When returning a rule_result struct, also include a set of field names
used by all exceptions for this rule. This may make building exception
values a bit easier.
Signed-off-by: Mark Stemm <mark.stemm@gmail.com>
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>
Take advantage of the changes to support exceptions and refactor rules
to use them whenever feasible:
- Define exceptions for every rule. In cases where no practical
exception exists e.g. "K8s <obj> Created/Deleted", define an empty
exception property just to avoid warnings when loading rules.
- Go through all rules and convert macros-used-as-exceptions that
matched against 2-3 filter fields into exceptions. In most cases,
switching from equality (e.g proc.name=nginx) to in (e.g. proc.name
in (nginx)) allowed for better groupings into a smaller set of
exception items.
- In cases where the exception had complex combinations of fields, keep
the macro as is.
Signed-off-by: Mark Stemm <mark.stemm@gmail.com>
When running falco with -V/valdiate <rules file>, you won't get any
event counts. All prior tests didn't get this far as they also resulted
in rules parsing errors.
However, validating can now result in warnings only. This won't exit but
won't print event counts either.
Signed-off-by: Mark Stemm <mark.stemm@gmail.com>
Handle various positive and negative cases. Should handle every error
and warning path when reading exceptions objects or rule exception
fields, and various positive cases of using exceptions to prevent
alerts.
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>
The format of error responses has changed to include a summary of errors
and/or warnings. This changed many test cases that were looking for
specific outputs.
Update to add counts and other minor formatting changes.
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>
If an exception item has a single value for fields, all the values are
combined together into a single set to build an expression field
cmp (val1, val2, ...)
Signed-off-by: Mark Stemm <mark.stemm@gmail.com>
Instead of oveloading the exception item name as the key of the object,
just have a flat array of object with a name property.
A bit more verbose, but makes it easier to understand what the schema is.
Signed-off-by: Mark Stemm <mark.stemm@gmail.com>
