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Merge pull request #780 from libexpat/xml-dtd-undefined-fix-ext-parser-create-null-dereference

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xmlparse.c: Fix `NULL` pointer dereference in `setContext` via `XML_ExternalEntityParserCreate` for `XML_DTD` undefined
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Sebastian Pipping 2023-10-24 17:05:31 +02:00 • committed by GitHub
commit 9e1c41343c
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2 changed files with 23 additions and 0 deletions
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4
expat/lib/xmlparse.c
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@ -6645,6 +6645,10 @@ getContext(XML_Parser parser) {
static XML_Bool
setContext(XML_Parser parser, const XML_Char *context) {
if (context == NULL) {
return XML_FALSE;
}
DTD *const dtd = parser->m_dtd; /* save one level of indirection */
const XML_Char *s = context;

19
expat/tests/misc_tests.c
View file

@ -389,6 +389,23 @@ START_TEST(test_misc_tag_mismatch_reset_leak) {
}
END_TEST
START_TEST(test_misc_create_external_entity_parser_with_null_context) {
// With XML_DTD undefined, the only supported case of external entities
// is pattern "<!ENTITY entity123 SYSTEM 'filename123'>". A NULL context
// was causing a segfault through a null pointer dereference in function
// setContext, previously.
XML_Parser parser = XML_ParserCreate(NULL);
XML_Parser ext_parser = XML_ExternalEntityParserCreate(parser, NULL, NULL);
#ifdef XML_DTD
assert_true(ext_parser != NULL);
XML_ParserFree(ext_parser);
#else
assert_true(ext_parser == NULL);
#endif /* XML_DTD */
XML_ParserFree(parser);
}
END_TEST
void
make_miscellaneous_test_case(Suite *s) {
TCase *tc_misc = tcase_create("miscellaneous tests");
@ -409,4 +426,6 @@ make_miscellaneous_test_case(Suite *s) {
tcase_add_test__ifdef_xml_dtd(
tc_misc, test_misc_deny_internal_entity_closing_doctype_issue_317);
tcase_add_test(tc_misc, test_misc_tag_mismatch_reset_leak);
tcase_add_test(tc_misc,
test_misc_create_external_entity_parser_with_null_context);
}