54 lines
1.5 KiB
Go
54 lines
1.5 KiB
Go
package auditrelay
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import (
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"bytes"
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"encoding/base64"
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"encoding/json"
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"errors"
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"io"
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"os"
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"regexp"
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)
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var keyIDPattern = regexp.MustCompile(`^[A-Za-z0-9][A-Za-z0-9._-]{0,63}$`)
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type keyFile struct {
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Version int `json:"version"`
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Keys []struct {
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KeyID string `json:"key_id"`
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Secret string `json:"secret_base64url"`
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} `json:"keys"`
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}
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func LoadKey(path, keyID string) ([]byte, error) {
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raw, err := os.ReadFile(path)
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if err != nil {
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return nil, errors.New("read audit relay key file")
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}
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var document keyFile
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decoder := json.NewDecoder(bytes.NewReader(raw))
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decoder.DisallowUnknownFields()
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if err := decoder.Decode(&document); err != nil || document.Version != 1 || len(document.Keys) == 0 {
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return nil, errors.New("invalid audit relay key file")
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}
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var trailing any
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if err := decoder.Decode(&trailing); !errors.Is(err, io.EOF) {
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return nil, errors.New("invalid audit relay key file")
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}
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values := make(map[string][]byte, len(document.Keys))
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for _, candidate := range document.Keys {
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secret, err := base64.RawURLEncoding.DecodeString(candidate.Secret)
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if err != nil || !keyIDPattern.MatchString(candidate.KeyID) || len(secret) < 32 {
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return nil, errors.New("invalid audit relay secret")
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}
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if _, duplicate := values[candidate.KeyID]; duplicate {
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return nil, errors.New("duplicate audit relay key ID")
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}
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values[candidate.KeyID] = secret
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}
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if secret, exists := values[keyID]; exists {
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return secret, nil
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}
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return nil, errors.New("audit relay key ID not found")
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}
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