From 06a03d1ada3d7b0598aa02ea536d83baf2b46215 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?G=C3=BCnter=20Obiltschnig?= <guenter.obiltschnig@appinf.com>
Date: Sat, 14 Oct 2023 11:34:59 +0200
Subject: [PATCH] Poco::TemporaryFile: fix possible naming collisions due to
 random zero increment

---
 Foundation/include/Poco/TemporaryFile.h |  4 ++++
 Foundation/src/TemporaryFile.cpp        |  2 +-
 Foundation/testsuite/src/FileTest.cpp   | 23 +++++++++++++++++++++--
 Foundation/testsuite/src/FileTest.h     |  1 +
 4 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/Foundation/include/Poco/TemporaryFile.h b/Foundation/include/Poco/TemporaryFile.h
index 9246846c2..9314613b3 100644
--- a/Foundation/include/Poco/TemporaryFile.h
+++ b/Foundation/include/Poco/TemporaryFile.h
@@ -40,6 +40,10 @@ class Foundation_API TemporaryFile: public File
 	/// The class does, however, delete the temporary
 	/// file - either in the destructor, or immediately
 	/// before the application terminates.
+	///
+	/// Note: Due to the way the temporary file names are generated,
+	/// collisions may be possible after 400-500 Million 
+	/// file names generated by a single process.
 {
 public:
 	TemporaryFile();
diff --git a/Foundation/src/TemporaryFile.cpp b/Foundation/src/TemporaryFile.cpp
index a3777499b..463ee32d1 100644
--- a/Foundation/src/TemporaryFile.cpp
+++ b/Foundation/src/TemporaryFile.cpp
@@ -161,7 +161,7 @@ std::string TemporaryFile::tempName(const std::string& tempDir)
 				randomChars.append(alphabet);
 			}
 		}
-		n = (count += random.next(1000));
+		n = (count += random.next(1000) + 1);
 	}
 
 	std::ostringstream name;
diff --git a/Foundation/testsuite/src/FileTest.cpp b/Foundation/testsuite/src/FileTest.cpp
index 2663953fc..a42899cc8 100644
--- a/Foundation/testsuite/src/FileTest.cpp
+++ b/Foundation/testsuite/src/FileTest.cpp
@@ -380,6 +380,7 @@ void FileTest::testCopy()
 	f1.setWriteable().remove();
 }
 
+
 void FileTest::testCopyFailIfDestinationFileExists()
 {
 	std::ofstream ostr("testfile.dat");
@@ -414,6 +415,7 @@ void FileTest::testMove()
 	assertTrue (f1 == f2);
 }
 
+
 void FileTest::testMoveFailIfDestinationFileExists() {
 	std::ofstream ostr("testfile.dat");
 	ostr << "Hello, world!" << std::endl;
@@ -430,6 +432,7 @@ void FileTest::testMoveFailIfDestinationFileExists() {
 	f1.setWriteable().remove();
 }
 
+
 void FileTest::testCopyDirectory()
 {
 	Path pd1("testdir");
@@ -499,6 +502,7 @@ void FileTest::testCopyDirectory()
 	fd3.remove(true);
 }
 
+
 void FileTest::testCopyDirectoryFailIfExists()
 {
 	Path pd1("testdir");
@@ -538,6 +542,7 @@ void FileTest::testCopyDirectoryFailIfExists()
 	fd2.remove(true);
 }
 
+
 void FileTest::testRename()
 {
 	std::ofstream ostr("testfile.dat");
@@ -555,6 +560,7 @@ void FileTest::testRename()
 	f2.remove();
 }
 
+
 void FileTest::testRenameFailIfExists() {
 	std::ofstream ostr("testfile.dat");
 	ostr << "Hello, world!" << std::endl;
@@ -580,8 +586,6 @@ void FileTest::testRenameFailIfExists() {
 }
 
 
-
-
 void FileTest::testLongPath()
 {
 #if defined(_WIN32) && !defined(_WIN32_WCE)
@@ -620,6 +624,20 @@ void FileTest::testUnixFileExtension()
 	assertEqual("", path2.getExtension());
 }
 
+
+void FileTest::testTemporaryFile()
+{
+	const int COUNT = 10000;
+	std::set<std::string> paths;
+	for (int i = 0; i < COUNT; i++)
+	{
+		Poco::TemporaryFile f;
+		paths.insert(f.path());
+	}
+	assertTrue (paths.size() == COUNT);
+}
+
+
 void FileTest::setUp()
 {
 	File f("testfile.dat");
@@ -669,6 +687,7 @@ CppUnit::Test* FileTest::suite()
 	CppUnit_addTest(pSuite, FileTest, testRootDir);
 	CppUnit_addTest(pSuite, FileTest, testLongPath);
 	CppUnit_addTest(pSuite, FileTest, testUnixFileExtension);
+	CppUnit_addTest(pSuite, FileTest, testTemporaryFile);
 
 	return pSuite;
 }
diff --git a/Foundation/testsuite/src/FileTest.h b/Foundation/testsuite/src/FileTest.h
index c5448b457..65acb507c 100644
--- a/Foundation/testsuite/src/FileTest.h
+++ b/Foundation/testsuite/src/FileTest.h
@@ -43,6 +43,7 @@ public:
 	void testRootDir();
 	void testLongPath();
 	void testUnixFileExtension();
+	void testTemporaryFile();
 
 	void setUp();
 	void tearDown();