feat: support self-signed certificates for remote taskfiles (#2537)

CHANGELOG.md

@@ -8,6 +8,9 @@
 - Included Taskfiles with `silent: true` now properly propagate silence to their
   tasks, while still allowing individual tasks to override with `silent: false`
   (#2640, #1319 by @trulede).
+- Added TLS certificate options for Remote Taskfiles: use `--cacert` for
+  self-signed certificates and `--cert`/`--cert-key` for mTLS authentication
+  (#2537, #2242 by @vmaerten).
 
 ## v3.47.0 - 2026-01-24
 

completion/bash/task.bash

@@ -26,6 +26,10 @@ function _task()
       _filedir -d
       return $?
     ;;
+    --cacert|--cert|--cert-key)
+      _filedir
+      return $?
+    ;;
     -t|--taskfile)
       _filedir yaml || return $?
       _filedir yml

completion/fish/task.fish

@@ -111,6 +111,9 @@ complete -c $GO_TASK_PROGNAME -n "__task_is_experiment_enabled REMOTE_TASKFILES"
 complete -c $GO_TASK_PROGNAME -n "__task_is_experiment_enabled REMOTE_TASKFILES" -l timeout          -d 'timeout for remote Taskfile downloads'
 complete -c $GO_TASK_PROGNAME -n "__task_is_experiment_enabled REMOTE_TASKFILES" -l expiry           -d 'cache expiry duration'
 complete -c $GO_TASK_PROGNAME -n "__task_is_experiment_enabled REMOTE_TASKFILES" -l remote-cache-dir -d 'directory to cache remote Taskfiles' -xa "(__fish_complete_directories)"
+complete -c $GO_TASK_PROGNAME -n "__task_is_experiment_enabled REMOTE_TASKFILES" -l cacert           -d 'custom CA certificate for TLS' -r
+complete -c $GO_TASK_PROGNAME -n "__task_is_experiment_enabled REMOTE_TASKFILES" -l cert             -d 'client certificate for mTLS' -r
+complete -c $GO_TASK_PROGNAME -n "__task_is_experiment_enabled REMOTE_TASKFILES" -l cert-key         -d 'client certificate private key' -r
 
 # RemoteTaskfiles experiment - Operations
 complete -c $GO_TASK_PROGNAME -n "__task_is_experiment_enabled REMOTE_TASKFILES" -l download    -d 'download remote Taskfile'

completion/ps/task.ps1

@@ -77,6 +77,9 @@ Register-ArgumentCompleter -CommandName task -ScriptBlock {
 			$completions += [CompletionResult]::new('--timeout', '--timeout', [CompletionResultType]::ParameterName, 'download timeout')
 			$completions += [CompletionResult]::new('--expiry', '--expiry', [CompletionResultType]::ParameterName, 'cache expiry')
 			$completions += [CompletionResult]::new('--remote-cache-dir', '--remote-cache-dir', [CompletionResultType]::ParameterName, 'cache directory')
+			$completions += [CompletionResult]::new('--cacert', '--cacert', [CompletionResultType]::ParameterName, 'custom CA certificate')
+			$completions += [CompletionResult]::new('--cert', '--cert', [CompletionResultType]::ParameterName, 'client certificate')
+			$completions += [CompletionResult]::new('--cert-key', '--cert-key', [CompletionResultType]::ParameterName, 'client private key')
 			# Operations
 			$completions += [CompletionResult]::new('--download', '--download', [CompletionResultType]::ParameterName, 'download remote Taskfile')
 			$completions += [CompletionResult]::new('--clear-cache', '--clear-cache', [CompletionResultType]::ParameterName, 'clear cache')

completion/zsh/_task

@@ -117,6 +117,9 @@ _task() {
             '(--timeout)--timeout[timeout for remote Taskfile downloads]:duration: '
             '(--expiry)--expiry[cache expiry duration]:duration: '
             '(--remote-cache-dir)--remote-cache-dir[directory to cache remote Taskfiles]:cache dir:_dirs'
+            '(--cacert)--cacert[custom CA certificate for TLS]:file:_files'
+            '(--cert)--cert[client certificate for mTLS]:file:_files'
+            '(--cert-key)--cert-key[client certificate private key]:file:_files'
         )
     fi
 

executor.go

@@ -38,6 +38,9 @@ type (
 		Timeout             time.Duration
 		CacheExpiryDuration time.Duration
 		RemoteCacheDir      string
+		CACert              string
+		Cert                string
+		CertKey             string
 		Watch               bool
 		Verbose             bool
 		Silent              bool
@@ -287,6 +290,45 @@ func (o *remoteCacheDirOption) ApplyToExecutor(e *Executor) {
 	e.RemoteCacheDir = o.dir
 }
 
+// WithCACert sets the path to a custom CA certificate for TLS connections.
+func WithCACert(caCert string) ExecutorOption {
+	return &caCertOption{caCert: caCert}
+}
+
+type caCertOption struct {
+	caCert string
+}
+
+func (o *caCertOption) ApplyToExecutor(e *Executor) {
+	e.CACert = o.caCert
+}
+
+// WithCert sets the path to a client certificate for TLS connections.
+func WithCert(cert string) ExecutorOption {
+	return &certOption{cert: cert}
+}
+
+type certOption struct {
+	cert string
+}
+
+func (o *certOption) ApplyToExecutor(e *Executor) {
+	e.Cert = o.cert
+}
+
+// WithCertKey sets the path to a client certificate key for TLS connections.
+func WithCertKey(certKey string) ExecutorOption {
+	return &certKeyOption{certKey: certKey}
+}
+
+type certKeyOption struct {
+	certKey string
+}
+
+func (o *certKeyOption) ApplyToExecutor(e *Executor) {
+	e.CertKey = o.certKey
+}
+
 // WithWatch tells the [Executor] to keep running in the background and watch
 // for changes to the fingerprint of the tasks that are run. When changes are
 // detected, a new task run is triggered.

internal/flags/flags.go

@@ -83,6 +83,9 @@ var (
 	Timeout             time.Duration
 	CacheExpiryDuration time.Duration
 	RemoteCacheDir      string
+	CACert              string
+	Cert                string
+	CertKey             string
 	Interactive         bool
 )
 
@@ -168,6 +171,9 @@ func init() {
 		pflag.BoolVar(&ClearCache, "clear-cache", false, "Clear the remote cache.")
 		pflag.DurationVar(&CacheExpiryDuration, "expiry", getConfig(config, func() *time.Duration { return config.Remote.CacheExpiry }, 0), "Expiry duration for cached remote Taskfiles.")
 		pflag.StringVar(&RemoteCacheDir, "remote-cache-dir", getConfig(config, func() *string { return config.Remote.CacheDir }, env.GetTaskEnv("REMOTE_DIR")), "Directory to cache remote Taskfiles.")
+		pflag.StringVar(&CACert, "cacert", getConfig(config, func() *string { return config.Remote.CACert }, ""), "Path to a custom CA certificate for HTTPS connections.")
+		pflag.StringVar(&Cert, "cert", getConfig(config, func() *string { return config.Remote.Cert }, ""), "Path to a client certificate for HTTPS connections.")
+		pflag.StringVar(&CertKey, "cert-key", getConfig(config, func() *string { return config.Remote.CertKey }, ""), "Path to a client certificate key for HTTPS connections.")
 	}
 	pflag.Parse()
 
@@ -236,6 +242,11 @@ func Validate() error {
 		return errors.New("task: --nested only applies to --json with --list or --list-all")
 	}
 
+	// Validate certificate flags
+	if (Cert != "" && CertKey == "") || (Cert == "" && CertKey != "") {
+		return errors.New("task: --cert and --cert-key must be provided together")
+	}
+
 	return nil
 }
 
@@ -278,6 +289,9 @@ func (o *flagsOption) ApplyToExecutor(e *task.Executor) {
 		task.WithTimeout(Timeout),
 		task.WithCacheExpiryDuration(CacheExpiryDuration),
 		task.WithRemoteCacheDir(RemoteCacheDir),
+		task.WithCACert(CACert),
+		task.WithCert(Cert),
+		task.WithCertKey(CertKey),
 		task.WithWatch(Watch),
 		task.WithVerbose(Verbose),
 		task.WithSilent(Silent),

setup.go

@@ -55,7 +55,11 @@ func (e *Executor) Setup() error {
 }
 
 func (e *Executor) getRootNode() (taskfile.Node, error) {
-	node, err := taskfile.NewRootNode(e.Entrypoint, e.Dir, e.Insecure, e.Timeout)
+	node, err := taskfile.NewRootNode(e.Entrypoint, e.Dir, e.Insecure, e.Timeout,
+		taskfile.WithCACert(e.CACert),
+		taskfile.WithCert(e.Cert),
+		taskfile.WithCertKey(e.CertKey),
+	)
 	if os.IsNotExist(err) {
 		return nil, errors.TaskfileNotFoundError{
 			URI:     fsext.DefaultDir(e.Entrypoint, e.Dir),
@@ -87,6 +91,9 @@ func (e *Executor) readTaskfile(node taskfile.Node) error {
 		taskfile.WithTrustedHosts(e.TrustedHosts),
 		taskfile.WithTempDir(e.TempDir.Remote),
 		taskfile.WithCacheExpiryDuration(e.CacheExpiryDuration),
+		taskfile.WithReaderCACert(e.CACert),
+		taskfile.WithReaderCert(e.Cert),
+		taskfile.WithReaderCertKey(e.CertKey),
 		taskfile.WithDebugFunc(debugFunc),
 		taskfile.WithPromptFunc(promptFunc),
 	)

taskfile/node.go

@@ -34,13 +34,14 @@ func NewRootNode(
 	dir string,
 	insecure bool,
 	timeout time.Duration,
+	opts ...NodeOption,
 ) (Node, error) {
 	dir = fsext.DefaultDir(entrypoint, dir)
 	// If the entrypoint is "-", we read from stdin
 	if entrypoint == "-" {
 		return NewStdinNode(dir)
 	}
-	return NewNode(entrypoint, dir, insecure)
+	return NewNode(entrypoint, dir, insecure, opts...)
 }
 
 func NewNode(

taskfile/node_base.go

@@ -10,6 +10,9 @@ type (
 		parent   Node
 		dir      string
 		checksum string
+		caCert   string
+		cert     string
+		certKey  string
 	}
 )
 
@@ -54,3 +57,21 @@ func (node *baseNode) Checksum() string {
 func (node *baseNode) Verify(checksum string) bool {
 	return node.checksum == "" || node.checksum == checksum
 }
+
+func WithCACert(caCert string) NodeOption {
+	return func(node *baseNode) {
+		node.caCert = caCert
+	}
+}
+
+func WithCert(cert string) NodeOption {
+	return func(node *baseNode) {
+		node.cert = cert
+	}
+}
+
+func WithCertKey(certKey string) NodeOption {
+	return func(node *baseNode) {
+		node.certKey = certKey
+	}
+}

taskfile/node_http.go

@@ -2,10 +2,13 @@ package taskfile
 
 import (
 	"context"
+	"crypto/tls"
+	"crypto/x509"
 	"fmt"
 	"io"
 	"net/http"
 	"net/url"
+	"os"
 	"path/filepath"
 	"strings"
 
@@ -17,7 +20,54 @@ import (
 // An HTTPNode is a node that reads a Taskfile from a remote location via HTTP.
 type HTTPNode struct {
 	*baseNode
-	url *url.URL // stores url pointing actual remote file. (e.g. with Taskfile.yml)
+	url    *url.URL     // stores url pointing actual remote file. (e.g. with Taskfile.yml)
+	client *http.Client // HTTP client with optional TLS configuration
+}
+
+// buildHTTPClient creates an HTTP client with optional TLS configuration.
+// If no certificate options are provided, it returns http.DefaultClient.
+func buildHTTPClient(insecure bool, caCert, cert, certKey string) (*http.Client, error) {
+	// Validate that cert and certKey are provided together
+	if (cert != "" && certKey == "") || (cert == "" && certKey != "") {
+		return nil, fmt.Errorf("both --cert and --cert-key must be provided together")
+	}
+
+	// If no TLS customization is needed, return the default client
+	if !insecure && caCert == "" && cert == "" {
+		return http.DefaultClient, nil
+	}
+
+	tlsConfig := &tls.Config{
+		InsecureSkipVerify: insecure,
+	}
+
+	// Load custom CA certificate if provided
+	if caCert != "" {
+		caCertData, err := os.ReadFile(caCert)
+		if err != nil {
+			return nil, fmt.Errorf("failed to read CA certificate: %w", err)
+		}
+		caCertPool := x509.NewCertPool()
+		if !caCertPool.AppendCertsFromPEM(caCertData) {
+			return nil, fmt.Errorf("failed to parse CA certificate")
+		}
+		tlsConfig.RootCAs = caCertPool
+	}
+
+	// Load client certificate and key if provided
+	if cert != "" && certKey != "" {
+		clientCert, err := tls.LoadX509KeyPair(cert, certKey)
+		if err != nil {
+			return nil, fmt.Errorf("failed to load client certificate: %w", err)
+		}
+		tlsConfig.Certificates = []tls.Certificate{clientCert}
+	}
+
+	return &http.Client{
+		Transport: &http.Transport{
+			TLSClientConfig: tlsConfig,
+		},
+	}, nil
 }
 
 func NewHTTPNode(
@@ -34,9 +84,16 @@ func NewHTTPNode(
 	if url.Scheme == "http" && !insecure {
 		return nil, &errors.TaskfileNotSecureError{URI: url.Redacted()}
 	}
+
+	client, err := buildHTTPClient(insecure, base.caCert, base.cert, base.certKey)
+	if err != nil {
+		return nil, err
+	}
+
 	return &HTTPNode{
 		baseNode: base,
 		url:      url,
+		client:   client,
 	}, nil
 }
 
@@ -49,7 +106,7 @@ func (node *HTTPNode) Read() ([]byte, error) {
 }
 
 func (node *HTTPNode) ReadContext(ctx context.Context) ([]byte, error) {
-	url, err := RemoteExists(ctx, *node.url)
+	url, err := RemoteExists(ctx, *node.url, node.client)
 	if err != nil {
 		return nil, err
 	}
@@ -58,7 +115,7 @@ func (node *HTTPNode) ReadContext(ctx context.Context) ([]byte, error) {
 		return nil, errors.TaskfileFetchFailedError{URI: node.Location()}
 	}
 
-	resp, err := http.DefaultClient.Do(req.WithContext(ctx))
+	resp, err := node.client.Do(req.WithContext(ctx))
 	if err != nil {
 		if ctx.Err() != nil {
 			return nil, err

taskfile/node_http_test.go

@@ -1,7 +1,18 @@
 package taskfile
 
 import (
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rand"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/pem"
+	"math/big"
+	"net/http"
+	"os"
+	"path/filepath"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -47,3 +58,227 @@ func TestHTTPNode_CacheKey(t *testing.T) {
 		assert.Equal(t, tt.expectedKey, key)
 	}
 }
+
+func TestBuildHTTPClient_Default(t *testing.T) {
+	t.Parallel()
+
+	// When no TLS customization is needed, should return http.DefaultClient
+	client, err := buildHTTPClient(false, "", "", "")
+	require.NoError(t, err)
+	assert.Equal(t, http.DefaultClient, client)
+}
+
+func TestBuildHTTPClient_Insecure(t *testing.T) {
+	t.Parallel()
+
+	client, err := buildHTTPClient(true, "", "", "")
+	require.NoError(t, err)
+	require.NotNil(t, client)
+	assert.NotEqual(t, http.DefaultClient, client)
+
+	// Check that InsecureSkipVerify is set
+	transport, ok := client.Transport.(*http.Transport)
+	require.True(t, ok)
+	require.NotNil(t, transport.TLSClientConfig)
+	assert.True(t, transport.TLSClientConfig.InsecureSkipVerify)
+}
+
+func TestBuildHTTPClient_CACert(t *testing.T) {
+	t.Parallel()
+
+	// Create a temporary CA cert file
+	tempDir := t.TempDir()
+	caCertPath := filepath.Join(tempDir, "ca.crt")
+
+	// Generate a valid CA certificate
+	caCertPEM := generateTestCACert(t)
+	err := os.WriteFile(caCertPath, caCertPEM, 0o600)
+	require.NoError(t, err)
+
+	client, err := buildHTTPClient(false, caCertPath, "", "")
+	require.NoError(t, err)
+	require.NotNil(t, client)
+	assert.NotEqual(t, http.DefaultClient, client)
+
+	// Check that custom RootCAs is set
+	transport, ok := client.Transport.(*http.Transport)
+	require.True(t, ok)
+	require.NotNil(t, transport.TLSClientConfig)
+	assert.NotNil(t, transport.TLSClientConfig.RootCAs)
+}
+
+func TestBuildHTTPClient_CACertNotFound(t *testing.T) {
+	t.Parallel()
+
+	client, err := buildHTTPClient(false, "/nonexistent/ca.crt", "", "")
+	assert.Error(t, err)
+	assert.Nil(t, client)
+	assert.Contains(t, err.Error(), "failed to read CA certificate")
+}
+
+func TestBuildHTTPClient_CACertInvalid(t *testing.T) {
+	t.Parallel()
+
+	// Create a temporary file with invalid content
+	tempDir := t.TempDir()
+	caCertPath := filepath.Join(tempDir, "invalid.crt")
+	err := os.WriteFile(caCertPath, []byte("not a valid certificate"), 0o600)
+	require.NoError(t, err)
+
+	client, err := buildHTTPClient(false, caCertPath, "", "")
+	assert.Error(t, err)
+	assert.Nil(t, client)
+	assert.Contains(t, err.Error(), "failed to parse CA certificate")
+}
+
+func TestBuildHTTPClient_CertWithoutKey(t *testing.T) {
+	t.Parallel()
+
+	client, err := buildHTTPClient(false, "", "/path/to/cert.crt", "")
+	assert.Error(t, err)
+	assert.Nil(t, client)
+	assert.Contains(t, err.Error(), "both --cert and --cert-key must be provided together")
+}
+
+func TestBuildHTTPClient_KeyWithoutCert(t *testing.T) {
+	t.Parallel()
+
+	client, err := buildHTTPClient(false, "", "", "/path/to/key.pem")
+	assert.Error(t, err)
+	assert.Nil(t, client)
+	assert.Contains(t, err.Error(), "both --cert and --cert-key must be provided together")
+}
+
+func TestBuildHTTPClient_CertAndKey(t *testing.T) {
+	t.Parallel()
+
+	// Create temporary cert and key files
+	tempDir := t.TempDir()
+	certPath := filepath.Join(tempDir, "client.crt")
+	keyPath := filepath.Join(tempDir, "client.key")
+
+	// Generate a self-signed certificate and key for testing
+	cert, key := generateTestCertAndKey(t)
+	err := os.WriteFile(certPath, cert, 0o600)
+	require.NoError(t, err)
+	err = os.WriteFile(keyPath, key, 0o600)
+	require.NoError(t, err)
+
+	client, err := buildHTTPClient(false, "", certPath, keyPath)
+	require.NoError(t, err)
+	require.NotNil(t, client)
+	assert.NotEqual(t, http.DefaultClient, client)
+
+	// Check that client certificate is set
+	transport, ok := client.Transport.(*http.Transport)
+	require.True(t, ok)
+	require.NotNil(t, transport.TLSClientConfig)
+	assert.Len(t, transport.TLSClientConfig.Certificates, 1)
+}
+
+func TestBuildHTTPClient_CertNotFound(t *testing.T) {
+	t.Parallel()
+
+	client, err := buildHTTPClient(false, "", "/nonexistent/cert.crt", "/nonexistent/key.pem")
+	assert.Error(t, err)
+	assert.Nil(t, client)
+	assert.Contains(t, err.Error(), "failed to load client certificate")
+}
+
+func TestBuildHTTPClient_InsecureWithCACert(t *testing.T) {
+	t.Parallel()
+
+	// Create a temporary CA cert file
+	tempDir := t.TempDir()
+	caCertPath := filepath.Join(tempDir, "ca.crt")
+
+	// Generate a valid CA certificate
+	caCertPEM := generateTestCACert(t)
+	err := os.WriteFile(caCertPath, caCertPEM, 0o600)
+	require.NoError(t, err)
+
+	// Both insecure and CA cert can be set together
+	client, err := buildHTTPClient(true, caCertPath, "", "")
+	require.NoError(t, err)
+	require.NotNil(t, client)
+
+	transport, ok := client.Transport.(*http.Transport)
+	require.True(t, ok)
+	require.NotNil(t, transport.TLSClientConfig)
+	assert.True(t, transport.TLSClientConfig.InsecureSkipVerify)
+	assert.NotNil(t, transport.TLSClientConfig.RootCAs)
+}
+
+// generateTestCertAndKey generates a self-signed certificate and key for testing
+func generateTestCertAndKey(t *testing.T) (certPEM, keyPEM []byte) {
+	t.Helper()
+
+	// Generate a new ECDSA private key
+	privateKey, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	require.NoError(t, err)
+
+	// Create a certificate template
+	template := x509.Certificate{
+		SerialNumber: big.NewInt(1),
+		Subject: pkix.Name{
+			Organization: []string{"Task Org"},
+		},
+		NotBefore:             time.Now(),
+		NotAfter:              time.Now().Add(time.Hour),
+		KeyUsage:              x509.KeyUsageDigitalSignature,
+		ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth},
+		BasicConstraintsValid: true,
+	}
+
+	// Create the certificate
+	certDER, err := x509.CreateCertificate(rand.Reader, &template, &template, &privateKey.PublicKey, privateKey)
+	require.NoError(t, err)
+
+	// Encode certificate to PEM
+	certPEM = pem.EncodeToMemory(&pem.Block{
+		Type:  "CERTIFICATE",
+		Bytes: certDER,
+	})
+
+	// Encode private key to PEM
+	keyDER, err := x509.MarshalECPrivateKey(privateKey)
+	require.NoError(t, err)
+	keyPEM = pem.EncodeToMemory(&pem.Block{
+		Type:  "EC PRIVATE KEY",
+		Bytes: keyDER,
+	})
+
+	return certPEM, keyPEM
+}
+
+// generateTestCACert generates a self-signed CA certificate for testing
+func generateTestCACert(t *testing.T) []byte {
+	t.Helper()
+
+	// Generate a new ECDSA private key
+	privateKey, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	require.NoError(t, err)
+
+	// Create a CA certificate template
+	template := x509.Certificate{
+		SerialNumber: big.NewInt(1),
+		Subject: pkix.Name{
+			Organization: []string{"Test CA"},
+		},
+		NotBefore:             time.Now(),
+		NotAfter:              time.Now().Add(time.Hour),
+		KeyUsage:              x509.KeyUsageCertSign | x509.KeyUsageCRLSign,
+		IsCA:                  true,
+		BasicConstraintsValid: true,
+	}
+
+	// Create the certificate
+	certDER, err := x509.CreateCertificate(rand.Reader, &template, &template, &privateKey.PublicKey, privateKey)
+	require.NoError(t, err)
+
+	// Encode certificate to PEM
+	return pem.EncodeToMemory(&pem.Block{
+		Type:  "CERTIFICATE",
+		Bytes: certDER,
+	})
+}

taskfile/reader.go

@@ -47,6 +47,9 @@ type (
 		trustedHosts        []string
 		tempDir             string
 		cacheExpiryDuration time.Duration
+		caCert              string
+		cert                string
+		certKey             string
 		debugFunc           DebugFunc
 		promptFunc          PromptFunc
 		promptMutex         sync.Mutex
@@ -199,6 +202,45 @@ func (o *promptFuncOption) ApplyToReader(r *Reader) {
 	r.promptFunc = o.promptFunc
 }
 
+// WithReaderCACert sets the path to a custom CA certificate for TLS connections.
+func WithReaderCACert(caCert string) ReaderOption {
+	return &readerCACertOption{caCert: caCert}
+}
+
+type readerCACertOption struct {
+	caCert string
+}
+
+func (o *readerCACertOption) ApplyToReader(r *Reader) {
+	r.caCert = o.caCert
+}
+
+// WithReaderCert sets the path to a client certificate for TLS connections.
+func WithReaderCert(cert string) ReaderOption {
+	return &readerCertOption{cert: cert}
+}
+
+type readerCertOption struct {
+	cert string
+}
+
+func (o *readerCertOption) ApplyToReader(r *Reader) {
+	r.cert = o.cert
+}
+
+// WithReaderCertKey sets the path to a client certificate key for TLS connections.
+func WithReaderCertKey(certKey string) ReaderOption {
+	return &readerCertKeyOption{certKey: certKey}
+}
+
+type readerCertKeyOption struct {
+	certKey string
+}
+
+func (o *readerCertKeyOption) ApplyToReader(r *Reader) {
+	r.certKey = o.certKey
+}
+
 // Read will read the Taskfile defined by the [Reader]'s [Node] and recurse
 // through any [ast.Includes] it finds, reading each included Taskfile and
 // building an [ast.TaskfileGraph] as it goes. If any errors occur, they will be
@@ -314,6 +356,9 @@ func (r *Reader) include(ctx context.Context, node Node) error {
 			includeNode, err := NewNode(entrypoint, include.Dir, r.insecure,
 				WithParent(node),
 				WithChecksum(include.Checksum),
+				WithCACert(r.caCert),
+				WithCert(r.cert),
+				WithCertKey(r.certKey),
 			)
 			if err != nil {
 				if include.Optional {

taskfile/taskfile.go

@@ -38,7 +38,7 @@ var (
 // at the given URL with any of the default Taskfile files names. If any of
 // these match a file, the first matching path will be returned. If no files are
 // found, an error will be returned.
-func RemoteExists(ctx context.Context, u url.URL) (*url.URL, error) {
+func RemoteExists(ctx context.Context, u url.URL, client *http.Client) (*url.URL, error) {
 	// Create a new HEAD request for the given URL to check if the resource exists
 	req, err := http.NewRequestWithContext(ctx, "HEAD", u.String(), nil)
 	if err != nil {
@@ -46,7 +46,7 @@ func RemoteExists(ctx context.Context, u url.URL) (*url.URL, error) {
 	}
 
 	// Request the given URL
-	resp, err := http.DefaultClient.Do(req)
+	resp, err := client.Do(req)
 	if err != nil {
 		if ctx.Err() != nil {
 			return nil, fmt.Errorf("checking remote file: %w", ctx.Err())
@@ -78,7 +78,7 @@ func RemoteExists(ctx context.Context, u url.URL) (*url.URL, error) {
 		req.URL = alt
 
 		// Try the alternative URL
-		resp, err = http.DefaultClient.Do(req)
+		resp, err = client.Do(req)
 		if err != nil {
 			return nil, errors.TaskfileFetchFailedError{URI: u.Redacted()}
 		}

taskrc/ast/taskrc.go

@@ -28,6 +28,9 @@ type Remote struct {
 	CacheExpiry  *time.Duration `yaml:"cache-expiry"`
 	CacheDir     *string        `yaml:"cache-dir"`
 	TrustedHosts []string       `yaml:"trusted-hosts"`
+	CACert       *string        `yaml:"cacert"`
+	Cert         *string        `yaml:"cert"`
+	CertKey      *string        `yaml:"cert-key"`
 }
 
 // Merge combines the current TaskRC with another TaskRC, prioritizing non-nil fields from the other TaskRC.
@@ -55,6 +58,9 @@ func (t *TaskRC) Merge(other *TaskRC) {
 		slices.Sort(merged)
 		t.Remote.TrustedHosts = slices.Compact(merged)
 	}
+	t.Remote.CACert = cmp.Or(other.Remote.CACert, t.Remote.CACert)
+	t.Remote.Cert = cmp.Or(other.Remote.Cert, t.Remote.Cert)
+	t.Remote.CertKey = cmp.Or(other.Remote.CertKey, t.Remote.CertKey)
 
 	t.Verbose = cmp.Or(other.Verbose, t.Verbose)
 	t.Color = cmp.Or(other.Color, t.Color)

website/src/docs/experiments/remote-taskfiles.md

@@ -263,6 +263,38 @@ Taskfile that is downloaded via an unencrypted connection. Sources that are not
 protected by TLS are vulnerable to man-in-the-middle attacks and should be
 avoided unless you know what you are doing.
 
+#### Custom Certificates
+
+If your remote Taskfiles are hosted on a server that uses a custom CA
+certificate (e.g., a corporate internal server), you can specify the CA
+certificate using the `--cacert` flag:
+
+```shell
+task --taskfile https://internal.example.com/Taskfile.yml --cacert /path/to/ca.crt
+```
+
+For servers that require client certificate authentication (mTLS), you can
+provide a client certificate and key:
+
+```shell
+task --taskfile https://secure.example.com/Taskfile.yml \
+  --cert /path/to/client.crt \
+  --cert-key /path/to/client.key
+```
+
+::: warning
+
+Encrypted private keys are not currently supported. If your key is encrypted,
+you must decrypt it first:
+
+```shell
+openssl rsa -in encrypted.key -out decrypted.key
+```
+
+:::
+
+These options can also be configured in the [configuration file](#configuration).
+
 ## Caching & Running Offline
 
 Whenever you run a remote Taskfile, the latest copy will be downloaded from the
@@ -313,6 +345,9 @@ remote:
   trusted-hosts:
     - github.com
     - gitlab.com
+  cacert: ""
+  cert: ""
+  cert-key: ""
 ```
 
 #### `insecure`
@@ -410,3 +445,36 @@ task --trusted-hosts github.com,gitlab.com -t https://github.com/user/repo.git//
 # Trust a host with a specific port
 task --trusted-hosts example.com:8080 -t https://example.com:8080/Taskfile.yml
 ```
+
+#### `cacert`
+
+- **Type**: `string`
+- **Default**: `""`
+- **Description**: Path to a custom CA certificate file for TLS verification
+
+```yaml
+remote:
+  cacert: "/path/to/ca.crt"
+```
+
+#### `cert`
+
+- **Type**: `string`
+- **Default**: `""`
+- **Description**: Path to a client certificate file for mTLS authentication
+
+```yaml
+remote:
+  cert: "/path/to/client.crt"
+```
+
+#### `cert-key`
+
+- **Type**: `string`
+- **Default**: `""`
+- **Description**: Path to the client certificate private key file
+
+```yaml
+remote:
+  cert-key: "/path/to/client.key"
+```