90 lines
1.8 KiB
Go
90 lines
1.8 KiB
Go
package acme
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import (
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"bytes"
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"crypto/ecdsa"
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"crypto/rsa"
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"fmt"
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"net/http"
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"github.com/letsencrypt/go-jose"
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)
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type jws struct {
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privKey *rsa.PrivateKey
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nonces []string
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}
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func keyAsJWK(key *ecdsa.PublicKey) jose.JsonWebKey {
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return jose.JsonWebKey{
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Key: key,
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Algorithm: "EC",
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}
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}
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// Posts a JWS signed message to the specified URL
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func (j *jws) post(url string, content []byte) (*http.Response, error) {
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if len(j.nonces) == 0 {
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err := j.getNonce(url)
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if err != nil {
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return nil, fmt.Errorf("Could not get a nonce for request: %s\n\t\tError: %v", url, err)
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}
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}
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signedContent, err := j.signContent(content)
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if err != nil {
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return nil, err
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}
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resp, err := http.Post(url, "application/jose+json", bytes.NewBuffer([]byte(signedContent.FullSerialize())))
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if err != nil {
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return nil, err
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}
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j.getNonceFromResponse(resp)
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return resp, err
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}
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func (j *jws) signContent(content []byte) (*jose.JsonWebSignature, error) {
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// TODO: support other algorithms - RS512
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signer, err := jose.NewSigner(jose.RS256, j.privKey)
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if err != nil {
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return nil, err
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}
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signed, err := signer.Sign(content, j.consumeNonce())
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if err != nil {
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return nil, err
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}
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return signed, nil
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}
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func (j *jws) getNonceFromResponse(resp *http.Response) error {
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nonce := resp.Header.Get("Replay-Nonce")
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if nonce == "" {
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return fmt.Errorf("Server did not respond with a proper nonce header.")
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}
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j.nonces = append(j.nonces, nonce)
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return nil
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}
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func (j *jws) getNonce(url string) error {
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resp, err := http.Head(url)
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if err != nil {
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return err
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}
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return j.getNonceFromResponse(resp)
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}
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func (j *jws) consumeNonce() string {
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nonce := ""
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if len(j.nonces) == 0 {
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return nonce
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}
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nonce, j.nonces = j.nonces[len(j.nonces)-1], j.nonces[:len(j.nonces)-1]
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return nonce
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}
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