From 9ceb7cb555b1355bbd7c26550c46000d05fd1e37 Mon Sep 17 00:00:00 2001 From: Alex Henrie Date: Wed, 15 Nov 2023 09:36:06 -0700 Subject: [PATCH] QMimeDatabase: handle buggy type definitions with circular inheritance This fixes an infinite loop reported by a user who had both the definition of text/javascript from shared-mime-info 2.3 and the definition of text/javascript from shared-mime-info 2.4 installed at the same time. In 2.3, text/javascript is a subtype of application/ecmascript, but in 2.4 application/ecmascript is a subtype of text/javascript. Having both at the same time resulted in circular inheritance. https://gitlab.freedesktop.org/xdg/shared-mime-info/-/merge_requests/258#note_2167707 [ChangeLog][QtCore][QMimeDatabase] Added code to detect and break circular inheritance loops in the MIME data, which were causing infinite loops Pick-to: 6.5 Change-Id: Ic207b1593a49c7bb88e4fd810d8f88aa630087ce Reviewed-by: Thiago Macieira Reviewed-by: David Faure (cherry picked from commit 54656da9ace06caf4a0eeb1832989c0ab211a4a0) Reviewed-by: Alex Henrie --- src/corelib/mimetypes/qmimedatabase.cpp | 9 +++++++-- src/corelib/mimetypes/qmimetype.cpp | 7 +++++-- .../qmimedatabase/circular-inheritance.xml | 13 +++++++++++++ .../qmimedatabase-cache/CMakeLists.txt | 1 + .../qmimedatabase/qmimedatabase-xml/CMakeLists.txt | 1 + .../mimetypes/qmimedatabase/tst_qmimedatabase.cpp | 8 ++++++++ 6 files changed, 35 insertions(+), 4 deletions(-) create mode 100644 tests/auto/corelib/mimetypes/qmimedatabase/circular-inheritance.xml diff --git a/src/corelib/mimetypes/qmimedatabase.cpp b/src/corelib/mimetypes/qmimedatabase.cpp index e39ca68fe1e..f2786f3723c 100644 --- a/src/corelib/mimetypes/qmimedatabase.cpp +++ b/src/corelib/mimetypes/qmimedatabase.cpp @@ -10,6 +10,7 @@ #include "qmimeprovider_p.h" #include "qmimetype_p.h" +#include #include #include @@ -509,6 +510,7 @@ QList QMimeDatabasePrivate::allMimeTypes() bool QMimeDatabasePrivate::inherits(const QString &mime, const QString &parent) { const QString resolvedParent = resolveAlias(parent); + QDuplicateTracker seen; std::stack toCheck; toCheck.push(mime); while (!toCheck.empty()) { @@ -517,8 +519,11 @@ bool QMimeDatabasePrivate::inherits(const QString &mime, const QString &parent) const QString mimeName = toCheck.top(); toCheck.pop(); const auto parentList = parents(mimeName); - for (const QString &par : parentList) - toCheck.push(resolveAlias(par)); + for (const QString &par : parentList) { + const QString resolvedPar = resolveAlias(par); + if (!seen.hasSeen(resolvedPar)) + toCheck.push(resolvedPar); + } } return false; } diff --git a/src/corelib/mimetypes/qmimetype.cpp b/src/corelib/mimetypes/qmimetype.cpp index 1ad41ac4314..94df48c6959 100644 --- a/src/corelib/mimetypes/qmimetype.cpp +++ b/src/corelib/mimetypes/qmimetype.cpp @@ -358,14 +358,17 @@ QStringList QMimeType::parentMimeTypes() const static void collectParentMimeTypes(const QString &mime, QStringList &allParents) { const QStringList parents = QMimeDatabasePrivate::instance()->mimeParents(mime); + QStringList newParents; for (const QString &parent : parents) { // I would use QSet, but since order matters I better not - if (!allParents.contains(parent)) + if (!allParents.contains(parent)) { allParents.append(parent); + newParents.append(parent); + } } // We want a breadth-first search, so that the least-specific parent (octet-stream) is last // This means iterating twice, unfortunately. - for (const QString &parent : parents) + for (const QString &parent : newParents) collectParentMimeTypes(parent, allParents); } diff --git a/tests/auto/corelib/mimetypes/qmimedatabase/circular-inheritance.xml b/tests/auto/corelib/mimetypes/qmimedatabase/circular-inheritance.xml new file mode 100644 index 00000000000..466f039803d --- /dev/null +++ b/tests/auto/corelib/mimetypes/qmimedatabase/circular-inheritance.xml @@ -0,0 +1,13 @@ + + + + It's more accurate to say that ECMAScript is a subset of JavaScript + + + + + than to say that JavaScript is a subset of ECMAScript + + + + diff --git a/tests/auto/corelib/mimetypes/qmimedatabase/qmimedatabase-cache/CMakeLists.txt b/tests/auto/corelib/mimetypes/qmimedatabase/qmimedatabase-cache/CMakeLists.txt index d9e055380e5..bf4a73545cd 100644 --- a/tests/auto/corelib/mimetypes/qmimedatabase/qmimedatabase-cache/CMakeLists.txt +++ b/tests/auto/corelib/mimetypes/qmimedatabase/qmimedatabase-cache/CMakeLists.txt @@ -23,6 +23,7 @@ qt_internal_add_test(tst_qmimedatabase-cache #"mime/packages/freedesktop.org.xml" #) set(testdata_resource_files + "../circular-inheritance.xml" "../invalid-magic1.xml" "../invalid-magic2.xml" "../invalid-magic3.xml" diff --git a/tests/auto/corelib/mimetypes/qmimedatabase/qmimedatabase-xml/CMakeLists.txt b/tests/auto/corelib/mimetypes/qmimedatabase/qmimedatabase-xml/CMakeLists.txt index e44ea7b5ebf..287ad0b4cf7 100644 --- a/tests/auto/corelib/mimetypes/qmimedatabase/qmimedatabase-xml/CMakeLists.txt +++ b/tests/auto/corelib/mimetypes/qmimedatabase/qmimedatabase-xml/CMakeLists.txt @@ -23,6 +23,7 @@ qt_internal_add_test(tst_qmimedatabase-xml #"mime/packages/freedesktop.org.xml" #) set(testdata_resource_files + "../circular-inheritance.xml" "../invalid-magic1.xml" "../invalid-magic2.xml" "../invalid-magic3.xml" diff --git a/tests/auto/corelib/mimetypes/qmimedatabase/tst_qmimedatabase.cpp b/tests/auto/corelib/mimetypes/qmimedatabase/tst_qmimedatabase.cpp index ee9e430b911..b67304bde86 100644 --- a/tests/auto/corelib/mimetypes/qmimedatabase/tst_qmimedatabase.cpp +++ b/tests/auto/corelib/mimetypes/qmimedatabase/tst_qmimedatabase.cpp @@ -38,6 +38,7 @@ static const char *const additionalMimeFiles[] = { "yast2-metapackage-handler-mi "invalid-magic2.xml", "invalid-magic3.xml", "magic-and-hierarchy.xml", + "circular-inheritance.xml", 0 }; static const auto s_resourcePrefix = ":/qt-project.org/qmime/"_L1; @@ -403,6 +404,13 @@ void tst_QMimeDatabase::inheritance() const QMimeType mswordTemplate = db.mimeTypeForName(QString::fromLatin1("application/msword-template")); QVERIFY(mswordTemplate.isValid()); QVERIFY(mswordTemplate.inherits(QLatin1String("application/msword"))); + + // Check that buggy type definitions that have circular inheritance don't cause an infinite + // loop, especially when resolving a conflict between the file's name and its contents + const QMimeType ecmascript = db.mimeTypeForName(QString::fromLatin1("application/ecmascript")); + QVERIFY(ecmascript.allAncestors().contains("text/plain")); + const QMimeType javascript = db.mimeTypeForFileNameAndData("xml.js", ""); + QVERIFY(javascript.inherits(QString::fromLatin1("text/javascript"))); } void tst_QMimeDatabase::aliases()