If a list:
- list: foo
items: [a, b, c]
Was referenced in another list:
- list: bar
items: [foo, d, e, f]
The first list would not be marked as used, when it should.
This avoids mistaken messages like "list xxx not refered to by any rule/macro/list"
Signed-off-by: Mark Stemm <mark.stemm@gmail.com>
Support exceptions properties on rules as described in
https://github.com/falcosecurity/falco/pull/1376.
- When parsing rules, add an empty exceptions table if not specified.
- If exceptions are specified, they must contain names and lists of
fields, and optionally can contain lists of comps and lists of lists of
values.
- If comps are not specified, = is used.
- If a rule has exceptions and append:true, add values to the original rule's
exception values with the matching name.
- It's a warning but not an error to have exception values with a name
not matching any fields.
After loading all rules, build the exception condition string based on
any exceptions:
- If an exception has a single value for the "fields" property, values are
combined into a single set to build a condition string like "field
cmp (val1, val2, ...)".
- Otherwise, iterate through each rule's exception
values, finding the matching field names (field1, field2, ...) and
comp operators (cmp1, cmp2, ...), then
iterating over the list of field values (val1a, val1b, ...), (val2a,
val2b, ...), building up a string of the form:
and not ((field1 cmp1 val1a and field2 cmp2 val1b and ...) or
(field1 cmp1 val2a and field2 cmp2 val2b and ...)...
)"
- If a value is not already quoted and contains a space, quote it in the
string.
Signed-off-by: Mark Stemm <mark.stemm@gmail.com>
When parsing a rules file, if a top level object is not one of the known
types rule, macro, list, required_engine_version, instead of failing
parsing, add a warning instead.
This adds some forwards-compatibility to rules files.
Signed-off-by: Mark Stemm <mark.stemm@gmail.com>
Add the notion of warnings when loading rules, which are printed if
verbose is true:
- load_rules now returns a tuple (success, required engine version,
error array, warnings array) instead of (true, required engine
version) or (false, error string)
- build_error/build_error_with_context now returns an array instead of
string value.
- warnings are combined across calls to load_rules_doc
- Current warnings include:
- a rule that contains an unknown filter
- a macro not referred to by any rule
- a list not referred to by any rule/macro/list
Any errors/warnings are concatenated into the exception if success was
false. Any errors/warnings will be printed if verbose is true.
Signed-off-by: Mark Stemm <mark.stemm@gmail.com>
This is needed because Luajit does not support many architectures
such as aarch64 and ppcle64.
Note: some operating systems, such as Alpine, already use moonjit as a dropin
replacement for luajit.
Signed-off-by: Lorenzo Fontana <fontanalorenz@gmail.com>
Previously, formatters were freed by LUA code when re-opening outputs.
Since now, outputs are not controlling anymore the falco_formats class (see #1412), we just free formatters only if were already initialized.
That is needed when the engine restarts (see #1446).
By doing so, we also ensure that correct inspector instance is set to the formatter cache.
Signed-off-by: Leonardo Grasso <me@leonardograsso.com>
Currently, when calling enable_rule, the provided rule name pattern is a
substring match, that is if the rules file has a rule "My fantastic
rule", and you call engine->enable_rule("fantastic", true), the rule
will be enabled.
This can cause problems if one rule name is a complete subset of another
rule name e.g. rules "My rule" and "My rule is great", and calling
engine->enable_rule("My rule", true).
To allow for this case, add an alternate method enable_rule_exact() in
both default ruleset and ruleset variants. In this case, the rule name
must be an exact match.
In the underlying ruleset code, add a "match_exact" option to
falco_ruleset::enable() that denotes whether the substring is an exact
or substring match.
This doesn't change the default behavior of falco in any way, as the
existing calls still use enable_rule().
Signed-off-by: Mark Stemm <mark.stemm@gmail.com>
BAN_ALTERNATIVE is same as BAN but the message also provides an alternative
function that the user could use instead of the banned function.
Fixes#1035
Signed-off-by: Vaibhav <vrongmeal@gmail.com>
These include:
* vsprintf()
* sprintf()
* strcat()
* strncat()
* strncpy()
* swprintf()
* vswprintf()
This also changes `userspace/falco/logger.cpp` to remove a `sprintf`
statement. The statement did not affect the codebase in any form so
it was simply removed rather than being substituted.
Fixes#1035
Signed-off-by: Vaibhav <vrongmeal@gmail.com>
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>
Callers aren't expected to catch execeptions and instead rely on the
bool return value to indicate whether or not the parsing was successful.
Signed-off-by: Mark Stemm <mark.stemm@gmail.com>
Currently, the json object POSTed to the /k8s_audit endpoint is assumed
to be an obect, with a "type" of either "Event" or "EventList". When the
K8s API Server POSTs events, it aggregates them into an EventList,
ensuring that there is always a single object.
However, we're going to add some intermediate tools that tail log files
and send them to the endpoint, and the easiest way to send a batch of
events is to pass them as a json array instead of a single object.
To properly handle this, modify parse_k8s_audit_event_json to also
handle a json array. For arrays, it iterates over the objects, calling
parse_k8s_audit_json recursively. This only iterates an initial top
level array to avoid excessive recursion/attacks involving degenerate
json objects with excessively nested arrays.
Signed-off-by: Mark Stemm <mark.stemm@gmail.com>
In all extraction functions, always catch json type errors alongside
json out of range errors. Both cases result in not extracting any value
from the event.
Signed-off-by: Mark Stemm <mark.stemm@gmail.com>
First of a handful of PRs to start clarifying the independence of Falco
I don't see any breaking changes here, just cosmetic changes.
Signed-off-by: Kris Nova <kris@nivenly.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>
As a part of the changes in
https://github.com/falcosecurity/falco/pull/826/, we added several
breaking changes to rules files like renaming/removing some filter
fields. This isn't ideal for customers who are using their own rules
files.
We shouldn't break older rules files in this way, so add some minimal
backwards compatibility which adds back the fields that were
removed *and* actually used in k8s_audit_rules.yaml. They have the same
functionality as before. One exception is
ka.req.binding.subject.has_name, which was only used in a single output
field for debugging and shouldn't have been in the rules file in the
first place. This always returns the string "N/A".
Signed-off-by: Mark Stemm <mark.stemm@gmail.com>
Support the notion of a message for all fields in a single class, and
making sure it's wrapped as well as the other fields.
This is used to display a single message about how indexing working for
ka.* filter fields and what IDX_ALLOWED/IDX_NUMERIC/IDX_KEY means,
rather than repeating the same text over and over in every field.
The wrapping is handled by a function falco::utils::wrap_text.
Signed-off-by: Mark Stemm <mark.stemm@gmail.com>
Refactor how JSON event/k8s audit events extract values in two important
ways:
1. An event can now extract multiple values.
2. The extracted value is a class json_event_value instead of a simple
string.
The driver for 1. was that some filtercheck fields like
"ka.req.container.privileged" actually should extract multiple values,
as a pod can have multiple containers and it doesn't make sense to
summarize that down to a single value.
The driver for 2. is that by having an object represent a single
extracted value, you can also hold things like numbers e.g. ports, uids,
gids, etc. and ranges e.g. [0:3]. With an object, you can override
operators ==, <, etc. to do comparisons between the numbers and ranges,
or even set membership tests between extracted numbers and sets of
ranges.
This is really handy for a lot of new fields implemented as a part of
PSP support, where you end up having to check for overlaps between the
paths, images, ports, uids, etc in a K8s Audit Event and the acceptable
values, ranges, path prefixes enumerated in a PSP.
Implementing these changes also involve an overhaul of how aliases are
implemented. Instead of having an optional "formatting" function, where
arguments to the formatting function were expressed as text within the
index, define optional extraction and indexing functions. If an
extraction function is defined, it's responsible for taking the full
json object and calling add_extracted_value() to add values. There's a
default extraction function that uses a list of json_pointers with
automatic iteration over array values returned by a json pointer.
There's still a notion of filter fields supporting indexes--that's
simply handled within the default extraction or custom extraction
function. And for most fields, there won't be a need to write a custom
extraction function simply to implement indexing.
Within a json_event_filter_check object, instead of having a single
extracted value as a string, hold a vector of extracted json_event_value
objects (vector because order matters) and a set of json_event_value
objects (for set comparisons) as m_evalues. Values on the right hand
side of the expression are held as a set m_values.
json_event_filter_check::compare now supports IN/INTERSECTS as set
comparisons. It also supports PMATCH using path_prefix_search objects,
which simplifies checks like ka.req.pod.volumes.hostpath--now they can
be expressed as "ka.req.pod.volumes.hostpath intersects (/proc,
/var/run/docker.sock, /, /etc, /root)" instead of
"ka.req.volume.hostpath[/proc]=true or
ka.req.volume.hostpath[/root]=true or ...".
Define ~10 new filtercheck fields that extract pod properties like
hostIpc, readOnlyRootFilesystem, etc. that are relevant for PSP validation.
As a part of these changes, also clarify the names of filter fields
related to pods to always have a .pod in the name. Furthermore, fields
dealing with containers in a pod always have a .pod.containers prefix in
the name.
Finally, change the comparisons for existing k8s audit rules to use
"intersects" and/or "in" when appropriate instead of a single equality
comparison.
Signed-off-by: Mark Stemm <mark.stemm@gmail.com>
Related to the changes in https://github.com/draios/sysdig/pull/1501,
add support for an "intersects" operator that verifies if any of the
values in the rhs of an expression are found in the set of extracted
values.
For example:
(a,b,c) in (a,b) is false, but (a,b,c) intersects (a,b) is true.
The code that implements CO_INTERSECTS is in a different commit.
Signed-off-by: Mark Stemm <mark.stemm@gmail.com>
