QStandardPaths: Don't change permissions of XDG_RUNTIME_DIR

Conform to the XDG Base Directory Specification: "If, when attempting to write a file, the destination directory is non-existent an attempt should be made to create it with permission 0700. If the destination directory exists already the permissions should not be changed." At the same time the spec states about XDG_RUNTIME_DIR that "its Unix access mode MUST be 0700", so don't consider the directory with wrong permissions correct and use a fallback. Task-number: QTBUG-68338 Pick-to: 5.15 5.12 Change-Id: I03c6b35b3f7d5ceb8e6326695bfc8207da92ea67 Reviewed-by: Thiago Macieira <[email protected]> Reviewed-by: David Faure <[email protected]>
fwcd · Nov 30, 2020 · 68de00e · 68de00e
1 parent d27d2b5
commit 68de00e
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Showing 2 changed files with 37 additions and 30 deletions.
diff --git a/src/corelib/io/qstandardpaths_unix.cpp b/src/corelib/io/qstandardpaths_unix.cpp
@@ -94,6 +94,30 @@ static QLatin1String xdg_key_name(QStandardPaths::StandardLocation type)
 }
 #endif
 
+static QByteArray unixPermissionsText(QFile::Permissions permissions)
+{
+    mode_t perms = 0;
+    if (permissions & QFile::ReadOwner)
+        perms |= S_IRUSR;
+    if (permissions & QFile::WriteOwner)
+        perms |= S_IWUSR;
+    if (permissions & QFile::ExeOwner)
+        perms |= S_IXUSR;
+    if (permissions & QFile::ReadGroup)
+        perms |= S_IRGRP;
+    if (permissions & QFile::WriteGroup)
+        perms |= S_IWGRP;
+    if (permissions & QFile::ExeGroup)
+        perms |= S_IXGRP;
+    if (permissions & QFile::ReadOther)
+        perms |= S_IROTH;
+    if (permissions & QFile::WriteOther)
+        perms |= S_IWOTH;
+    if (permissions & QFile::ExeOther)
+        perms |= S_IXOTH;
+    return '0' + QByteArray::number(perms, 8);
+}
+
 static bool checkXdgRuntimeDir(const QString &xdgRuntimeDir)
 {
     auto describeMetaData = [](const QFileSystemMetaData &metaData) -> QByteArray {
@@ -113,27 +137,7 @@ static bool checkXdgRuntimeDir(const QString &xdgRuntimeDir)
         else
             description += "a block device";
 
-        // convert QFileSystemMetaData permissions back to Unix
-        mode_t perms = 0;
-        if (metaData.permissions() & QFile::ReadOwner)
-            perms |= S_IRUSR;
-        if (metaData.permissions() & QFile::WriteOwner)
-            perms |= S_IWUSR;
-        if (metaData.permissions() & QFile::ExeOwner)
-            perms |= S_IXUSR;
-        if (metaData.permissions() & QFile::ReadGroup)
-            perms |= S_IRGRP;
-        if (metaData.permissions() & QFile::WriteGroup)
-            perms |= S_IWGRP;
-        if (metaData.permissions() & QFile::ExeGroup)
-            perms |= S_IXGRP;
-        if (metaData.permissions() & QFile::ReadOther)
-            perms |= S_IROTH;
-        if (metaData.permissions() & QFile::WriteOther)
-            perms |= S_IWOTH;
-        if (metaData.permissions() & QFile::ExeOther)
-            perms |= S_IXOTH;
-        description += " permissions 0" + QByteArray::number(perms, 8);
+        description += " permissions " + unixPermissionsText(metaData.permissions());
 
         return description
                 + " owned by UID " + QByteArray::number(metaData.userId())
@@ -186,14 +190,11 @@ static bool checkXdgRuntimeDir(const QString &xdgRuntimeDir)
 
     // "and he MUST be the only one having read and write access to it. Its Unix access mode MUST be 0700."
     if (metaData.permissions() != wantedPerms) {
-        // attempt to correct:
-        QSystemError error;
-        if (!QFileSystemEngine::setPermissions(entry, wantedPerms, error)) {
-            qErrnoWarning("QStandardPaths: could not set correct permissions on runtime directory "
-                          "'%ls', which is %s", qUtf16Printable(xdgRuntimeDir),
-                          describeMetaData(metaData).constData());
-            return false;
-        }
+        qWarning("QStandardPaths: wrong permissions on runtime directory %ls, %s instead of %s",
+                 qUtf16Printable(xdgRuntimeDir),
+                 unixPermissionsText(metaData.permissions()).constData(),
+                 unixPermissionsText(wantedPerms).constData());
+        return false;
     }
 
     return true;

diff --git a/tests/auto/corelib/io/qstandardpaths/tst_qstandardpaths.cpp b/tests/auto/corelib/io/qstandardpaths/tst_qstandardpaths.cpp
@@ -528,7 +528,12 @@ void tst_qstandardpaths::testCustomRuntimeDirectory_data()
         d.mkdir("runtime");
         QFile::setPermissions(p, QFile::ReadOwner | QFile::WriteOwner | QFile::ExeOwner |
                                  QFile::ExeGroup | QFile::ExeOther);
-        return updateRuntimeDir(p);
+        updateRuntimeDir(p);
+        QTest::ignoreMessage(QtWarningMsg,
+                             QString("QStandardPaths: wrong permissions on runtime directory %1, "
+                                     "0711 instead of 0700")
+                             .arg(p).toLatin1());
+        return fallbackXdgRuntimeDir();
     });
 
     addRow("environment:wrong-owner", [](QDir &) {
@@ -593,6 +598,7 @@ void tst_qstandardpaths::testCustomRuntimeDirectory_data()
         clearRuntimeDir();
         QString p = fallbackXdgRuntimeDir();
         d.mkdir(p);         // probably has wrong permissions
+        QFile::setPermissions(p, QFile::ReadOwner | QFile::WriteOwner | QFile::ExeOwner);
         return p;
     });