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fix uhv underscore header sanitization use-after-free path #44086

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fix uhv underscore header sanitization use-after-free path #44086

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11 changes: 8 additions & 3 deletions source/extensions/http/header_validators/envoy_default/header_validator.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@
#include "source/common/runtime/runtime_features.h"
#include "source/extensions/http/header_validators/envoy_default/character_tables.h"

#include "absl/container/flat_hash_set.h"
#include "absl/container/node_hash_set.h"
#include "absl/strings/match.h"

Expand Down Expand Up @@ -634,19 +635,23 @@ void HeaderValidator::sanitizeHeadersWithUnderscores(::Envoy::Http::HeaderMap& h
return;
}

std::vector<absl::string_view> drop_headers;
// Store owning copies because removing one duplicate header can free the
// underlying storage for another matching entry. Using absl::string_view
// would still be unsafe here as the view may dangle after the first removal.
// We only need unique names.
absl::flat_hash_set<std::string> drop_headers;
header_map.iterate([&drop_headers](const ::Envoy::Http::HeaderEntry& header_entry)
-> ::Envoy::Http::HeaderMap::Iterate {
const absl::string_view header_name = header_entry.key().getStringView();
if (absl::StrContains(header_name, '_')) {
drop_headers.push_back(header_name);
drop_headers.emplace(header_name);
}

return ::Envoy::Http::HeaderMap::Iterate::Continue;
});

ASSERT(drop_headers.empty() || underscore_action == HeaderValidatorConfig::DROP_HEADER);
for (auto& name : drop_headers) {
for (const auto& name : drop_headers) {
stats_.incDroppedHeadersWithUnderscores();
header_map.remove(::Envoy::Http::LowerCaseString(name));
}
Expand Down
17 changes: 17 additions & 0 deletions test/extensions/http/header_validators/envoy_default/http1_header_validator_test.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -497,6 +497,23 @@ TEST_F(Http1HeaderValidatorTest, ValidateRequestHeaderMapDropUnderscoreHeaders)
{{":scheme", "https"}, {":method", "GET"}, {":path", "/"}, {":authority", "envoy.com"}}));
}

TEST_F(Http1HeaderValidatorTest, ValidateRequestHeaderMapDropDuplicateUnderscoreHeaders) {
::Envoy::Http::TestRequestHeaderMapImpl headers{{":scheme", "https"},
{":method", "GET"},
{":path", "/"},
{":authority", "envoy.com"},
{"x_foo", "bar"}};
headers.addCopy("x_foo", "baz");
auto uhv = createH1(drop_headers_with_underscores_config);

EXPECT_ACCEPT(uhv->validateRequestHeaders(headers));
EXPECT_ACCEPT(uhv->transformRequestHeaders(headers));
EXPECT_EQ(
headers,
TestRequestHeaderMapImpl(
{{":scheme", "https"}, {":method", "GET"}, {":path", "/"}, {":authority", "envoy.com"}}));
}

TEST_F(Http1HeaderValidatorTest, RejectUnderscoreHeadersFromRequestHeadersWhenConfigured) {
::Envoy::Http::TestRequestHeaderMapImpl headers{{":scheme", "https"},
{":method", "GET"},
Expand Down
17 changes: 17 additions & 0 deletions test/extensions/http/header_validators/envoy_default/http2_header_validator_test.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -260,6 +260,23 @@ TEST_F(Http2HeaderValidatorTest, ValidateRequestHeaderMapDropUnderscoreHeaders)
{{":scheme", "https"}, {":method", "GET"}, {":path", "/"}, {":authority", "envoy.com"}}));
}

TEST_F(Http2HeaderValidatorTest, ValidateRequestHeaderMapDropDuplicateUnderscoreHeaders) {
::Envoy::Http::TestRequestHeaderMapImpl headers{{":scheme", "https"},
{":method", "GET"},
{":path", "/"},
{":authority", "envoy.com"},
{"x_foo", "bar"}};
headers.addCopy("x_foo", "baz");
auto uhv = createH2ServerUhv(drop_headers_with_underscores_config);

EXPECT_ACCEPT(uhv->validateRequestHeaders(headers));
EXPECT_ACCEPT(uhv->transformRequestHeaders(headers));
EXPECT_EQ(
headers,
::Envoy::Http::TestRequestHeaderMapImpl(
{{":scheme", "https"}, {":method", "GET"}, {":path", "/"}, {":authority", "envoy.com"}}));
}

TEST_F(Http2HeaderValidatorTest, ValidateRequestHeaderMapRejectUnderscoreHeaders) {
::Envoy::Http::TestRequestHeaderMapImpl headers{{":scheme", "https"},
{":method", "GET"},
Expand Down