SSH: Make it configurable whether to check server data pedantically.

While we want to conform to the specs, there are systems out there today
whose SSH servers send non-conforming identifications strings. We now
enable API clients to switch the respecive checks off, and we do so
ourselves in the RemoteLinux plugin, since the only known problems
are with OpenSSH servers.

Change-Id: I9e6f9076f2dc7435a0bde7016f99cfb2fcb30a9c
Reviewed-by: Tobias Hunger <[email protected]>

1 files changed, 15 insertions, 12 deletions

diff --git a/src/libs/ssh/sshconnection.cpp b/src/libs/ssh/sshconnection.cpp
index 8c4abf2347c..5b7db878d6a 100644
--- a/src/libs/ssh/sshconnection.cpp
+++ b/src/libs/ssh/sshconnection.cpp
@@ -81,8 +81,10 @@ namespace {
 
 
 SshConnectionParameters::SshConnectionParameters() :
-    timeout(0),  authenticationType(AuthenticationByKey), port(0), options(SshIgnoreDefaultProxy)
+    timeout(0),  authenticationType(AuthenticationByKey), port(0)
 {
+    options |= SshIgnoreDefaultProxy;
+    options |= SshEnableStrictConformanceChecks;
 }
 
 static inline bool equals(const SshConnectionParameters &p1, const SshConnectionParameters &p2)
@@ -398,18 +400,19 @@ void SshConnectionPrivate::handleServerId()
                     .arg(serverProtoVersion));
     }
 
-    // Disable this check to accept older OpenSSH servers that do this wrong.
-    if (serverProtoVersion == QLatin1String("2.0") && !hasCarriageReturn) {
-        throw SshServerException(SSH_DISCONNECT_PROTOCOL_ERROR,
-            "Identification string is invalid.",
-            tr("Server identification string is invalid (missing carriage return)."));
-    }
+    if (m_connParams.options & SshEnableStrictConformanceChecks) {
+        if (serverProtoVersion == QLatin1String("2.0") && !hasCarriageReturn) {
+            throw SshServerException(SSH_DISCONNECT_PROTOCOL_ERROR,
+                    "Identification string is invalid.",
+                    tr("Server identification string is invalid (missing carriage return)."));
+        }
 
-    if (serverProtoVersion == QLatin1String("1.99") && m_serverHasSentDataBeforeId) {
-        throw SshServerException(SSH_DISCONNECT_PROTOCOL_ERROR,
-            "No extra data preceding identification string allowed for 1.99.",
-            tr("Server reports protocol version 1.99, but sends data "
-               "before the identification string, which is not allowed."));
+        if (serverProtoVersion == QLatin1String("1.99") && m_serverHasSentDataBeforeId) {
+            throw SshServerException(SSH_DISCONNECT_PROTOCOL_ERROR,
+                    "No extra data preceding identification string allowed for 1.99.",
+                    tr("Server reports protocol version 1.99, but sends data "
+                       "before the identification string, which is not allowed."));
+        }
     }
 
     m_keyExchange.reset(new SshKeyExchange(m_sendFacility));