81 lines
2.3 KiB
Go
81 lines
2.3 KiB
Go
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package auth
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import (
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"bytes"
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"encoding/json"
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"fmt"
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"os/exec"
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"path/filepath"
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"github.com/hashicorp/terraform/svchost"
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)
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type helperProgramCredentialsSource struct {
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executable string
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args []string
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}
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// HelperProgramCredentialsSource returns a CredentialsSource that runs the
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// given program with the given arguments in order to obtain credentials.
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//
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// The given executable path must be an absolute path; it is the caller's
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// responsibility to validate and process a relative path or other input
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// provided by an end-user. If the given path is not absolute, this
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// function will panic.
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//
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// When credentials are requested, the program will be run in a child process
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// with the given arguments along with two additional arguments added to the
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// end of the list: the literal string "get", followed by the requested
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// hostname in ASCII compatibility form (punycode form).
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func HelperProgramCredentialsSource(executable string, args ...string) CredentialsSource {
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if !filepath.IsAbs(executable) {
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panic("NewCredentialsSourceHelperProgram requires absolute path to executable")
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}
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fullArgs := make([]string, len(args)+1)
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fullArgs[0] = executable
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copy(fullArgs[1:], args)
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return &helperProgramCredentialsSource{
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executable: executable,
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args: fullArgs,
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}
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}
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func (s *helperProgramCredentialsSource) ForHost(host svchost.Hostname) (HostCredentials, error) {
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args := make([]string, len(s.args), len(s.args)+2)
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copy(args, s.args)
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args = append(args, "get")
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args = append(args, string(host))
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outBuf := bytes.Buffer{}
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errBuf := bytes.Buffer{}
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cmd := exec.Cmd{
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Path: s.executable,
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Args: args,
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Stdin: nil,
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Stdout: &outBuf,
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Stderr: &errBuf,
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}
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err := cmd.Run()
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if _, isExitErr := err.(*exec.ExitError); isExitErr {
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errText := errBuf.String()
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if errText == "" {
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// Shouldn't happen for a well-behaved helper program
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return nil, fmt.Errorf("error in %s, but it produced no error message", s.executable)
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}
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return nil, fmt.Errorf("error in %s: %s", s.executable, errText)
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} else if err != nil {
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return nil, fmt.Errorf("failed to run %s: %s", s.executable, err)
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}
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var m map[string]interface{}
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err = json.Unmarshal(outBuf.Bytes(), &m)
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if err != nil {
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return nil, fmt.Errorf("malformed output from %s: %s", s.executable, err)
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}
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return HostCredentialsFromMap(m), nil
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}
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