Check for Invalid Characters in Output Filename (#274)

Fixes #268.

libmediation/fs/directory.cpp

@@ -33,14 +33,9 @@ char getDirSeparator()
 
 string extractFileDir(const string& fileName)
 {
-    size_t index = fileName.find_last_of('/');
+    size_t index = fileName.find_last_of(getDirSeparator());
     if (index != string::npos)
         return fileName.substr(0, index + 1);
-#ifdef _WIN32
-    index = fileName.find_last_of('\\');
-    if (index != string::npos)
-        return fileName.substr(0, index + 1);
-#endif
 
     return "";
 }

libmediation/types/types.cpp

@@ -5,6 +5,7 @@
 #include <cstring>
 #include <iomanip>
 #include <ostream>
+#include <regex>
 #include <sstream>
 
 #ifndef _WIN32
@@ -19,6 +20,25 @@
 
 #include "fs/directory.h"
 
+namespace
+{
+const std::regex& invalidChars()
+{
+    static const std::regex invalid(
+#ifndef _WIN32
+        // / and ASCII 0 to 31
+        "[/\\x00-\\x1F]"
+#else
+        // <>:"/|?\*, ASCII 0 to 31 and all reserved names such as CON or LPT1
+        // see here: https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file#naming-conventions
+        "[:<>\"/|?\\*\\x00-\\x1F]|^CON$|^PRN$|^AUX$|^NUL$|^COM\d$|^LPT\d$"
+#endif
+        ,
+        std::regex_constants::ECMAScript | std::regex_constants::optimize);
+    return invalid;
+}
+}  // namespace
+
 using namespace std;
 
 uint64_t my_ntohll(const uint64_t& original)
@@ -303,7 +323,7 @@ string extractFileName(const string& src)
             if (endPos == src.size())
                 endPos = i;
         }
-        else if (src[i] == '/' || src[i] == '\\')
+        else if (src[i] == getDirSeparator())
         {
             string rez = src.substr(i + 1, endPos - i - 1);
             if (rez.size() > 0 && rez[rez.size() - 1] == '\"')
@@ -319,10 +339,7 @@ string extractFileName2(const string& src, bool withExt)
     string fileName = src;
 
     size_t extSep = fileName.find_last_of('.');
-    size_t dirSep = fileName.find_last_of('/');
-
-    if (dirSep == string::npos)
-        dirSep = fileName.find_last_of('\\');
+    size_t dirSep = fileName.find_last_of(getDirSeparator());
 
     if (extSep != string::npos && !withExt)
         fileName = fileName.substr(0, extSep);
@@ -336,7 +353,7 @@ string extractFileName2(const string& src, bool withExt)
 string extractFilePath(const string& src)
 {
     for (int i = src.size() - 1; i >= 0; i--)
-        if (src[i] == '/' || src[i] == '\\')
+        if (src[i] == getDirSeparator())
         {
             string rez = src.substr(0, i);
             return rez;
@@ -350,11 +367,21 @@ string closeDirPath(const string& src, char delimiter)
         delimiter = getDirSeparator();
     if (src.length() == 0)
         return src;
-    if (src[src.length() - 1] == '/' || src[src.length() - 1] == '\\')
+    if (src[src.length() - 1] == getDirSeparator())
         return src;
     return src + delimiter;
 }
 
+// extract the filename from a path, check for invalid characters
+bool isValidFileName(const string& src)
+{
+    string filename = extractFileName(src);
+
+    // invalidChars() returns a different regex pattern for Windows or Unix
+    bool isvalid = !(std::regex_search(filename, invalidChars()));
+    return isvalid;
+}
+
 string trimStr(const string& value)
 {
     const char* bufStart = value.c_str();

libmediation/types/types.h

@@ -2,6 +2,7 @@
 #define __T_TYPES_H
 
 #include <cstdint>
+#include <regex>
 #include <string>
 #include <vector>
 
@@ -45,6 +46,7 @@ std::string extractFileName(const std::string& src);
 std::string extractFileName2(const std::string& src, bool withExt = true);
 std::string extractFilePath(const std::string& src);
 std::string closeDirPath(const std::string& src, char delimiter = ' ');
+bool isValidFileName(const std::string& src);
 
 std::vector<std::string> splitQuotedStr(const char* str, char splitter);
 

tsMuxer/main.cpp

@@ -735,8 +735,13 @@ int main(int argc, char** argv)
                 LTRACE(LT_INFO, 2, "HEVC stream detected: changing Blu-Ray version to V3.");
                 V3_flags |= HDMV_V3;
             }
+
+            // output path - is checked for invalid characters on our platform
             string dstFile = unquoteStr(argv[2]);
 
+            if (!isValidFileName(dstFile))
+                throw runtime_error(string("Output filename is invalid: ") + dstFile);
+
             if (dt != DT_NONE)
             {
                 if (!blurayHelper.open(dstFile, dt, muxerManager.totalSize(), muxerManager.getExtraISOBlocks()))
@@ -803,8 +808,15 @@ int main(int argc, char** argv)
             sMuxer.openMetaFile(argv[1]);
             if (sMuxer.getTrackCnt() == 0)
                 THROW(ERR_COMMON, "No tracks selected");
-            createDir(unquoteStr(argv[2]), true);
-            sMuxer.doMux(unquoteStr(argv[2]), 0);
+
+            // output path - is checked for invalid characters on our platform
+            string dstFile = unquoteStr(argv[2]);
+
+            if (!isValidFileName(dstFile))
+                throw runtime_error(string("Output filename is invalid: ") + dstFile);
+
+            createDir(dstFile, true);
+            sMuxer.doMux(dstFile, 0);
             LTRACE(LT_INFO, 2, "Demux complete.");
         }
         auto endTime = std::chrono::steady_clock::now();