lego/providers/dns/azuredns/oidc.go
2024-02-08 03:16:48 +01:00

105 lines
2.9 KiB
Go

package azuredns
import (
"context"
"encoding/json"
"errors"
"fmt"
"io"
"net/http"
"net/url"
"os"
"strings"
)
func checkOIDCConfig(config *Config) error {
if config.TenantID == "" {
return errors.New("azuredns: TenantID is missing")
}
if config.ClientID == "" {
return errors.New("azuredns: ClientID is missing")
}
if config.OIDCToken == "" && config.OIDCTokenFilePath == "" && (config.OIDCRequestURL == "" || config.OIDCRequestToken == "") {
return errors.New("azuredns: OIDCToken, OIDCTokenFilePath or OIDCRequestURL and OIDCRequestToken must be set")
}
return nil
}
func getOIDCAssertion(config *Config) func(ctx context.Context) (string, error) {
return func(ctx context.Context) (string, error) {
var token string
if config.OIDCToken != "" {
token = strings.TrimSpace(config.OIDCToken)
}
if config.OIDCTokenFilePath != "" {
fileTokenRaw, err := os.ReadFile(config.OIDCTokenFilePath)
if err != nil {
return "", fmt.Errorf("azuredns: error retrieving token file with path %s: %w", config.OIDCTokenFilePath, err)
}
fileToken := strings.TrimSpace(string(fileTokenRaw))
if config.OIDCToken != fileToken {
return "", fmt.Errorf("azuredns: token file with path %s does not match token from environment variable", config.OIDCTokenFilePath)
}
token = fileToken
}
if token == "" && config.OIDCRequestURL != "" && config.OIDCRequestToken != "" {
return getOIDCToken(config)
}
return token, nil
}
}
func getOIDCToken(config *Config) (string, error) {
req, err := http.NewRequest(http.MethodGet, config.OIDCRequestURL, http.NoBody)
if err != nil {
return "", fmt.Errorf("azuredns: failed to build OIDC request: %w", err)
}
query, err := url.ParseQuery(req.URL.RawQuery)
if err != nil {
return "", errors.New("azuredns: cannot parse OIDC request URL query")
}
if query.Get("audience") == "" {
query.Set("audience", "api://AzureADTokenExchange")
req.URL.RawQuery = query.Encode()
}
req.Header.Set("Accept", "application/json")
req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", config.OIDCRequestToken))
req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
resp, err := config.HTTPClient.Do(req)
if err != nil {
return "", fmt.Errorf("azuredns: cannot request OIDC token: %w", err)
}
defer func() { _ = resp.Body.Close() }()
body, err := io.ReadAll(io.LimitReader(resp.Body, 1<<20))
if err != nil {
return "", fmt.Errorf("azuredns: cannot parse OIDC token response: %w", err)
}
if resp.StatusCode < http.StatusOK || resp.StatusCode >= http.StatusNoContent {
return "", fmt.Errorf("azuredns: OIDC token request received HTTP status %d with response: %s", resp.StatusCode, body)
}
var returnedToken struct {
Count int `json:"count"`
Value string `json:"value"`
}
if err := json.Unmarshal(body, &returnedToken); err != nil {
return "", fmt.Errorf("azuredns: cannot unmarshal OIDC token response: %w", err)
}
return returnedToken.Value, nil
}