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lgoldstein pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/mina-sshd.git
commit 23d2763f79be6067ee881c761659b85c610ae99e
Author: Lyor Goldstein <lgoldst...@apache.org>
AuthorDate: Thu Feb 27 11:21:01 2020 +0200
[SSHD-968] Added SessionHelper#preProcessEncodeBuffer
---
.../common/session/helpers/AbstractSession.java | 17 ++++++-----
.../sshd/common/session/helpers/SessionHelper.java | 33 +++++++++++++++++++++-
2 files changed, 42 insertions(+), 8 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 4468276..05e6275 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
@@ -1069,15 +1069,18 @@ public abstract class AbstractSession extends
SessionHelper {
// Check that the packet has some free space for the header
int curPos = buffer.rpos();
int cmd = buffer.rawByte(curPos) & 0xFF; // usually the 1st byte
is an SSH opcode
- if (curPos < SshConstants.SSH_PACKET_HEADER_LEN) {
- log.warn("encode({}) command={}[{}] performance cost:
available buffer packet header length ({}) below min. required ({})",
- this, cmd, SshConstants.getCommandMessageName(cmd),
- curPos, SshConstants.SSH_PACKET_HEADER_LEN);
- Buffer nb = new ByteArrayBuffer(buffer.available() +
Long.SIZE, false);
- nb.wpos(SshConstants.SSH_PACKET_HEADER_LEN);
- nb.putBuffer(buffer);
+ Buffer nb = preProcessEncodeBuffer(cmd, buffer);
+ if (nb != buffer) {
buffer = nb;
curPos = buffer.rpos();
+
+ int newCmd = buffer.rawByte(curPos) & 0xFF;
+ if (cmd != newCmd) {
+ log.warn("encode({}) - command changed from {}[{}] to
{}[{}] by pre-processor",
+ this, cmd, SshConstants.getCommandMessageName(cmd),
+ newCmd, SshConstants.getCommandMessageName(newCmd));
+ cmd = newCmd;
+ }
}
// Grab the length of the packet (excluding the 5 header bytes)
diff --git
a/sshd-core/src/main/java/org/apache/sshd/common/session/helpers/SessionHelper.java
b/sshd-core/src/main/java/org/apache/sshd/common/session/helpers/SessionHelper.java
index 6003372..8fd2b44 100644
---
a/sshd-core/src/main/java/org/apache/sshd/common/session/helpers/SessionHelper.java
+++
b/sshd-core/src/main/java/org/apache/sshd/common/session/helpers/SessionHelper.java
@@ -996,9 +996,40 @@ public abstract class SessionHelper extends
AbstractKexFactoryManager implements
listener.sessionNegotiationEnd(this, c2sOptions, s2cOptions,
negotiatedGuess, null);
}
+ /**
+ * Invoked by the session before encoding the buffer in order to make sure
that it is
+ * at least of size {@link SshConstants#SSH_PACKET_HEADER_LEN
SSH_PACKET_HEADER_LEN}.
+ * This is required in order to efficiently handle the encoding. If
necessary, it
+ * re-allocates a new buffer and returns it instead.
+ *
+ * @param cmd The command stored in the buffer
+ * @param buffer The original {@link Buffer} - assumed to be properly
formatted
+ * and be of at least the required minimum length.
+ * @return The adjusted {@link Buffer}. <B>Note:</B> users may use this
method to
+ * totally alter the contents of the buffer being sent but it is highly
discouraged
+ * as it may have unexpected results.
+ * @throws IOException If failed to process the buffer
+ */
+ protected Buffer preProcessEncodeBuffer(int cmd, Buffer buffer) throws
IOException {
+ int curPos = buffer.rpos();
+ if (curPos >= SshConstants.SSH_PACKET_HEADER_LEN) {
+ return buffer;
+ }
+
+ log.warn("preProcessEncodeBuffer({}) command={}[{}] performance cost:"
+ + " available buffer packet header length ({}) below min. required
({})",
+ this, cmd, SshConstants.getCommandMessageName(cmd),
+ curPos, SshConstants.SSH_PACKET_HEADER_LEN);
+ Buffer nb = new ByteArrayBuffer(buffer.available() + Long.SIZE, false);
+ nb.wpos(SshConstants.SSH_PACKET_HEADER_LEN);
+ nb.putBuffer(buffer);
+ return nb;
+ }
+
@Override
public void disconnect(int reason, String msg) throws IOException {
- log.info("Disconnecting({}): {} - {}", this,
SshConstants.getDisconnectReasonName(reason), msg);
+ log.info("Disconnecting({}): {} - {}",
+ this, SshConstants.getDisconnectReasonName(reason), msg);
String languageTag = ""; // TODO configure language...
signalDisconnect(reason, msg, languageTag, true);
