Properly parse numbers in condition fields #1598
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Falco won't properly parse a rule like this:
---
- rule: Some Rule
desc: Some Desc
condition: evt.type=execve and container.image.repository = 271931939120.dkr
output: Some output
priority: INFO
---
This is the error when validating the rules:
Tue Mar 30 12:00:40 2021: Validating rules file(s):
Tue Mar 30 12:00:40 2021: /home/mstemm/test.yaml
1 errors:
Compilation error when compiling "evt.type=execve and container.image.repository = 271931939120.dkr": 63: syntax error, unexpected 'dkr', expecting 'or', 'and'
The parsing of the string on the right hand side stops at the period
before the dkr. The dkr then doesn't match the grammar, resulting in the
error.
Looking at the parser implementation more closely, the problem is in the
definition of "Number":
---
- Number = C(V "Hex" + V "Float" + V "Int") / function(n)
return tonumber(n)
end,
---
Note that it stops after the number, but does not have any requirement
about what follows.
This changes the definition of number to require that what follows the
number is not an identifier character. With this change, values that are
only numbers are parsed as numbers, and values that start with numbers
don't match the Number definition and are parsed as BareStrings instead.
Signed-off-by: Mark Stemm <mark.stemm@gmail.com>
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/milestone 0.28.0 |
fntlnz
approved these changes
Apr 6, 2021
|
LGTM label has been added. Git tree hash: 8e75c3118886908c5d0ac48cd17349cb0ca54b34
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leogr
approved these changes
Apr 6, 2021
leodido
approved these changes
Apr 7, 2021
|
[APPROVALNOTIFIER] This PR is APPROVED This pull-request has been approved by: fntlnz, leodido, leogr The full list of commands accepted by this bot can be found here. The pull request process is described here
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What type of PR is this?
/kind bug
Any specific area of the project related to this PR?
/area engine
What this PR does / why we need it:
Fix a bug in rule condition parsing that allows fields starting with numbers to be parsed properly.
Which issue(s) this PR fixes:
Fixes #
Special notes for your reviewer:
Does this PR introduce a user-facing change?: