When compiling many dynamically changing scripts, parameterized
scripts (<https://www.elastic.co/guide/en/elasticsearch/reference/master/modules-scripting-using.html#prefer-params>)
should be preferred. This enforces a limit to the number of scripts that
can be compiled within a minute. A new dynamic setting is added -
`script.max_compilations_per_minute`, which defaults to 15.
If more dynamic scripts are sent, a user will get the following
exception:
```json
{
"error" : {
"root_cause" : [
{
"type" : "circuit_breaking_exception",
"reason" : "[script] Too many dynamic script compilations within one minute, max: [15/min]; please use on-disk, indexed, or scripts with parameters instead",
"bytes_wanted" : 0,
"bytes_limit" : 0
}
],
"type" : "search_phase_execution_exception",
"reason" : "all shards failed",
"phase" : "query",
"grouped" : true,
"failed_shards" : [
{
"shard" : 0,
"index" : "i",
"node" : "a5V1eXcZRYiIk8lecjZ4Jw",
"reason" : {
"type" : "general_script_exception",
"reason" : "Failed to compile inline script [\"aaaaaaaaaaaaaaaa\"] using lang [painless]",
"caused_by" : {
"type" : "circuit_breaking_exception",
"reason" : "[script] Too many dynamic script compilations within one minute, max: [15/min]; please use on-disk, indexed, or scripts with parameters instead",
"bytes_wanted" : 0,
"bytes_limit" : 0
}
}
}
],
"caused_by" : {
"type" : "general_script_exception",
"reason" : "Failed to compile inline script [\"aaaaaaaaaaaaaaaa\"] using lang [painless]",
"caused_by" : {
"type" : "circuit_breaking_exception",
"reason" : "[script] Too many dynamic script compilations within one minute, max: [15/min]; please use on-disk, indexed, or scripts with parameters instead",
"bytes_wanted" : 0,
"bytes_limit" : 0
}
}
},
"status" : 500
}
```
This also fixes a bug in `ScriptService` where requests being executed
concurrently on a single node could cause a script to be compiled
multiple times (many in the case of a powerful node with many shards)
due to no synchronization between checking the cache and compiling the
script. There is now synchronization so that a script being compiled
will only be compiled once regardless of the number of concurrent
searches on a node.
Relates to #19396
Today, certain bootstrap properties are set and read via system
properties. This action-at-distance way of managing these properties is
rather confusing, and completely unnecessary. But another problem exists
with setting these as system properties. Namely, these system properties
are interpreted as Elasticsearch settings, not all of which are
registered. This leads to Elasticsearch failing to startup if any of
these special properties are set. Instead, these properties should be
kept as local as possible, and passed around as method parameters where
needed. This eliminates the action-at-distance way of handling these
properties, and eliminates the need to register these non-setting
properties. This commit does exactly that.
Additionally, today we use the "-D" command line flag to set the
properties, but this is confusing because "-D" is a special flag to the
JVM for setting system properties. This creates confusion because some
"-D" properties should be passed via arguments to the JVM (so via
ES_JAVA_OPTS), and some should be passed as arguments to
Elasticsearch. This commit changes the "-D" flag for Elasticsearch
settings to "-E".
This fixes the `lenient` parameter to be `missingClasses`. I will remove this boolean and we can handle them via the normal whitelist.
It also adds a check for sheisty classes (jar hell with the jdk).
This is inspired by the lucene "sheisty" classes check, but it has false positives. This check is more evil, it validates every class file against the extension classloader as a resource, to see if it exists there. If so: jar hell.
This jar hell is a problem for several reasons:
1. causes insanely-hard-to-debug problems (like bugs in forbidden-apis)
2. hides problems (like internal api access)
3. the code you think is executing, is not really executing
4. security permissions are not what you think they are
5. brings in unnecessary dependencies
6. its jar hell
The more difficult problems are stuff like jython, where these classes are simply 'uberjared' directly in, so you cant just fix them by removing a bogus dependency. And there is a legit reason for them to do that, they want to support java 1.4.
Lee Hinman
Martijn van Groningen
Jason Tedor
Ryan Ernst
Yannick Welsch
Nik Everett
Robert Muir