- fixed path traversal vulnerability in MMS file services (LIB61850-357)

hal/filesystem/linux/file_provider_linux.c

@@ -37,7 +37,6 @@ struct sDirectoryHandle {
     DIR* handle;
 };
 
-
 FileHandle
 FileSystem_openFile(char* fileName, bool readWrite)
 {

src/mms/inc_private/mms_common_internal.h

@@ -82,6 +82,9 @@ mmsMsg_createExtendedFilename(const char* basepath, int bufSize, char* extendedF
 LIB61850_INTERNAL FileHandle
 mmsMsg_openFile(const char* basepath, char* fileName, bool readWrite);
 
+LIB61850_INTERNAL bool
+mmsMsg_isFilenameSave(const char* filename);
+
 #endif /* (MMS_FILE_SERVICE == 1) */
 
 typedef struct sMmsServiceError

src/mms/iso_mms/client/mms_client_files.c

@@ -71,7 +71,6 @@ getFrsm(MmsConnection connection, int32_t frsmId)
     return frsm;
 }
 
-
 static int32_t
 getNextFrsmId(MmsConnection connection)
 {
@@ -125,38 +124,48 @@ mmsClient_handleFileOpenRequest(
 
     if (hasFileName) {
 
-        MmsFileReadStateMachine* frsm = getFreeFrsm(connection);
+        if (mmsMsg_isFilenameSave(filename) == false) {
+            /* potential attack */
 
-        if (frsm != NULL) {
+            if (DEBUG_MMS_CLIENT)
+                printf("MMS_CLIENT: client provided unsave filename -> rejected\n");
 
-            MmsOutstandingCall obtainFileCall = mmsClient_getMatchingObtainFileRequest(connection, filename);
+             mmsMsg_createServiceErrorPdu(invokeId, response, MMS_ERROR_FILE_FILE_NON_EXISTENT);
+        }
+        else {
+            MmsFileReadStateMachine* frsm = getFreeFrsm(connection);
 
-            if (obtainFileCall) {
+            if (frsm != NULL) {
 
-                if (DEBUG_MMS_CLIENT)
-                    printf("MMS_CLIENT: file open is matching obtain file request for file %s\n", filename);
+                MmsOutstandingCall obtainFileCall = mmsClient_getMatchingObtainFileRequest(connection, filename);
 
-                obtainFileCall->timeout = Hal_getTimeInMs() + connection->requestTimeout;
-            }
+                if (obtainFileCall) {
 
-            FileHandle fileHandle = mmsMsg_openFile(MmsConnection_getFilestoreBasepath(connection), filename, false);
+                    if (DEBUG_MMS_CLIENT)
+                        printf("MMS_CLIENT: file open is matching obtain file request for file %s\n", filename);
 
-            if (fileHandle != NULL) {
+                    obtainFileCall->timeout = Hal_getTimeInMs() + connection->requestTimeout;
+                }
 
-                frsm->fileHandle = fileHandle;
-                frsm->readPosition = filePosition;
-                frsm->frsmId = getNextFrsmId(connection);
-                frsm->obtainRequest = obtainFileCall;
+                FileHandle fileHandle = mmsMsg_openFile(MmsConnection_getFilestoreBasepath(connection), filename, false);
+
+                if (fileHandle != NULL) {
+
+                    frsm->fileHandle = fileHandle;
+                    frsm->readPosition = filePosition;
+                    frsm->frsmId = getNextFrsmId(connection);
+                    frsm->obtainRequest = obtainFileCall;
+
+                    mmsMsg_createFileOpenResponse(MmsConnection_getFilestoreBasepath(connection),
+                            invokeId, response, filename, frsm);
+                }
+                else
+                    mmsMsg_createServiceErrorPdu(invokeId, response, MMS_ERROR_FILE_FILE_NON_EXISTENT);
 
-                mmsMsg_createFileOpenResponse(MmsConnection_getFilestoreBasepath(connection),
-                        invokeId, response, filename, frsm);
             }
             else
-                mmsMsg_createServiceErrorPdu(invokeId, response, MMS_ERROR_FILE_FILE_NON_EXISTENT);
-
+                mmsMsg_createServiceErrorPdu(invokeId, response, MMS_ERROR_RESOURCE_OTHER);
         }
-        else
-            mmsMsg_createServiceErrorPdu(invokeId, response, MMS_ERROR_RESOURCE_OTHER);
     }
     else
         goto exit_invalid_parameter;

src/mms/iso_mms/common/mms_common_msg.c

@@ -570,6 +570,24 @@ mmsMsg_createExtendedFilename(const char* basepath, int bufSize, char* extendedF
 #endif
 }
 
+bool
+mmsMsg_isFilenameSave(const char* filename)
+{
+    if (filename)
+    {
+        if (strstr(filename, ".."))
+            return false;
+
+        if (strstr(filename, "./"))
+            return false;
+
+        return true;
+    }
+    else {
+        return false;
+    }
+}
+
 FileHandle
 mmsMsg_openFile(const char* basepath, char* fileName, bool readWrite)
 {
@@ -620,7 +638,7 @@ mmsMsg_parseFileName(char* filename, uint8_t* buffer, int* bufPos, int maxBufPos
      * characters.
      */
     if (strstr(filename, "..") != NULL) {
-        mmsMsg_createServiceErrorPdu(invokeId, response, MMS_ERROR_FILE_FILENAME_SYNTAX_ERROR);
+        mmsMsg_createServiceErrorPdu(invokeId, response, MMS_ERROR_FILE_FILE_NON_EXISTENT);
         return false;
     }
 

src/mms/iso_mms/server/mms_file_service.c

@@ -235,8 +235,6 @@ mmsMsg_createFileOpenResponse(const char* basepath, uint32_t invokeId, ByteBuffe
     response->size = bufPos;
 }
 
-
-
 void
 mmsServer_handleFileDeleteRequest(
     MmsServerConnection connection,
@@ -266,6 +264,16 @@ mmsServer_handleFileDeleteRequest(
     if (DEBUG_MMS_SERVER)
         printf("MMS_SERVER: mms_file_service.c: Delete file (%s)\n", filename);
 
+    if (mmsMsg_isFilenameSave(filename) == false)
+    {
+        if (DEBUG_MMS_SERVER)
+            printf("MMS_SERVER: remote provided unsave filename -> rejected\n");
+
+        mmsMsg_createServiceErrorPdu(invokeId, response, MMS_ERROR_FILE_FILE_NON_EXISTENT);
+
+        return;
+    }
+
     if (connection->server->fileAccessHandler != NULL) {
         MmsError access = connection->server->fileAccessHandler(connection->server->fileAccessHandlerParameter,
                             connection, MMS_FILE_ACCESS_TYPE_DELETE, filename, NULL);
@@ -344,6 +352,17 @@ mmsServer_handleFileOpenRequest(
 
     if (hasFileName) {
 
+        if (mmsMsg_isFilenameSave(filename) == false) {
+            /* potential attack */
+
+            if (DEBUG_MMS_CLIENT)
+                printf("MMS_SERVER: remote provided unsave filename -> rejected\n");
+
+             mmsMsg_createServiceErrorPdu(invokeId, response, MMS_ERROR_FILE_FILE_NON_EXISTENT);
+
+             return;
+        }
+
         if (connection->server->fileAccessHandler != NULL) {
             MmsError access = connection->server->fileAccessHandler(connection->server->fileAccessHandlerParameter,
                                 connection, MMS_FILE_ACCESS_TYPE_OPEN, filename, NULL);
@@ -690,6 +709,15 @@ mmsServer_handleObtainFileRequest(
 
     if (hasSourceFileName && hasDestinationFilename) {
 
+        if (mmsMsg_isFilenameSave(destinationFilename) == false) {
+            /* potential attack */
+
+            if (DEBUG_MMS_SERVER)
+                printf("MMS_SERVER: remote provided unsave filename -> rejected\n");
+
+            goto exit_invalid_parameter;
+        }
+
         /* Call user to check if access is allowed */
         if (connection->server->fileAccessHandler != NULL) {
             MmsError access = connection->server->fileAccessHandler(connection->server->fileAccessHandlerParameter,
@@ -1023,6 +1051,17 @@ createFileDirectoryResponse(const char* basepath, uint32_t invokeId, ByteBuffer*
             continueAfterFileName = NULL;
     }
 
+    if ((directoryName && mmsMsg_isFilenameSave(directoryName) == false) || 
+        (continueAfterFileName && mmsMsg_isFilenameSave(continueAfterFileName) == false))
+    {
+        if (DEBUG_MMS_SERVER)
+            printf("MMS_SERVER: remote provided unsave filename -> rejected\n");
+
+       mmsMsg_createServiceErrorPdu(invokeId, response, MMS_ERROR_FILE_FILE_NON_EXISTENT);
+
+       return;
+    }
+
     tempCurPos = addFileEntriesToResponse(basepath, buffer, tempCurPos, maxSize, directoryName, &continueAfterFileName, &moreFollows);
 
 	if (tempCurPos < 0) {
@@ -1128,6 +1167,16 @@ mmsServer_handleFileRenameRequest(
 
     if ((strlen(currentFileName) != 0) && (strlen(newFileName) != 0)) {
 
+        if ((mmsMsg_isFilenameSave(currentFileName) == false) || (mmsMsg_isFilenameSave(newFileName) == false))
+        {
+            if (DEBUG_MMS_SERVER)
+                printf("MMS_SERVER: remote provided unsave filename -> rejected\n");
+
+            mmsMsg_createServiceErrorPdu(invokeId, response, MMS_ERROR_FILE_FILE_NON_EXISTENT);
+
+            return;
+        }
+
         /* Call user to check if access is allowed */
         if (connection->server->fileAccessHandler != NULL) {
             MmsError access = connection->server->fileAccessHandler(connection->server->fileAccessHandlerParameter,