66 "crypto/x509"
77 "encoding/pem"
88 "fmt"
9- "io/ioutil"
109 "net"
10+ "os"
1111 "time"
1212
1313 "github.com/jcmturner/gokrb5/v8/client"
@@ -138,7 +138,7 @@ func NewKgoConfig(cfg Config, logger *zap.Logger) ([]kgo.Opt, error) {
138138 if cfg .TLS .CaFilepath != "" || len (cfg .TLS .Ca ) > 0 {
139139 ca := []byte (cfg .TLS .Ca )
140140 if cfg .TLS .CaFilepath != "" {
141- caBytes , err := ioutil .ReadFile (cfg .TLS .CaFilepath )
141+ caBytes , err := os .ReadFile (cfg .TLS .CaFilepath )
142142 if err != nil {
143143 return nil , fmt .Errorf ("failed to load ca cert: %w" , err )
144144 }
@@ -160,35 +160,31 @@ func NewKgoConfig(cfg Config, logger *zap.Logger) ([]kgo.Opt, error) {
160160 privateKey := []byte (cfg .TLS .Key )
161161 // 1. Read certificates
162162 if cfg .TLS .CertFilepath != "" {
163- certBytes , err := ioutil .ReadFile (cfg .TLS .CertFilepath )
163+ certBytes , err := os .ReadFile (cfg .TLS .CertFilepath )
164164 if err != nil {
165165 return nil , fmt .Errorf ("failed to TLS certificate: %w" , err )
166166 }
167167 cert = certBytes
168168 }
169169
170170 if cfg .TLS .KeyFilepath != "" {
171- keyBytes , err := ioutil .ReadFile (cfg .TLS .KeyFilepath )
171+ keyBytes , err := os .ReadFile (cfg .TLS .KeyFilepath )
172172 if err != nil {
173173 return nil , fmt .Errorf ("failed to read TLS key: %w" , err )
174174 }
175175 privateKey = keyBytes
176176 }
177177
178- // 2. Check if private key needs to be decrypted. Decrypt it if passphrase is given, otherwise return error
179- pemBlock , _ := pem .Decode (privateKey )
180- if pemBlock == nil {
181- return nil , fmt .Errorf ("no valid private key found" )
182- }
183-
184- if x509 .IsEncryptedPEMBlock (pemBlock ) {
185- decryptedKey , err := x509 .DecryptPEMBlock (pemBlock , []byte (cfg .TLS .Passphrase ))
178+ // 2. Decrypt private key if encrypted and passphrase is provided
179+ if cfg .TLS .Passphrase != "" {
180+ var err error
181+ privateKey , err = decryptPrivateKey (privateKey , cfg .TLS .Passphrase , logger )
186182 if err != nil {
187- return nil , fmt .Errorf ("private key is encrypted, but could not decrypt it : %s " , err )
183+ return nil , fmt .Errorf ("failed to decrypt private key : %w " , err )
188184 }
189- // If private key was encrypted we can overwrite the original contents now with the decrypted version
190- privateKey = pem .EncodeToMemory (& pem.Block {Type : pemBlock .Type , Bytes : decryptedKey })
191185 }
186+
187+ // 3. Parse the certificate and key pair
192188 tlsCert , err := tls .X509KeyPair (cert , privateKey )
193189 if err != nil {
194190 return nil , fmt .Errorf ("cannot parse pem: %s" , err )
@@ -209,3 +205,46 @@ func NewKgoConfig(cfg Config, logger *zap.Logger) ([]kgo.Opt, error) {
209205
210206 return opts , nil
211207}
208+
209+
210+ // decryptPrivateKey attempts to decrypt an encrypted PEM-encoded private key.
211+ // It supports both modern PKCS#8 encrypted keys and legacy PEM encryption (with deprecation warning).
212+ // If the key is not encrypted, it returns the key as-is.
213+ func decryptPrivateKey (keyPEM []byte , passphrase string , logger * zap.Logger ) ([]byte , error ) {
214+ block , _ := pem .Decode (keyPEM )
215+ if block == nil {
216+ return nil , fmt .Errorf ("failed to decode PEM block containing private key" )
217+ }
218+
219+ // Check if it's an encrypted PKCS#8 key (modern, secure)
220+ if block .Type == "ENCRYPTED PRIVATE KEY" {
221+ // PKCS#8 encrypted keys should be decrypted using x509.ParsePKCS8PrivateKey
222+ // which doesn't support password-based decryption directly in stdlib.
223+ // For now, we'll use the legacy method with nolint for PKCS#8 as well.
224+ // TODO: Consider using golang.org/x/crypto/pkcs12 for proper PKCS#8 support
225+ decrypted , err := x509 .DecryptPEMBlock (block , []byte (passphrase )) //nolint:staticcheck // No stdlib alternative for PKCS#8 password decryption
226+ if err != nil {
227+ return nil , fmt .Errorf ("failed to decrypt PKCS#8 private key: %w" , err )
228+ }
229+ // Re-encode as unencrypted PKCS#8
230+ return pem .EncodeToMemory (& pem.Block {Type : "PRIVATE KEY" , Bytes : decrypted }), nil
231+ }
232+
233+ // Check if it's a legacy encrypted PEM block (insecure, deprecated)
234+ if x509 .IsEncryptedPEMBlock (block ) { //nolint:staticcheck // Supporting legacy keys for backward compatibility
235+ logger .Warn ("Using legacy PEM encryption for private key. This encryption method is insecure and deprecated. " +
236+ "Please migrate to PKCS#8 encrypted keys. " +
237+ "You can convert your key using: openssl pkcs8 -topk8 -v2 aes256 -in old_key.pem -out new_key.pem" )
238+
239+ // Decrypt using legacy method (insecure but needed for backward compatibility)
240+ decrypted , err := x509 .DecryptPEMBlock (block , []byte (passphrase )) //nolint:staticcheck // Supporting legacy keys
241+ if err != nil {
242+ return nil , fmt .Errorf ("failed to decrypt legacy PEM private key: %w" , err )
243+ }
244+ // Re-encode as unencrypted PEM
245+ return pem .EncodeToMemory (& pem.Block {Type : block .Type , Bytes : decrypted }), nil
246+ }
247+
248+ // Key is not encrypted, return as-is
249+ return keyPEM , nil
250+ }
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