lgoldstein commented on code in PR #446:
URL: https://github.com/apache/mina-sshd/pull/446#discussion_r1435260568
##########
sshd-core/src/main/java/org/apache/sshd/common/session/helpers/AbstractSession.java:
##########
@@ -1741,6 +1979,143 @@ protected byte[] sendKexInit(Map<KexProposalOption,
String> proposal) throws Exc
return data;
}
+ protected String adjustOutgoingKexProposalOption(
+ KexProposalOption option, String value, boolean debugEnabled) {
+ if (GenericUtils.isBlank(value)) {
+ return value; // can happen for language (e.g.)
+ }
+
+ if (option != KexProposalOption.ALGORITHMS) {
+ return value;
+ }
+
+ if (!CoreModuleProperties.USE_STRICT_KEX.getRequired(this)) {
+ return value;
+ }
+
+ /*
+ * According to
https://github.com/openssh/openssh-portable/blob/master/PROTOCOL - section 1.9
+ *
+ * These pseudo-algorithms are only valid in the initial
SSH2_MSG_KEXINIT and
+ * MUST be ignored if they are present in subsequent
SSH2_MSG_KEXINIT packets.
+ *
+ * Therefore, if this is not the 1st outgoing packet don't bother
appending
+ */
+ long outgoingCount = totalOutgingPacketsCount.get();
+ if (outgoingCount > 0L) {
+ if (debugEnabled) {
+ log.debug("adjustKexOutgoingProposalOption({})[{}] not first
outgoing packet ({}) for proposal={}",
+ this, option, outgoingCount, value);
+ }
+ return value;
+ }
+
+ /*
+ * According to
https://github.com/openssh/openssh-portable/blob/master/PROTOCOL - section 1.9
+ *
+ * The client may append "kex-strict-c-...@openssh.com" to its
kex_algorithms
+ * and the server may append "kex-strict-s-...@openssh.com"
+ *
+ */
+ String proposal = isServerSession()
+ ? KexExtensions.STRICT_KEX_SERVER_EXTENSION
+ : KexExtensions.STRICT_KEX_CLIENT_EXTENSION;
+ String adjusted = value + "," + proposal;
+ if (debugEnabled) {
+ log.debug("adjustOutgoingKexProposalOption({})[{}] adjusted={}",
this, option, adjusted);
+ }
+
+ return adjusted;
+ }
+
+ protected String preProcessIncomingKexProposalOption(
+ KexProposalOption option, String value, boolean debugEnabled) {
+ if (GenericUtils.isBlank(value)) {
+ return value; // can happen for language (e.g.)
+ }
+
+ if (option != KexProposalOption.ALGORITHMS) {
+ return value;
+ }
+
+ if (!CoreModuleProperties.USE_STRICT_KEX.getRequired(this)) {
+ return value;
+ }
+
+ String peerValue = isServerSession()
+ ? KexExtensions.STRICT_KEX_CLIENT_EXTENSION
+ : KexExtensions.STRICT_KEX_SERVER_EXTENSION;
+ if (!value.contains(peerValue)) {
+ return value;
+ }
+
+ // Just a bit of paranoia...
Review Comment:
I'll consider it, but I am inclined not to do it. The code is complex
already - if we start second guessing our own piece of code then we will have
code that checks its own validity to death. Why stop there ? Why not remove
proposals that it knows it could not have possibly made ?
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: dev-unsubscr...@mina.apache.org
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscr...@mina.apache.org
For additional commands, e-mail: dev-h...@mina.apache.org
