cmd: continuing linter fixes

.golangci.yml

@@ -242,6 +242,10 @@ linters:
       check-type-assertions: true
       exclude-functions:
         - (*git.wntrmute.dev/kyle/goutils/sbuf.Buffer).Write
+        - git.wntrmute.dev/kyle/goutils/lib.Warn
+        - git.wntrmute.dev/kyle/goutils/lib.Warnx
+        - git.wntrmute.dev/kyle/goutils/lib.Err
+        - git.wntrmute.dev/kyle/goutils/lib.Errx
 
     exhaustive:
       # Program elements to check for exhaustiveness.
@@ -333,6 +337,12 @@ linters:
         # https://github.com/godoc-lint/godoc-lint?tab=readme-ov-file#no-unused-link
         - no-unused-link
 
+    gosec:
+      excludes:
+        - G104 # handled by errcheck
+        - G301
+        - G306
+
     govet:
       # Enable all analyzers.
       # Default: false
@@ -368,6 +378,12 @@ linters:
         - os.WriteFile
         - prometheus.ExponentialBuckets.*
         - prometheus.LinearBuckets
+      ignored-numbers:
+        - 1
+        - 2
+        - 3
+        - 4
+        - 8
 
     nakedret:
       # Make an issue if func has more lines of code than this setting, and it has naked returns.
@@ -436,6 +452,8 @@ linters:
         # Omit embedded fields from selector expression.
         # https://staticcheck.dev/docs/checks/#QF1008
         - -QF1008
+        # We often explicitly enable old/deprecated ciphers for research.
+        - -SA1019
 
     usetesting:
       # Enable/disable `os.TempDir()` detections.

certlib/helpers.go

@@ -458,8 +458,6 @@ func GetKeyDERFromPEM(in []byte, password []byte) ([]byte, error) {
 	}
 	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)

cmd/certchain/main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"crypto/tls"
 	"encoding/pem"
 	"flag"
@@ -22,22 +23,26 @@ func main() {
 			server += ":443"
 		}
 
-		var chain string
-
-		conn, err := tls.Dial("tcp", server, nil)
+		d := &tls.Dialer{Config: &tls.Config{}} // #nosec G402
+		nc, err := d.DialContext(context.Background(), "tcp", server)
 		die.If(err)
+		conn, ok := nc.(*tls.Conn)
+		if !ok {
+			die.With("invalid TLS connection (not a *tls.Conn)")
+		}
+
+		defer conn.Close()
 
 		details := conn.ConnectionState()
-		var chainSb30 strings.Builder
+		var chain strings.Builder
 		for _, cert := range details.PeerCertificates {
 			p := pem.Block{
 				Type:  "CERTIFICATE",
 				Bytes: cert.Raw,
 			}
-			chainSb30.WriteString(string(pem.EncodeToMemory(&p)))
+			chain.Write(pem.EncodeToMemory(&p))
 		}
-		chain += chainSb30.String()
 
-		fmt.Fprintln(os.Stdout, chain)
+		fmt.Fprintln(os.Stdout, chain.String())
 	}
 }

cmd/certdump/main.go

@@ -3,6 +3,7 @@ package main
 
 import (
 	"bytes"
+	"context"
 	"crypto/dsa"
 	"crypto/ecdsa"
 	"crypto/elliptic"
@@ -246,18 +247,34 @@ func displayAllCerts(in []byte, leafOnly bool) {
 
 func displayAllCertsWeb(uri string, leafOnly bool) {
 	ci := getConnInfo(uri)
-	conn, err := tls.Dial("tcp", ci.Addr, permissiveConfig())
+	d := &tls.Dialer{Config: permissiveConfig()}
+	nc, err := d.DialContext(context.Background(), "tcp", ci.Addr)
 	if err != nil {
 		_, _ = lib.Warn(err, "couldn't connect to %s", ci.Addr)
 		return
 	}
+
+	conn, ok := nc.(*tls.Conn)
+	if !ok {
+		_, _ = lib.Warnx("invalid TLS connection (not a *tls.Conn)")
+		return
+	}
 	defer conn.Close()
 
 	state := conn.ConnectionState()
-	conn.Close()
+	if err = conn.Close(); err != nil {
+		_, _ = lib.Warn(err, "couldn't close TLS connection")
+	}
 
-	conn, err = tls.Dial("tcp", ci.Addr, verifyConfig(ci.Host))
+	d = &tls.Dialer{Config: verifyConfig(ci.Host)}
+	nc, err = d.DialContext(context.Background(), "tcp", ci.Addr)
 	if err == nil {
+		conn, ok = nc.(*tls.Conn)
+		if !ok {
+			_, _ = lib.Warnx("invalid TLS connection (not a *tls.Conn)")
+			return
+		}
+
 		err = conn.VerifyHostname(ci.Host)
 		if err == nil {
 			state = conn.ConnectionState()
@@ -293,14 +310,19 @@ func displayAllCertsWeb(uri string, leafOnly bool) {
 	}
 }
 
-func main() {
-	var leafOnly bool
-	flag.BoolVar(&showHash, "d", false, "show hashes of raw DER contents")
-	flag.StringVar(&dateFormat, "s", oneTrueDateFormat, "date `format` in Go time format")
-	flag.BoolVar(&leafOnly, "l", false, "only show the leaf certificate")
-	flag.Parse()
+func shouldReadStdin(argc int, argv []string) bool {
+	if argc == 0 {
+		return true
+	}
 
-	if flag.NArg() == 0 || (flag.NArg() == 1 && flag.Arg(0) == "-") {
+	if argc == 1 && argv[0] == "-" {
+		return true
+	}
+
+	return false
+}
+
+func readStdin(leafOnly bool) {
 	certs, err := io.ReadAll(os.Stdin)
 	if err != nil {
 		_, _ = lib.Warn(err, "couldn't read certificates from standard input")
@@ -312,7 +334,20 @@ func main() {
 	certs = bytes.ReplaceAll(certs, []byte(`\n`), []byte{0xa})
 	certs = bytes.Trim(certs, `"`)
 	displayAllCerts(certs, leafOnly)
-	} else {
+}
+
+func main() {
+	var leafOnly bool
+	flag.BoolVar(&showHash, "d", false, "show hashes of raw DER contents")
+	flag.StringVar(&dateFormat, "s", oneTrueDateFormat, "date `format` in Go time format")
+	flag.BoolVar(&leafOnly, "l", false, "only show the leaf certificate")
+	flag.Parse()
+
+	if shouldReadStdin(flag.NArg(), flag.Args()) {
+		readStdin(leafOnly)
+		return
+	}
+
 	for _, filename := range flag.Args() {
 		fmt.Fprintf(os.Stdout, "--%s ---%s", filename, "\n")
 		if strings.HasPrefix(filename, "https://") {
@@ -328,4 +363,3 @@ func main() {
 		}
 	}
 }
-}

cmd/certdump/util.go

@@ -13,6 +13,11 @@ import (
 // following two lifted from CFSSL, (replace-regexp "\(.+\): \(.+\),"
 // "\2: \1,")
 
+const (
+	sSHA256 = "SHA256"
+	sSHA512 = "SHA512"
+)
+
 var keyUsage = map[x509.KeyUsage]string{
 	x509.KeyUsageDigitalSignature:  "digital signature",
 	x509.KeyUsageContentCommitment: "content committment",
@@ -70,19 +75,19 @@ func sigAlgoHash(a x509.SignatureAlgorithm) string {
 	case x509.SHA1WithRSA, x509.ECDSAWithSHA1, x509.DSAWithSHA1:
 		return "SHA1"
 	case x509.SHA256WithRSA, x509.ECDSAWithSHA256, x509.DSAWithSHA256:
-		return "SHA256"
+		return sSHA256
 	case x509.SHA256WithRSAPSS:
-		return "SHA256"
+		return sSHA256
 	case x509.SHA384WithRSA, x509.ECDSAWithSHA384:
 		return "SHA384"
 	case x509.SHA384WithRSAPSS:
 		return "SHA384"
 	case x509.SHA512WithRSA, x509.ECDSAWithSHA512:
-		return "SHA512"
+		return sSHA512
 	case x509.SHA512WithRSAPSS:
-		return "SHA512"
+		return sSHA512
 	case x509.PureEd25519:
-		return "SHA512"
+		return sSHA512
 	case x509.UnknownSignatureAlgorithm:
 		return "unknown hash algorithm"
 	default:
@@ -144,14 +149,14 @@ func dumpHex(in []byte) string {
 func permissiveConfig() *tls.Config {
 	return &tls.Config{
 		InsecureSkipVerify: true,
-	}
+	} // #nosec G402
 }
 
 // verifyConfig returns a config that will verify the connection.
 func verifyConfig(hostname string) *tls.Config {
 	return &tls.Config{
 		ServerName: hostname,
-	}
+	} // #nosec G402
 }
 
 type connInfo struct {

cmd/clustersh/main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"bufio"
+	"context"
 	"errors"
 	"flag"
 	"fmt"
@@ -57,7 +58,7 @@ var modes = ssh.TerminalModes{
 }
 
 func sshAgent() ssh.AuthMethod {
-	a, err := net.Dial("unix", os.Getenv("SSH_AUTH_SOCK"))
+	a, err := (&net.Dialer{}).DialContext(context.Background(), "unix", os.Getenv("SSH_AUTH_SOCK"))
 	if err == nil {
 		return ssh.PublicKeysCallback(agent.NewClient(a).Signers)
 	}
@@ -116,7 +117,7 @@ func exec(wg *sync.WaitGroup, user, host string, commands []string) {
 	}
 	shutdown = append(shutdown, session.Close)
 
-	if err := session.RequestPty("xterm", 80, 40, modes); err != nil {
+	if err = session.RequestPty("xterm", 80, 40, modes); err != nil {
 		session.Close()
 		logError(host, err, "request for pty failed")
 		return

cmd/cruntar/main.go

@@ -26,7 +26,7 @@ func setupFile(hdr *tar.Header, file *os.File) error {
 		if verbose {
 			fmt.Printf("\tchmod %0#o\n", hdr.Mode)
 		}
-		err := file.Chmod(os.FileMode(hdr.Mode))
+		err := file.Chmod(os.FileMode(hdr.Mode & 0xFFFFFFFF)) // #nosec G115
 		if err != nil {
 			return err
 		}
@@ -55,7 +55,9 @@ func processFile(tfr *tar.Reader, hdr *tar.Header, top string) error {
 	if verbose {
 		fmt.Println(hdr.Name)
 	}
+
 	filePath := filepath.Clean(filepath.Join(top, hdr.Name))
+
 	switch hdr.Typeflag {
 	case tar.TypeReg:
 		file, err := os.Create(filePath)
@@ -109,7 +111,7 @@ func processFile(tfr *tar.Reader, hdr *tar.Header, top string) error {
 			return err
 		}
 	case tar.TypeDir:
-		err := os.MkdirAll(filePath, os.FileMode(hdr.Mode))
+		err := os.MkdirAll(filePath, os.FileMode(hdr.Mode&0xFFFFFFFF)) // #nosec G115
 		if err != nil {
 			return err
 		}
@@ -261,8 +263,9 @@ func main() {
 	die.If(err)
 
 	tfr := tar.NewReader(r)
+	var hdr *tar.Header
 	for {
-		hdr, err := tfr.Next()
+		hdr, err = tfr.Next()
 		if errors.Is(err, io.EOF) {
 			break
 		}

cmd/csrpubdump/main.go

@@ -47,7 +47,7 @@ func main() {
 			Bytes: out,
 		}
 
-		err = os.WriteFile(fileName+".pub", pem.EncodeToMemory(p), 0o644)
+		err = os.WriteFile(fileName+".pub", pem.EncodeToMemory(p), 0o644) // #nosec G306
 		die.If(err)
 		fmt.Fprintf(os.Stdout, "[+] wrote %s.\n", fileName+".pub")
 	}

cmd/data_sync/main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"flag"
 	"fmt"
 	"io"
@@ -152,7 +153,7 @@ func rsync(syncDir, target, excludeFile string, verboseRsync bool) error {
 		return err
 	}
 
-	cmd := exec.Command(path, args...)
+	cmd := exec.CommandContext(context.Background(), path, args...)
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr
 	return cmd.Run()
@@ -218,7 +219,7 @@ func main() {
 	if excludeFile != "" {
 		defer func() {
 			log.Infof("removing exclude file %s", excludeFile)
-			if err := os.Remove(excludeFile); err != nil {
+			if rmErr := os.Remove(excludeFile); rmErr != nil {
 				log.Warningf("failed to remove temp file %s", excludeFile)
 			}
 		}()

cmd/diskimg/main.go

@@ -30,7 +30,7 @@ func openImage(imageFile string) (*os.File, []byte, error) {
 		return nil, nil, err
 	}
 
-	if _, err := f.Seek(0, 0); err != nil {
+	if _, err = f.Seek(0, 0); err != nil {
 		return nil, nil, err
 	}
 
@@ -103,12 +103,12 @@ func main() {
 	die.If(err)
 
 	if !bytes.Equal(deviceHash, hash) {
-		fmt.Fprintln(os.Stderr, "Hash mismatch:")
-		fmt.Fprintf(os.Stderr, "\t%s: %s\n", imageFile, hash)
-		fmt.Fprintf(os.Stderr, "\t%s: %s\n", devicePath, deviceHash)
-		os.Exit(1)
+		buf := &bytes.Buffer{}
+		fmt.Fprintln(buf, "Hash mismatch:")
+		fmt.Fprintf(buf, "\t%s: %s\n", imageFile, hash)
+		fmt.Fprintf(buf, "\t%s: %s\n", devicePath, deviceHash)
+		die.With(buf.String())
 	}
 
 	debug.Println("OK")
-	os.Exit(0)
 }

cmd/dumpbytes/main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"errors"
 	"flag"
 	"fmt"
 	"io"
@@ -37,10 +38,11 @@ func dumpFile(path string, indentLevel int) error {
 	defer file.Close()
 
 	fmt.Printf("%svar buffer = []byte{\n", indent.String())
+	var n int
 	for {
 		buf := make([]byte, 8)
-		n, err := file.Read(buf)
-		if err == io.EOF {
+		n, err = file.Read(buf)
+		if errors.Is(err, io.EOF) {
 			if n > 0 {
 				fmt.Printf("%s", indent.String())
 				printBytes(buf[:n])

cmd/eig/main.go

@@ -26,7 +26,7 @@ func main() {
 		path = flag.Arg(0)
 	}
 
-	fillByte := uint8(*fill)
+	fillByte := uint8(*fill & 0xff) // #nosec G115 clearing out of bounds bits
 
 	buf := make([]byte, pageSize)
 	for i := range pageSize {

cmd/fragment/main.go

@@ -72,9 +72,7 @@ func main() {
 
 	if end < start {
 		fmt.Fprintln(os.Stderr, "[!] end < start, swapping values")
-		tmp := end
-		end = start
-		start = tmp
+		start, end = end, start
 	}
 
 	var fmtStr string

cmd/host/main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"flag"
 	"fmt"
 	"log"
@@ -8,7 +9,8 @@ import (
 )
 
 func lookupHost(host string) error {
-	cname, err := net.LookupCNAME(host)
+	r := &net.Resolver{}
+	cname, err := r.LookupCNAME(context.Background(), host)
 	if err != nil {
 		return err
 	}
@@ -18,7 +20,7 @@ func lookupHost(host string) error {
 		host = cname
 	}
 
-	addrs, err := net.LookupHost(host)
+	addrs, err := r.LookupHost(context.Background(), host)
 	if err != nil {
 		return err
 	}

cmd/kgz/README

@@ -12,6 +12,9 @@ based on whether the source filename ends in ".gz".
 Flags:
 	-l level	Compression level (0-9). Only meaninful when
 			    compressing a file.
+    -u          Do not restrict the size during decompression. As
+                a safeguard against gzip bombs, the maximum size
+                allowed is 32 * the compressed file size.
 
 
 

cmd/kgz/main.go

@@ -40,26 +40,42 @@ func compress(path, target string, level int) error {
 	return nil
 }
 
-func uncompress(path, target string) error {
+func uncompress(path, target string, unrestrict bool) error {
 	sourceFile, err := os.Open(path)
 	if err != nil {
 		return fmt.Errorf("opening file for read: %w", err)
 	}
 	defer sourceFile.Close()
 
+	fi, err := sourceFile.Stat()
+	if err != nil {
+		return fmt.Errorf("reading file stats: %w", err)
+	}
+
+	maxDecompressionSize := fi.Size() * 32
+
 	gzipUncompressor, err := gzip.NewReader(sourceFile)
 	if err != nil {
 		return fmt.Errorf("reading gzip headers: %w", err)
 	}
 	defer gzipUncompressor.Close()
 
+	var reader io.Reader = &io.LimitedReader{
+		R: gzipUncompressor,
+		N: maxDecompressionSize,
+	}
+
+	if unrestrict {
+		reader = gzipUncompressor
+	}
+
 	destFile, err := os.Create(target)
 	if err != nil {
 		return fmt.Errorf("opening file for write: %w", err)
 	}
 	defer destFile.Close()
 
-	_, err = io.Copy(destFile, gzipUncompressor)
+	_, err = io.Copy(destFile, reader)
 	if err != nil {
 		return fmt.Errorf("uncompressing file: %w", err)
 	}
@@ -87,8 +103,8 @@ func isDir(path string) bool {
 	file, err := os.Open(path)
 	if err == nil {
 		defer file.Close()
-		stat, err := file.Stat()
-		if err != nil {
+		stat, err2 := file.Stat()
+		if err2 != nil {
 			return false
 		}
 
@@ -132,8 +148,11 @@ func main() {
 	var level int
 	var path string
 	var target = "."
+	var err error
+	var unrestrict bool
 
 	flag.IntVar(&level, "l", flate.DefaultCompression, "compression level")
+	flag.BoolVar(&unrestrict, "u", false, "do not restrict decompression")
 	flag.Parse()
 
 	if flag.NArg() < 1 || flag.NArg() > 2 {
@@ -147,20 +166,22 @@ func main() {
 	}
 
 	if strings.HasSuffix(path, gzipExt) {
-		target, err := pathForUncompressing(path, target)
+		target, err = pathForUncompressing(path, target)
 		if err != nil {
 			fmt.Fprintf(os.Stderr, "%s\n", err)
 			os.Exit(1)
 		}
 
-		err = uncompress(path, target)
+		err = uncompress(path, target, unrestrict)
 		if err != nil {
 			os.Remove(target)
 			fmt.Fprintf(os.Stderr, "%s\n", err)
 			os.Exit(1)
 		}
-	} else {
-		target, err := pathForCompressing(path, target)
+		return
+	}
+
+	target, err = pathForCompressing(path, target)
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "%s\n", err)
 		os.Exit(1)
@@ -173,4 +194,3 @@ func main() {
 		os.Exit(1)
 	}
 }
-}

cmd/pembody/main.go

@@ -32,7 +32,7 @@ func main() {
 	if p == nil {
 		lib.Errx(lib.ExitFailure, "%s isn't a PEM-encoded file", flag.Arg(0))
 	}
-	if _, err := os.Stdout.Write(p.Bytes); err != nil {
+	if _, err = os.Stdout.Write(p.Bytes); err != nil {
 		lib.Err(lib.ExitFailure, err, "writing body")
 	}
 }

cmd/readchain/main.go

@@ -27,7 +27,8 @@ func main() {
 				break
 			}
 
-			cert, err := x509.ParseCertificate(p.Bytes)
+			var cert *x509.Certificate
+			cert, err = x509.ParseCertificate(p.Bytes)
 			if err != nil {
 				fmt.Fprintf(os.Stderr, "[!] %s: %v\n", fileName, err)
 				break

cmd/rhash/main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"flag"
 	"fmt"
 	"io"
@@ -76,7 +77,13 @@ func main() {
 			continue
 		}
 
-		resp, err := http.Get(remote)
+		req, reqErr := http.NewRequestWithContext(context.Background(), http.MethodGet, remote, nil)
+		if reqErr != nil {
+			_, _ = lib.Warn(reqErr, "building request for %s", remote)
+			continue
+		}
+		client := &http.Client{}
+		resp, err := client.Do(req)
 		if err != nil {
 			_, _ = lib.Warn(err, "fetching %s", remote)
 			continue

cmd/rolldie/main.go

@@ -18,7 +18,7 @@ func rollDie(count, sides int) []int {
 	var rolls []int
 
 	for range count {
-		roll := rand.IntN(sides) + 1
+		roll := rand.IntN(sides) + 1 // #nosec G404
 		sum += roll
 		rolls = append(rolls, roll)
 	}

cmd/showimp/main.go

@@ -75,13 +75,14 @@ func walkFile(path string, _ os.FileInfo, err error) error {
 
 	for _, importSpec := range f.Imports {
 		importPath := strings.Trim(importSpec.Path.Value, `"`)
-		if stdLibRegexp.MatchString(importPath) {
+		switch {
+		case stdLibRegexp.MatchString(importPath):
 			debug.Println("standard lib:", importPath)
 			continue
-		} else if strings.HasPrefix(importPath, project) {
+		case strings.HasPrefix(importPath, project):
 			debug.Println("internal import:", importPath)
 			continue
-		} else if strings.HasPrefix(importPath, "golang.org/") {
+		case strings.HasPrefix(importPath, "golang.org/"):
 			debug.Println("extended lib:", importPath)
 			continue
 		}

cmd/ski/main.go

@@ -5,7 +5,7 @@ import (
 	"crypto"
 	"crypto/ecdsa"
 	"crypto/rsa"
-	"crypto/sha1"
+	"crypto/sha1" // #nosec G505
 	"crypto/x509"
 	"crypto/x509/pkix"
 	"encoding/asn1"
@@ -20,6 +20,11 @@ import (
 	"git.wntrmute.dev/kyle/goutils/lib"
 )
 
+const (
+	keyTypeRSA   = "RSA"
+	keyTypeECDSA = "ECDSA"
+)
+
 func usage(w io.Writer) {
 	fmt.Fprintf(w, `ski: print subject key info for PEM-encoded files
 
@@ -94,10 +99,10 @@ func parseKey(data []byte) ([]byte, string) {
 	switch p := privInterface.(type) {
 	case *rsa.PrivateKey:
 		priv = p
-		kt = "RSA"
+		kt = keyTypeRSA
 	case *ecdsa.PrivateKey:
 		priv = p
-		kt = "ECDSA"
+		kt = keyTypeECDSA
 	default:
 		die.With("unknown private key type %T", privInterface)
 	}
@@ -116,9 +121,9 @@ func parseCertificate(data []byte) ([]byte, string) {
 	var kt string
 	switch pub.(type) {
 	case *rsa.PublicKey:
-		kt = "RSA"
+		kt = keyTypeRSA
 	case *ecdsa.PublicKey:
-		kt = "ECDSA"
+		kt = keyTypeECDSA
 	default:
 		die.With("unknown public key type %T", pub)
 	}
@@ -136,9 +141,9 @@ func parseCSR(data []byte) ([]byte, string) {
 	var kt string
 	switch pub.(type) {
 	case *rsa.PublicKey:
-		kt = "RSA"
+		kt = keyTypeRSA
 	case *ecdsa.PublicKey:
-		kt = "ECDSA"
+		kt = keyTypeECDSA
 	default:
 		die.With("unknown public key type %T", pub)
 	}
@@ -186,7 +191,7 @@ func main() {
 			continue
 		}
 
-		pubHash := sha1.Sum(subPKI.SubjectPublicKey.Bytes)
+		pubHash := sha1.Sum(subPKI.SubjectPublicKey.Bytes) // #nosec G401 this is the standard
 		pubHashString := dumpHex(pubHash[:])
 		if ski == "" {
 			ski = pubHashString

cmd/sprox/main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"flag"
 	"io"
 	"net"
@@ -10,7 +11,7 @@ import (
 )
 
 func proxy(conn net.Conn, inside string) error {
-	proxyConn, err := net.Dial("tcp", inside)
+	proxyConn, err := (&net.Dialer{}).DialContext(context.Background(), "tcp", inside)
 	if err != nil {
 		return err
 	}
@@ -31,18 +32,20 @@ func main() {
 	flag.StringVar(&inside, "p", "4000", "inside port")
 	flag.Parse()
 
-	l, err := net.Listen("tcp", "0.0.0.0:"+outside)
+	lc := &net.ListenConfig{}
+	l, err := lc.Listen(context.Background(), "tcp", "0.0.0.0:"+outside)
 	die.If(err)
 
 	for {
-		conn, err := l.Accept()
+		var conn net.Conn
+		conn, err = l.Accept()
 		if err != nil {
 			_, _ = lib.Warn(err, "accept failed")
 			continue
 		}
 
 		go func() {
-			if err := proxy(conn, "127.0.0.1:"+inside); err != nil {
+			if err = proxy(conn, "127.0.0.1:"+inside); err != nil {
 				_, _ = lib.Warn(err, "proxy error")
 			}
 		}()

cmd/stealchain-server/main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"crypto/rand"
 	"crypto/tls"
 	"crypto/x509"
@@ -15,7 +16,7 @@ import (
 )
 
 func main() {
-	cfg := &tls.Config{}
+	cfg := &tls.Config{} // #nosec G402
 
 	var sysRoot, listenAddr, certFile, keyFile string
 	var verify bool
@@ -46,7 +47,8 @@ func main() {
 	}
 	cfg.Certificates = append(cfg.Certificates, cert)
 	if sysRoot != "" {
-		pemList, err := os.ReadFile(sysRoot)
+		var pemList []byte
+		pemList, err = os.ReadFile(sysRoot)
 		die.If(err)
 
 		roots := x509.NewCertPool()
@@ -58,14 +60,16 @@ func main() {
 		cfg.RootCAs = roots
 	}
 
-	l, err := net.Listen("tcp", listenAddr)
+	lc := &net.ListenConfig{}
+	l, err := lc.Listen(context.Background(), "tcp", listenAddr)
 	if err != nil {
 		fmt.Println(err.Error())
 		os.Exit(1)
 	}
 
 	for {
-		conn, err := l.Accept()
+		var conn net.Conn
+		conn, err = l.Accept()
 		if err != nil {
 			fmt.Println(err.Error())
 			continue
@@ -79,7 +83,7 @@ func handleConn(conn net.Conn, cfg *tls.Config) {
 	defer conn.Close()
 	raddr := conn.RemoteAddr()
 	tconn := tls.Server(conn, cfg)
-	if err := tconn.Handshake(); err != nil {
+	if err := tconn.HandshakeContext(context.Background()); err != nil {
 		fmt.Printf("[+] %v: failed to complete handshake: %v\n", raddr, err)
 		return
 	}

cmd/stealchain/main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"crypto/tls"
 	"crypto/x509"
 	"encoding/pem"
@@ -13,7 +14,7 @@ import (
 )
 
 func main() {
-	var cfg = &tls.Config{}
+	var cfg = &tls.Config{} // #nosec G402
 
 	var sysRoot, serverName string
 	flag.StringVar(&sysRoot, "ca", "", "provide an alternate CA bundle")
@@ -43,10 +44,13 @@ func main() {
 		if err != nil {
 			site += ":443"
 		}
-		conn, err := tls.Dial("tcp", site, cfg)
-		if err != nil {
-			fmt.Println(err.Error())
-			os.Exit(1)
+		d := &tls.Dialer{Config: cfg}
+		nc, err := d.DialContext(context.Background(), "tcp", site)
+		die.If(err)
+
+		conn, ok := nc.(*tls.Conn)
+		if !ok {
+			die.With("invalid TLS connection (not a *tls.Conn)")
 		}
 
 		cs := conn.ConnectionState()
@@ -62,6 +66,7 @@ func main() {
 
 		err = os.WriteFile(site+".pem", chain, 0644)
 		die.If(err)
+
 		fmt.Printf("[+] wrote %s.pem.\n", site)
 	}
 }

cmd/tlsinfo/main.go

@@ -1,10 +1,14 @@
 package main
 
 import (
+	"context"
 	"crypto/tls"
 	"crypto/x509"
 	"fmt"
 	"os"
+
+	"git.wntrmute.dev/kyle/goutils/certlib/hosts"
+	"git.wntrmute.dev/kyle/goutils/die"
 )
 
 func main() {
@@ -13,16 +17,23 @@ func main() {
 		os.Exit(1)
 	}
 
-	hostPort := os.Args[1]
-	conn, err := tls.Dial("tcp", hostPort, &tls.Config{
-		InsecureSkipVerify: true,
-	})
+	hostPort, err := hosts.ParseHost(os.Args[1])
+	die.If(err)
 
-	if err != nil {
-		fmt.Printf("Failed to connect to the TLS server: %v\n", err)
-		os.Exit(1)
+	d := &tls.Dialer{Config: &tls.Config{
+		InsecureSkipVerify: true,
+	}} // #nosec G402
+
+	nc, err := d.DialContext(context.Background(), "tcp", hostPort.String())
+	die.If(err)
+
+	conn, ok := nc.(*tls.Conn)
+	if !ok {
+		die.With("invalid TLS connection (not a *tls.Conn)")
 	}
+
 	defer conn.Close()
+
 	state := conn.ConnectionState()
 	printConnectionDetails(state)
 }

cmd/utc/main.go

@@ -253,15 +253,16 @@ func main() {
 		showTime(time.Now())
 		os.Exit(0)
 	case 1:
-		if flag.Arg(0) == "-" {
+		switch {
+		case flag.Arg(0) == "-":
 			s := bufio.NewScanner(os.Stdin)
 
 			for s.Scan() {
 				times = append(times, s.Text())
 			}
-		} else if flag.Arg(0) == "help" {
+		case flag.Arg(0) == "help":
 			usageExamples()
-		} else {
+		default:
 			times = flag.Args()
 		}
 	default:

cmd/yamll/main.go

@@ -11,9 +11,8 @@ import (
 
 type empty struct{}
 
-func errorf(format string, args ...any) {
-	format += "\n"
-	fmt.Fprintf(os.Stderr, format, args...)
+func errorf(path string, err error) {
+	fmt.Fprintf(os.Stderr, "%s FAILED: %s\n", path, err)
 }
 
 func usage(w io.Writer) {
@@ -45,14 +44,14 @@ func main() {
 		path := "stdin"
 		in, err := io.ReadAll(os.Stdin)
 		if err != nil {
-			errorf("%s FAILED: %s", path, err)
+			errorf(path, err)
 			os.Exit(1)
 		}
 
 		var e empty
 		err = yaml.Unmarshal(in, &e)
 		if err != nil {
-			errorf("%s FAILED: %s", path, err)
+			errorf(path, err)
 			os.Exit(1)
 		}
 
@@ -66,14 +65,14 @@ func main() {
 	for _, path := range flag.Args() {
 		in, err := os.ReadFile(path)
 		if err != nil {
-			errorf("%s FAILED: %s", path, err)
+			errorf(path, err)
 			continue
 		}
 
 		var e empty
 		err = yaml.Unmarshal(in, &e)
 		if err != nil {
-			errorf("%s FAILED: %s", path, err)
+			errorf(path, err)
 			continue
 		}
 

cmd/zsearch/main.go

@@ -14,16 +14,16 @@ import (
 	"os"
 	"path/filepath"
 	"regexp"
+
+	"git.wntrmute.dev/kyle/goutils/lib"
 )
 
 const defaultDirectory = ".git/objects"
 
-func errorf(format string, a ...any) {
-	fmt.Fprintf(os.Stderr, format, a...)
-	if format[len(format)-1] != '\n' {
-		fmt.Fprintf(os.Stderr, "\n")
-	}
-}
+// maxDecompressedSize limits how many bytes we will decompress from a zlib
+// stream to mitigate decompression bombs (gosec G110).
+// Increase this if you expect larger objects.
+const maxDecompressedSize int64 = 64 << 30 // 64 GiB
 
 func isDir(path string) bool {
 	fi, err := os.Stat(path)
@@ -48,17 +48,21 @@ func loadFile(path string) ([]byte, error) {
 	}
 	defer zread.Close()
 
-	_, err = io.Copy(buf, zread)
-	if err != nil {
+	// Protect against decompression bombs by limiting how much we read.
+	lr := io.LimitReader(zread, maxDecompressedSize+1)
+	if _, err = buf.ReadFrom(lr); err != nil {
 		return nil, err
 	}
+	if int64(buf.Len()) > maxDecompressedSize {
+		return nil, fmt.Errorf("decompressed size exceeds limit (%d bytes)", maxDecompressedSize)
+	}
 	return buf.Bytes(), nil
 }
 
 func showFile(path string) {
 	fileData, err := loadFile(path)
 	if err != nil {
-		errorf("%v", err)
+		lib.Warn(err, "failed to load %s", path)
 		return
 	}
 
@@ -68,37 +72,69 @@ func showFile(path string) {
 func searchFile(path string, search *regexp.Regexp) error {
 	file, err := os.Open(path)
 	if err != nil {
-		errorf("%v", err)
+		lib.Warn(err, "failed to open %s", path)
 		return err
 	}
 	defer file.Close()
 
 	zread, err := zlib.NewReader(file)
 	if err != nil {
-		errorf("%v", err)
+		lib.Warn(err, "failed to decompress %s", path)
 		return err
 	}
 	defer zread.Close()
 
-	zbuf := bufio.NewReader(zread)
-	if search.MatchReader(zbuf) {
+	// Limit how much we scan to avoid DoS via huge decompression.
+	lr := io.LimitReader(zread, maxDecompressedSize+1)
+	zbuf := bufio.NewReader(lr)
+	if !search.MatchReader(zbuf) {
+		return nil
+	}
+
 	fileData, err := loadFile(path)
 	if err != nil {
-			errorf("%v", err)
+		lib.Warn(err, "failed to load %s", path)
 		return err
 	}
 	fmt.Printf("%s:\n%s\n", path, fileData)
-	}
 	return nil
 }
 
 func buildWalker(searchExpr *regexp.Regexp) filepath.WalkFunc {
 	return func(path string, info os.FileInfo, _ error) error {
-		if info.Mode().IsRegular() {
-			return searchFile(path, searchExpr)
-		}
+		if !info.Mode().IsRegular() {
 			return nil
 		}
+		return searchFile(path, searchExpr)
+	}
+}
+
+// runSearch compiles the search expression and processes the provided paths.
+// It returns an error for fatal conditions; per-file errors are logged.
+func runSearch(expr string) error {
+	search, err := regexp.Compile(expr)
+	if err != nil {
+		return fmt.Errorf("invalid regexp: %w", err)
+	}
+
+	pathList := flag.Args()
+	if len(pathList) == 0 {
+		pathList = []string{defaultDirectory}
+	}
+
+	for _, path := range pathList {
+		if isDir(path) {
+			if err2 := filepath.Walk(path, buildWalker(search)); err2 != nil {
+				return err2
+			}
+			continue
+		}
+		if err2 := searchFile(path, search); err2 != nil {
+			// Non-fatal: keep going, but report it.
+			lib.Warn(err2, "non-fatal error while searching files")
+		}
+	}
+	return nil
 }
 
 func main() {
@@ -109,29 +145,10 @@ func main() {
 		for _, path := range flag.Args() {
 			showFile(path)
 		}
-	} else {
-		search, err := regexp.Compile(*flSearch)
-		if err != nil {
-			errorf("Bad regexp: %v", err)
 		return
 	}
 
-		pathList := flag.Args()
-		if len(pathList) == 0 {
-			pathList = []string{defaultDirectory}
-		}
-
-		for _, path := range pathList {
-			if isDir(path) {
-				if err := filepath.Walk(path, buildWalker(search)); err != nil {
-					errorf("%v", err)
-					return
-				}
-			} else {
-				if err := searchFile(path, search); err != nil {
-					errorf("%v", err)
-				}
-			}
-		}
+	if err := runSearch(*flSearch); err != nil {
+		lib.Err(lib.ExitFailure, err, "failed to run search")
 	}
 }