Merge pull request #2637 from Gibheer/ssh-publickeys
allow native and ssh-keygen public key check
This commit is contained in:
Unknwon
commit
83c74878df
4 changed files with 230 additions and 12 deletions
16
conf/app.ini
16
conf/app.ini
|
|
@ -71,6 +71,13 @@ SSH_PORT = 22
|
|||
SSH_LISTEN_PORT = %(SSH_PORT)s
|
||||
; Root path of SSH directory, default is '~/.ssh', but you have to use '/home/git/.ssh'.
|
||||
SSH_ROOT_PATH =
|
||||
; override engine choice to check public keys (default: 'ssh-keygen' when
|
||||
; DISABLE_SSH is set to false else 'native')
|
||||
SSH_PUBLICKEY_CHECK =
|
||||
; directory to create temporary files when using ssh-keygen (default: /tmp)
|
||||
SSH_WORK_PATH =
|
||||
; path to ssh-keygen (default: result of `which ssh-keygen`)
|
||||
SSH_KEYGEN_PATH =
|
||||
; Disable CDN even in "prod" mode
|
||||
OFFLINE_MODE = false
|
||||
DISABLE_ROUTER_LOG = false
|
||||
|
|
@ -132,6 +139,15 @@ ENABLE_REVERSE_PROXY_AUTHENTICATION = false
|
|||
ENABLE_REVERSE_PROXY_AUTO_REGISTRATION = false
|
||||
; Enable captcha validation for registration
|
||||
ENABLE_CAPTCHA = true
|
||||
; Do not check minimum key size with corresponding type
|
||||
ENABLE_MINIMUM_KEY_SIZE_CHECK = false
|
||||
|
||||
; define allowed algorithms and their minimum key length (use -1 to disable a type)
|
||||
[service.minimum_key_sizes]
|
||||
ED25519 = 256
|
||||
ECDSA = 256
|
||||
RSA = 2048
|
||||
DSA = 1024
|
||||
|
||||
[webhook]
|
||||
; Hook task queue length
|
||||
|
|
|
|||
|
|
@ -12,9 +12,11 @@ import (
|
|||
"fmt"
|
||||
"io"
|
||||
"io/ioutil"
|
||||
"math/big"
|
||||
"os"
|
||||
"path"
|
||||
"path/filepath"
|
||||
"strconv"
|
||||
"strings"
|
||||
"sync"
|
||||
"time"
|
||||
|
|
@ -33,7 +35,10 @@ const (
|
|||
_TPL_PUBLICK_KEY = `command="%s serv key-%d --config='%s'",no-port-forwarding,no-X11-forwarding,no-agent-forwarding,no-pty %s` + "\n"
|
||||
)
|
||||
|
||||
var sshOpLocker = sync.Mutex{}
|
||||
var (
|
||||
sshOpLocker = sync.Mutex{}
|
||||
SSHUnknownKeyType = fmt.Errorf("unknown key type")
|
||||
)
|
||||
|
||||
type KeyType int
|
||||
|
||||
|
|
@ -153,7 +158,110 @@ func parseKeyString(content string) (string, error) {
|
|||
return keyType + " " + keyContent + " " + keyComment, nil
|
||||
}
|
||||
|
||||
// extract key type and length using ssh-keygen
|
||||
func SSHKeyGenParsePublicKey(key string) (string, int, error) {
|
||||
// The ssh-keygen in Windows does not print key type, so no need go further.
|
||||
if setting.IsWindows {
|
||||
return "", 0, nil
|
||||
}
|
||||
|
||||
tmpFile, err := ioutil.TempFile(setting.SSHWorkPath, "gogs_keytest")
|
||||
if err != nil {
|
||||
return "", 0, err
|
||||
}
|
||||
tmpName := tmpFile.Name()
|
||||
defer os.Remove(tmpName)
|
||||
|
||||
if ln, err := tmpFile.WriteString(key); err != nil {
|
||||
tmpFile.Close()
|
||||
return "", 0, err
|
||||
} else if ln != len(key) {
|
||||
tmpFile.Close()
|
||||
return "", 0, fmt.Errorf("could not write complete public key (written: %d, should be: %d): %s", ln, len(key), key)
|
||||
}
|
||||
tmpFile.Close()
|
||||
|
||||
stdout, stderr, err := process.Exec("CheckPublicKeyString", setting.SSHKeyGenPath, "-lf", tmpName)
|
||||
if err != nil {
|
||||
return "", 0, fmt.Errorf("public key check failed with error '%s': %s", err, stderr)
|
||||
}
|
||||
if strings.HasSuffix(stdout, "is not a public key file.") {
|
||||
return "", 0, SSHUnknownKeyType
|
||||
}
|
||||
fields := strings.Split(stdout, " ")
|
||||
if len(fields) < 4 {
|
||||
return "", 0, fmt.Errorf("invalid public key line: %s", stdout)
|
||||
}
|
||||
|
||||
length, err := strconv.Atoi(fields[0])
|
||||
if err != nil {
|
||||
return "", 0, err
|
||||
}
|
||||
keyType := strings.Trim(fields[len(fields)-1], "()\r\n")
|
||||
return strings.ToLower(keyType), length, nil
|
||||
}
|
||||
|
||||
// extract the key type and length using the golang ssh library
|
||||
func SSHNativeParsePublicKey(keyLine string) (string, int, error) {
|
||||
fields := strings.Fields(keyLine)
|
||||
if len(fields) < 2 {
|
||||
return "", 0, fmt.Errorf("not enough fields in public key line: %s", string(keyLine))
|
||||
}
|
||||
|
||||
raw, err := base64.StdEncoding.DecodeString(fields[1])
|
||||
if err != nil {
|
||||
return "", 0, err
|
||||
}
|
||||
|
||||
pkey, err := ssh.ParsePublicKey(raw)
|
||||
if err != nil {
|
||||
if strings.HasPrefix(err.Error(), "ssh: unknown key algorithm") {
|
||||
return "", 0, SSHUnknownKeyType
|
||||
}
|
||||
return "", 0, err
|
||||
}
|
||||
|
||||
// The ssh library can parse the key, so next we find out what key exactly we
|
||||
// have.
|
||||
switch pkey.Type() {
|
||||
case ssh.KeyAlgoDSA:
|
||||
rawPub := struct {
|
||||
Name string
|
||||
P, Q, G, Y *big.Int
|
||||
}{}
|
||||
if err := ssh.Unmarshal(pkey.Marshal(), &rawPub); err != nil {
|
||||
return "", 0, err
|
||||
}
|
||||
// as per https://bugzilla.mindrot.org/show_bug.cgi?id=1647 we should never
|
||||
// see dsa keys != 1024 bit, but as it seems to work, we will not check here
|
||||
return "dsa", rawPub.P.BitLen(), nil // use P as per crypto/dsa/dsa.go (is L)
|
||||
case ssh.KeyAlgoRSA:
|
||||
rawPub := struct {
|
||||
Name string
|
||||
E *big.Int
|
||||
N *big.Int
|
||||
}{}
|
||||
if err := ssh.Unmarshal(pkey.Marshal(), &rawPub); err != nil {
|
||||
return "", 0, err
|
||||
}
|
||||
return "rsa", rawPub.N.BitLen(), nil // use N as per crypto/rsa/rsa.go (is bits)
|
||||
case ssh.KeyAlgoECDSA256:
|
||||
return "ecdsa", 256, nil
|
||||
case ssh.KeyAlgoECDSA384:
|
||||
return "ecdsa", 384, nil
|
||||
case ssh.KeyAlgoECDSA521:
|
||||
return "ecdsa", 521, nil
|
||||
case "ssh-ed25519": // TODO replace with ssh constant when available
|
||||
return "ed25519", 256, nil
|
||||
default:
|
||||
return "", 0, fmt.Errorf("no support for key length detection for type %s", pkey.Type())
|
||||
}
|
||||
return "", 0, fmt.Errorf("SSHNativeParsePublicKey failed horribly, please investigate why")
|
||||
}
|
||||
|
||||
// CheckPublicKeyString checks if the given public key string is recognized by SSH.
|
||||
//
|
||||
// The function returns the actual public key line on success.
|
||||
func CheckPublicKeyString(content string) (_ string, err error) {
|
||||
content, err = parseKeyString(content)
|
||||
if err != nil {
|
||||
|
|
@ -168,23 +276,35 @@ func CheckPublicKeyString(content string) (_ string, err error) {
|
|||
// remove any unnecessary whitespace now
|
||||
content = strings.TrimSpace(content)
|
||||
|
||||
fields := strings.Fields(content)
|
||||
if len(fields) < 2 {
|
||||
return "", errors.New("too less fields")
|
||||
var (
|
||||
keyType string
|
||||
length int
|
||||
)
|
||||
if setting.SSHPublicKeyCheck == setting.SSH_PUBLICKEY_CHECK_NATIVE {
|
||||
keyType, length, err = SSHNativeParsePublicKey(content)
|
||||
} else if setting.SSHPublicKeyCheck == setting.SSH_PUBLICKEY_CHECK_KEYGEN {
|
||||
keyType, length, err = SSHKeyGenParsePublicKey(content)
|
||||
} else {
|
||||
log.Error(4, "invalid public key check type: %s", setting.SSHPublicKeyCheck)
|
||||
return "", fmt.Errorf("invalid public key check type")
|
||||
}
|
||||
|
||||
key, err := base64.StdEncoding.DecodeString(fields[1])
|
||||
if err != nil {
|
||||
return "", fmt.Errorf("StdEncoding.DecodeString: %v", err)
|
||||
}
|
||||
pkey, err := ssh.ParsePublicKey([]byte(key))
|
||||
if err != nil {
|
||||
log.Trace("invalid public key of type '%s' with length %d: %s", keyType, length, err)
|
||||
return "", fmt.Errorf("ParsePublicKey: %v", err)
|
||||
}
|
||||
log.Trace("Key type: %s", pkey.Type())
|
||||
log.Trace("Key type: %s", keyType)
|
||||
|
||||
if !setting.Service.EnableMinimumKeySizeCheck {
|
||||
return content, nil
|
||||
}
|
||||
if minLen, found := setting.Service.MinimumKeySizes[keyType]; found && length >= minLen {
|
||||
return content, nil
|
||||
} else if found && length < minLen {
|
||||
return "", fmt.Errorf("key not large enough - got %d, needs %d", length, minLen)
|
||||
}
|
||||
return "", fmt.Errorf("key type '%s' is not allowed", keyType)
|
||||
}
|
||||
|
||||
// saveAuthorizedKeyFile writes SSH key content to authorized_keys file.
|
||||
func saveAuthorizedKeyFile(keys ...*PublicKey) error {
|
||||
|
|
@ -247,7 +367,7 @@ func addKey(e Engine, key *PublicKey) (err error) {
|
|||
}
|
||||
stdout, stderr, err := process.Exec("AddPublicKey", "ssh-keygen", "-lf", tmpPath)
|
||||
if err != nil {
|
||||
return errors.New("ssh-keygen -lf: " + stderr)
|
||||
return fmt.Errorf("'ssh-keygen -lf %s' failed with error '%s': %s", tmpPath, err, stderr)
|
||||
} else if len(stdout) < 2 {
|
||||
return errors.New("not enough output for calculating fingerprint: " + stdout)
|
||||
}
|
||||
|
|
@ -267,6 +387,7 @@ func addKey(e Engine, key *PublicKey) (err error) {
|
|||
|
||||
// AddPublicKey adds new public key to database and authorized_keys file.
|
||||
func AddPublicKey(ownerID int64, name, content string) (*PublicKey, error) {
|
||||
log.Trace(content)
|
||||
if err := checkKeyContent(content); err != nil {
|
||||
return nil, err
|
||||
}
|
||||
|
|
|
|||
39
models/ssh_key_test.go
Normal file
39
models/ssh_key_test.go
Normal file
|
|
@ -0,0 +1,39 @@
|
|||
package models
|
||||
|
||||
import (
|
||||
"github.com/gogits/gogs/modules/setting"
|
||||
"testing"
|
||||
)
|
||||
|
||||
func TestSSHKeyVerification(t *testing.T) {
|
||||
setting.SSHWorkPath = "/tmp"
|
||||
setting.SSHKeyGenPath = "/usr/bin/ssh-keygen"
|
||||
|
||||
keys := map[string]string{
|
||||
"dsa-1024": string("ssh-dss 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 nocomment"),
|
||||
"rsa-1024": string("ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAAAgQDAu7tvIvX6ZHrRXuZNfkR3XLHSsuCK9Zn3X58lxBcQzuo5xZgB6vRwwm/QtJuF+zZPtY5hsQILBLmF+BZ5WpKZp1jBeSjH2G7lxet9kbcH+kIVj0tPFEoyKI9wvWqIwC4prx/WVk2wLTJjzBAhyNxfEq7C9CeiX9pQEbEqJfkKCQ== nocomment\n"),
|
||||
"rsa-2048": string("ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDMZXh+1OBUwSH9D45wTaxErQIN9IoC9xl7MKJkqvTvv6O5RR9YW/IK9FbfjXgXsppYGhsCZo1hFOOsXHMnfOORqu/xMDx4yPuyvKpw4LePEcg4TDipaDFuxbWOqc/BUZRZcXu41QAWfDLrInwsltWZHSeG7hjhpacl4FrVv9V1pS6Oc5Q1NxxEzTzuNLS/8diZrTm/YAQQ/+B+mzWI3zEtF4miZjjAljWd1LTBPvU23d29DcBmmFahcZ441XZsTeAwGxG/Q6j8NgNXj9WxMeWwxXV2jeAX/EBSpZrCVlCQ1yJswT6xCp8TuBnTiGWYMBNTbOZvPC4e0WI2/yZW/s5F nocomment"),
|
||||
"ecdsa-256": string("ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBFQacN3PrOll7PXmN5B/ZNVahiUIqI05nbBlZk1KXsO3d06ktAWqbNflv2vEmA38bTFTfJ2sbn2B5ksT52cDDbA= nocomment"),
|
||||
"ecdsa-384": string("ecdsa-sha2-nistp384 AAAAE2VjZHNhLXNoYTItbmlzdHAzODQAAAAIbmlzdHAzODQAAABhBINmioV+XRX1Fm9Qk2ehHXJ2tfVxW30ypUWZw670Zyq5GQfBAH6xjygRsJ5wWsHXBsGYgFUXIHvMKVAG1tpw7s6ax9oA+dJOJ7tj+vhn8joFqT+sg3LYHgZkHrfqryRasQ== nocomment"),
|
||||
"ecdsa-512": string("ecdsa-sha2-nistp521 AAAAE2VjZHNhLXNoYTItbmlzdHA1MjEAAAAIbmlzdHA1MjEAAACFBACGt3UG3EzRwNOI17QR84l6PgiAcvCE7v6aXPj/SC6UWKg4EL8vW9ZBcdYL9wzs4FZXh4MOV8jAzu3KRWNTwb4k2wFNUpGOt7l28MztFFEtH5BDDrtAJSPENPy8pvPLMfnPg5NhvWycqIBzNcHipem5wSJFN5PdpNOC2xMrPWKNqj+ZjQ== nocomment"),
|
||||
}
|
||||
|
||||
for name, pubkey := range keys {
|
||||
keyTypeN, lengthN, errN := SSHNativeParsePublicKey(pubkey)
|
||||
if errN != nil {
|
||||
if errN != SSHUnknownKeyType {
|
||||
t.Errorf("error parsing public key '%s': %s", name, errN)
|
||||
continue
|
||||
}
|
||||
}
|
||||
keyTypeK, lengthK, errK := SSHKeyGenParsePublicKey(pubkey)
|
||||
if errK != nil {
|
||||
t.Errorf("error parsing public key '%s': %s", name, errK)
|
||||
continue
|
||||
}
|
||||
// we know that ed25519 is currently not supported by native and returns SSHUnknownKeyType
|
||||
if (keyTypeN != keyTypeK || lengthN != lengthK) && errN != SSHUnknownKeyType {
|
||||
t.Errorf("key mismatch for '%s': native: %s(%d), ssh-keygen: %s(%d)", name, keyTypeN, lengthN, keyTypeK, lengthK)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
@ -27,6 +27,11 @@ import (
|
|||
"github.com/gogits/gogs/modules/user"
|
||||
)
|
||||
|
||||
const (
|
||||
SSH_PUBLICKEY_CHECK_NATIVE = "native"
|
||||
SSH_PUBLICKEY_CHECK_KEYGEN = "ssh-keygen"
|
||||
)
|
||||
|
||||
type Scheme string
|
||||
|
||||
const (
|
||||
|
|
@ -67,6 +72,9 @@ var (
|
|||
SSHPort int
|
||||
SSHListenPort int
|
||||
SSHRootPath string
|
||||
SSHPublicKeyCheck string
|
||||
SSHWorkPath string
|
||||
SSHKeyGenPath string
|
||||
OfflineMode bool
|
||||
DisableRouterLog bool
|
||||
CertFile, KeyFile string
|
||||
|
|
@ -330,6 +338,29 @@ func NewContext() {
|
|||
if err := os.MkdirAll(SSHRootPath, 0700); err != nil {
|
||||
log.Fatal(4, "Fail to create '%s': %v", SSHRootPath, err)
|
||||
}
|
||||
checkDefault := SSH_PUBLICKEY_CHECK_KEYGEN
|
||||
if StartSSHServer {
|
||||
checkDefault = SSH_PUBLICKEY_CHECK_NATIVE
|
||||
}
|
||||
SSHPublicKeyCheck = sec.Key("SSH_PUBLICKEY_CHECK").MustString(checkDefault)
|
||||
if SSHPublicKeyCheck != SSH_PUBLICKEY_CHECK_NATIVE &&
|
||||
SSHPublicKeyCheck != SSH_PUBLICKEY_CHECK_KEYGEN {
|
||||
log.Fatal(4, "SSH_PUBLICKEY_CHECK must be ssh-keygen or native")
|
||||
}
|
||||
SSHWorkPath = sec.Key("SSH_WORK_PATH").MustString(os.TempDir())
|
||||
if !DisableSSH && (!StartSSHServer || SSHPublicKeyCheck == SSH_PUBLICKEY_CHECK_KEYGEN) {
|
||||
if tmpDirStat, err := os.Stat(SSHWorkPath); err != nil || !tmpDirStat.IsDir() {
|
||||
log.Fatal(4, "directory '%s' set in SSHWorkPath is not a directory: %s", SSHWorkPath, err)
|
||||
}
|
||||
}
|
||||
SSHKeyGenPath = sec.Key("SSH_KEYGEN_PATH").MustString("")
|
||||
if !DisableSSH && !StartSSHServer &&
|
||||
SSHKeyGenPath == "" && SSHPublicKeyCheck == SSH_PUBLICKEY_CHECK_KEYGEN {
|
||||
SSHKeyGenPath, err = exec.LookPath("ssh-keygen")
|
||||
if err != nil {
|
||||
log.Fatal(4, "could not find ssh-keygen, maybe set DISABLE_SSH to use the internal ssh server")
|
||||
}
|
||||
}
|
||||
OfflineMode = sec.Key("OFFLINE_MODE").MustBool()
|
||||
DisableRouterLog = sec.Key("DISABLE_ROUTER_LOG").MustBool()
|
||||
StaticRootPath = sec.Key("STATIC_ROOT_PATH").MustString(workDir)
|
||||
|
|
@ -461,6 +492,8 @@ var Service struct {
|
|||
EnableReverseProxyAuth bool
|
||||
EnableReverseProxyAutoRegister bool
|
||||
EnableCaptcha bool
|
||||
EnableMinimumKeySizeCheck bool
|
||||
MinimumKeySizes map[string]int
|
||||
}
|
||||
|
||||
func newService() {
|
||||
|
|
@ -473,6 +506,15 @@ func newService() {
|
|||
Service.EnableReverseProxyAuth = sec.Key("ENABLE_REVERSE_PROXY_AUTHENTICATION").MustBool()
|
||||
Service.EnableReverseProxyAutoRegister = sec.Key("ENABLE_REVERSE_PROXY_AUTO_REGISTRATION").MustBool()
|
||||
Service.EnableCaptcha = sec.Key("ENABLE_CAPTCHA").MustBool()
|
||||
Service.EnableMinimumKeySizeCheck = sec.Key("ENABLE_MINIMUM_KEY_SIZE_CHECK").MustBool()
|
||||
Service.MinimumKeySizes = map[string]int{}
|
||||
|
||||
minimumKeySizes := Cfg.Section("service.minimum_key_sizes").Keys()
|
||||
for _, key := range minimumKeySizes {
|
||||
if key.MustInt() != -1 {
|
||||
Service.MinimumKeySizes[strings.ToLower(key.Name())] = key.MustInt()
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
var logLevels = map[string]string{
|
||||
|
|
|
|||
Loading…
Reference in a new issue