Algorithm negotiation fail connecting to Ubuntu 20.04 server about davos

[mneumark]

Also getting this. The server I am connecting to recently updated SFTP to a version that removes vulnerable key exchange algorithms:

2022-01-18 10:45:19.672 -  INFO - [HostServiceImpl] - Attempting to test connection to host
2022-01-18 10:45:19.672 - DEBUG - [HostServiceImpl] - Credentials: <USER> : <PASSWORD>
2022-01-18 10:45:19.672 - DEBUG - [HostServiceImpl] - Making connection on port 22
2022-01-18 10:45:19.672 - DEBUG - [SFTPClient] - Configuring connection credentials and options on session
2022-01-18 10:45:19.673 - DEBUG - [SFTPClient] - Username: <USER>
2022-01-18 10:45:19.942 - ERROR - [APIController] - Failed to connect to host
2022-01-18 10:45:19.942 - DEBUG - [APIController] - Exception:
io.linuxserver.davos.transfer.ftp.exception.ClientConnectionException: Unable to connect to host viking.whatbox.ca on port 22
	at io.linuxserver.davos.transfer.ftp.client.SFTPClient.connect(SFTPClient.java:45) ~[classes!/:?]
	at io.linuxserver.davos.delegation.services.HostServiceImpl.testConnection(HostServiceImpl.java:98) ~[classes!/:?]
	at io.linuxserver.davos.web.controller.APIController.testConnection(APIController.java:193) [classes!/:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_302]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_302]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_302]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_302]
	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:220) [spring-web-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:134) [spring-web-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:116) [spring-webmvc-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) [spring-webmvc-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) [spring-webmvc-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) [spring-webmvc-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963) [spring-webmvc-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897) [spring-webmvc-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) [spring-webmvc-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
	at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872) [spring-webmvc-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:648) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) [spring-webmvc-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) [tomcat-embed-websocket-8.5.6.jar!/:8.5.6]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) [spring-web-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:89) [spring-web-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77) [spring-web-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) [spring-web-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:108) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:784) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:802) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1410) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_302]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_302]
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
	at java.lang.Thread.run(Thread.java:748) [?:1.8.0_302]
Caused by: com.jcraft.jsch.JSchException: Algorithm negotiation fail
	at com.jcraft.jsch.Session.receive_kexinit(Session.java:582) ~[jsch-0.1.50.jar!/:?]
	at com.jcraft.jsch.Session.connect(Session.java:320) ~[jsch-0.1.50.jar!/:?]
	at com.jcraft.jsch.Session.connect(Session.java:183) ~[jsch-0.1.50.jar!/:?]
	at io.linuxserver.davos.transfer.ftp.client.SFTPClient.configureSessionAndConnect(SFTPClient.java:86) ~[classes!/:?]
	at io.linuxserver.davos.transfer.ftp.client.SFTPClient.connect(SFTPClient.java:41) ~[classes!/:?]
	... 56 more

Any chance you just need to update the implementation of SFTP you use?

[mneumark]

Update: I think the issue is not having an updated copy of OpenSSL ( > 1.1.1) and my server removing 1.1.1 support.

[NickSChristiansen]

Same. Server running OpenSSL 1.1.1n from 15th of March 2022.

2022-05-12 22:09:25.532 - INFO - [HostServiceImpl] - Attempting to test connection to host
2022-05-12 22:09:25.532 - DEBUG - [HostServiceImpl] - Credentials: user:password
2022-05-12 22:09:25.532 - DEBUG - [HostServiceImpl] - Making connection on port 6969
2022-05-12 22:09:25.532 - DEBUG - [SFTPClient] - Configuring connection credentials and options on session
2022-05-12 22:09:25.532 - DEBUG - [SFTPClient] - Username: user
2022-05-12 22:09:25.611 - ERROR - [APIController] - Failed to connect to host
2022-05-12 22:09:25.611 - DEBUG - [APIController] - Exception:
io.linuxserver.davos.transfer.ftp.exception.ClientConnectionException: Unable to connect to host xx.xx.xx.xxx on port xxxx
at io.linuxserver.davos.transfer.ftp.client.SFTPClient.connect(SFTPClient.java:45) ~[classes!/:?]
at io.linuxserver.davos.delegation.services.HostServiceImpl.testConnection(HostServiceImpl.java:98) ~[classes!/:?]
at io.linuxserver.davos.web.controller.APIController.testConnection(APIController.java:193) [classes!/:?]
at sun.reflect.GeneratedMethodAccessor69.invoke(Unknown Source) ~[?:?]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_302]
at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_302]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:220) [spring-web-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:134) [spring-web-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:116) [spring-webmvc-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) [spring-webmvc-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) [spring-webmvc-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) [spring-webmvc-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963) [spring-webmvc-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897) [spring-webmvc-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) [spring-webmvc-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872) [spring-webmvc-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:648) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) [spring-webmvc-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) [tomcat-embed-websocket-8.5.6.jar!/:8.5.6]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) [spring-web-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:89) [spring-web-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77) [spring-web-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) [spring-web-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.4.RELEASE.jar!/:4.3.4.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:108) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:784) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:802) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1410) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_302]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_302]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.6.jar!/:8.5.6]
at java.lang.Thread.run(Thread.java:748) [?:1.8.0_302]
Caused by: com.jcraft.jsch.JSchException: Algorithm negotiation fail
at com.jcraft.jsch.Session.receive_kexinit(Session.java:582) ~[jsch-0.1.50.jar!/:?]
at com.jcraft.jsch.Session.connect(Session.java:320) ~[jsch-0.1.50.jar!/:?]
at com.jcraft.jsch.Session.connect(Session.java:183) ~[jsch-0.1.50.jar!/:?]
at io.linuxserver.davos.transfer.ftp.client.SFTPClient.configureSessionAndConnect(SFTPClient.java:86) ~[classes!/:?]
at io.linuxserver.davos.transfer.ftp.client.SFTPClient.connect(SFTPClient.java:41) ~[classes!/:?]
... 55 more

[nagash79]

+1
server: sftpgo running in docker container (drakkan/sftpgo)

{"level":"debug","time":"2022-08-30T22:52:17.232","sender":"sftpd","message":"failed to accept an incoming connection: ssh: no common algorithm for key exchange; client offered: [diffie-hellman-group1-sha1 diffie-hellman-group14-sha1 diffie-hellman-group-exchange-sha1], server offered: [curve25519-sha256 [email protected] ecdh-sha2-nistp256 ecdh-sha2-nistp384 ecdh-sha2-nistp521 diffie-hellman-group14-sha256 ext-info-s]"}

[MetziFetzi]

Is there any fix out now?
I try to connect to my MagicMirror and get the Error: Algorithm negotiation fail

[AndreasWelch]

Since this has been a problem for nearly 3 years and that's about the same length of time since there was an update to this codebase, I'm guessing this isn't going to be fixed and the project will slowly die as software gets updated and it stops working.