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CSRF: supports on every methods #41258

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5 changes: 2 additions & 3 deletions docs/root/configuration/http/http_filters/csrf_filter.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -28,9 +28,8 @@ a request originated from the same host:
When the filter is evaluating a request, it ensures both pieces of information are present
and compares their values. If the source origin is missing or the origins do not match
the request is rejected. The exception to this being if the source origin has been
added to the policy as valid. Because CSRF attacks specifically target state-changing
requests, the filter only acts on HTTP requests that have a state-changing method
(POST, PUT, etc.).
added to the policy as valid. The filter acts on both HTTP requests that have a state-changing method and
non-state-changing method for safety.

.. note::
Due to differing functionality between browsers this filter will determine
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14 changes: 0 additions & 14 deletions source/extensions/filters/http/csrf/csrf_filter.cc
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Expand Up @@ -26,16 +26,6 @@ using RcDetails = ConstSingleton<RcDetailsValues>;
namespace {
constexpr absl::string_view NullOrigin{"null"};

bool isModifyMethod(const Http::RequestHeaderMap& headers) {
const absl::string_view method_type = headers.getMethodValue();
if (method_type.empty()) {
return false;
}
const auto& method_values = Http::Headers::get().MethodValues;
return (method_type == method_values.Post || method_type == method_values.Put ||
method_type == method_values.Delete || method_type == method_values.Patch);
}

std::string hostAndPort(const absl::string_view absolute_url) {
Http::Utility::Url url;
if (!absolute_url.empty()) {
Expand Down Expand Up @@ -102,10 +92,6 @@ Http::FilterHeadersStatus CsrfFilter::decodeHeaders(Http::RequestHeaderMap& head
return Http::FilterHeadersStatus::Continue;
}

if (!isModifyMethod(headers)) {
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This is user visible behavior change that needs either configuration option or runtime guard. I suggest in this case adding a config option that enables CSRF check on all methods.

return Http::FilterHeadersStatus::Continue;
}

const auto source_origin = sourceOriginValue(headers);
if (source_origin.empty()) {
config_->stats().missing_source_origin_.inc();
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12 changes: 6 additions & 6 deletions test/extensions/filters/http/csrf/csrf_filter_integration_test.cc
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Expand Up @@ -108,24 +108,24 @@ TEST_P(CsrfFilterIntegrationTest, TestCsrfDisabled) {
EXPECT_EQ(response->headers().getStatusValue(), "200");
}

TEST_P(CsrfFilterIntegrationTest, TestNonMutationMethod) {
TEST_P(CsrfFilterIntegrationTest, TestOriginMismatch) {
config_helper_.prependFilter(CSRF_FILTER_ENABLED_CONFIG);
Http::TestRequestHeaderMapImpl headers = {{
{":method", "GET"},
{":method", "PUT"},
{":path", "/"},
{":scheme", "http"},
{"origin", "http://cross-origin"},
{"host", "test-origin"},
}};
const auto& response = sendRequestAndWaitForResponse(headers);
const auto& response = sendRequest(headers);
EXPECT_TRUE(response->complete());
EXPECT_EQ(response->headers().getStatusValue(), "200");
EXPECT_EQ(response->headers().getStatusValue(), "403");
}

TEST_P(CsrfFilterIntegrationTest, TestOriginMismatch) {
TEST_P(CsrfFilterIntegrationTest, TestEnforcesGet) {
config_helper_.prependFilter(CSRF_FILTER_ENABLED_CONFIG);
Http::TestRequestHeaderMapImpl headers = {{
{":method", "PUT"},
{":method", "GET"},
{":path", "/"},
{":scheme", "http"},
{"origin", "http://cross-origin"},
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15 changes: 0 additions & 15 deletions test/extensions/filters/http/csrf/csrf_filter_test.cc
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Expand Up @@ -97,21 +97,6 @@ class CsrfFilterTest : public testing::Test {
Http::TestRequestTrailerMapImpl request_trailers_;
};

TEST_F(CsrfFilterTest, RequestWithNonMutableMethod) {
Http::TestRequestHeaderMapImpl request_headers{
{":method", "GET"}, {"host", "localhost"}, {":scheme", "http"}};

EXPECT_EQ(Http::FilterHeadersStatus::Continue, filter_.decodeHeaders(request_headers, false));
EXPECT_EQ(Http::FilterDataStatus::Continue, filter_.decodeData(data_, false));
Http::MetadataMap metadata_map{{"metadata", "metadata"}};
EXPECT_EQ(Http::FilterMetadataStatus::Continue, filter_.decodeMetadata(metadata_map));
EXPECT_EQ(Http::FilterTrailersStatus::Continue, filter_.decodeTrailers(request_trailers_));

EXPECT_EQ(0U, config_->stats().missing_source_origin_.value());
EXPECT_EQ(0U, config_->stats().request_invalid_.value());
EXPECT_EQ(0U, config_->stats().request_valid_.value());
}

TEST_F(CsrfFilterTest, RequestWithoutOriginAndWithoutDestination) {
Http::TestRequestHeaderMapImpl request_headers{{":method", "PUT"}, {":scheme", "http"}};

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