Share one ID counter for SFTP handles

- Merge fileIdCount and dirIdCount into a single handleIdCount.
- File and directory handle IDs now share one namespace.
- A close or other handle op cannot match the wrong resource type.

Author: ejohnstown

src/wolfsftp.c

@@ -2357,9 +2357,9 @@ int wolfSSH_SFTP_RecvOpen(WOLFSSH* ssh, int reqId, byte* data, word32 maxSz)
 
     if (ret == WS_SUCCESS) {
         /* Generate unique file handle ID and add to tracking list */
-        id[0] = ssh->fileIdCount[0];
-        id[1] = ssh->fileIdCount[1];
-        AddAssign64(ssh->fileIdCount, 1);
+        id[0] = ssh->handleIdCount[0];
+        id[1] = ssh->handleIdCount[1];
+        AddAssign64(ssh->handleIdCount, 1);
 
         if ((ret = SFTP_AddFileHandle(ssh, fd, dir, id)) != WS_SUCCESS) {
             WLOG(WS_LOG_SFTP, "Unable to store handle");
@@ -2541,9 +2541,9 @@ int wolfSSH_SFTP_RecvOpen(WOLFSSH* ssh, int reqId, byte* data, word32 maxSz)
 
     if (ret == WS_SUCCESS) {
         /* Generate unique file handle ID and add to tracking list */
-        id[0] = ssh->fileIdCount[0];
-        id[1] = ssh->fileIdCount[1];
-        AddAssign64(ssh->fileIdCount, 1);
+        id[0] = ssh->handleIdCount[0];
+        id[1] = ssh->handleIdCount[1];
+        AddAssign64(ssh->handleIdCount, 1);
 
         if (SFTP_AddFileHandle(ssh, fileHandle, dir, id) != WS_SUCCESS) {
             WLOG(WS_LOG_SFTP, "Unable to store handle");
@@ -2713,11 +2713,11 @@ int wolfSSH_SFTP_RecvOpenDir(WOLFSSH* ssh, int reqId, byte* data, word32 maxSz)
 #else
         cur->dir  = ctx;
 #endif
-        cur->id[0] = id[0] = ssh->dirIdCount[0];
-        cur->id[1] = id[1] = ssh->dirIdCount[1];
+        cur->id[0] = id[0] = ssh->handleIdCount[0];
+        cur->id[1] = id[1] = ssh->handleIdCount[1];
         c32toa(id[0], idFlat);
         c32toa(id[1], idFlat + UINT32_SZ);
-        AddAssign64(ssh->dirIdCount, 1);
+        AddAssign64(ssh->handleIdCount, 1);
         cur->isEof = 0;
         cur->next  = ssh->dirList;
         ssh->dirList          = cur;
@@ -2872,11 +2872,11 @@ int wolfSSH_SFTP_RecvOpenDir(WOLFSSH* ssh, int reqId, byte* data, word32 maxSz)
             return WS_MEMORY_E;
         }
         cur->dir = INVALID_HANDLE_VALUE;
-        cur->id[0] = id[0] = ssh->dirIdCount[0];
-        cur->id[1] = id[1] = ssh->dirIdCount[1];
+        cur->id[0] = id[0] = ssh->handleIdCount[0];
+        cur->id[1] = id[1] = ssh->handleIdCount[1];
         c32toa(id[0], idFlat);
         c32toa(id[1], idFlat + UINT32_SZ);
-        AddAssign64(ssh->dirIdCount, 1);
+        AddAssign64(ssh->handleIdCount, 1);
         cur->isEof = 0;
         cur->dirName = dirName; /* take over ownership of buffer */
         cur->next    = ssh->dirList;

wolfssh/internal.h

@@ -920,9 +920,11 @@ struct WOLFSSH {
     char* sftpDefaultPath;
 #ifndef NO_WOLFSSH_DIR
     WS_DIR_LIST* dirList;
-    word32 dirIdCount[2];
 #endif
-    word32 fileIdCount[2];
+    /* Shared counter for both file and directory handle IDs. A single
+     * namespace guarantees IDs are unique across files and directories so a
+     * close request cannot match the wrong resource type. */
+    word32 handleIdCount[2];
     WS_FILE_LIST* fileList;
     struct WS_SFTP_RECV_INIT_STATE* recvInitState;
     struct WS_SFTP_RECV_STATE* recvState;