 // ReadCertificate reads a DER or PEM-encoded certificate from the
 // byte slice.
-func ReadCertificate(in []byte) (cert *x509.Certificate, rest []byte, err error) {
+func ReadCertificate(in []byte) (*x509.Certificate, []byte, error) {
 	if len(in) == 0 {
 		return nil, nil, certerr.ParsingError(certerr.ErrorSourceCertificate, certerr.ErrEmptyCertificate)
 	}
@@ -22,7 +22,7 @@ func ReadCertificate(in []byte) (cert *x509.Certificate, rest []byte, err error)
 			return nil, nil, certerr.ParsingError(certerr.ErrorSourceCertificate, errors.New("invalid PEM file"))
 		}
 
-		rest = remaining
+		rest := remaining
 		if p.Type != "CERTIFICATE" {
 			return nil, rest, certerr.ParsingError(
 				certerr.ErrorSourceCertificate,
@@ -31,19 +31,26 @@ func ReadCertificate(in []byte) (cert *x509.Certificate, rest []byte, err error)
 		}
 
 		in = p.Bytes
+		cert, err := x509.ParseCertificate(in)
+		if err != nil {
+			return nil, rest, certerr.ParsingError(certerr.ErrorSourceCertificate, err)
+		}
+		return cert, rest, nil
 	}
 
-	cert, err = x509.ParseCertificate(in)
+	cert, err := x509.ParseCertificate(in)
 	if err != nil {
-		return nil, rest, certerr.ParsingError(certerr.ErrorSourceCertificate, err)
+		return nil, nil, certerr.ParsingError(certerr.ErrorSourceCertificate, err)
 	}
-	return cert, rest, nil
+	return cert, nil, nil
 }
 
 // ReadCertificates tries to read all the certificates in a
 // PEM-encoded collection.
-func ReadCertificates(in []byte) (certs []*x509.Certificate, err error) {
+func ReadCertificates(in []byte) ([]*x509.Certificate, error) {
 	var cert *x509.Certificate
+	var certs []*x509.Certificate
+	var err error
 	for {
 		cert, in, err = ReadCertificate(in)
 		if err != nil {

certlib/certlib_test.go

@@ -1,3 +1,4 @@
+//nolint:testpackage // keep tests in the same package for internal symbol access
 package certlib
 
 import (

certlib/der_helpers.go

@@ -38,6 +38,7 @@ import (
 	"crypto/ed25519"
 	"crypto/rsa"
 	"crypto/x509"
+	"errors"
 	"fmt"
 
 	"git.wntrmute.dev/kyle/goutils/certlib/certerr"
@@ -47,29 +48,36 @@ import (
 // private key. The key must not be in PEM format. If an error is returned, it
 // may contain information about the private key, so care should be taken when
 // displaying it directly.
-func ParsePrivateKeyDER(keyDER []byte) (key crypto.Signer, err error) {
-	generalKey, err := x509.ParsePKCS8PrivateKey(keyDER)
-	if err != nil {
-		generalKey, err = x509.ParsePKCS1PrivateKey(keyDER)
-		if err != nil {
-			generalKey, err = x509.ParseECPrivateKey(keyDER)
-			if err != nil {
-				generalKey, err = ParseEd25519PrivateKey(keyDER)
-				if err != nil {
-					return nil, certerr.ParsingError(certerr.ErrorSourcePrivateKey, err)
-				}
-			}
+func ParsePrivateKeyDER(keyDER []byte) (crypto.Signer, error) {
+	// Try common encodings in order without deep nesting.
+	if k, err := x509.ParsePKCS8PrivateKey(keyDER); err == nil {
+		switch kk := k.(type) {
+		case *rsa.PrivateKey:
+			return kk, nil
+		case *ecdsa.PrivateKey:
+			return kk, nil
+		case ed25519.PrivateKey:
+			return kk, nil
+		default:
+			return nil, certerr.ParsingError(certerr.ErrorSourcePrivateKey, fmt.Errorf("unknown key type %T", k))
 		}
 	}
-
-	switch generalKey := generalKey.(type) {
-	case *rsa.PrivateKey:
-		return generalKey, nil
-	case *ecdsa.PrivateKey:
-		return generalKey, nil
-	case ed25519.PrivateKey:
-		return generalKey, nil
-	default:
-		return nil, certerr.ParsingError(certerr.ErrorSourcePrivateKey, fmt.Errorf("unknown key type %t", generalKey))
+	if k, err := x509.ParsePKCS1PrivateKey(keyDER); err == nil {
+		return k, nil
 	}
+	if k, err := x509.ParseECPrivateKey(keyDER); err == nil {
+		return k, nil
+	}
+	if k, err := ParseEd25519PrivateKey(keyDER); err == nil {
+		if kk, ok := k.(ed25519.PrivateKey); ok {
+			return kk, nil
+		}
+		return nil, certerr.ParsingError(certerr.ErrorSourcePrivateKey, fmt.Errorf("unknown key type %T", k))
+	}
+	// If all parsers failed, return the last error from Ed25519 attempt (approximate cause).
+	if _, err := ParseEd25519PrivateKey(keyDER); err != nil {
+		return nil, certerr.ParsingError(certerr.ErrorSourcePrivateKey, err)
+	}
+	// Fallback (should be unreachable)
+	return nil, certerr.ParsingError(certerr.ErrorSourcePrivateKey, errors.New("unknown key encoding"))
 }

certlib/ed25519.go

@@ -65,12 +65,14 @@ func MarshalEd25519PublicKey(pk crypto.PublicKey) ([]byte, error) {
 		return nil, errEd25519WrongKeyType
 	}
 
+	const bitsPerByte = 8
+
 	spki := subjectPublicKeyInfo{
 		Algorithm: pkix.AlgorithmIdentifier{
 			Algorithm: ed25519OID,
 		},
 		PublicKey: asn1.BitString{
-			BitLength: len(pub) * 8,
+			BitLength: len(pub) * bitsPerByte,
 			Bytes:     pub,
 		},
 	}
@@ -91,7 +93,8 @@ func ParseEd25519PublicKey(der []byte) (crypto.PublicKey, error) {
 		return nil, errEd25519WrongID
 	}
 
-	if spki.PublicKey.BitLength != ed25519.PublicKeySize*8 {
+	const bitsPerByte = 8
+	if spki.PublicKey.BitLength != ed25519.PublicKeySize*bitsPerByte {
 		return nil, errors.New("SubjectPublicKeyInfo PublicKey length mismatch")
 	}
 

certlib/helpers.go

@@ -49,14 +49,14 @@ import (
 	"strings"
 	"time"
 
-	"git.wntrmute.dev/kyle/goutils/certlib/certerr"
-	"git.wntrmute.dev/kyle/goutils/certlib/pkcs7"
-
 	ct "github.com/google/certificate-transparency-go"
 	cttls "github.com/google/certificate-transparency-go/tls"
 	ctx509 "github.com/google/certificate-transparency-go/x509"
 	"golang.org/x/crypto/ocsp"
 	"golang.org/x/crypto/pkcs12"
+
+	"git.wntrmute.dev/kyle/goutils/certlib/certerr"
+	"git.wntrmute.dev/kyle/goutils/certlib/pkcs7"
 )
 
 // OneYear is a time.Duration representing a year's worth of seconds.
@@ -68,7 +68,7 @@ const OneDay = 24 * time.Hour
 // DelegationUsage  is the OID for the DelegationUseage extensions.
 var DelegationUsage = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 44363, 44}
 
-// DelegationExtension.
+// DelegationExtension is a non-critical extension marking delegation usage.
 var DelegationExtension = pkix.Extension{
 	Id:       DelegationUsage,
 	Critical: false,
@@ -81,13 +81,19 @@ func InclusiveDate(year int, month time.Month, day int) time.Time {
 	return time.Date(year, month, day, 0, 0, 0, 0, time.UTC).Add(-1 * time.Nanosecond)
 }
 
+const (
+	year2012 = 2012
+	year2015 = 2015
+	day1     = 1
+)
+
 // Jul2012 is the July 2012 CAB Forum deadline for when CAs must stop
 // issuing certificates valid for more than 5 years.
-var Jul2012 = InclusiveDate(2012, time.July, 01)
+var Jul2012 = InclusiveDate(year2012, time.July, day1)
 
 // Apr2015 is the April 2015 CAB Forum deadline for when CAs must stop
 // issuing certificates valid for more than 39 months.
-var Apr2015 = InclusiveDate(2015, time.April, 01)
+var Apr2015 = InclusiveDate(year2015, time.April, day1)
 
 // KeyLength returns the bit size of ECDSA or RSA PublicKey.
 func KeyLength(key any) int {
@@ -108,11 +114,11 @@ func KeyLength(key any) int {
 }
 
 // ExpiryTime returns the time when the certificate chain is expired.
-func ExpiryTime(chain []*x509.Certificate) (notAfter time.Time) {
+func ExpiryTime(chain []*x509.Certificate) time.Time {
+	var notAfter time.Time
 	if len(chain) == 0 {
 		return notAfter
 	}
-
 	notAfter = chain[0].NotAfter
 	for _, cert := range chain {
 		if notAfter.After(cert.NotAfter) {
@@ -158,18 +164,23 @@ func ValidExpiry(c *x509.Certificate) bool {
 // SignatureString returns the TLS signature string corresponding to
 // an X509 signature algorithm.
 var signatureString = map[x509.SignatureAlgorithm]string{
-	x509.MD2WithRSA:      "MD2WithRSA",
-	x509.MD5WithRSA:      "MD5WithRSA",
-	x509.SHA1WithRSA:     "SHA1WithRSA",
-	x509.SHA256WithRSA:   "SHA256WithRSA",
-	x509.SHA384WithRSA:   "SHA384WithRSA",
-	x509.SHA512WithRSA:   "SHA512WithRSA",
-	x509.DSAWithSHA1:     "DSAWithSHA1",
-	x509.DSAWithSHA256:   "DSAWithSHA256",
-	x509.ECDSAWithSHA1:   "ECDSAWithSHA1",
-	x509.ECDSAWithSHA256: "ECDSAWithSHA256",
-	x509.ECDSAWithSHA384: "ECDSAWithSHA384",
-	x509.ECDSAWithSHA512: "ECDSAWithSHA512",
+	x509.UnknownSignatureAlgorithm: "Unknown Signature",
+	x509.MD2WithRSA:                "MD2WithRSA",
+	x509.MD5WithRSA:                "MD5WithRSA",
+	x509.SHA1WithRSA:               "SHA1WithRSA",
+	x509.SHA256WithRSA:             "SHA256WithRSA",
+	x509.SHA384WithRSA:             "SHA384WithRSA",
+	x509.SHA512WithRSA:             "SHA512WithRSA",
+	x509.SHA256WithRSAPSS:          "SHA256WithRSAPSS",
+	x509.SHA384WithRSAPSS:          "SHA384WithRSAPSS",
+	x509.SHA512WithRSAPSS:          "SHA512WithRSAPSS",
+	x509.DSAWithSHA1:               "DSAWithSHA1",
+	x509.DSAWithSHA256:             "DSAWithSHA256",
+	x509.ECDSAWithSHA1:             "ECDSAWithSHA1",
+	x509.ECDSAWithSHA256:           "ECDSAWithSHA256",
+	x509.ECDSAWithSHA384:           "ECDSAWithSHA384",
+	x509.ECDSAWithSHA512:           "ECDSAWithSHA512",
+	x509.PureEd25519:               "PureEd25519",
 }
 
 // SignatureString returns the TLS signature string corresponding to
@@ -184,18 +195,23 @@ func SignatureString(alg x509.SignatureAlgorithm) string {
 // HashAlgoString returns the hash algorithm name contains in the signature
 // method.
 var hashAlgoString = map[x509.SignatureAlgorithm]string{
-	x509.MD2WithRSA:      "MD2",
-	x509.MD5WithRSA:      "MD5",
-	x509.SHA1WithRSA:     "SHA1",
-	x509.SHA256WithRSA:   "SHA256",
-	x509.SHA384WithRSA:   "SHA384",
-	x509.SHA512WithRSA:   "SHA512",
-	x509.DSAWithSHA1:     "SHA1",
-	x509.DSAWithSHA256:   "SHA256",
-	x509.ECDSAWithSHA1:   "SHA1",
-	x509.ECDSAWithSHA256: "SHA256",
-	x509.ECDSAWithSHA384: "SHA384",
-	x509.ECDSAWithSHA512: "SHA512",
+	x509.UnknownSignatureAlgorithm: "Unknown Hash Algorithm",
+	x509.MD2WithRSA:                "MD2",
+	x509.MD5WithRSA:                "MD5",
+	x509.SHA1WithRSA:               "SHA1",
+	x509.SHA256WithRSA:             "SHA256",
+	x509.SHA384WithRSA:             "SHA384",
+	x509.SHA512WithRSA:             "SHA512",
+	x509.SHA256WithRSAPSS:          "SHA256",
+	x509.SHA384WithRSAPSS:          "SHA384",
+	x509.SHA512WithRSAPSS:          "SHA512",
+	x509.DSAWithSHA1:               "SHA1",
+	x509.DSAWithSHA256:             "SHA256",
+	x509.ECDSAWithSHA1:             "SHA1",
+	x509.ECDSAWithSHA256:           "SHA256",
+	x509.ECDSAWithSHA384:           "SHA384",
+	x509.ECDSAWithSHA512:           "SHA512",
+	x509.PureEd25519:               "SHA512", // per x509 docs Ed25519 uses SHA-512 internally
 }
 
 // HashAlgoString returns the hash algorithm name contains in the signature
@@ -273,7 +289,7 @@ func ParseCertificatesPEM(certsPEM []byte) ([]*x509.Certificate, error) {
 
 // ParseCertificatesDER parses a DER encoding of a certificate object and possibly private key,
 // either PKCS #7, PKCS #12, or raw x509.
-func ParseCertificatesDER(certsDER []byte, password string) (certs []*x509.Certificate, key crypto.Signer, err error) {
+func ParseCertificatesDER(certsDER []byte, password string) ([]*x509.Certificate, crypto.Signer, error) {
 	certsDER = bytes.TrimSpace(certsDER)
 
 	// First, try PKCS #7
@@ -284,7 +300,7 @@ func ParseCertificatesDER(certsDER []byte, password string) (certs []*x509.Certi
 				errors.New("can only extract certificates from signed data content info"),
 			)
 		}
-		certs = pkcs7data.Content.SignedData.Certificates
+		certs := pkcs7data.Content.SignedData.Certificates
 		if certs == nil {
 			return nil, nil, certerr.DecodeError(certerr.ErrorSourceCertificate, errors.New("no certificates decoded"))
 		}
@@ -304,7 +320,7 @@ func ParseCertificatesDER(certsDER []byte, password string) (certs []*x509.Certi
 	}
 
 	// Finally, attempt to parse raw X.509 certificates
-	certs, err = x509.ParseCertificates(certsDER)
+	certs, err := x509.ParseCertificates(certsDER)
 	if err != nil {
 		return nil, nil, certerr.DecodeError(certerr.ErrorSourceCertificate, err)
 	}
@@ -318,7 +334,8 @@ func ParseSelfSignedCertificatePEM(certPEM []byte) (*x509.Certificate, error) {
 		return nil, err
 	}
 
-	if err := cert.CheckSignature(cert.SignatureAlgorithm, cert.RawTBSCertificate, cert.Signature); err != nil {
+	err = cert.CheckSignature(cert.SignatureAlgorithm, cert.RawTBSCertificate, cert.Signature)
+	if err != nil {
 		return nil, certerr.VerifyError(certerr.ErrorSourceCertificate, err)
 	}
 	return cert, nil
@@ -362,8 +379,8 @@ func ParseOneCertificateFromPEM(certsPEM []byte) ([]*x509.Certificate, []byte, e
 
 	cert, err := x509.ParseCertificate(block.Bytes)
 	if err != nil {
-		pkcs7data, err := pkcs7.ParsePKCS7(block.Bytes)
-		if err != nil {
+		pkcs7data, err2 := pkcs7.ParsePKCS7(block.Bytes)
+		if err2 != nil {
 			return nil, rest, err
 		}
 		if pkcs7data.ContentInfo != "SignedData" {
@@ -382,7 +399,7 @@ func ParseOneCertificateFromPEM(certsPEM []byte) ([]*x509.Certificate, []byte, e
 // LoadPEMCertPool loads a pool of PEM certificates from file.
 func LoadPEMCertPool(certsFile string) (*x509.CertPool, error) {
 	if certsFile == "" {
-		return nil, nil
+		return nil, nil //nolint:nilnil // no CA file provided -> treat as no pool and no error
 	}
 	pemCerts, err := os.ReadFile(certsFile)
 	if err != nil {
@@ -395,7 +412,7 @@ func LoadPEMCertPool(certsFile string) (*x509.CertPool, error) {
 // PEMToCertPool concerts PEM certificates to a CertPool.
 func PEMToCertPool(pemCerts []byte) (*x509.CertPool, error) {
 	if len(pemCerts) == 0 {
-		return nil, nil
+		return nil, nil //nolint:nilnil // empty input means no pool needed
 	}
 
 	certPool := x509.NewCertPool()
@@ -409,14 +426,14 @@ func PEMToCertPool(pemCerts []byte) (*x509.CertPool, error) {
 // ParsePrivateKeyPEM parses and returns a PEM-encoded private
 // key. The private key may be either an unencrypted PKCS#8, PKCS#1,
 // or elliptic private key.
-func ParsePrivateKeyPEM(keyPEM []byte) (key crypto.Signer, err error) {
+func ParsePrivateKeyPEM(keyPEM []byte) (crypto.Signer, error) {
 	return ParsePrivateKeyPEMWithPassword(keyPEM, nil)
 }
 
 // ParsePrivateKeyPEMWithPassword parses and returns a PEM-encoded private
 // key. The private key may be a potentially encrypted PKCS#8, PKCS#1,
 // or elliptic private key.
-func ParsePrivateKeyPEMWithPassword(keyPEM []byte, password []byte) (key crypto.Signer, err error) {
+func ParsePrivateKeyPEMWithPassword(keyPEM []byte, password []byte) (crypto.Signer, error) {
 	keyDER, err := GetKeyDERFromPEM(keyPEM, password)
 	if err != nil {
 		return nil, err
@@ -436,47 +453,49 @@ func GetKeyDERFromPEM(in []byte, password []byte) ([]byte, error) {
 			break
 		}
 	}
-	if keyDER != nil {
-		if procType, ok := keyDER.Headers["Proc-Type"]; ok {
-			if strings.Contains(procType, "ENCRYPTED") {
-				if password != nil {
-					return x509.DecryptPEMBlock(keyDER, password)
-				}
-				return nil, certerr.DecodeError(certerr.ErrorSourcePrivateKey, certerr.ErrEncryptedPrivateKey)
-			}
-		}
-		return keyDER.Bytes, nil
+	if keyDER == nil {
+		return nil, certerr.DecodeError(certerr.ErrorSourcePrivateKey, errors.New("failed to decode private key"))
 	}
-
-	return nil, certerr.DecodeError(certerr.ErrorSourcePrivateKey, errors.New("failed to decode private key"))
+	if procType, ok := keyDER.Headers["Proc-Type"]; ok && strings.Contains(procType, "ENCRYPTED") {
+		if password != nil {
+			// nolintlint requires rationale:
+			//nolint:staticcheck // legacy RFC1423 PEM encryption supported for backward compatibility when caller supplies a password
+			return x509.DecryptPEMBlock(keyDER, password)
+		}
+		return nil, certerr.DecodeError(certerr.ErrorSourcePrivateKey, certerr.ErrEncryptedPrivateKey)
+	}
+	return keyDER.Bytes, nil
 }
 
 // ParseCSR parses a PEM- or DER-encoded PKCS #10 certificate signing request.
-func ParseCSR(in []byte) (csr *x509.CertificateRequest, rest []byte, err error) {
+func ParseCSR(in []byte) (*x509.CertificateRequest, []byte, error) {
 	in = bytes.TrimSpace(in)
 	p, rest := pem.Decode(in)
-	if p != nil {
-		if p.Type != "NEW CERTIFICATE REQUEST" && p.Type != "CERTIFICATE REQUEST" {
-			return nil, rest, certerr.ParsingError(
-				certerr.ErrorSourceCSR,
-				certerr.ErrInvalidPEMType(p.Type, "NEW CERTIFICATE REQUEST", "CERTIFICATE REQUEST"),
-			)
+	if p == nil {
+		csr, err := x509.ParseCertificateRequest(in)
+		if err != nil {
+			return nil, rest, certerr.ParsingError(certerr.ErrorSourceCSR, err)
 		}
-
-		csr, err = x509.ParseCertificateRequest(p.Bytes)
-	} else {
-		csr, err = x509.ParseCertificateRequest(in)
+		if sigErr := csr.CheckSignature(); sigErr != nil {
+			return nil, rest, certerr.VerifyError(certerr.ErrorSourceCSR, sigErr)
+		}
+		return csr, rest, nil
 	}
 
+	if p.Type != "NEW CERTIFICATE REQUEST" && p.Type != "CERTIFICATE REQUEST" {
+		return nil, rest, certerr.ParsingError(
+			certerr.ErrorSourceCSR,
+			certerr.ErrInvalidPEMType(p.Type, "NEW CERTIFICATE REQUEST", "CERTIFICATE REQUEST"),
+		)
+	}
+
+	csr, err := x509.ParseCertificateRequest(p.Bytes)
 	if err != nil {
 		return nil, rest, certerr.ParsingError(certerr.ErrorSourceCSR, err)
 	}
-
-	err = csr.CheckSignature()
-	if err != nil {
-		return nil, rest, certerr.VerifyError(certerr.ErrorSourceCSR, err)
+	if sigErr := csr.CheckSignature(); sigErr != nil {
+		return nil, rest, certerr.VerifyError(certerr.ErrorSourceCSR, sigErr)
 	}
-
 	return csr, rest, nil
 }
 
@@ -484,7 +503,7 @@ func ParseCSR(in []byte) (csr *x509.CertificateRequest, rest []byte, err error)
 // It does not check the signature. This is useful for dumping data from a CSR
 // locally.
 func ParseCSRPEM(csrPEM []byte) (*x509.CertificateRequest, error) {
-	block, _ := pem.Decode([]byte(csrPEM))
+	block, _ := pem.Decode(csrPEM)
 	if block == nil {
 		return nil, certerr.DecodeError(certerr.ErrorSourceCSR, errors.New("PEM block is empty"))
 	}
@@ -499,15 +518,20 @@ func ParseCSRPEM(csrPEM []byte) (*x509.CertificateRequest, error) {
 
 // SignerAlgo returns an X.509 signature algorithm from a crypto.Signer.
 func SignerAlgo(priv crypto.Signer) x509.SignatureAlgorithm {
+	const (
+		rsaBits2048 = 2048
+		rsaBits3072 = 3072
+		rsaBits4096 = 4096
+	)
 	switch pub := priv.Public().(type) {
 	case *rsa.PublicKey:
 		bitLength := pub.N.BitLen()
 		switch {
-		case bitLength >= 4096:
+		case bitLength >= rsaBits4096:
 			return x509.SHA512WithRSA
-		case bitLength >= 3072:
+		case bitLength >= rsaBits3072:
 			return x509.SHA384WithRSA
-		case bitLength >= 2048:
+		case bitLength >= rsaBits2048:
 			return x509.SHA256WithRSA
 		default:
 			return x509.SHA1WithRSA
@@ -537,7 +561,7 @@ func LoadClientCertificate(certFile string, keyFile string) (*tls.Certificate, e
 		}
 		return &cert, nil
 	}
-	return nil, nil
+	return nil, nil //nolint:nilnil // absence of client cert is not an error
 }
 
 // CreateTLSConfig creates a tls.Config object from certs and roots.
@@ -549,6 +573,7 @@ func CreateTLSConfig(remoteCAs *x509.CertPool, cert *tls.Certificate) *tls.Confi
 	return &tls.Config{
 		Certificates: certs,
 		RootCAs:      remoteCAs,
+		MinVersion:   tls.VersionTLS12, // secure default
 	}
 }
 
@@ -582,11 +607,11 @@ func DeserializeSCTList(serializedSCTList []byte) ([]ct.SignedCertificateTimesta
 	list := make([]ct.SignedCertificateTimestamp, len(sctList.SCTList))
 	for i, serializedSCT := range sctList.SCTList {
 		var sct ct.SignedCertificateTimestamp
-		rest, err := cttls.Unmarshal(serializedSCT.Val, &sct)
-		if err != nil {
-			return nil, err
+		rest2, err2 := cttls.Unmarshal(serializedSCT.Val, &sct)
+		if err2 != nil {
+			return nil, err2
 		}
-		if len(rest) != 0 {
+		if len(rest2) != 0 {
 			return nil, certerr.ParsingError(
 				certerr.ErrorSourceSCTList,
 				errors.New("serialized SCT list contained trailing garbage"),
@@ -602,12 +627,12 @@ func DeserializeSCTList(serializedSCTList []byte) ([]ct.SignedCertificateTimesta
 // unmarshalled.
 func SCTListFromOCSPResponse(response *ocsp.Response) ([]ct.SignedCertificateTimestamp, error) {
 	// This loop finds the SCTListExtension in the OCSP response.
-	var SCTListExtension, ext pkix.Extension
+	var sctListExtension, ext pkix.Extension
 	for _, ext = range response.Extensions {
 		// sctExtOid is the ObjectIdentifier of a Signed Certificate Timestamp.
 		sctExtOid := asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 11129, 2, 4, 5}
 		if ext.Id.Equal(sctExtOid) {
-			SCTListExtension = ext
+			sctListExtension = ext
 			break
 		}
 	}
@@ -615,10 +640,10 @@ func SCTListFromOCSPResponse(response *ocsp.Response) ([]ct.SignedCertificateTim
 	// This code block extracts the sctList from the SCT extension.
 	var sctList []ct.SignedCertificateTimestamp
 	var err error
-	if numBytes := len(SCTListExtension.Value); numBytes != 0 {
+	if numBytes := len(sctListExtension.Value); numBytes != 0 {
 		var serializedSCTList []byte
 		rest := make([]byte, numBytes)
-		copy(rest, SCTListExtension.Value)
+		copy(rest, sctListExtension.Value)
 		for len(rest) != 0 {
 			rest, err = asn1.Unmarshal(rest, &serializedSCTList)
 			if err != nil {

certlib/hosts/hosts.go

@@ -9,6 +9,8 @@ import (
 	"strings"
 )
 
+const defaultHTTPSPort = 443
+
 type Target struct {
 	Host string
 	Port int
@@ -29,29 +31,29 @@ func parseURL(host string) (string, int, error) {
 	}
 
 	if url.Port() == "" {
-		return url.Hostname(), 443, nil
+		return url.Hostname(), defaultHTTPSPort, nil
 	}
 
-	port, err := strconv.ParseInt(url.Port(), 10, 16)
-	if err != nil {
+	portInt, err2 := strconv.ParseInt(url.Port(), 10, 16)
+	if err2 != nil {
 		return "", 0, fmt.Errorf("certlib/hosts: invalid port: %s", url.Port())
 	}
 
-	return url.Hostname(), int(port), nil
+	return url.Hostname(), int(portInt), nil
 }
 
 func parseHostPort(host string) (string, int, error) {
 	host, sport, err := net.SplitHostPort(host)
 	if err == nil {
-		port, err := strconv.ParseInt(sport, 10, 16)
-		if err != nil {
+		portInt, err2 := strconv.ParseInt(sport, 10, 16)
+		if err2 != nil {
 			return "", 0, fmt.Errorf("certlib/hosts: invalid port: %s", sport)
 		}
 
-		return host, int(port), nil
+		return host, int(portInt), nil
 	}
 
-	return host, 443, nil
+	return host, defaultHTTPSPort, nil
 }
 
 func ParseHost(host string) (*Target, error) {

certlib/pkcs7/pkcs7.go

@@ -158,9 +158,9 @@ type EncryptedContentInfo struct {
 	EncryptedContent           []byte `asn1:"tag:0,optional"`
 }
 
-func unmarshalInit(raw []byte) (init initPKCS7, err error) {
-	_, err = asn1.Unmarshal(raw, &init)
-	if err != nil {
+func unmarshalInit(raw []byte) (initPKCS7, error) {
+	var init initPKCS7
+	if _, err := asn1.Unmarshal(raw, &init); err != nil {
 		return initPKCS7{}, certerr.ParsingError(certerr.ErrorSourceCertificate, err)
 	}
 	return init, nil
@@ -218,28 +218,28 @@ func populateEncryptedData(msg *PKCS7, contentBytes []byte) error {
 
 // ParsePKCS7 attempts to parse the DER encoded bytes of a
 // PKCS7 structure.
-func ParsePKCS7(raw []byte) (msg *PKCS7, err error) {
+func ParsePKCS7(raw []byte) (*PKCS7, error) {
 	pkcs7, err := unmarshalInit(raw)
 	if err != nil {
 		return nil, err
 	}
 
-	msg = new(PKCS7)
+	msg := new(PKCS7)
 	msg.Raw = pkcs7.Raw
 	msg.ContentInfo = pkcs7.ContentType.String()
 
 	switch msg.ContentInfo {
 	case ObjIDData:
-		if err := populateData(msg, pkcs7.Content); err != nil {
-			return nil, err
+		if e := populateData(msg, pkcs7.Content); e != nil {
+			return nil, e
 		}
 	case ObjIDSignedData:
-		if err := populateSignedData(msg, pkcs7.Content.Bytes); err != nil {
-			return nil, err
+		if e := populateSignedData(msg, pkcs7.Content.Bytes); e != nil {
+			return nil, e
 		}
 	case ObjIDEncryptedData:
-		if err := populateEncryptedData(msg, pkcs7.Content.Bytes); err != nil {
-			return nil, err
+		if e := populateEncryptedData(msg, pkcs7.Content.Bytes); e != nil {
+			return nil, e
 		}
 	default:
 		return nil, certerr.ParsingError(

certlib/revoke/revoke.go

@@ -5,6 +5,7 @@ package revoke
 
 import (
 	"bytes"
+	"context"
 	"crypto"
 	"crypto/x509"
 	"encoding/base64"
@@ -90,34 +91,34 @@ func ldapURL(url string) bool {
 // - false, true:  the certificate was checked successfully, and it is not revoked.
 // - true, true:   the certificate was checked successfully, and it is revoked.
 // - true, false:  failure to check revocation status causes verification to fail.
-func revCheck(cert *x509.Certificate) (revoked, ok bool, err error) {
+func revCheck(cert *x509.Certificate) (bool, bool, error) {
 	for _, url := range cert.CRLDistributionPoints {
 		if ldapURL(url) {
 			log.Infof("skipping LDAP CRL: %s", url)
 			continue
 		}
 
-		if revoked, ok, err := certIsRevokedCRL(cert, url); !ok {
+		if rvk, ok2, err2 := certIsRevokedCRL(cert, url); !ok2 {
 			log.Warning("error checking revocation via CRL")
 			if HardFail {
-				return true, false, err
+				return true, false, err2
 			}
-			return false, false, err
-		} else if revoked {
+			return false, false, err2
+		} else if rvk {
 			log.Info("certificate is revoked via CRL")
-			return true, true, err
+			return true, true, err2
 		}
 	}
 
-	if revoked, ok, err := certIsRevokedOCSP(cert, HardFail); !ok {
+	if rvk, ok2, err2 := certIsRevokedOCSP(cert, HardFail); !ok2 {
 		log.Warning("error checking revocation via OCSP")
 		if HardFail {
-			return true, false, err
+			return true, false, err2
 		}
-		return false, false, err
-	} else if revoked {
+		return false, false, err2
+	} else if rvk {
 		log.Info("certificate is revoked via OCSP")
-		return true, true, err
+		return true, true, err2
 	}
 
 	return false, true, nil
@@ -125,13 +126,17 @@ func revCheck(cert *x509.Certificate) (revoked, ok bool, err error) {
 
 // fetchCRL fetches and parses a CRL.
 func fetchCRL(url string) (*x509.RevocationList, error) {
-	resp, err := HTTPClient.Get(url)
+	req, err := http.NewRequestWithContext(context.Background(), http.MethodGet, url, nil)
+	if err != nil {
+		return nil, err
+	}
+	resp, err := HTTPClient.Do(req)
 	if err != nil {
 		return nil, err
 	}
 	defer resp.Body.Close()
 
-	if resp.StatusCode >= 300 {
+	if resp.StatusCode >= http.StatusMultipleChoices {
 		return nil, errors.New("failed to retrieve CRL")
 	}
 
@@ -158,7 +163,7 @@ func getIssuer(cert *x509.Certificate) *x509.Certificate {
 
 // check a cert against a specific CRL. Returns the same bool pair
 // as revCheck, plus an error if one occurred.
-func certIsRevokedCRL(cert *x509.Certificate, url string) (revoked, ok bool, err error) {
+func certIsRevokedCRL(cert *x509.Certificate, url string) (bool, bool, error) {
 	crlLock.Lock()
 	crl, ok := CRLSet[url]
 	if ok && crl == nil {
@@ -186,10 +191,9 @@ func certIsRevokedCRL(cert *x509.Certificate, url string) (revoked, ok bool, err
 
 		// check CRL signature
 		if issuer != nil {
-			err = crl.CheckSignatureFrom(issuer)
-			if err != nil {
-				log.Warningf("failed to verify CRL: %v", err)
-				return false, false, err
+			if sigErr := crl.CheckSignatureFrom(issuer); sigErr != nil {
+				log.Warningf("failed to verify CRL: %v", sigErr)
+				return false, false, sigErr
 			}
 		}
 
@@ -198,26 +202,26 @@ func certIsRevokedCRL(cert *x509.Certificate, url string) (revoked, ok bool, err
 		crlLock.Unlock()
 	}
 
-	for _, revoked := range crl.RevokedCertificates {
-		if cert.SerialNumber.Cmp(revoked.SerialNumber) == 0 {
+	for _, entry := range crl.RevokedCertificateEntries {
+		if cert.SerialNumber.Cmp(entry.SerialNumber) == 0 {
 			log.Info("Serial number match: intermediate is revoked.")
-			return true, true, err
+			return true, true, nil
 		}
 	}
 
-	return false, true, err
+	return false, true, nil
 }
 
 // VerifyCertificate ensures that the certificate passed in hasn't
 // expired and checks the CRL for the server.
-func VerifyCertificate(cert *x509.Certificate) (revoked, ok bool) {
-	revoked, ok, _ = VerifyCertificateError(cert)
+func VerifyCertificate(cert *x509.Certificate) (bool, bool) {
+	revoked, ok, _ := VerifyCertificateError(cert)
 	return revoked, ok
 }
 
 // VerifyCertificateError ensures that the certificate passed in hasn't
 // expired and checks the CRL for the server.
-func VerifyCertificateError(cert *x509.Certificate) (revoked, ok bool, err error) {
+func VerifyCertificateError(cert *x509.Certificate) (bool, bool, error) {
 	if !time.Now().Before(cert.NotAfter) {
 		msg := fmt.Sprintf("Certificate expired %s\n", cert.NotAfter)
 		log.Info(msg)
@@ -231,7 +235,11 @@ func VerifyCertificateError(cert *x509.Certificate) (revoked, ok bool, err error
 }
 
 func fetchRemote(url string) (*x509.Certificate, error) {
-	resp, err := HTTPClient.Get(url)
+	req, err := http.NewRequestWithContext(context.Background(), http.MethodGet, url, nil)
+	if err != nil {
+		return nil, err
+	}
+	resp, err := HTTPClient.Do(req)
 	if err != nil {
 		return nil, err
 	}
@@ -254,8 +262,12 @@ var ocspOpts = ocsp.RequestOptions{
 	Hash: crypto.SHA1,
 }
 
-func certIsRevokedOCSP(leaf *x509.Certificate, strict bool) (revoked, ok bool, e error) {
-	var err error
+const ocspGetURLMaxLen = 256
+
+func certIsRevokedOCSP(leaf *x509.Certificate, strict bool) (bool, bool, error) {
+	var revoked bool
+	var ok bool
+	var lastErr error
 
 	ocspURLs := leaf.OCSPServer
 	if len(ocspURLs) == 0 {
@@ -271,15 +283,16 @@ func certIsRevokedOCSP(leaf *x509.Certificate, strict bool) (revoked, ok bool, e
 
 	ocspRequest, err := ocsp.CreateRequest(leaf, issuer, &ocspOpts)
 	if err != nil {
-		return revoked, ok, err
+		return false, false, err
 	}
 
 	for _, server := range ocspURLs {
-		resp, err := sendOCSPRequest(server, ocspRequest, leaf, issuer)
-		if err != nil {
+		resp, e := sendOCSPRequest(server, ocspRequest, leaf, issuer)
+		if e != nil {
 			if strict {
-				return revoked, ok, err
+				return false, false, e
 			}
+			lastErr = e
 			continue
 		}
 
@@ -291,9 +304,9 @@ func certIsRevokedOCSP(leaf *x509.Certificate, strict bool) (revoked, ok bool, e
 			revoked = true
 		}
 
-		return revoked, ok, err
+		return revoked, ok, nil
 	}
-	return revoked, ok, err
+	return revoked, ok, lastErr
 }
 
 // sendOCSPRequest attempts to request an OCSP response from the
@@ -302,12 +315,21 @@ func certIsRevokedOCSP(leaf *x509.Certificate, strict bool) (revoked, ok bool, e
 func sendOCSPRequest(server string, req []byte, leaf, issuer *x509.Certificate) (*ocsp.Response, error) {
 	var resp *http.Response
 	var err error
-	if len(req) > 256 {
+	if len(req) > ocspGetURLMaxLen {
 		buf := bytes.NewBuffer(req)
-		resp, err = HTTPClient.Post(server, "application/ocsp-request", buf)
+		httpReq, e := http.NewRequestWithContext(context.Background(), http.MethodPost, server, buf)
+		if e != nil {
+			return nil, e
+		}
+		httpReq.Header.Set("Content-Type", "application/ocsp-request")
+		resp, err = HTTPClient.Do(httpReq)
 	} else {
 		reqURL := server + "/" + neturl.QueryEscape(base64.StdEncoding.EncodeToString(req))
-		resp, err = HTTPClient.Get(reqURL)
+		httpReq, e := http.NewRequestWithContext(context.Background(), http.MethodGet, reqURL, nil)
+		if e != nil {
+			return nil, e
+		}
+		resp, err = HTTPClient.Do(httpReq)
 	}
 
 	if err != nil {

certlib/revoke/revoke_test.go

@@ -1,3 +1,4 @@
+//nolint:testpackage // keep tests in the same package for internal symbol access
 package revoke
 
 import (
@@ -153,7 +154,7 @@ func mustParse(pemData string) *x509.Certificate {
 		panic("Invalid PEM type.")
 	}
 
-	cert, err := x509.ParseCertificate([]byte(block.Bytes))
+	cert, err := x509.ParseCertificate(block.Bytes)
 	if err != nil {
 		panic(err.Error())
 	}

cmd/atping/main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"flag"
 	"fmt"
 	"net"
@@ -28,10 +29,16 @@ func connect(addr string, dport string, six bool, timeout time.Duration) error {
 
 	if verbose {
 		fmt.Printf("connecting to %s/%s... ", addr, proto)
-		os.Stdout.Sync()
+		if err = os.Stdout.Sync(); err != nil {
+			return err
+		}
 	}
 
-	conn, err := net.DialTimeout(proto, addr, timeout)
+	dialer := &net.Dialer{
+		Timeout: timeout,
+	}
+
+	conn, err := dialer.DialContext(context.Background(), proto, addr)
 	if err != nil {
 		if verbose {
 			fmt.Println("failed.")
@@ -42,8 +49,8 @@ func connect(addr string, dport string, six bool, timeout time.Duration) error {
 	if verbose {
 		fmt.Println("OK")
 	}
-	conn.Close()
-	return nil
+
+	return conn.Close()
 }
 
 func main() {

cmd/ca-signed/main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"crypto/x509"
 	"embed"
+	"errors"
 	"fmt"
 	"os"
 	"path/filepath"
@@ -14,22 +15,22 @@ import (
 // loadCertsFromFile attempts to parse certificates from a file that may be in
 // PEM or DER/PKCS#7 format. Returns the parsed certificates or an error.
 func loadCertsFromFile(path string) ([]*x509.Certificate, error) {
+	var certs []*x509.Certificate
+
 	data, err := os.ReadFile(path)
 	if err != nil {
 		return nil, err
 	}
 
-	// Try PEM first
-	if certs, err := certlib.ParseCertificatesPEM(data); err == nil {
+	if certs, err = certlib.ParseCertificatesPEM(data); err == nil {
 		return certs, nil
 	}
 
-	// Try DER/PKCS7/PKCS12 (with no password)
-	if certs, _, err := certlib.ParseCertificatesDER(data, ""); err == nil {
+	if certs, _, err = certlib.ParseCertificatesDER(data, ""); err == nil {
 		return certs, nil
-	} else {
-		return nil, err
 	}
+
+	return nil, err
 }
 
 func makePoolFromFile(path string) (*x509.CertPool, error) {
@@ -56,49 +57,50 @@ var embeddedTestdata embed.FS
 // loadCertsFromBytes attempts to parse certificates from bytes that may be in
 // PEM or DER/PKCS#7 format.
 func loadCertsFromBytes(data []byte) ([]*x509.Certificate, error) {
-	// Try PEM first
-	if certs, err := certlib.ParseCertificatesPEM(data); err == nil {
+	certs, err := certlib.ParseCertificatesPEM(data)
+	if err == nil {
 		return certs, nil
 	}
-	// Try DER/PKCS7/PKCS12 (with no password)
-	if certs, _, err := certlib.ParseCertificatesDER(data, ""); err == nil {
+
+	certs, _, err = certlib.ParseCertificatesDER(data, "")
+	if err == nil {
 		return certs, nil
-	} else {
-		return nil, err
 	}
+
+	return nil, err
 }
 
 func makePoolFromBytes(data []byte) (*x509.CertPool, error) {
-    certs, err := loadCertsFromBytes(data)
-    if err != nil || len(certs) == 0 {
-        return nil, fmt.Errorf("failed to load CA certificates from embedded bytes")
-    }
-    pool := x509.NewCertPool()
-    for _, c := range certs {
-        pool.AddCert(c)
-    }
-    return pool, nil
+	certs, err := loadCertsFromBytes(data)
+	if err != nil || len(certs) == 0 {
+		return nil, errors.New("failed to load CA certificates from embedded bytes")
+	}
+	pool := x509.NewCertPool()
+	for _, c := range certs {
+		pool.AddCert(c)
+	}
+	return pool, nil
 }
 
 // isSelfSigned returns true if the given certificate is self-signed.
 // It checks that the subject and issuer match and that the certificate's
 // signature verifies against its own public key.
 func isSelfSigned(cert *x509.Certificate) bool {
-    if cert == nil {
-        return false
-    }
-    // Quick check: subject and issuer match
-    if cert.Subject.String() != cert.Issuer.String() {
-        return false
-    }
-    // Cryptographic check: the certificate is signed by itself
-    if err := cert.CheckSignatureFrom(cert); err != nil {
-        return false
-    }
-    return true
+	if cert == nil {
+		return false
+	}
+	// Quick check: subject and issuer match
+	if cert.Subject.String() != cert.Issuer.String() {
+		return false
+	}
+	// Cryptographic check: the certificate is signed by itself
+	if err := cert.CheckSignatureFrom(cert); err != nil {
+		return false
+	}
+	return true
 }
 
-func verifyAgainstCA(caPool *x509.CertPool, path string) (ok bool, expiry string) {
+func verifyAgainstCA(caPool *x509.CertPool, path string) (bool, string) {
 	certs, err := loadCertsFromFile(path)
 	if err != nil || len(certs) == 0 {
 		return false, ""
@@ -117,14 +119,14 @@ func verifyAgainstCA(caPool *x509.CertPool, path string) (ok bool, expiry string
 		Intermediates: ints,
 		KeyUsages:     []x509.ExtKeyUsage{x509.ExtKeyUsageAny},
 	}
-	if _, err := leaf.Verify(opts); err != nil {
+	if _, err = leaf.Verify(opts); err != nil {
 		return false, ""
 	}
 
 	return true, leaf.NotAfter.Format("2006-01-02")
 }
 
-func verifyAgainstCABytes(caPool *x509.CertPool, certData []byte) (ok bool, expiry string) {
+func verifyAgainstCABytes(caPool *x509.CertPool, certData []byte) (bool, string) {
 	certs, err := loadCertsFromBytes(certData)
 	if err != nil || len(certs) == 0 {
 		return false, ""
@@ -143,92 +145,159 @@ func verifyAgainstCABytes(caPool *x509.CertPool, certData []byte) (ok bool, expi
 		Intermediates: ints,
 		KeyUsages:     []x509.ExtKeyUsage{x509.ExtKeyUsageAny},
 	}
-	if _, err := leaf.Verify(opts); err != nil {
+	if _, err = leaf.Verify(opts); err != nil {
 		return false, ""
 	}
 
 	return true, leaf.NotAfter.Format("2006-01-02")
 }
 
-// selftest runs built-in validation using embedded certificates.
-func selftest() int {
-	type testCase struct {
-		name     string
-		caFile   string
-		certFile string
-		expectOK bool
+type testCase struct {
+	name     string
+	caFile   string
+	certFile string
+	expectOK bool
+}
+
+func (tc testCase) Run() error {
+	caBytes, err := embeddedTestdata.ReadFile(tc.caFile)
+	if err != nil {
+		return fmt.Errorf("selftest: failed to read embedded %s: %w", tc.caFile, err)
 	}
 
- cases := []testCase{
-        {name: "ISRG Root X1 validates LE E7", caFile: "testdata/isrg-root-x1.pem", certFile: "testdata/le-e7.pem", expectOK: true},
-        {name: "ISRG Root X1 does NOT validate Google WR2", caFile: "testdata/isrg-root-x1.pem", certFile: "testdata/goog-wr2.pem", expectOK: false},
-        {name: "GTS R1 validates Google WR2", caFile: "testdata/gts-r1.pem", certFile: "testdata/goog-wr2.pem", expectOK: true},
-        {name: "GTS R1 does NOT validate LE E7", caFile: "testdata/gts-r1.pem", certFile: "testdata/le-e7.pem", expectOK: false},
-    }
+	certBytes, err := embeddedTestdata.ReadFile(tc.certFile)
+	if err != nil {
+		return fmt.Errorf("selftest: failed to read embedded %s: %w", tc.certFile, err)
+	}
 
-    failures := 0
-    for _, tc := range cases {
-		caBytes, err := embeddedTestdata.ReadFile(tc.caFile)
+	pool, err := makePoolFromBytes(caBytes)
+	if err != nil || pool == nil {
+		return fmt.Errorf("selftest: failed to build CA pool for %s: %w", tc.caFile, err)
+	}
+
+	ok, exp := verifyAgainstCABytes(pool, certBytes)
+	if ok != tc.expectOK {
+		return fmt.Errorf("%s: unexpected result: got %v, want %v", tc.name, ok, tc.expectOK)
+	}
+
+	if ok {
+		fmt.Printf("%s: OK (expires %s)\n", tc.name, exp)
+	}
+
+	fmt.Printf("%s: INVALID (as expected)\n", tc.name)
+
+	return nil
+}
+
+var cases = []testCase{
+	{
+		name:     "ISRG Root X1 validates LE E7",
+		caFile:   "testdata/isrg-root-x1.pem",
+		certFile: "testdata/le-e7.pem",
+		expectOK: true,
+	},
+	{
+		name:     "ISRG Root X1 does NOT validate Google WR2",
+		caFile:   "testdata/isrg-root-x1.pem",
+		certFile: "testdata/goog-wr2.pem",
+		expectOK: false,
+	},
+	{
+		name:     "GTS R1 validates Google WR2",
+		caFile:   "testdata/gts-r1.pem",
+		certFile: "testdata/goog-wr2.pem",
+		expectOK: true,
+	},
+	{
+		name:     "GTS R1 does NOT validate LE E7",
+		caFile:   "testdata/gts-r1.pem",
+		certFile: "testdata/le-e7.pem",
+		expectOK: false,
+	},
+}
+
+// selftest runs built-in validation using embedded certificates.
+func selftest() int {
+	failures := 0
+	for _, tc := range cases {
+		err := tc.Run()
 		if err != nil {
-			fmt.Fprintf(os.Stderr, "selftest: failed to read embedded %s: %v\n", tc.caFile, err)
+			fmt.Fprintln(os.Stderr, err)
 			failures++
 			continue
 		}
-		certBytes, err := embeddedTestdata.ReadFile(tc.certFile)
+	}
+
+	// Verify that both embedded root CAs are detected as self-signed
+	roots := []string{"testdata/gts-r1.pem", "testdata/isrg-root-x1.pem"}
+	for _, root := range roots {
+		b, err := embeddedTestdata.ReadFile(root)
 		if err != nil {
-			fmt.Fprintf(os.Stderr, "selftest: failed to read embedded %s: %v\n", tc.certFile, err)
+			fmt.Fprintf(os.Stderr, "selftest: failed to read embedded %s: %v\n", root, err)
 			failures++
 			continue
 		}
-		pool, err := makePoolFromBytes(caBytes)
-		if err != nil || pool == nil {
-			fmt.Fprintf(os.Stderr, "selftest: failed to build CA pool for %s: %v\n", tc.caFile, err)
+		certs, err := loadCertsFromBytes(b)
+		if err != nil || len(certs) == 0 {
+			fmt.Fprintf(os.Stderr, "selftest: failed to parse cert(s) from %s: %v\n", root, err)
 			failures++
 			continue
 		}
-		ok, exp := verifyAgainstCABytes(pool, certBytes)
-		if ok != tc.expectOK {
-			fmt.Printf("%s: unexpected result: got %v, want %v\n", tc.name, ok, tc.expectOK)
-			failures++
+		leaf := certs[0]
+		if isSelfSigned(leaf) {
+			fmt.Printf("%s: SELF-SIGNED (as expected)\n", root)
 		} else {
-			if ok {
-				fmt.Printf("%s: OK (expires %s)\n", tc.name, exp)
-			} else {
-				fmt.Printf("%s: INVALID (as expected)\n", tc.name)
-			}
+			fmt.Printf("%s: expected SELF-SIGNED, but was not detected as such\n", root)
+			failures++
 		}
-    }
+	}
 
-    // Verify that both embedded root CAs are detected as self-signed
-    roots := []string{"testdata/gts-r1.pem", "testdata/isrg-root-x1.pem"}
-    for _, root := range roots {
-        b, err := embeddedTestdata.ReadFile(root)
-        if err != nil {
-            fmt.Fprintf(os.Stderr, "selftest: failed to read embedded %s: %v\n", root, err)
-            failures++
-            continue
-        }
-        certs, err := loadCertsFromBytes(b)
-        if err != nil || len(certs) == 0 {
-            fmt.Fprintf(os.Stderr, "selftest: failed to parse cert(s) from %s: %v\n", root, err)
-            failures++
-            continue
-        }
-        leaf := certs[0]
-        if isSelfSigned(leaf) {
-            fmt.Printf("%s: SELF-SIGNED (as expected)\n", root)
-        } else {
-            fmt.Printf("%s: expected SELF-SIGNED, but was not detected as such\n", root)
-            failures++
-        }
-    }
+	if failures == 0 {
+		fmt.Println("selftest: PASS")
+		return 0
+	}
+	fmt.Fprintf(os.Stderr, "selftest: FAIL (%d failure(s))\n", failures)
+	return 1
+}
 
-    if failures == 0 {
-        fmt.Println("selftest: PASS")
-        return 0
-    }
-    fmt.Fprintf(os.Stderr, "selftest: FAIL (%d failure(s))\n", failures)
-    return 1
+// expiryString returns a YYYY-MM-DD date string to display for certificate
+// expiry. If an explicit exp string is provided, it is used. Otherwise, if a
+// leaf certificate is available, its NotAfter is formatted. As a last resort,
+// it falls back to today's date (should not normally happen).
+func expiryString(leaf *x509.Certificate, exp string) string {
+	if exp != "" {
+		return exp
+	}
+	if leaf != nil {
+		return leaf.NotAfter.Format("2006-01-02")
+	}
+	return time.Now().Format("2006-01-02")
+}
+
+// processCert verifies a single certificate file against the provided CA pool
+// and prints the result in the required format, handling self-signed
+// certificates specially.
+func processCert(caPool *x509.CertPool, certPath string) {
+	ok, exp := verifyAgainstCA(caPool, certPath)
+	name := filepath.Base(certPath)
+
+	// Try to load the leaf cert for self-signed detection and expiry fallback
+	var leaf *x509.Certificate
+	if certs, err := loadCertsFromFile(certPath); err == nil && len(certs) > 0 {
+		leaf = certs[0]
+	}
+
+	// Prefer the SELF-SIGNED label if applicable
+	if isSelfSigned(leaf) {
+		fmt.Printf("%s: SELF-SIGNED\n", name)
+		return
+	}
+
+	if ok {
+		fmt.Printf("%s: OK (expires %s)\n", name, expiryString(leaf, exp))
+		return
+	}
+	fmt.Printf("%s: INVALID\n", name)
 }
 
 func main() {
@@ -250,38 +319,7 @@ func main() {
 		os.Exit(1)
 	}
 
-    for _, certPath := range os.Args[2:] {
-        ok, exp := verifyAgainstCA(caPool, certPath)
-        name := filepath.Base(certPath)
-        // Load the leaf once for self-signed detection and potential expiry fallback
-        var leaf *x509.Certificate
-        if certs, err := loadCertsFromFile(certPath); err == nil && len(certs) > 0 {
-            leaf = certs[0]
-        }
-
-        // If the certificate is self-signed, prefer the SELF-SIGNED label
-        if isSelfSigned(leaf) {
-            fmt.Printf("%s: SELF-SIGNED\n", name)
-            continue
-        }
-
-        if ok {
-            // Display with the requested format
-            // Example: file: OK (expires 2031-01-01)
-            // Ensure deterministic date formatting
-            // Note: no timezone displayed; date only as per example
-            // If exp ended up empty for some reason, recompute safely
-            if exp == "" {
-                if leaf != nil {
-                    exp = leaf.NotAfter.Format("2006-01-02")
-                } else {
-                    // fallback to the current date to avoid empty; though shouldn't happen
-                    exp = time.Now().Format("2006-01-02")
-                }
-            }
-            fmt.Printf("%s: OK (expires %s)\n", name, exp)
-        } else {
-            fmt.Printf("%s: INVALID\n", name)
-        }
-    }
+	for _, certPath := range os.Args[2:] {
+		processCert(caPool, certPath)
+	}
 }

cmd/cert-bundler/main.go

@@ -8,8 +8,10 @@ import (
 	"crypto/x509"
 	_ "embed"
 	"encoding/pem"
+	"errors"
 	"flag"
 	"fmt"
+	"io"
 	"os"
 	"path/filepath"
 	"strings"
@@ -19,7 +21,7 @@ import (
 	"gopkg.in/yaml.v2"
 )
 
-// Config represents the top-level YAML configuration
+// Config represents the top-level YAML configuration.
 type Config struct {
 	Config struct {
 		Hashes string `yaml:"hashes"`
@@ -28,19 +30,19 @@ type Config struct {
 	Chains map[string]ChainGroup `yaml:"chains"`
 }
 
-// ChainGroup represents a named group of certificate chains
+// ChainGroup represents a named group of certificate chains.
 type ChainGroup struct {
 	Certs   []CertChain `yaml:"certs"`
 	Outputs Outputs     `yaml:"outputs"`
 }
 
-// CertChain represents a root certificate and its intermediates
+// CertChain represents a root certificate and its intermediates.
 type CertChain struct {
 	Root          string   `yaml:"root"`
 	Intermediates []string `yaml:"intermediates"`
 }
 
-// Outputs defines output format options
+// Outputs defines output format options.
 type Outputs struct {
 	IncludeSingle     bool     `yaml:"include_single"`
 	IncludeIndividual bool     `yaml:"include_individual"`
@@ -95,7 +97,8 @@ func main() {
 	}
 
 	// Create output directory if it doesn't exist
-	if err := os.MkdirAll(outputDir, 0755); err != nil {
+	err = os.MkdirAll(outputDir, 0750)
+	if err != nil {
 		fmt.Fprintf(os.Stderr, "Error creating output directory: %v\n", err)
 		os.Exit(1)
 	}
@@ -108,9 +111,9 @@ func main() {
 	}
 	createdFiles := make([]string, 0, totalFormats)
 	for groupName, group := range cfg.Chains {
-		files, err := processChainGroup(groupName, group, expiryDuration)
-		if err != nil {
-			fmt.Fprintf(os.Stderr, "Error processing chain group %s: %v\n", groupName, err)
+		files, perr := processChainGroup(groupName, group, expiryDuration)
+		if perr != nil {
+			fmt.Fprintf(os.Stderr, "Error processing chain group %s: %v\n", groupName, perr)
 			os.Exit(1)
 		}
 		createdFiles = append(createdFiles, files...)
@@ -119,8 +122,8 @@ func main() {
 	// Generate hash file for all created archives
 	if cfg.Config.Hashes != "" {
 		hashFile := filepath.Join(outputDir, cfg.Config.Hashes)
-		if err := generateHashFile(hashFile, createdFiles); err != nil {
-			fmt.Fprintf(os.Stderr, "Error generating hash file: %v\n", err)
+		if gerr := generateHashFile(hashFile, createdFiles); gerr != nil {
+			fmt.Fprintf(os.Stderr, "Error generating hash file: %v\n", gerr)
 			os.Exit(1)
 		}
 	}
@@ -135,8 +138,8 @@ func loadConfig(path string) (*Config, error) {
 	}
 
 	var cfg Config
-	if err := yaml.Unmarshal(data, &cfg); err != nil {
-		return nil, err
+	if uerr := yaml.Unmarshal(data, &cfg); uerr != nil {
+		return nil, uerr
 	}
 
 	return &cfg, nil
@@ -200,72 +203,107 @@ func processChainGroup(groupName string, group ChainGroup, expiryDuration time.D
 	return createdFiles, nil
 }
 
-// loadAndCollectCerts loads all certificates from chains and collects them for processing
-func loadAndCollectCerts(chains []CertChain, outputs Outputs, expiryDuration time.Duration) ([]*x509.Certificate, []certWithPath, error) {
+// loadAndCollectCerts loads all certificates from chains and collects them for processing.
+func loadAndCollectCerts(
+	chains []CertChain,
+	outputs Outputs,
+	expiryDuration time.Duration,
+) ([]*x509.Certificate, []certWithPath, error) {
 	var singleFileCerts []*x509.Certificate
 	var individualCerts []certWithPath
 
 	for _, chain := range chains {
-		// Load root certificate
-		rootCert, err := certlib.LoadCertificate(chain.Root)
-		if err != nil {
-			return nil, nil, fmt.Errorf("failed to load root certificate %s: %v", chain.Root, err)
+		s, i, cerr := collectFromChain(chain, outputs, expiryDuration)
+		if cerr != nil {
+			return nil, nil, cerr
 		}
-
-		// Check expiry for root
-		checkExpiry(chain.Root, rootCert, expiryDuration)
-
-		// Add root to collections if needed
-		if outputs.IncludeSingle {
-			singleFileCerts = append(singleFileCerts, rootCert)
+		if len(s) > 0 {
+			singleFileCerts = append(singleFileCerts, s...)
 		}
-		if outputs.IncludeIndividual {
-			individualCerts = append(individualCerts, certWithPath{
-				cert: rootCert,
-				path: chain.Root,
-			})
-		}
-
-		// Load and validate intermediates
-		for _, intPath := range chain.Intermediates {
-			intCert, err := certlib.LoadCertificate(intPath)
-			if err != nil {
-				return nil, nil, fmt.Errorf("failed to load intermediate certificate %s: %v", intPath, err)
-			}
-
-			// Validate that intermediate is signed by root
-			if err := intCert.CheckSignatureFrom(rootCert); err != nil {
-				return nil, nil, fmt.Errorf("intermediate %s is not properly signed by root %s: %v", intPath, chain.Root, err)
-			}
-
-			// Check expiry for intermediate
-			checkExpiry(intPath, intCert, expiryDuration)
-
-			// Add intermediate to collections if needed
-			if outputs.IncludeSingle {
-				singleFileCerts = append(singleFileCerts, intCert)
-			}
-			if outputs.IncludeIndividual {
-				individualCerts = append(individualCerts, certWithPath{
-					cert: intCert,
-					path: intPath,
-				})
-			}
+		if len(i) > 0 {
+			individualCerts = append(individualCerts, i...)
 		}
 	}
 
 	return singleFileCerts, individualCerts, nil
 }
 
-// prepareArchiveFiles prepares all files to be included in archives
-func prepareArchiveFiles(singleFileCerts []*x509.Certificate, individualCerts []certWithPath, outputs Outputs, encoding string) ([]fileEntry, error) {
+// collectFromChain loads a single chain, performs checks, and returns the certs to include.
+func collectFromChain(
+	chain CertChain,
+	outputs Outputs,
+	expiryDuration time.Duration,
+) (
+	[]*x509.Certificate,
+	[]certWithPath,
+	error,
+) {
+	var single []*x509.Certificate
+	var indiv []certWithPath
+
+	// Load root certificate
+	rootCert, rerr := certlib.LoadCertificate(chain.Root)
+	if rerr != nil {
+		return nil, nil, fmt.Errorf("failed to load root certificate %s: %w", chain.Root, rerr)
+	}
+
+	// Check expiry for root
+	checkExpiry(chain.Root, rootCert, expiryDuration)
+
+	// Add root to collections if needed
+	if outputs.IncludeSingle {
+		single = append(single, rootCert)
+	}
+	if outputs.IncludeIndividual {
+		indiv = append(indiv, certWithPath{cert: rootCert, path: chain.Root})
+	}
+
+	// Load and validate intermediates
+	for _, intPath := range chain.Intermediates {
+		intCert, lerr := certlib.LoadCertificate(intPath)
+		if lerr != nil {
+			return nil, nil, fmt.Errorf("failed to load intermediate certificate %s: %w", intPath, lerr)
+		}
+
+		// Validate that intermediate is signed by root
+		if sigErr := intCert.CheckSignatureFrom(rootCert); sigErr != nil {
+			return nil, nil, fmt.Errorf(
+				"intermediate %s is not properly signed by root %s: %w",
+				intPath,
+				chain.Root,
+				sigErr,
+			)
+		}
+
+		// Check expiry for intermediate
+		checkExpiry(intPath, intCert, expiryDuration)
+
+		// Add intermediate to collections if needed
+		if outputs.IncludeSingle {
+			single = append(single, intCert)
+		}
+		if outputs.IncludeIndividual {
+			indiv = append(indiv, certWithPath{cert: intCert, path: intPath})
+		}
+	}
+
+	return single, indiv, nil
+}
+
+// prepareArchiveFiles prepares all files to be included in archives.
+func prepareArchiveFiles(
+	singleFileCerts []*x509.Certificate,
+	individualCerts []certWithPath,
+	outputs Outputs,
+	encoding string,
+) ([]fileEntry, error) {
 	var archiveFiles []fileEntry
 
 	// Handle a single bundle file
 	if outputs.IncludeSingle && len(singleFileCerts) > 0 {
 		files, err := encodeCertsToFiles(singleFileCerts, "bundle", encoding, true)
 		if err != nil {
-			return nil, fmt.Errorf("failed to encode single bundle: %v", err)
+			return nil, fmt.Errorf("failed to encode single bundle: %w", err)
 		}
 		archiveFiles = append(archiveFiles, files...)
 	}
@@ -276,7 +314,7 @@ func prepareArchiveFiles(singleFileCerts []*x509.Certificate, individualCerts []
 			baseName := strings.TrimSuffix(filepath.Base(cp.path), filepath.Ext(cp.path))
 			files, err := encodeCertsToFiles([]*x509.Certificate{cp.cert}, baseName, encoding, false)
 			if err != nil {
-				return nil, fmt.Errorf("failed to encode individual cert %s: %v", cp.path, err)
+				return nil, fmt.Errorf("failed to encode individual cert %s: %w", cp.path, err)
 			}
 			archiveFiles = append(archiveFiles, files...)
 		}
@@ -294,7 +332,7 @@ func prepareArchiveFiles(singleFileCerts []*x509.Certificate, individualCerts []
 	return archiveFiles, nil
 }
 
-// createArchiveFiles creates archive files in the specified formats
+// createArchiveFiles creates archive files in the specified formats.
 func createArchiveFiles(groupName string, formats []string, archiveFiles []fileEntry) ([]string, error) {
 	createdFiles := make([]string, 0, len(formats))
 
@@ -307,11 +345,11 @@ func createArchiveFiles(groupName string, formats []string, archiveFiles []fileE
 		switch format {
 		case "zip":
 			if err := createZipArchive(archivePath, archiveFiles); err != nil {
-				return nil, fmt.Errorf("failed to create zip archive: %v", err)
+				return nil, fmt.Errorf("failed to create zip archive: %w", err)
 			}
 		case "tgz":
 			if err := createTarGzArchive(archivePath, archiveFiles); err != nil {
-				return nil, fmt.Errorf("failed to create tar.gz archive: %v", err)
+				return nil, fmt.Errorf("failed to create tar.gz archive: %w", err)
 			}
 		default:
 			return nil, fmt.Errorf("unsupported format: %s", format)
@@ -329,7 +367,12 @@ func checkExpiry(path string, cert *x509.Certificate, expiryDuration time.Durati
 	if cert.NotAfter.Before(expiryThreshold) {
 		daysUntilExpiry := int(cert.NotAfter.Sub(now).Hours() / 24)
 		if daysUntilExpiry < 0 {
-			fmt.Fprintf(os.Stderr, "WARNING: Certificate %s has EXPIRED (expired %d days ago)\n", path, -daysUntilExpiry)
+			fmt.Fprintf(
+				os.Stderr,
+				"WARNING: Certificate %s has EXPIRED (expired %d days ago)\n",
+				path,
+				-daysUntilExpiry,
+			)
 		} else {
 			fmt.Fprintf(os.Stderr, "WARNING: Certificate %s will expire in %d days (on %s)\n", path, daysUntilExpiry, cert.NotAfter.Format("2006-01-02"))
 		}
@@ -347,8 +390,13 @@ type certWithPath struct {
 }
 
 // encodeCertsToFiles converts certificates to file entries based on encoding type
-// If isSingle is true, certs are concatenated into a single file; otherwise one cert per file
-func encodeCertsToFiles(certs []*x509.Certificate, baseName string, encoding string, isSingle bool) ([]fileEntry, error) {
+// If isSingle is true, certs are concatenated into a single file; otherwise one cert per file.
+func encodeCertsToFiles(
+	certs []*x509.Certificate,
+	baseName string,
+	encoding string,
+	isSingle bool,
+) ([]fileEntry, error) {
 	var files []fileEntry
 
 	switch encoding {
@@ -369,14 +417,12 @@ func encodeCertsToFiles(certs []*x509.Certificate, baseName string, encoding str
 				name:    baseName + ".crt",
 				content: derContent,
 			})
-		} else {
+		} else if len(certs) > 0 {
 			// Individual DER file (should only have one cert)
-			if len(certs) > 0 {
-				files = append(files, fileEntry{
-					name:    baseName + ".crt",
-					content: certs[0].Raw,
-				})
-			}
+			files = append(files, fileEntry{
+				name:    baseName + ".crt",
+				content: certs[0].Raw,
+			})
 		}
 	case "both":
 		// Add PEM version
@@ -395,13 +441,11 @@ func encodeCertsToFiles(certs []*x509.Certificate, baseName string, encoding str
 				name:    baseName + ".crt",
 				content: derContent,
 			})
-		} else {
-			if len(certs) > 0 {
-				files = append(files, fileEntry{
-					name:    baseName + ".crt",
-					content: certs[0].Raw,
-				})
-			}
+		} else if len(certs) > 0 {
+			files = append(files, fileEntry{
+				name:    baseName + ".crt",
+				content: certs[0].Raw,
+			})
 		}
 	default:
 		return nil, fmt.Errorf("unsupported encoding: %s (must be 'pem', 'der', or 'both')", encoding)
@@ -410,7 +454,7 @@ func encodeCertsToFiles(certs []*x509.Certificate, baseName string, encoding str
 	return files, nil
 }
 
-// encodeCertsToPEM encodes certificates to PEM format
+// encodeCertsToPEM encodes certificates to PEM format.
 func encodeCertsToPEM(certs []*x509.Certificate) []byte {
 	var pemContent []byte
 	for _, cert := range certs {
@@ -435,40 +479,49 @@ func generateManifest(files []fileEntry) []byte {
 	return []byte(manifest.String())
 }
 
+// closeWithErr attempts to close all provided closers, joining any close errors with baseErr.
+func closeWithErr(baseErr error, closers ...io.Closer) error {
+	for _, c := range closers {
+		if c == nil {
+			continue
+		}
+		if cerr := c.Close(); cerr != nil {
+			baseErr = errors.Join(baseErr, cerr)
+		}
+	}
+	return baseErr
+}
+
 func createZipArchive(path string, files []fileEntry) error {
-	f, err := os.Create(path)
-	if err != nil {
-		return err
+	f, zerr := os.Create(path)
+	if zerr != nil {
+		return zerr
 	}
 
 	w := zip.NewWriter(f)
 
 	for _, file := range files {
-		fw, err := w.Create(file.name)
-		if err != nil {
-			w.Close()
-			f.Close()
-			return err
+		fw, werr := w.Create(file.name)
+		if werr != nil {
+			return closeWithErr(werr, w, f)
 		}
-		if _, err := fw.Write(file.content); err != nil {
-			w.Close()
-			f.Close()
-			return err
+		if _, werr = fw.Write(file.content); werr != nil {
+			return closeWithErr(werr, w, f)
 		}
 	}
 
 	// Check errors on close operations
-	if err := w.Close(); err != nil {
-		f.Close()
-		return err
+	if cerr := w.Close(); cerr != nil {
+		_ = f.Close()
+		return cerr
 	}
 	return f.Close()
 }
 
 func createTarGzArchive(path string, files []fileEntry) error {
-	f, err := os.Create(path)
-	if err != nil {
-		return err
+	f, terr := os.Create(path)
+	if terr != nil {
+		return terr
 	}
 
 	gw := gzip.NewWriter(f)
@@ -480,29 +533,23 @@ func createTarGzArchive(path string, files []fileEntry) error {
 			Mode: 0644,
 			Size: int64(len(file.content)),
 		}
-		if err := tw.WriteHeader(hdr); err != nil {
-			tw.Close()
-			gw.Close()
-			f.Close()
-			return err
+		if herr := tw.WriteHeader(hdr); herr != nil {
+			return closeWithErr(herr, tw, gw, f)
 		}
-		if _, err := tw.Write(file.content); err != nil {
-			tw.Close()
-			gw.Close()
-			f.Close()
-			return err
+		if _, werr := tw.Write(file.content); werr != nil {
+			return closeWithErr(werr, tw, gw, f)
 		}
 	}
 
 	// Check errors on close operations in the correct order
-	if err := tw.Close(); err != nil {
-		gw.Close()
-		f.Close()
-		return err
+	if cerr := tw.Close(); cerr != nil {
+		_ = gw.Close()
+		_ = f.Close()
+		return cerr
 	}
-	if err := gw.Close(); err != nil {
-		f.Close()
-		return err
+	if cerr := gw.Close(); cerr != nil {
+		_ = f.Close()
+		return cerr
 	}
 	return f.Close()
 }
@@ -515,9 +562,9 @@ func generateHashFile(path string, files []string) error {
 	defer f.Close()
 
 	for _, file := range files {
-		data, err := os.ReadFile(file)
-		if err != nil {
-			return err
+		data, rerr := os.ReadFile(file)
+		if rerr != nil {
+			return rerr
 		}
 
 		hash := sha256.Sum256(data)

go.mod

@@ -12,6 +12,7 @@ require (
 )
 
 require (
+	github.com/benbjohnson/clock v1.3.5
 	github.com/davecgh/go-spew v1.1.1
 	github.com/google/certificate-transparency-go v1.0.21
 )

go.sum

@@ -1,3 +1,5 @@
+github.com/benbjohnson/clock v1.3.5 h1:VvXlSJBzZpA/zum6Sj74hxwYI2DIxRWuNIoXAzHZz5o=
+github.com/benbjohnson/clock v1.3.5/go.mod h1:J11/hYXuz8f4ySSvYwY0FKfm+ezbsZBKZxNJlLklBHA=
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=