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https://issues.apache.org/jira/browse/HADOOP-16122?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16772596#comment-16772596
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chendihao edited comment on HADOOP-16122 at 2/20/19 4:27 AM:
-------------------------------------------------------------
Here is the code which leads to this problem.
In `UserGroupInformation.java`, The `keytabPrincipal` and `keytabFile` are
static properties. So all the UGI objects in the same process use these same
properties.
{code:java}
public class UserGroupInformation {
private static UserGroupInformation loginUser = null;
private static String keytabPrincipal = null;
private static String keytabFile = null;
}{code}
When we invoke `reloginFromKeytab()`, we use "hadoop-keytab-kerberos" to create
the `LoginContext`.
{code:java}
public synchronized void reloginFromKeytab() throws IOException {
if(isSecurityEnabled() && this.user.getAuthenticationMethod() ==
UserGroupInformation.AuthenticationMethod.KERBEROS && this.isKeytab) {
long now = Time.now();
if(shouldRenewImmediatelyForTests ||
this.hasSufficientTimeElapsed(now)) {
KerberosTicket tgt = this.getTGT();
if(tgt == null || shouldRenewImmediatelyForTests || now >=
this.getRefreshTime(tgt)) {
LoginContext login = this.getLogin();
if(login != null && keytabFile != null) {
long start = 0L;
this.user.setLastLogin(now);
try {
if(LOG.isDebugEnabled()) {
LOG.debug("Initiating logout for " +
this.getUserName());
}
Class var7 = UserGroupInformation.class;
synchronized(UserGroupInformation.class) {
login.logout();
login = newLoginContext("hadoop-keytab-kerberos",
this.getSubject(), new UserGroupInformation.HadoopConfiguration(null));
if(LOG.isDebugEnabled()) {
LOG.debug("Initiating re-login for " +
keytabPrincipal);
}
start = Time.now();
login.login();
metrics.loginSuccess.add(Time.now() - start);
this.setLogin(login);
}
} catch (LoginException var10) {
if(start > 0L) {
metrics.loginFailure.add(Time.now() - start);
}
throw new IOException("Login failure for " +
keytabPrincipal + " from keytab " + keytabFile, var10);
}
} else {
throw new IOException("loginUserFromKeyTab must be done
first");
}
}
}
}
} {code}
In the implementation of `HadoopConfiguration.getAppConfigurationEntry()`, it
uses the static `keytabFile` and `keytabPrincipal` for "hadoop-keytab-kerberos".
{code:java}
public AppConfigurationEntry[] getAppConfigurationEntry(String appName) {
if("hadoop-simple".equals(appName)) {
return SIMPLE_CONF;
} else if("hadoop-user-kerberos".equals(appName)) {
return USER_KERBEROS_CONF;
} else if("hadoop-keytab-kerberos".equals(appName)) {
if(PlatformName.IBM_JAVA) {
KEYTAB_KERBEROS_OPTIONS.put("useKeytab",
UserGroupInformation.prependFileAuthority(UserGroupInformation.keytabFile));
} else {
KEYTAB_KERBEROS_OPTIONS.put("keyTab",
UserGroupInformation.keytabFile);
}
KEYTAB_KERBEROS_OPTIONS.put("principal",
UserGroupInformation.keytabPrincipal);
return KEYTAB_KERBEROS_CONF;
} else {
return null;
}
}
{code}
And the static `keytabFile` and `keytabPrincipal` are alway from the first
login UGI. Here is the code of `loginUserFromKeytabAndReturnUGI()` and finally
it update the static keytabFile and keytabFilePrincipal with the last one if it
exists.
{code:java}
public static synchronized UserGroupInformation
loginUserFromKeytabAndReturnUGI(String user, String path) throws IOException {
if(!isSecurityEnabled()) {
return getCurrentUser();
} else {
String oldKeytabFile = null;
String oldKeytabPrincipal = null;
long start = 0L;
UserGroupInformation var9;
try {
oldKeytabFile = keytabFile;
oldKeytabPrincipal = keytabPrincipal;
keytabFile = path;
keytabPrincipal = user;
Subject subject = new Subject();
LoginContext login = newLoginContext("hadoop-keytab-kerberos",
subject, new UserGroupInformation.HadoopConfiguration(null));
start = Time.now();
login.login();
metrics.loginSuccess.add(Time.now() - start);
UserGroupInformation newLoginUser = new
UserGroupInformation(subject);
newLoginUser.setLogin(login);
newLoginUser.setAuthenticationMethod(UserGroupInformation.AuthenticationMethod.KERBEROS);
var9 = newLoginUser;
} catch (LoginException var13) {
if(start > 0L) {
metrics.loginFailure.add(Time.now() - start);
}
throw new IOException("Login failure for " + user + " from keytab "
+ path, var13);
} finally {
if(oldKeytabFile != null) {
keytabFile = oldKeytabFile;
}
if(oldKeytabPrincipal != null) {
keytabPrincipal = oldKeytabPrincipal;
}
}
return var9;
}
}
{code}
It means that different UGI objects can call non-static `reloginFromKeytab()`
but always use the same login UGI's keytab and keytabPrincipal(maybe the first
login UGI even though we useloginUserFromKeytabAndReturnUGI for multiple times)
to pass to `Krb5LoginModule`.
For the first time, `loginUserFromKeytabAndReturnUGI` works because it updates
the global static keytab and keytabPrincipal before creating `LoginContext`
with "hadoop-keytab-kerberos". But it throws these properties for all UGIs(only
keep the first one in static) and the logic of login can not do that correctly.
was (Author: tobe):
Here is the code which leads to this problem.
In `UserGroupInformation.java`, The `keytabPrincipal` and `keytabFile` are
static properties. So all the UGI objects in the same process use these same
properties.
{code:java}
public class UserGroupInformation {
private static UserGroupInformation loginUser = null;
private static String keytabPrincipal = null;
private static String keytabFile = null;
}{code}
When we invoke `reloginFromKeytab()`, we use "hadoop-keytab-kerberos" to create
the `LoginContext`.
{code:java}
public synchronized void reloginFromKeytab() throws IOException {
if(isSecurityEnabled() && this.user.getAuthenticationMethod() ==
UserGroupInformation.AuthenticationMethod.KERBEROS && this.isKeytab) {
long now = Time.now();
if(shouldRenewImmediatelyForTests ||
this.hasSufficientTimeElapsed(now)) {
KerberosTicket tgt = this.getTGT();
if(tgt == null || shouldRenewImmediatelyForTests || now >=
this.getRefreshTime(tgt)) {
LoginContext login = this.getLogin();
if(login != null && keytabFile != null) {
long start = 0L;
this.user.setLastLogin(now);
try {
if(LOG.isDebugEnabled()) {
LOG.debug("Initiating logout for " +
this.getUserName());
}
Class var7 = UserGroupInformation.class;
synchronized(UserGroupInformation.class) {
login.logout();
login = newLoginContext("hadoop-keytab-kerberos",
this.getSubject(), new UserGroupInformation.HadoopConfiguration(null));
if(LOG.isDebugEnabled()) {
LOG.debug("Initiating re-login for " +
keytabPrincipal);
}
start = Time.now();
login.login();
metrics.loginSuccess.add(Time.now() - start);
this.setLogin(login);
}
} catch (LoginException var10) {
if(start > 0L) {
metrics.loginFailure.add(Time.now() - start);
}
throw new IOException("Login failure for " +
keytabPrincipal + " from keytab " + keytabFile, var10);
}
} else {
throw new IOException("loginUserFromKeyTab must be done
first");
}
}
}
}
} {code}
In the implementation of `HadoopConfiguration.getAppConfigurationEntry()`, it
uses the static `keytabFile` and `keytabPrincipal` for "hadoop-keytab-kerberos".
{code:java}
public AppConfigurationEntry[] getAppConfigurationEntry(String appName) {
if("hadoop-simple".equals(appName)) {
return SIMPLE_CONF;
} else if("hadoop-user-kerberos".equals(appName)) {
return USER_KERBEROS_CONF;
} else if("hadoop-keytab-kerberos".equals(appName)) {
if(PlatformName.IBM_JAVA) {
KEYTAB_KERBEROS_OPTIONS.put("useKeytab",
UserGroupInformation.prependFileAuthority(UserGroupInformation.keytabFile));
} else {
KEYTAB_KERBEROS_OPTIONS.put("keyTab",
UserGroupInformation.keytabFile);
}
KEYTAB_KERBEROS_OPTIONS.put("principal",
UserGroupInformation.keytabPrincipal);
return KEYTAB_KERBEROS_CONF;
} else {
return null;
}
}
{code}
And the static `keytabFile` and `keytabPrincipal` are alway from the first
login UGI. Here is the code of `loginUserFromKeytabAndReturnUGI()` and finally
it update the static keytabFile and keytabFilePrincipal with the last one if it
exists.
{code:java}
public static synchronized UserGroupInformation
loginUserFromKeytabAndReturnUGI(String user, String path) throws IOException {
if(!isSecurityEnabled()) {
return getCurrentUser();
} else {
String oldKeytabFile = null;
String oldKeytabPrincipal = null;
long start = 0L;
UserGroupInformation var9;
try {
oldKeytabFile = keytabFile;
oldKeytabPrincipal = keytabPrincipal;
keytabFile = path;
keytabPrincipal = user;
Subject subject = new Subject();
LoginContext login = newLoginContext("hadoop-keytab-kerberos",
subject, new UserGroupInformation.HadoopConfiguration(null));
start = Time.now();
login.login();
metrics.loginSuccess.add(Time.now() - start);
UserGroupInformation newLoginUser = new
UserGroupInformation(subject);
newLoginUser.setLogin(login);
newLoginUser.setAuthenticationMethod(UserGroupInformation.AuthenticationMethod.KERBEROS);
var9 = newLoginUser;
} catch (LoginException var13) {
if(start > 0L) {
metrics.loginFailure.add(Time.now() - start);
}
throw new IOException("Login failure for " + user + " from keytab "
+ path, var13);
} finally {
if(oldKeytabFile != null) {
keytabFile = oldKeytabFile;
}
if(oldKeytabPrincipal != null) {
keytabPrincipal = oldKeytabPrincipal;
}
}
return var9;
}
}
{code}
It means that different UGI objects can call non-static `reloginFromKeytab()`
but always use the first login UGI's keytab and keytabPrincipal to pass to
`Krb5LoginModule`.
For the first time, `loginUserFromKeytabAndReturnUGI` works because it updates
the global static keytab and keytabPrincipal before creating `LoginContext`
with "hadoop-keytab-kerberos". But it throws these properties for all UGIs(only
keep the first one in static) and the logic of login can not do that correctly.
> Re-login from keytab for multiple UGI will use the same and incorrect
> keytabPrincipal
> -------------------------------------------------------------------------------------
>
> Key: HADOOP-16122
> URL: https://issues.apache.org/jira/browse/HADOOP-16122
> Project: Hadoop Common
> Issue Type: Bug
> Components: auth
> Reporter: chendihao
> Priority: Major
>
> In our scenario, we have a service to allow multiple users to access HDFS
> with their keytab. The users use different Hadoop user and permission to
> access the HDFS files. This service will run with multi-threads and create
> independent UGI object for each user and use its own UGI to create Hadoop
> FileSystem object to read/write HDFS.
>
> Since we have multiple Hadoop users in the same process, we have to use
> `loginUserFromKeytabAndReturnUGI` instead of `loginUserFromKeytab`. The
> `loginUserFromKeytabAndReturnUGI` will not do the re-login automatically.
> Then we have to call `checkTGTAndReloginFromKeytab` or `reloginFromKeytab`
> before the kerberos ticket expires.
>
> The issue is that `reloginFromKeytab` will always re-login with the same and
> incorrect keytab instead of the one from the expected UGI object. Because of
> this issue, we can only support multiple Hadoop users to login with their own
> keytabs at the first time but not re-login when the tickets expire. The logic
> of login and re-login is slightly different especially for updating the
> global static properties and it may be the bug of the implementation of that.
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