Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Fix AppSec crash when parsing integer http headers #3790

Merged
merged 4 commits into from
Jul 24, 2024
Merged

Fix AppSec crash when parsing integer http headers #3790

Show file tree
Hide file tree
Changes from 1 commit
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
50a7ef9
Fix AppSec crash when parsing integer http headers
vpellan Jul 17, 2024
86b882a
Fix header collection for case insensitive duplicates
vpellan Jul 19, 2024
fa699c8
Applied performance related suggestions
vpellan Jul 19, 2024
2701a76
Revert to Rack compliant behaviour
vpellan Jul 23, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 1 addition & 1 deletion lib/datadog/appsec/contrib/rack/gateway/request.rb
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -41,7 +41,7 @@ def method

def headers
result = request.env.each_with_object({}) do |(k, v), h|
h[k.gsub(/^HTTP_/, '').downcase!.tr('_', '-')] = v if k =~ /^HTTP_/
h[k.gsub(/^HTTP_/, '').tap(&:downcase!).tap { |s| s.tr!('_', '-') }] = v if k =~ /^HTTP_/
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The test indicates that you are keeping all of the values, therefore in my opinion:

  1. There should also be a test for mixed-case string input, e.g. HTTP_Foo
  2. I think the logic as currently proposed will result in the mixed case being preserved which I think is not the right behavior

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

As you pointed in your second comment, HTTP header names are uppercased by Rack (as HTTP header names are case-insensitive according to RFC 2616) and Rack will also drop empty headers so 'HTTP_' should not be possible either. But there's the case of someone adding a middleware to Rack that changes the headers for exemple. I believe that in these case, we still want to send everything to the WAF, as an attack could still be present in the value of these headers.

end

result['content-type'] = request.content_type if request.content_type
Expand Down
27 changes: 27 additions & 0 deletions spec/datadog/appsec/contrib/rack/gateway/request_spec.rb
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,33 @@
}
expect(request.headers).to eq(expected_headers)
end

context 'with malformed headers' do
let(:request) do
described_class.new(
Rack::MockRequest.env_for(
'http://example.com:8080/?a=foo&a=bar&b=baz',
{
'REQUEST_METHOD' => 'GET', 'REMOTE_ADDR' => '10.10.10.10', 'CONTENT_TYPE' => 'text/html',
'HTTP_COOKIE' => 'foo=bar', 'HTTP_USER_AGENT' => 'WebKit',
'HTTP_' => 'empty header', 'HTTP_123' => 'numbered header'
}
)
)
end

it 'returns the header information. Strip the HTTP_ prefix and append content-type and content-length information' do
expected_headers = {
'content-type' => 'text/html',
'cookie' => 'foo=bar',
'user-agent' => 'WebKit',
'content-length' => '0',
'' => 'empty header',
'123' => 'numbered header'
}
expect(request.headers).to eq(expected_headers)
end
end
end

describe '#body' do
Expand Down
Loading