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Posted to commits@trafficserver.apache.org by bn...@apache.org on 2026/09/22 20:22:32 UTC
(trafficserver) branch master updated: Handle all cachekey regex capture groups (#13653)
This is an automated email from the ASF dual-hosted git repository.
bneradt pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/trafficserver.git
The following commit(s) were added to refs/heads/master by this push:
new f39ee5f5b7 Handle all cachekey regex capture groups (#13653)
f39ee5f5b7 is described below
commit f39ee5f5b78722252689c23a46fadd577a2a95ea
Author: Brian Neradt <br...@gmail.com>
AuthorDate: Tue Sep 22 15:22:26 2026 -0500
Handle all cachekey regex capture groups (#13653)
Cachekey patterns with ten or more capture groups can crash ATS when
building a cache key because a successful match leaves the capture
vector empty. Replacement patterns also reject valid group references
when the match buffer is too small or trailing optional groups do not
participate in a match.
This patch sizes match buffers from the validated pattern capture count
and checks replacement references at initialization. Unmatched optional
groups contribute empty strings. Unit and replay coverage verifies full
cache keys across the capture limit and optional-group combinations.
Fixes: #13638
Co-authored-by: GPT-6 Astra Light
Co-authored-by: GPT-6 Astra Medium
Co-authored-by: bneradt <bn...@yahooinc.com>
---
plugins/cachekey/pattern.cc | 37 ++-
plugins/cachekey/pattern.h | 3 +-
plugins/cachekey/unit_tests/pattern_test.cc | 42 ++-
.../pluginTest/cachekey/cachekey_capture.test.py | 19 ++
.../pluginTest/cachekey/capture.replay.yaml | 294 +++++++++++++++++++++
5 files changed, 376 insertions(+), 19 deletions(-)
diff --git a/plugins/cachekey/pattern.cc b/plugins/cachekey/pattern.cc
index 515cd8f4f0..45743815e2 100644
--- a/plugins/cachekey/pattern.cc
+++ b/plugins/cachekey/pattern.cc
@@ -152,7 +152,7 @@ Pattern::process(const String &subject, StringVector &result)
} else {
/* Replacement was not provided so return all capturing groups except the group zero. */
StringVector captures;
- if (capture(subject, captures)) {
+ if (capture(subject, captures) && !captures.empty()) {
if (captures.size() == 1) {
result.push_back(captures[0]);
} else {
@@ -210,7 +210,7 @@ Pattern::capture(const String &subject, StringVector &result)
return false;
}
- RegexMatches matches;
+ RegexMatches matches(_captureCount + 1);
int matchCount = _re.exec(subject, matches, RE_NOTEMPTY);
if (matchCount < 0) {
if (matchCount != RE_ERROR_NOMATCH) {
@@ -219,7 +219,7 @@ Pattern::capture(const String &subject, StringVector &result)
return false;
}
- for (int i = 0; i < matchCount; i++) {
+ for (int i = 0; i < matches.size(); i++) {
std::string_view capture = matches[i];
String dst(capture.data(), capture.length());
@@ -246,7 +246,7 @@ Pattern::replace(const String &subject, String &result)
return false;
}
- RegexMatches matches;
+ RegexMatches matches(_captureCount + 1);
int matchCount = _re.exec(subject, matches, RE_NOTEMPTY);
if (matchCount < 0) {
if (matchCount != RE_ERROR_NOMATCH) {
@@ -255,18 +255,11 @@ Pattern::replace(const String &subject, String &result)
return false;
}
- /* Verify the replacement has the right number of matching groups */
- for (int i = 0; i < _tokenCount; i++) {
- if (_tokens[i] >= matchCount) {
- CacheKeyError("invalid reference in replacement string: $%d", _tokens[i]);
- return false;
- }
- }
-
int previous = 0;
for (int i = 0; i < _tokenCount; i++) {
- int replIndex = _tokens[i];
- std::string_view capture = matches[replIndex];
+ int replIndex = _tokens[i];
+ // Trailing optional groups may not participate in this match.
+ std::string_view capture = (replIndex < matches.size()) ? matches[replIndex] : std::string_view{""};
String src(_replacement, _tokenOffset[i], 2);
String dst(capture.data(), capture.length());
@@ -304,6 +297,12 @@ Pattern::compile()
return false;
}
+ _captureCount = _re.get_capture_count();
+ if (_captureCount < 0) {
+ CacheKeyError("failed to get capture count for pattern '%s'", _pattern.c_str());
+ return false;
+ }
+
if (!_replace) {
/* No replacement necessary - we are done. */
return true;
@@ -336,6 +335,16 @@ Pattern::compile()
}
}
+ if (success) {
+ for (int i = 0; i < _tokenCount; i++) {
+ if (_tokens[i] > _captureCount) {
+ CacheKeyError("invalid reference $%d in replacement '%s': pattern defines only %d group(s)", _tokens[i],
+ _replacement.c_str(), _captureCount);
+ return false;
+ }
+ }
+ }
+
return success;
}
diff --git a/plugins/cachekey/pattern.h b/plugins/cachekey/pattern.h
index e3f441d27a..1392849b37 100644
--- a/plugins/cachekey/pattern.h
+++ b/plugins/cachekey/pattern.h
@@ -50,7 +50,8 @@ public:
private:
bool compile();
- Regex _re; /**< @brief Regex compiled object */
+ Regex _re; /**< @brief Regex compiled object */
+ int32_t _captureCount = 0; ///< Number of capture groups defined by the compiled pattern.
String _pattern; /**< @brief Regex pattern string, containing regex patterns and capturing groups. */
String
diff --git a/plugins/cachekey/unit_tests/pattern_test.cc b/plugins/cachekey/unit_tests/pattern_test.cc
index 2b9adb90d4..d0637e0d35 100644
--- a/plugins/cachekey/unit_tests/pattern_test.cc
+++ b/plugins/cachekey/unit_tests/pattern_test.cc
@@ -202,13 +202,47 @@ TEST_CASE("Pattern compile and match behavior", "[cachekey][pattern]")
CHECK(res == "num=123;");
}
- SECTION("Replacement with invalid group reference")
+ SECTION("Replacement with invalid group reference fails at initialization")
{
Pattern p;
- REQUIRE(p.init("(\\w+)", "$5", true)); // only 2 groups (0 and 1)
+
+ CHECK_FALSE(p.init("(\\w+)", "$5", true));
+ CHECK_FALSE(p.init("(a)(b)?", "$3", true));
+ CHECK_FALSE(p.init("literal", "$1", true));
+ }
+
+ SECTION("Replacement with optional capture groups")
+ {
+ Pattern p;
+
+ REQUIRE(p.init("^(a)(b)?(c)?$", "$1-$2-$3", true));
+ for (const auto &[subject, expected] : {
+ std::pair{"a", "a--" },
+ {"ab", "a-b-" },
+ {"ac", "a--c" },
+ {"abc", "a-b-c"}
+ }) {
+ String res;
+
+ REQUIRE(p.replace(subject, res));
+ CHECK(res == expected);
+ }
+ }
+
+ SECTION("Capture and replacement beyond the inline match buffer")
+ {
+ Pattern p;
+ StringVector result;
+
+ REQUIRE(p.init("(a)(b)(c)(d)(e)(f)(g)(h)(i)(j)(k)(l)"));
+ REQUIRE(p.process("abcdefghijkl", result));
+ CHECK(result == StringVector{"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l"});
+
+ REQUIRE(p.init("(a)(b)(c)(d)(e)(f)(g)(h)(i)(j)(k)(l)", "$9$1", true));
String res;
- // Should fail because $5 doesn't exist
- CHECK(p.replace("test", res) == false);
+
+ REQUIRE(p.replace("abcdefghijkl", res));
+ CHECK(res == "ia");
}
SECTION("process() method - capture mode (no replacement)")
diff --git a/tests/gold_tests/pluginTest/cachekey/cachekey_capture.test.py b/tests/gold_tests/pluginTest/cachekey/cachekey_capture.test.py
new file mode 100644
index 0000000000..72451b0440
--- /dev/null
+++ b/tests/gold_tests/pluginTest/cachekey/cachekey_capture.test.py
@@ -0,0 +1,19 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements. See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership. The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License. You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+Test.Summary = 'Verify cachekey patterns preserve all capture groups.'
+Test.SkipUnless(Condition.PluginExists('cachekey.so'), Condition.PluginExists('xdebug.so'))
+Test.ATSReplayTest(replay_file='capture.replay.yaml')
diff --git a/tests/gold_tests/pluginTest/cachekey/capture.replay.yaml b/tests/gold_tests/pluginTest/cachekey/capture.replay.yaml
new file mode 100644
index 0000000000..3c5f668f23
--- /dev/null
+++ b/tests/gold_tests/pluginTest/cachekey/capture.replay.yaml
@@ -0,0 +1,294 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements. See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership. The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License. You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+meta:
+ version: '1.0'
+
+autest:
+ description: 'Cachekey captures beyond the default regex match capacity'
+ server:
+ name: server
+ client:
+ name: client
+ ats:
+ name: ts
+ records_config:
+ proxy.config.diags.debug.enabled: 1
+ proxy.config.diags.debug.tags: cachekey
+ plugin_config:
+ - 'xdebug.so --enable=x-cache-key'
+ remap_config:
+ - from: 'http://nine.example.com/'
+ to: 'http://127.0.0.1:{SERVER_HTTP_PORT}/'
+ plugins:
+ - name: cachekey.so
+ args:
+ - '--static-prefix=capture'
+ - '--capture-path=(a)(b)(c)(d)(e)(f)(g)(h)(i)'
+ - from: 'http://ten.example.com/'
+ to: 'http://127.0.0.1:{SERVER_HTTP_PORT}/'
+ plugins:
+ - name: cachekey.so
+ args:
+ - '--static-prefix=capture'
+ - '--capture-path=(a)(b)(c)(d)(e)(f)(g)(h)(i)(j)'
+ - from: 'http://twelve.example.com/'
+ to: 'http://127.0.0.1:{SERVER_HTTP_PORT}/'
+ plugins:
+ - name: cachekey.so
+ args:
+ - '--static-prefix=capture'
+ - '--capture-path=(a)(b)(c)(d)(e)(f)(g)(h)(i)(j)(k)(l)'
+ - from: 'http://replace.example.com/'
+ to: 'http://127.0.0.1:{SERVER_HTTP_PORT}/'
+ plugins:
+ - name: cachekey.so
+ args:
+ - '--static-prefix=capture'
+ - '--capture-path=/(a)(b)(c)(d)(e)(f)(g)(h)(i)(j)(k)(l)/$9$1/'
+ - from: 'http://whole.example.com/'
+ to: 'http://127.0.0.1:{SERVER_HTTP_PORT}/'
+ plugins:
+ - name: cachekey.so
+ args:
+ - '--static-prefix=capture'
+ - '--capture-path=abcdef'
+ - from: 'http://no-match.example.com/'
+ to: 'http://127.0.0.1:{SERVER_HTTP_PORT}/'
+ plugins:
+ - name: cachekey.so
+ args:
+ - '--static-prefix=capture'
+ - '--capture-path=(z)'
+ - from: 'http://optional.example.com/'
+ to: 'http://127.0.0.1:{SERVER_HTTP_PORT}/'
+ plugins:
+ - name: cachekey.so
+ args:
+ - '--static-prefix=capture'
+ - '--capture-path=/(a)(b)?(c)?/$1-$2-$3/'
+
+sessions:
+- transactions:
+ - client-request:
+ method: GET
+ url: /abcdefghi
+ version: '1.1'
+ headers:
+ fields:
+ - [Host, nine.example.com]
+ - [uuid, nine]
+ - [X-Debug, x-cache-key]
+ server-response:
+ status: 200
+ reason: OK
+ headers:
+ fields:
+ - [Content-Length, 0]
+ proxy-response:
+ status: 200
+ headers:
+ fields:
+ - [X-Cache-Key, {value: '/capture/a/b/c/d/e/f/g/h/i', as: equal}]
+
+ - client-request:
+ method: GET
+ url: /abcdefghij
+ version: '1.1'
+ headers:
+ fields:
+ - [Host, ten.example.com]
+ - [uuid, ten]
+ - [X-Debug, x-cache-key]
+ server-response:
+ status: 200
+ reason: OK
+ headers:
+ fields:
+ - [Content-Length, 0]
+ proxy-response:
+ status: 200
+ headers:
+ fields:
+ - [X-Cache-Key, {value: '/capture/a/b/c/d/e/f/g/h/i/j', as: equal}]
+
+ - client-request:
+ method: GET
+ url: /abcdefghijkl
+ version: '1.1'
+ headers:
+ fields:
+ - [Host, twelve.example.com]
+ - [uuid, twelve]
+ - [X-Debug, x-cache-key]
+ server-response:
+ status: 200
+ reason: OK
+ headers:
+ fields:
+ - [Content-Length, 0]
+ proxy-response:
+ status: 200
+ headers:
+ fields:
+ - [X-Cache-Key, {value: '/capture/a/b/c/d/e/f/g/h/i/j/k/l', as: equal}]
+
+ - client-request:
+ method: GET
+ url: /abcdefghijkl
+ version: '1.1'
+ headers:
+ fields:
+ - [Host, replace.example.com]
+ - [uuid, replace]
+ - [X-Debug, x-cache-key]
+ server-response:
+ status: 200
+ reason: OK
+ headers:
+ fields:
+ - [Content-Length, 0]
+ proxy-response:
+ status: 200
+ headers:
+ fields:
+ - [X-Cache-Key, {value: '/capture/ia', as: equal}]
+
+ - client-request:
+ method: GET
+ url: /abcdef
+ version: '1.1'
+ headers:
+ fields:
+ - [Host, whole.example.com]
+ - [uuid, whole]
+ - [X-Debug, x-cache-key]
+ server-response:
+ status: 200
+ reason: OK
+ headers:
+ fields:
+ - [Content-Length, 0]
+ proxy-response:
+ status: 200
+ headers:
+ fields:
+ - [X-Cache-Key, {value: '/capture/abcdef', as: equal}]
+
+ - client-request:
+ method: GET
+ url: /abcdef
+ version: '1.1'
+ headers:
+ fields:
+ - [Host, no-match.example.com]
+ - [uuid, no-match]
+ - [X-Debug, x-cache-key]
+ server-response:
+ status: 200
+ reason: OK
+ headers:
+ fields:
+ - [Content-Length, 0]
+ proxy-response:
+ status: 200
+ headers:
+ fields:
+ - [X-Cache-Key, {value: '/capture', as: equal}]
+
+ - client-request:
+ method: GET
+ url: /a
+ version: '1.1'
+ headers:
+ fields:
+ - [Host, optional.example.com]
+ - [uuid, optional-a]
+ - [X-Debug, x-cache-key]
+ server-response:
+ status: 200
+ reason: OK
+ headers:
+ fields:
+ - [Content-Length, 0]
+ proxy-response:
+ status: 200
+ headers:
+ fields:
+ - [X-Cache-Key, {value: '/capture/a--', as: equal}]
+
+ - client-request:
+ method: GET
+ url: /ab
+ version: '1.1'
+ headers:
+ fields:
+ - [Host, optional.example.com]
+ - [uuid, optional-ab]
+ - [X-Debug, x-cache-key]
+ server-response:
+ status: 200
+ reason: OK
+ headers:
+ fields:
+ - [Content-Length, 0]
+ proxy-response:
+ status: 200
+ headers:
+ fields:
+ - [X-Cache-Key, {value: '/capture/a-b-', as: equal}]
+
+ - client-request:
+ method: GET
+ url: /ac
+ version: '1.1'
+ headers:
+ fields:
+ - [Host, optional.example.com]
+ - [uuid, optional-ac]
+ - [X-Debug, x-cache-key]
+ server-response:
+ status: 200
+ reason: OK
+ headers:
+ fields:
+ - [Content-Length, 0]
+ proxy-response:
+ status: 200
+ headers:
+ fields:
+ - [X-Cache-Key, {value: '/capture/a--c', as: equal}]
+
+ - client-request:
+ method: GET
+ url: /abc
+ version: '1.1'
+ headers:
+ fields:
+ - [Host, optional.example.com]
+ - [uuid, optional-abc]
+ - [X-Debug, x-cache-key]
+ server-response:
+ status: 200
+ reason: OK
+ headers:
+ fields:
+ - [Content-Length, 0]
+ proxy-response:
+ status: 200
+ headers:
+ fields:
+ - [X-Cache-Key, {value: '/capture/a-b-c', as: equal}]