Both packageslave.cpp and textedit.cpp have instances of possibly exploitable

race conditions associated to files. The big deal is that it is quite typical
to use strings of pathnames to track files. But because that does not leverage
the filesystem would be attackers may be able to exploit time lags in uses
of filesystem functions (like stat and chmod or open) to get files with
suspect data into the files that the applications are working with.

This commit closes that potential hole even though there are no known exploits.
Better safe then sorry. There is no change in the behavior of the apps.

1 files changed, 28 insertions, 20 deletions

diff --git a/core/launcher/packageslave.cpp b/core/launcher/packageslave.cpp
index abbc610..965020e 100644
--- a/core/launcher/packageslave.cpp
+++ b/core/launcher/packageslave.cpp
@@ -214,32 +214,40 @@ void PackageHandler::cleanupPackageFiles( const QString &listfile  )
     QFile f(listfile);
 
     if ( f.open(IO_ReadOnly) ) {
-    QTextStream ts(&f);
-
-    QString s;
-    while ( !ts.eof() ) {        // until end of file...
-        s = ts.readLine();       // line of text excluding '\n'
-        // for s, do link/mkdir.
-        if ( s.right(1) == "/" ) {
-        //should rmdir if empty, after all files have been removed
-        } else {
+        QTextStream ts(&f);
+
+        QString s;
+        while ( !ts.eof() ) {        // until end of file...
+            s = ts.readLine();       // line of text excluding '\n'
+            // for s, do link/mkdir.
+            // @todo Right now we just move on if the name of the file we
+            // find is actually a directory. What we ought to do is check
+            // to see if the directory is empty and if so remove it.
+            if ( s.right(1) != "/" ) {
 #ifndef Q_OS_WIN32
-        odebug << "remove symlink for " << s.ascii() << "" << oendl;
-        //check if it is a symlink first (don't remove /etc/passwd...)
-        char buf[10]; //we don't care about the contents
-        if ( ::readlink( s.ascii(),buf, 10 >= 0 ) )
-             ::unlink( s.ascii() );
+                odebug << "remove symlink for " << s << oendl;
+                QFile symFile(s);
+                QFileInfo symFileInfo(symFile);
+                //check if it is a symlink first (don't remove /etc/passwd...)
+                if ( !symFileInfo.readLink().isNull())
+                     if (!symFile.remove())
+                         owarn << "Unable to remove symlink " << symFile.name()
+                               << " " << __FILE__ << ":" << __LINE__ << oendl;
 #else
-        // ### revise
-        owarn << "Unable to remove symlink " << __FILE__ << ":" << __LINE__ << "" << oendl;
+                // @todo If we actually want to be portable to other operating
+                // systems we ought to at least have a portable way of removing
+                // their notion of symlinks.
+                owarn << "Unable to remove symlink " << s " " << __FILE__
+                      << ":" << __LINE__ << oendl;
 #endif
+            }
         }
-    }
-    f.close();
+        f.close();
 
         //remove the list file
-    ::unlink( listfile.ascii() );
-
+        if (!f.remove())
+            owarn << "Unable to remove list file " << f.name() << " "
+                  << __FILE__ << ":" << __LINE__ << oendl;
     }
 }