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173 lines
6.3 KiB
173 lines
6.3 KiB
commit cd3b344e0dbd19a812d0b4f34f9d089ed7c5c411
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Author: Tomas Korbar <tkorbar@redhat.com>
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Date: Tue Mar 19 15:12:18 2024 +0100
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Fix CVE-2024-28757
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Upstream PRs #841 and #842
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diff --git a/expat/lib/xmlparse.c b/expat/lib/xmlparse.c
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index 2ae64e9..0896b16 100644
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--- a/expat/lib/xmlparse.c
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+++ b/expat/lib/xmlparse.c
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@@ -6164,7 +6164,7 @@ storeEntityValue(XML_Parser parser, const ENCODING *enc,
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dtd->keepProcessing = dtd->standalone;
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goto endEntityValue;
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}
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- if (entity->open) {
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+ if (entity->open || (entity == parser->m_declEntity)) {
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if (enc == parser->m_encoding)
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parser->m_eventPtr = entityTextPtr;
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result = XML_ERROR_RECURSIVE_ENTITY_REF;
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@@ -7680,6 +7680,8 @@ copyString(const XML_Char *s, const XML_Memory_Handling_Suite *memsuite) {
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static float
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accountingGetCurrentAmplification(XML_Parser rootParser) {
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+ // 1.........1.........12 => 22
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+ const size_t lenOfShortestInclude = sizeof("<!ENTITY a SYSTEM 'b'>") - 1;
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const XmlBigCount countBytesOutput
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= rootParser->m_accounting.countBytesDirect
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+ rootParser->m_accounting.countBytesIndirect;
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@@ -7687,7 +7689,9 @@ accountingGetCurrentAmplification(XML_Parser rootParser) {
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= rootParser->m_accounting.countBytesDirect
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? (countBytesOutput
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/ (float)(rootParser->m_accounting.countBytesDirect))
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- : 1.0f;
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+ : ((lenOfShortestInclude
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+ + rootParser->m_accounting.countBytesIndirect)
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+ / (float)lenOfShortestInclude);
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assert(! rootParser->m_parentParser);
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return amplificationFactor;
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}
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diff --git a/expat/tests/runtests.c b/expat/tests/runtests.c
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index 941f61d..93adc45 100644
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--- a/expat/tests/runtests.c
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+++ b/expat/tests/runtests.c
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@@ -1788,6 +1788,48 @@ START_TEST(test_wfc_no_recursive_entity_refs) {
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}
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END_TEST
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+START_TEST(test_recursive_external_parameter_entity_2) {
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+ struct TestCase {
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+ const char *doc;
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+ enum XML_Status expectedStatus;
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+ };
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+
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+ struct TestCase cases[] = {
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+ {"<!ENTITY % p1 '%p1;'>", XML_STATUS_ERROR},
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+ {"<!ENTITY % p1 '%p1;'>"
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+ "<!ENTITY % p1 'first declaration wins'>",
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+ XML_STATUS_ERROR},
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+ {"<!ENTITY % p1 'first declaration wins'>"
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+ "<!ENTITY % p1 '%p1;'>",
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+ XML_STATUS_OK},
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+ {"<!ENTITY % p1 '%p1;'>", XML_STATUS_OK},
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+ };
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+
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+ for (size_t i = 0; i < sizeof(cases) / sizeof(cases[0]); i++) {
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+ const char *const doc = cases[i].doc;
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+ const enum XML_Status expectedStatus = cases[i].expectedStatus;
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+
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+ XML_Parser parser = XML_ParserCreate(NULL);
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+ assert_true(parser != NULL);
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+
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+ XML_Parser ext_parser = XML_ExternalEntityParserCreate(parser, NULL, NULL);
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+ assert_true(ext_parser != NULL);
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+
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+ const enum XML_Status actualStatus
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+ = _XML_Parse_SINGLE_BYTES(ext_parser, doc, (int)strlen(doc), XML_TRUE);
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+
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+ assert_true(actualStatus == expectedStatus);
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+ if (actualStatus != XML_STATUS_OK) {
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+ assert_true(XML_GetErrorCode(ext_parser)
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+ == XML_ERROR_RECURSIVE_ENTITY_REF);
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+ }
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+
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+ XML_ParserFree(ext_parser);
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+ XML_ParserFree(parser);
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+ }
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+}
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+END_TEST
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+
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/* Test incomplete external entities are faulted */
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START_TEST(test_ext_entity_invalid_parse) {
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const char *text = "<!DOCTYPE doc [\n"
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@@ -12719,6 +12761,60 @@ START_TEST(test_helper_unsigned_char_to_printable) {
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fail("unsignedCharToPrintable result mistaken");
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}
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END_TEST
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+
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+START_TEST(test_amplification_isolated_external_parser) {
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+ // NOTE: Length 44 is precisely twice the length of "<!ENTITY a SYSTEM 'b'>"
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+ // (22) that is used in function accountingGetCurrentAmplification in
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+ // xmlparse.c.
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+ // 1.........1.........1.........1.........1..4 => 44
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+ const char doc[] = "<!ENTITY % p1 '123456789_123456789_1234567'>";
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+ const int docLen = (int)sizeof(doc) - 1;
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+ const float maximumToleratedAmplification = 2.0f;
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+
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+ struct TestCase {
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+ int offsetOfThreshold;
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+ enum XML_Status expectedStatus;
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+ };
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+
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+ struct TestCase cases[] = {
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+ {-2, XML_STATUS_ERROR}, {-1, XML_STATUS_ERROR}, {0, XML_STATUS_ERROR},
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+ {+1, XML_STATUS_OK}, {+2, XML_STATUS_OK},
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+ };
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+
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+ for (size_t i = 0; i < sizeof(cases) / sizeof(cases[0]); i++) {
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+ const int offsetOfThreshold = cases[i].offsetOfThreshold;
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+ const enum XML_Status expectedStatus = cases[i].expectedStatus;
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+ const unsigned long long activationThresholdBytes
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+ = docLen + offsetOfThreshold;
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+
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+ XML_Parser parser = XML_ParserCreate(NULL);
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+ assert_true(parser != NULL);
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+
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+ assert_true(XML_SetBillionLaughsAttackProtectionMaximumAmplification(
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+ parser, maximumToleratedAmplification)
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+ == XML_TRUE);
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+ assert_true(XML_SetBillionLaughsAttackProtectionActivationThreshold(
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+ parser, activationThresholdBytes)
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+ == XML_TRUE);
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+
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+ XML_Parser ext_parser = XML_ExternalEntityParserCreate(parser, NULL, NULL);
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+ assert_true(ext_parser != NULL);
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+
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+ const enum XML_Status actualStatus
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+ = _XML_Parse_SINGLE_BYTES(ext_parser, doc, docLen, XML_TRUE);
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+
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+ assert_true(actualStatus == expectedStatus);
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+ if (actualStatus != XML_STATUS_OK) {
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+ assert_true(XML_GetErrorCode(ext_parser)
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+ == XML_ERROR_AMPLIFICATION_LIMIT_BREACH);
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+ }
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+
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+ XML_ParserFree(ext_parser);
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+ XML_ParserFree(parser);
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+ }
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+}
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+END_TEST
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+
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#endif // defined(XML_DTD)
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static Suite *
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@@ -12871,6 +12967,8 @@ make_suite(void) {
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tcase_add_test__ifdef_xml_dtd(tc_basic, test_skipped_parameter_entity);
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tcase_add_test__ifdef_xml_dtd(tc_basic,
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test_recursive_external_parameter_entity);
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+ tcase_add_test__ifdef_xml_dtd(tc_basic,
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+ test_recursive_external_parameter_entity_2);
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tcase_add_test(tc_basic, test_undefined_ext_entity_in_external_dtd);
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tcase_add_test(tc_basic, test_suspend_xdecl);
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tcase_add_test(tc_basic, test_abort_epilog);
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@@ -13120,6 +13218,7 @@ make_suite(void) {
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tcase_add_test(tc_accounting, test_accounting_precision);
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tcase_add_test(tc_accounting, test_billion_laughs_attack_protection_api);
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tcase_add_test(tc_accounting, test_helper_unsigned_char_to_printable);
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+ tcase_add_test(tc_accounting, test_amplification_isolated_external_parser);
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#endif
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return s;
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