{"record":{"id":"1710b737154373c5","repo":"slackhq/nebula","slug":"error-computing-issuer-v","errorCode":null,"errorMessage":"error computing issuer: %v","messagePattern":"error computing issuer: (.+?)","errorType":"error_code","errorClass":null,"httpStatus":null,"severity":"error","filePath":"cert/sign.go","lineNumber":94,"sourceCode":"// You should only use SignWith if you do not have direct access to your private key.\nfunc (t *TBSCertificate) SignWith(signer Certificate, curve Curve, sp SignerLambda) (Certificate, error) {\n\tif curve != t.Curve {\n\t\treturn nil, fmt.Errorf(\"curve in cert and private key supplied don't match\")\n\t}\n\n\tif signer != nil {\n\t\tif t.IsCA {\n\t\t\treturn nil, fmt.Errorf(\"can not sign a CA certificate with another\")\n\t\t}\n\n\t\terr := checkCAConstraints(signer, t.NotBefore, t.NotAfter, t.Groups, t.Networks, t.UnsafeNetworks)\n\t\tif err != nil {\n\t\t\treturn nil, err\n\t\t}\n\n\t\tissuer, err := signer.Fingerprint()\n\t\tif err != nil {\n\t\t\treturn nil, fmt.Errorf(\"error computing issuer: %v\", err)\n\t\t}\n\t\tt.issuer = issuer\n\t} else {\n\t\tif !t.IsCA {\n\t\t\treturn nil, fmt.Errorf(\"self signed certificates must have IsCA set to true\")\n\t\t}\n\t}\n\n\tvar c beingSignedCertificate\n\tswitch t.Version {\n\tcase Version1:\n\t\tc = &certificateV1{}\n\t\terr := c.fromTBSCertificate(t)\n\t\tif err != nil {\n\t\t\treturn nil, err\n\t\t}\n\tcase Version2:\n\t\tc = &certificateV2{}","sourceCodeStart":76,"sourceCodeEnd":112,"githubUrl":"https://github.com/slackhq/nebula/blob/dd8f660c0ac37903ec4080ca4d3c861ba9342ceb/cert/sign.go#L76-L112","documentation":"After signing, the issuer field is set to the signer certificate's SHA fingerprint via signer.Fingerprint(). If that fingerprint computation fails, SignWith wraps the underlying error with \"error computing issuer\". This indicates an internal failure while hashing the signer certificate's raw bytes.","triggerScenarios":"Calling SignWith/Sign with a valid signer whose Fingerprint() returns an error (e.g. corrupted or marshaled-empty signer certificate data).","commonSituations":"Passing a signer certificate that was improperly deserialized or truncated, memory/hash failures from a malformed certificate, or custom Certificate implementations whose Marshal returns inconsistent bytes.","solutions":["Inspect the wrapped %v error for the root cause (usually a sha256 or marshal failure).","Re-load or re-parse the signer certificate from a known-good PEM file.","Verify the signer came from cert.UnmarshalNebulaCertificate and parsed without error before signing."],"exampleFix":"// before\nsigner, _ := cert.UnmarshalNebulaCertificate(rawBytes) // error ignored\nroot, err := cert.Sign(signer, key, t)\n\n// after\nsigner, err := cert.UnmarshalNebulaCertificate(rawBytes)\nif err != nil {\n    return err\n}\nroot, err := cert.Sign(signer, key, t)","handlingStrategy":"try-catch","validationCode":"if _, err := signer.Fingerprint(); err != nil {\n    return fmt.Errorf(\"signer fingerprint invalid before signing: %w\", err)\n}","typeGuard":null,"tryCatchPattern":"root, err := cert.Sign(signer, key, t)\nif err != nil {\n    var fe *fmt.Errorf\n    if errors.As(err, &fe) && strings.Contains(err.Error(), \"error computing issuer\") {\n        // re-load or re-parse the signer certificate\n    }\n    return err\n}","preventionTips":["Always check the error from UnmarshalNebulaCertificate before using a cert as a signer.","Load signers from trusted, verified PEM files.","Avoid hand-crafted Certificate implementations with inconsistent Marshal output."],"tags":["pki","certificate","fingerprint"],"backgroundTag":"certificate-fingerprint-computation-failed","analyzedSha":"dd8f660c0ac37903ec4080ca4d3c861ba9342ceb","analyzedAt":"2026-09-03T11:13:55.444Z","contentChangedAt":"2026-09-03T11:13:55.444Z","schemaVersion":2},"datasetVersion":"2026-09-10T17:17:09.494Z"}