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// Copyright 2021 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package asymkey
import (
"context"
"fmt"
"strings"
"code.gitea.io/gitea/models/db"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/process"
"code.gitea.io/gitea/modules/setting"
"code.gitea.io/gitea/modules/util"
"golang.org/x/crypto/ssh"
"xorm.io/builder"
)
// ___________.__ .__ __
// \_ _____/|__| ____ ____ ________________________|__| _____/ |_
// | __) | |/ \ / ___\_/ __ \_ __ \____ \_ __ \ |/ \ __\
// | \ | | | \/ /_/ > ___/| | \/ |_> > | \/ | | \ |
// \___ / |__|___| /\___ / \___ >__| | __/|__| |__|___| /__|
// \/ \//_____/ \/ |__| \/
//
// This file contains functions for fingerprinting SSH keys
//
// The database is used in checkKeyFingerprint however most of these functions probably belong in a module
// checkKeyFingerprint only checks if key fingerprint has been used as public key,
// it is OK to use same key as deploy key for multiple repositories/users.
func checkKeyFingerprint(ctx context.Context, fingerprint string) error {
has, err := db.Exist[PublicKey](ctx, builder.Eq{"fingerprint": fingerprint})
if err != nil {
return err
} else if has {
return ErrKeyAlreadyExist{0, fingerprint, ""}
}
return nil
}
func calcFingerprintSSHKeygen(publicKeyContent string) (string, error) {
// Calculate fingerprint.
tmpPath, err := writeTmpKeyFile(publicKeyContent)
if err != nil {
return "", err
}
defer func() {
if err := util.Remove(tmpPath); err != nil {
log.Warn("Unable to remove temporary key file: %s: Error: %v", tmpPath, err)
}
}()
stdout, stderr, err := process.GetManager().Exec("AddPublicKey", "ssh-keygen", "-lf", tmpPath)
if err != nil {
if strings.Contains(stderr, "is not a public key file") {
return "", ErrKeyUnableVerify{stderr}
}
return "", util.NewInvalidArgumentErrorf("'ssh-keygen -lf %s' failed with error '%s': %s", tmpPath, err, stderr)
} else if len(stdout) < 2 {
return "", util.NewInvalidArgumentErrorf("not enough output for calculating fingerprint: %s", stdout)
}
return strings.Split(stdout, " ")[1], nil
}
func calcFingerprintNative(publicKeyContent string) (string, error) {
// Calculate fingerprint.
pk, _, _, _, err := ssh.ParseAuthorizedKey([]byte(publicKeyContent))
if err != nil {
return "", err
}
return ssh.FingerprintSHA256(pk), nil
}
// CalcFingerprint calculate public key's fingerprint
func CalcFingerprint(publicKeyContent string) (string, error) {
// Call the method based on configuration
useNative := setting.SSH.KeygenPath == ""
calcFn := util.Iif(useNative, calcFingerprintNative, calcFingerprintSSHKeygen)
fp, err := calcFn(publicKeyContent)
if err != nil {
if IsErrKeyUnableVerify(err) {
return "", err
}
return "", fmt.Errorf("CalcFingerprint(%s): %w", util.Iif(useNative, "native", "ssh-keygen"), err)
}
return fp, nil
}
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