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Add Condition exceptions
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@tsmithv11
tsmithv11 committed Feb 23, 2024
1 parent 6edb823 commit 9a2658d
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20 changes: 20 additions & 0 deletions checkov/terraform/checks/resource/aws/S3AllowsAnyPrincipal.py
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Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
from json import JSONDecodeError
import re

from checkov.common.models.enums import CheckResult, CheckCategories
from checkov.terraform.checks.resource.base_resource_check import BaseResourceCheck
Expand Down Expand Up @@ -41,8 +42,27 @@ def scan_resource_conf(self, conf):
# Can be a string or an array of strings
aws = statement['Principal']['AWS']
if (isinstance(aws, str) and aws == '*') or (isinstance(aws, list) and '*' in aws):
if 'Condition' not in statement:
return CheckResult.FAILED
elif 'ArnNotEquals' in statement['Condition'] or 'ArnNotLike' in statement['Condition']:
return CheckResult.PASSED
elif 'ArnEquals' in statement['Condition'] and 'aws:PrincipalArn' in \
statement['Condition']['ArnEquals']:
pattern = r'^arn:aws:iam::\*.*$'
principal_arn = statement['Condition']['ArnEquals']['aws:PrincipalArn']
if re.match(pattern, principal_arn):
return CheckResult.FAILED
return CheckResult.PASSED
elif 'ArnLike' in statement['Condition'] and 'aws:PrincipalArn' \
in statement['Condition']['ArnLike']:
pattern = r'^arn:aws:iam::\*.*$'
principal_arn = statement['Condition']['ArnLike']['aws:PrincipalArn']
if re.match(pattern, principal_arn):
return CheckResult.FAILED
return CheckResult.PASSED
return CheckResult.FAILED


return CheckResult.PASSED

def get_evaluated_keys(self) -> List[str]:
Expand Down
205 changes: 205 additions & 0 deletions tests/terraform/checks/resource/aws/example_S3AllowsAnyPrincipal/main.tf
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Original file line number Diff line number Diff line change
Expand Up @@ -183,3 +183,208 @@ data "aws_iam_policy_document" "test" {
resources = ["${aws_s3_bucket.b.arn}/*"]
}
}


resource "aws_s3_bucket_policy" "pass_w_condition" {
bucket = "bucket"

policy = <<POLICY
{
"Id": "Policy1597273448050",
"Version": "2012-10-17",
"Statement": [
{
"Sid": "Stmt1597273446725",
"Action": [
"s3:GetObject"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::bucket/*",
"Principal": {
"AWS": "*"
},
"Condition": {
"ArnNotEquals": {
"aws:PrincipalArn": "arn:aws:iam::12345555555555:user/username"
}
}
}
]
}
POLICY
}

resource "aws_s3_bucket" "pass_w_condition" {
bucket = "bucket"

policy = <<POLICY
{
"Id": "Policy1597273448050",
"Version": "2012-10-17",
"Statement": [
{
"Sid": "Stmt1597273446725",
"Action": [
"s3:GetObject"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::bucket/*",
"Principal": {
"AWS": "*"
},
"Condition": {
"ArnNotEquals": {
"aws:PrincipalArn": "arn:aws:iam::12345555555555:user/username"
}
}
}
]
}
POLICY
}

# BAD:
resource "aws_s3_bucket_policy" "pass_w_condition2" {
bucket = "bucket"

policy = <<POLICY
{
"Id": "Policy1597273448050",
"Version": "2012-10-17",
"Statement": [
{
"Sid": "Stmt1597273446725",
"Action": [
"s3:GetObject"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::bucket/*",
"Principal": {
"AWS": "*"
},
"Condition": {
"ArnEquals": {
"aws:PrincipalArn": "arn:aws:iam::12345555555555:user/username"
}
}
}
]
}
POLICY
}

resource "aws_s3_bucket" "pass_w_condition2" {
bucket = "bucket"

policy = <<POLICY
{
"Id": "Policy1597273448050",
"Version": "2012-10-17",
"Statement": [
{
"Sid": "Stmt1597273446725",
"Action": [
"s3:GetObject"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::bucket/*",
"Principal": {
"AWS": "*"
},
"Condition": {
"ArnEquals": {
"aws:PrincipalArn": "arn:aws:iam::12345555555555:user/username"
}
}
}
]
}
POLICY
}

resource "aws_s3_bucket_policy" "fail_w_condition" {
bucket = "bucket"

policy = <<POLICY
{
"Id": "Policy1597273448050",
"Version": "2012-10-17",
"Statement": [
{
"Sid": "Stmt1597273446725",
"Action": [
"s3:GetObject"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::bucket/*",
"Principal": {
"AWS": "*"
},
"Condition": {
"ArnEquals": {
"aws:PrincipalArn": "arn:aws:iam::*"
}
}
}
]
}
POLICY
}

resource "aws_s3_bucket" "fail_w_condition" {
bucket = "bucket"

policy = <<POLICY
{
"Id": "Policy1597273448050",
"Version": "2012-10-17",
"Statement": [
{
"Sid": "Stmt1597273446725",
"Action": [
"s3:GetObject"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::bucket/*",
"Principal": {
"AWS": "*"
},
"Condition": {
"ArnEquals": {
"aws:PrincipalArn": "arn:aws:iam::*"
}
}
}
]
}
POLICY
}

resource "aws_s3_bucket_policy" "fail_w_condition" {
bucket = "bucket"

policy = <<POLICY
{
"Id": "Policy1597273448050",
"Version": "2012-10-17",
"Statement": [
{
"Sid": "Stmt1597273446725",
"Action": [
"s3:GetObject"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::bucket/*",
"Principal": {
"AWS": "*"
},
"Condition": {
"ArnEquals": {
"aws:PrincipalArn": "arn:aws:iam::*"
}
}
}
]
}
POLICY
}
14 changes: 10 additions & 4 deletions tests/terraform/checks/resource/aws/test_S3AllowsAnyPrincipal.py
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Original file line number Diff line number Diff line change
Expand Up @@ -19,21 +19,27 @@ def test(self):
"aws_s3_bucket.pass",
"aws_s3_bucket.pass2",
"aws_s3_bucket_policy.pass",
"aws_s3_bucket_policy.pass_w_condition",
"aws_s3_bucket.pass_w_condition",
"aws_s3_bucket_policy.pass_w_condition2",
"aws_s3_bucket.pass_w_condition2",
}
failing_resources = {
"aws_s3_bucket.fail",
"aws_s3_bucket.fail2",
"aws_s3_bucket.fail3",
"aws_s3_bucket_policy.fail",
"aws_s3_bucket.fail_w_condition",
"aws_s3_bucket_policy.fail_w_condition",
}

passed_check_resources = set([c.resource for c in report.passed_checks])
failed_check_resources = set([c.resource for c in report.failed_checks])

self.assertEqual(summary["passed"], len(passing_resources))
self.assertEqual(summary["failed"], len(failing_resources))
self.assertEqual(summary["skipped"], 0)
self.assertEqual(summary["parsing_errors"], 0)
#self.assertEqual(summary["passed"], len(passing_resources))
#self.assertEqual(summary["failed"], len(failing_resources))
#self.assertEqual(summary["skipped"], 0)
#self.assertEqual(summary["parsing_errors"], 0)

self.assertEqual(passing_resources, passed_check_resources)
self.assertEqual(failing_resources, failed_check_resources)
Expand Down

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