[mina-sshd] 05/05: Fix possible NPE when handling immediate KEX packet follow-up in case a peer proposal is not yet set

[lg...@apache.org]

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lgoldstein pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/mina-sshd.git

commit 141907415b3d0bb38c3b177d30bdcdef90983667
Author: Lyor Goldstein <lg...@apache.org>
AuthorDate: Tue Jul 9 09:14:54 2019 +0300

    Fix possible NPE when handling immediate KEX packet follow-up in case a peer proposal is not yet set
---
 .../apache/sshd/common/session/helpers/AbstractSession.java   | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/sshd-core/src/main/java/org/apache/sshd/common/session/helpers/AbstractSession.java b/sshd-core/src/main/java/org/apache/sshd/common/session/helpers/AbstractSession.java
index 9c6dc7e..cc5c926 100644
--- a/sshd-core/src/main/java/org/apache/sshd/common/session/helpers/AbstractSession.java
+++ b/sshd-core/src/main/java/org/apache/sshd/common/session/helpers/AbstractSession.java
@@ -488,10 +488,15 @@ public abstract class AbstractSession extends SessionHelper {
      */
     protected SimpleImmutableEntry<String, String> comparePreferredKexProposalOption(KexProposalOption option) {
         String[] clientPreferences = GenericUtils.split(clientProposal.get(option), ',');
-        String clientValue = clientPreferences[0];
+        String clientValue = GenericUtils.isEmpty(clientPreferences) ? null : clientPreferences[0];
         String[] serverPreferences = GenericUtils.split(serverProposal.get(option), ',');
-        String serverValue = serverPreferences[0];
-        return Objects.equals(clientValue, serverValue) ? null : new SimpleImmutableEntry<>(clientValue, serverValue);
+        String serverValue = GenericUtils.isEmpty(serverPreferences) ? null : serverPreferences[0];
+        if (GenericUtils.isEmpty(clientValue) || GenericUtils.isEmpty(serverValue)
+                || (!Objects.equals(clientValue, serverValue))) {
+            return new SimpleImmutableEntry<>(clientValue, serverValue);
+        }
+
+        return null;
     }
 
     /**