This defines certain functions as invalid tokens, i.e., when
compiled, the compiler throws an error.
Currently only `strcpy` is included as a banned function.
Fixes#788
Signed-off-by: Vaibhav <vrongmeal@gmail.com>
The call to rule_loader.load_rules only returns 2 values, so only pop
two values from the stack. This fixes#906.
Signed-off-by: Mark Stemm <mark.stemm@gmail.com>
Instead of relying on lua errors to pass back parse errors, pass back an
explicit true + required engine version or false + error message.
Also clean up the error message to display info + context on the
error. When the error related to yaml parsing, use the row number passed
back in lyaml's error string to print the specific line with the error.
When parsing rules/macros/lists, print the object being parsed alongside
the error.
Signed-off-by: Mark Stemm <mark.stemm@gmail.com>
Instead of iterating over the entire list of filters and doing pattern
matches against each defined filter, perform table lookups.
For filters that take arguments e.g. proc.aname[3] or evt.arg.xxx, split
the filtercheck string on bracket/dot and check the values against a
table.
There are now two tables of defined filters: defined_arg_filters and
defined_noarg_filters. Each filter is put into a table depending on
whether the filter takes an argument or not.
Signed-off-by: Mark Stemm <mark.stemm@gmail.com>
* Expose required_engine_version when loading rules
When loading a rules file, have alternate methods that return the
required_engine_version. The existing methods remain unchanged and just
call the new methods with a dummy placeholder.
* Add --support argument to print support bundle
Add an argument --support that can be used as a single way to collect
necessary support information, including the falco version, config,
commandline, and all rules files.
There might be a big of extra structure to the rules files, as they
actually support an array of "variants", but we're thinking ahead to
cases where there might be a comprehensive library of rules files and
choices, so we're adding the extra structure.
* Add ability to print field names only
Add ability to print field names only instead of all information about
fields (description, etc) using -N cmdline option.
This will be used to add some versioning support steps that check for a
changed set of fields.
* Add an engine version that changes w/ filter flds
Add a method falco_engine::engine_version() that returns the current
engine version (e.g. set of supported fields, rules objects, operators,
etc.). It's defined in falco_engine_version.h, starts at 2 and should be
updated whenever a breaking change is made.
The most common reason for an engine change will be an update to the set
of filter fields. To make this easy to diagnose, add a build time check
that compares the sha256 output of "falco --list -N" against a value
that's embedded in falco_engine_version.h. A mismatch fails the build.
* Check engine version when loading rules
A rules file can now have a field "required_engine_version N". If
present, the number is compared to the falco engine version. If the
falco engine version is less, an error is thrown.
* Unit tests for engine versioning
Add a required version: 2 to one trace file to check the positive case
and add a new test that verifies that a too-new rules file won't be loaded.
* Rename falco test docker image
Rename sysdig/falco to falcosecurity/falco in unit tests.
* Don't pin falco_rules.yaml to an engine version
Currently, falco_rules.yaml is compatible with versions <= 0.13.1 other
than the required_engine_version object itself, so keep that line
commented out so users can use this rules file with older falco
versions.
We'll uncomment it with the first incompatible falco engine change.
* Add new json/webserver libs, embedded webserver
Add two new external libraries:
- nlohmann-json is a better json library that has stronger use of c++
features like type deduction, better conversion from stl structures,
etc. We'll use it to hold generic json objects instead of jsoncpp.
- civetweb is an embeddable webserver that will allow us to accept
posted json data.
New files webserver.{cpp,h} start an embedded webserver that listens for
POSTS on a configurable url and passes the json data to the falco
engine.
New falco config items are under webserver:
- enabled: true|false. Whether to start the embedded webserver or not.
- listen_port. Port that webserver listens on
- k8s_audit_endpoint: uri on which to accept POSTed k8s audit events.
(This commit doesn't compile entirely on its own, but we're grouping
these related changes into one commit for clarity).
* Don't use relative paths to find lua code
You can look directly below PROJECT_SOURCE_DIR.
* Reorganize compiler lua code
The lua compiler code is generic enough to work on more than just
sinsp-based rules, so move the parts of the compiler related to event
types and filterchecks out into a standalone lua file
sinsp_rule_utils.lua.
The checks for event types/filterchecks are now done from rule_loader,
and are dependent on a "source" attribute of the rule being
"sinsp". We'll be adding additional types of events next that come from
sources other than system calls.
* Manage separate syscall/k8s audit rulesets
Add the ability to manage separate sets of rules (syscall and
k8s_audit). Stop using the sinsp_evttype_filter object from the sysdig
repo, replacing it with falco_ruleset/falco_sinsp_ruleset from
ruleset.{cpp,h}. It has the same methods to add rules, associate them
with rulesets, and (for syscall) quickly find the relevant rules for a
given syscall/event type.
At the falco engine level, there are new parallel interfaces for both
types of rules (syscall and k8s_audit) to:
- add a rule: add_k8s_audit_filter/add_sinsp_filter
- match an event against rules, possibly returning a result:
process_sinsp_event/process_k8s_audit_event
At the rule loading level, the mechanics of creating filterchecks
objects is handled two factories (sinsp_filter_factory and
json_event_filter_factory), both of which are held by the engine.
* Handle multiple rule types when parsing rules
Modify the steps of parsing a rule's filter expression to handle
multiple types of rules. Notable changes:
- In the rule loader/ast traversal, pass a filter api object down,
which is passed back up in the lua parser api calls like nest(),
bool_op(), rel_expr(), etc.
- The filter api object is either the sinsp factory or k8s audit
factory, depending on the rule type.
- When the rule is complete, the complete filter is passed to the
engine using either add_sinsp_filter()/add_k8s_audit_filter().
* Add multiple output formatting types
Add support for multiple output formatters. Notable changes:
- The falco engine is passed along to falco_formats to gain access to
the engine's factories.
- When creating a formatter, the source of the rule is passed along
with the format string, which controls which kind of output formatter
is created.
Also clean up exception handling a bit so all lua callbacks catch all
exceptions and convert them into lua errors.
* Add support for json, k8s audit filter fields
With some corresponding changes in sysdig, you can now create general
purpose filter fields and events, which can be tied together with
nesting, expressions, and relational operators. The classes here
represent an instance of these fields devoted to generic json objects as
well as k8s audit events. Notable changes:
- json_event: holds a json object, used by all of the below
- json_event_filter_check: Has the ability to extract values out of a
json_event object and has the ability to define macros that associate
a field like "group.field" with a json pointer expression that
extracts a single property's value out of the json object. The basic
field definition also allows creating an index
e.g. group.field[index], where a std::function is responsible for
performing the indexing. This class has virtual void methods so it
must be overridden.
- jevt_filter_check: subclass of json_event_filter_check and defines
the following fields:
- jevt.time/jevt.rawtime: extracts the time from the underlying json object.
- jevt.value[<json pointer>]: general purpose way to extract any
json value out of the underlying object. <json pointer> is a json
pointer expression
- jevt.obj: Return the entire object, stringified.
- k8s_audit_filter_check: implements fields that extract values from
k8s audit events. Most of the implementation is in the form of macros
like ka.user.name, ka.uri, ka.target.name, etc. that just use json
pointers to extact the appropriate value from a k8s audit event. More
advanced fields like ka.uri.param, ka.req.container.image use
indexing to extract individual values out of maps or arrays.
- json_event_filter_factory: used by things like the lua parser api,
output formatter, etc to create the necessary objects and return
them.
- json_event_formatter: given a format string, create the necessary
fields that will be used to create a resolved string when given a
json_event object.
* Add ability to list fields
Similar to sysdig's -l option, add --list (<source>) to list the fields
supported by falco. With no source specified, will print all
fields. Source can be "syscall" for inspector fields e.g. what is
supported by sysdig, or "k8s_audit" to list fields supported only by the
k8s audit support in falco.
* Initial set of k8s audit rules
Add an initial set of k8s audit rules. They're broken into 3 classes of
rules:
- Suspicious activity: this includes things like:
- A disallowed k8s user performing an operation
- A disallowed container being used in a pod.
- A pod created with a privileged pod.
- A pod created with a sensitive mount.
- A pod using host networking
- Creating a NodePort Service
- A configmap containing private credentials
- A request being made by an unauthenticated user.
- Attach/exec to a pod. (We eventually want to also do privileged
pods, but that will require some state management that we don't
currently have).
- Creating a new namespace outside of an allowed set
- Creating a pod in either of the kube-system/kube-public namespaces
- Creating a serviceaccount in either of the kube-system/kube-public
namespaces
- Modifying any role starting with "system:"
- Creating a clusterrolebinding to the cluster-admin role
- Creating a role that wildcards verbs or resources
- Creating a role with writable permissions/pod exec permissions.
- Resource tracking. This includes noting when a deployment, service,
- configmap, cluster role, service account, etc are created or destroyed.
- Audit tracking: This tracks all audit events.
To support these rules, add macros/new indexing functions as needed to
support the required fields and ways to index the results.
* Add ability to read trace files of k8s audit evts
Expand the use of the -e flag to cover both .scap files containing
system calls as well as jsonl files containing k8s audit events:
If a trace file is specified, first try to read it using the
inspector. If that throws an exception, try to read the first line as
json. If both fail, return an error.
Based on the results of the open, the main loop either calls
do_inspect(), looping over system events, or
read_k8s_audit_trace_file(), reading each line as json and passing it to
the engine and outputs.
* Example showing how to enable k8s audit logs.
An example of how to enable k8s audit logging for minikube.
* Add unit tests for k8s audit support
Initial unit test support for k8s audit events. A new multiplex file
falco_k8s_audit_tests.yaml defines the tests. Traces (jsonl files) are
in trace_files/k8s_audit and new rules files are in
test/rules/k8s_audit.
Current test cases include:
- User outside allowed set
- Creating disallowed pod.
- Creating a pod explicitly on the allowed list
- Creating a pod w/ a privileged container (or second container), or a
pod with no privileged container.
- Creating a pod w/ a sensitive mount container (or second container), or a
pod with no sensitive mount.
- Cases for a trace w/o the relevant property + the container being
trusted, and hostnetwork tests.
- Tests that create a Service w/ and w/o a NodePort type.
- Tests for configmaps: tries each disallowed string, ensuring each is
detected, and the other has a configmap with no disallowed string,
ensuring it is not detected.
- The anonymous user creating a namespace.
- Tests for all kactivity rules e.g. those that create/delete
resources as compared to suspicious activity.
- Exec/Attach to Pod
- Creating a namespace outside of an allowed set
- Creating a pod/serviceaccount in kube-system/kube-public namespaces
- Deleting/modifying a system cluster role
- Creating a binding to the cluster-admin role
- Creating a cluster role binding that wildcards verbs or resources
- Creating a cluster role with write/pod exec privileges
* Don't manually install gcc 4.8
gcc 4.8 should already be installed by default on the vm we use for
travis.
* Use correct copyright years.
Also include the start year.
* Improve copyright notices.
Use the proper start year instead of just 2018.
Add the right owner Draios dba Sysdig.
Add copyright notices to some files that were missing them.
Replace references to GNU Public License to Apache license in:
- COPYING file
- README
- all source code below falco
- rules files
- rules and code below test directory
- code below falco directory
- entrypoint for docker containers (but not the Dockerfiles)
I didn't generally add copyright notices to all the examples files, as
they aren't core falco. If they did refer to the gpl I changed them to
apache.
* Add ability to skip rules for unknown filters
Add the ability to skip a rule if its condition refers to a filtercheck
that doesn't exist. This allows defining a rules file that contains new
conditions that can still has limited backward compatibility with older
falco versions.
When compiling a filter, return a list of filtercheck names that are
present in the ast (which also includes filterchecks from any
macros). This set of filtercheck names is matched against the set of
filterchecks known to sinsp, expressed as lua patterns, and in the
global table defined_filters. If no match is found, the rule loader
throws an error.
The pattern changes slightly depending on whether the filter has
arguments or not. Two filters (proc.apid/proc.aname) can work with or
without arguments, so both styles of patterns are used.
If the rule has an attribute "skip-if-unknown-filter", the rule will be
skipped instead.
* Unit tests for skipping unknown filter
New unit test for skipping unknown filter. Test cases:
- A rule that refers to an unknown filter results in an error.
- A rule that refers to an unknown filter, but has
"skip-if-unknown-filter: true", can be read, but doesn't match any events.
- A rule that refers to an unknown filter, but has
"skip-if-unknown-filter: false", returns an error.
Also test the case of a filtercheck like evt.arg.xxx working properly
with the embedded patterns as well as proc.aname/apid which work both ways.
* Properly support syscalls in filter conditions
Syscalls have their own numbers but they weren't really handled within
falco. This meant that there wasn't a way to handle filters with
evt.type=xxx clauses where xxx was a value that didn't have a
corresponding event entry (like "madvise", for examples), or where a
syscall like open could also be done indirectly via syscall(__NR_open,
...).
First, add a new top-level global syscalls that maps from a string like
"madvise" to all the syscall nums for that id, just as we do for event
names/numbers.
In the compiler, when traversing the AST for evt.type=XXX or evt.type in
(XXX, ...) clauses, also try to match XXX against the global syscalls
table, and return any ids in a standalone table.
Also throw an error if an XXX doesn't match any event name or syscall name.
The syscall numbers are passed as an argument to sinsp_evttype_filter so
it can preindex the filters by syscall number.
This depends on https://github.com/draios/sysdig/pull/1100
* Add unit test for syscall support
This does a madvise, which doesn't have a ppm event type, both directly
and indirectly via syscall(__NR_madvise, ...), as well as an open
directly + indirectly. The corresponding rules file matches on madvise
and open.
The test ensures that both opens and both madvises are detected.
Clean up the handling of priority levels within rules. It used to be a
mix of strings handled in various places. Now, in falco_common.h there's
a consistent type for priority-as-number as well as a list of
priority-as-string values. Priorities are passed around as numbers
instead of strings. It's still permissive about capitalization.
Also add the ability to load rules by severity. New falco
config option "priority=<val>"/-o priority=<val> specifies the minimum
priority level of rules that will be loaded.
Add unit tests for same. The test suppresses INFO notifications for a
rule/trace file combination that would otherwise generate them.
In C functions that implement lua functions, don't directly throw
falco_exceptions, which results in opaque error messages like:
Mon Feb 27 10:09:58 2017: Runtime error: Error invoking function output:
C++ exception. Exiting.
Instead, return lua errors via lua_error().
- in lua, look for a tags attribute to each rule. This is passed up in
add_filter as a tags argument (as a lua table). If not present, an
empty table is used. The tags table is iterated to populate a set
of tags as strings, which is passed to add_filter().
- A new method falco_engine::enable_rule_by_tag is similar to
enable_rule(), but is given a set of tag strings. Any rules containing
one of the tags is enabled/disabled.
- The list of event types has been changed to a set to more accurately
reflect its purpose.
- New argument to falco -T allows disabling all rules matching a given
tag, via enable_rule_by_tag(). It can be provided multiple times.
- New argument to falco -t allows running those rules matching a given
tag. If provided all rules are first disabled. It can be
provided multiple times, but can not be combined with -T or
-D (disable rules by name)
- falco_enging supports the notion of a ruleset. The idea is that you
can choose a set of rules that are enabled/disabled by using
enable_rule()/enable_rule_by_tag() in combination with a
ruleset. Later, in process_event() you include that ruleset and the
rules you had previously enabled will be run.
- rulsets are provided as strings in enable_rule()/enable_rule_by_tag()
and as numbers in process_event()--this avoids the overhead of string
lookups per-event. Ruleset ids are created on the fly as needed. A
utility method find_ruleset_id() looks up the ruleset id for a given
name. The default ruleset is NULL string/0 numeric if not provided.
- Although the ruleset is a useful falco engine feature, it isn't that
important to the falco standalone program, so it's not
documented. However, you can change the ruleset by providing
FALCO_RULESET in the environment.
Add the ability to clear the set of loaded rules from lua. It simply
recreates the sinsp_evttype_filter instance m_evttype_filter, which is
now a unique_ptr.
container.info handling used to be handled by the the falco_outputs
object. However, this caused problems for applications that only used
the falco engine, doing their own output formatting for matching events.
Fix this by moving output formatting into the falco engine itself. The
part that replaces %container.info/adds extra formatting to the end of a
rule's output now happens while loading the rule.
If a rule has a enabled attribute, and if the value is false, call the
engine's enable_rule() method to disable the rule. Like add_filter,
there's a static method which takes the object as the first argument and
a non-static method that calls the engine.
This fixes#72.
Move the c++ and lua code implementing falco engine/falco common to its
own directory userspace/engine. It's compiled as a static library
libfalco_engine.a, and has its own CMakeLists.txt so it can be included
by other projects.
The engine's CMakeLists.txt has a add_subdirectory for the falco rules
directory, so including the engine also builds the rules.
The variables you need to set to use the engine's CMakeLists.txt are:
- CMAKE_INSTALL_PREFIX: the root directory below which everything is
installed.
- FALCO_ETC_DIR: where to install the rules file.
- FALCO_SHARE_DIR: where to install lua code, relative to the
- install/package root.
- LUAJIT_INCLUDE: where to find header files for lua.
- FALCO_SINSP_LIBRARY: the library containing sinsp code. It will be
- considered a dependency of the engine.
- LPEG_LIB/LYAML_LIB/LIBYAML_LIB: locations for third-party libraries.
- FALCO_COMPONENT: if set, will be included as a part of any install()
commands.
Instead of specifying /usr/share/falco in config_falco_*.h.in, use
CMAKE_INSTALL_PREFIX and FALCO_SHARE_DIR.
The lua code for the engine has also moved, so the two lua source
directories (userspace/engine/lua and userspace/falco/lua) need to be
available separately via falco_common, so make it an argument to
falco_common::init.
As a part of making it easy to include in another project, also clean up
LPEG build/defs. Modify build-lpeg to add a PREFIX argument to allow for
object files/libraries being in an alternate location, and when building
lpeg, put object files in a build/ subdirectory.
