louis-jaris opened a new issue, #636:
URL: https://github.com/apache/mina-sshd/issues/636
### Version
2.12.1
### Bug description
To reproduce the bug locally, you can create a temporary SSH Server using
docker (c.f. the following one liner):
```shell
docker run -it --rm -v ${PWD}:/home/sftpuser/some-directory -p 2222:22
atmoz/sftp sftpuser:pass123:1001
```
(More information on the `atmoz` [docker
image](https://hub.docker.com/r/atmoz/sftp/), and [github repo
associated](https://github.com/atmoz/sftp))
Then, get all the public keys of the server:
```shell
ssh-keyscan -p 2222 127.0.0.1
```
It will typically return something like:
```text
# 127.0.0.1:2222 SSH-2.0-OpenSSH_8.4p1 Debian-5+deb11u3
[127.0.0.1]:2222 ssh-ed25519
AAAAC3NzaC1lZDI1NTE5AAAAIPu6ntmyfSOkqLl3qPxD5XxwW7OONwwSG3KO+TGn+PFu
# 127.0.0.1:2222 SSH-2.0-OpenSSH_8.4p1 Debian-5+deb11u3
# 127.0.0.1:2222 SSH-2.0-OpenSSH_8.4p1 Debian-5+deb11u3
[127.0.0.1]:2222 ssh-rsa
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
# 127.0.0.1:2222 SSH-2.0-OpenSSH_8.4p1 Debian-5+deb11u3
# 127.0.0.1:2222 SSH-2.0-OpenSSH_8.4p1 Debian-5+deb11u3
```
Then, in Apache Mina, passing to `KnownHostEntry.readKnownHostEntries` all
the lines above as an input stream (actually, I'm using
`spring-integration-sftp` version `6.3.5` to do that), and then we get the
following exception:
```text
java.io.StreamCorruptedException: Failed (IllegalArgumentException) to parse
line #2 '[127.0.0.1]:2222 ssh-ed25519
AAAAC3NzaC1lZDI1NTE5AAAAIPu6ntmyfSOkqLl3qPxD5XxwW7OONwwSG3KO+TGn+PFu': Bad
format (no key data delimiter):
AAAAC3NzaC1lZDI1NTE5AAAAIPu6ntmyfSOkqLl3qPxD5XxwW7OONwwSG3KO+TGn+PFu
```
I've run a debugger up into Apache Mina implementation, and I was able to
determined that the algorithm `ssh-ed25519` is not supported -- ok fine, not a
problem, as we **should** be able to fallback to `ssh-rsa`, but **this is not
the case** as the Known Host Parsing is failling as soon as it encounters a non
supported key type.
----
The bug here is that `KnownHostEntry.readKnownHostEntries` should try to
return all the **_valid_** and supported `KnownHostEntry`, and let the
unsupported algorithm out of the collection returned on that function (and it
could fail if no usable/valid entry would have been found).
### Actual behavior
```
java.io.StreamCorruptedException: Failed (IllegalArgumentException) to parse
line #2 '[127.0.0.1]:2222 ssh-ed25519
AAAAC3NzaC1lZDI1NTE5AAAAIPu6ntmyfSOkqLl3qPxD5XxwW7OONwwSG3KO+TGn+PFu': Bad
format (no key data delimiter):
AAAAC3NzaC1lZDI1NTE5AAAAIPu6ntmyfSOkqLl3qPxD5XxwW7OONwwSG3KO+TGn+PFu
at
org.apache.sshd.client.config.hosts.KnownHostEntry.readKnownHostEntries(KnownHostEntry.java:208)
at
org.apache.sshd.client.config.hosts.KnownHostEntry.readKnownHostEntries(KnownHostEntry.java:165)
at
org.apache.sshd.client.config.hosts.KnownHostEntry.readKnownHostEntries(KnownHostEntry.java:159)
at
org.springframework.integration.sftp.session.ResourceKnownHostsServerKeyVerifier.lambda$getKnownHostSupplier$3(ResourceKnownHostsServerKeyVerifier.java:90)
at
org.apache.sshd.common.util.GenericUtils.lambda$memoizeLock$7(GenericUtils.java:893)
at
org.springframework.integration.sftp.session.ResourceKnownHostsServerKeyVerifier.verifyServerKey(ResourceKnownHostsServerKeyVerifier.java:68)
at
org.apache.sshd.client.session.AbstractClientSession.checkKeys(AbstractClientSession.java:637)
at
org.apache.sshd.common.session.helpers.AbstractSession.handleKexMessage(AbstractSession.java:766)
at
org.apache.sshd.common.session.helpers.AbstractSession.doHandleMessage(AbstractSession.java:621)
at
org.apache.sshd.common.session.helpers.AbstractSession.lambda$handleMessage$0(AbstractSession.java:545)
at
org.apache.sshd.common.util.threads.ThreadUtils.runAsInternal(ThreadUtils.java:68)
at
org.apache.sshd.common.session.helpers.AbstractSession.handleMessage(AbstractSession.java:544)
at
org.apache.sshd.common.session.helpers.AbstractSession.decode(AbstractSession.java:1688)
at
org.apache.sshd.common.session.helpers.AbstractSession.messageReceived(AbstractSession.java:505)
at
org.apache.sshd.common.session.helpers.AbstractSessionIoHandler.messageReceived(AbstractSessionIoHandler.java:64)
at
org.apache.sshd.common.io.nio2.Nio2Session.handleReadCycleCompletion(Nio2Session.java:409)
at
org.apache.sshd.common.io.nio2.Nio2Session$1.onCompleted(Nio2Session.java:382)
at
org.apache.sshd.common.io.nio2.Nio2Session$1.onCompleted(Nio2Session.java:377)
at
org.apache.sshd.common.io.nio2.Nio2CompletionHandler.lambda$completed$0(Nio2CompletionHandler.java:38)
at
java.base/java.security.AccessController.doPrivileged(AccessController.java:319)
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$1.run(AsynchronousChannelGroupImpl.java:113)
at
java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
at
java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
at java.base/java.lang.Thread.run(Thread.java:1583)
```
### Expected behavior
Have at least the KnownHost entry with the `ssh-rsa` algorithm, i.e. the
following entry:
```text
[127.0.0.1]:2222 ssh-rsa
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
```
### Relevant log output
_No response_
### Other information
Thank you for your work guys ! That's awesome to work with well maintained
libraries to do SSH/SFTP communication :pray
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