[SFTP] [v6 Regression] upload fails with "Server key did not validate"

[mysteryboy2000]

In what version(s) of Spring Integration are you seeing this issue?

• Integration core 6.1.3
• Spring Boot 3.1.4

Describe the bug

below is the stack trace.

Caused by: org.springframework.messaging.MessagingException: Failed to execute on session
	at org.springframework.integration.file.remote.RemoteFileTemplate.execute(RemoteFileTemplate.java:461)
	at [MASKED].NfsRepository.uploadFiles(NfsRepository.java:39)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
	at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:343)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:196)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:751)
	at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:137)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184)
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:751)
	at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:703)
	at [MASKED].NfsRepository$$SpringCGLIB$$0.uploadFiles(<generated>)

Caused by: org.springframework.integration.util.PoolItemNotAvailableException: Failed to obtain pooled item
	at org.springframework.integration.util.SimplePool.getItem(SimplePool.java:196)
	at org.springframework.integration.file.remote.session.CachingSessionFactory.getSession(CachingSessionFactory.java:134)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
	at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:343)
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:237)
	at jdk.proxy3/jdk.proxy3.$Proxy147.getSession(Unknown Source)
	at org.springframework.integration.file.remote.RemoteFileTemplate.execute(RemoteFileTemplate.java:447)
	... 172 common frames omitted

Caused by: java.lang.IllegalStateException: failed to create SFTP Session
	at org.springframework.integration.sftp.session.DefaultSftpSessionFactory.getSession(DefaultSftpSessionFactory.java:297)
	at org.springframework.integration.sftp.session.DefaultSftpSessionFactory.getSession(DefaultSftpSessionFactory.java:75)
	at org.springframework.integration.file.remote.session.CachingSessionFactory$1.createForPool(CachingSessionFactory.java:85)
	at org.springframework.integration.file.remote.session.CachingSessionFactory$1.createForPool(CachingSessionFactory.java:82)
	at org.springframework.integration.util.SimplePool.doGetItem(SimplePool.java:206)
	at org.springframework.integration.util.SimplePool.getItem(SimplePool.java:187)
	... 181 common frames omitted

Caused by: org.apache.sshd.common.SshException: Server key did not validate
	at org.apache.sshd.common.future.AbstractSshFuture.verifyResult(AbstractSshFuture.java:127)
	at org.apache.sshd.client.future.DefaultAuthFuture.verify(DefaultAuthFuture.java:39)
	at org.apache.sshd.client.future.DefaultAuthFuture.verify(DefaultAuthFuture.java:32)
	at org.apache.sshd.common.future.VerifiableFuture.verify(VerifiableFuture.java:43)
	at org.apache.sshd.common.future.VerifiableFuture.verify(VerifiableFuture.java:68)
	at org.springframework.integration.sftp.session.DefaultSftpSessionFactory.initClientSession(DefaultSftpSessionFactory.java:324)
	at org.springframework.integration.sftp.session.DefaultSftpSessionFactory.getSession(DefaultSftpSessionFactory.java:287)
	... 186 common frames omitted

Caused by: org.apache.sshd.common.SshException: Server key did not validate
	at org.apache.sshd.client.session.AbstractClientSession.checkKeys(AbstractClientSession.java:629)
	at org.apache.sshd.common.session.helpers.AbstractSession.handleKexMessage(AbstractSession.java:726)
	at org.apache.sshd.common.session.helpers.AbstractSession.doHandleMessage(AbstractSession.java:590)
	at org.apache.sshd.common.session.helpers.AbstractSession.lambda$handleMessage$0(AbstractSession.java:522)
	at org.apache.sshd.common.util.threads.ThreadUtils.runAsInternal(ThreadUtils.java:68)
	at org.apache.sshd.common.session.helpers.AbstractSession.handleMessage(AbstractSession.java:521)
	at org.apache.sshd.common.session.helpers.AbstractSession.decode(AbstractSession.java:1639)
	at org.apache.sshd.common.session.helpers.AbstractSession.messageReceived(AbstractSession.java:482)
	at org.apache.sshd.common.session.helpers.AbstractSessionIoHandler.messageReceived(AbstractSessionIoHandler.java:64)
	at org.apache.sshd.common.io.nio2.Nio2Session.handleReadCycleCompletion(Nio2Session.java:407)
	at org.apache.sshd.common.io.nio2.Nio2Session$1.onCompleted(Nio2Session.java:380)
	at org.apache.sshd.common.io.nio2.Nio2Session$1.onCompleted(Nio2Session.java:375)
	at org.apache.sshd.common.io.nio2.Nio2CompletionHandler.lambda$completed$0(Nio2CompletionHandler.java:38)
	at java.base/java.security.AccessController.doPrivileged(AccessController.java:318)
	at org.apache.sshd.common.io.nio2.Nio2CompletionHandler.completed(Nio2CompletionHandler.java:37)
	at java.base/sun.nio.ch.Invoker.invokeUnchecked(Invoker.java:129)
	at java.base/sun.nio.ch.Invoker$2.run(Invoker.java:221)
	at java.base/sun.nio.ch.AsynchronousChannelGroupImpl$1.run(AsynchronousChannelGroupImpl.java:113)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)

To Reproduce

works on

• spring-integration-sftp:6.0.2(integration core jar version5.5.15)
• Spring Boot version : 2.7.4

the known_host looks like this
10.0.0.100 ssh-rsa AAAAB3NzaC1yc[MASKED]PrL4NHSOuaXYZj52Q==

Expected behavior

upload success.

A bit more
may be same issue like 8693

[artembilan]

Yes. It is indeed looks like the same issue.
Is it hard for you to add a known_host entry based on host name, but not an IP address?

[artembilan]

More discussion is here: #8693.
So, closing this one as duplication of that.