SFTP file handle abstraction

[JacobBarthelmeh]

ZD20562

[Copilot]

Pull request overview

This pull request introduces a new file handle abstraction for the SFTP subsystem, replacing the old conditional WOLFSSH_STOREHANDLE mechanism with an always-on tracking system. Instead of sending raw file descriptors or handles to SFTP clients, the implementation now generates unique 8-byte IDs that are tracked internally in a linked list (WS_FILE_LIST), improving security and portability.

Changes:

• Removed old WOLFSSH_STOREHANDLE conditional compilation and associated functions (SFTP_AddHandleNode, SFTP_RemoveHandleNode, SFTP_GetHandleNode, SFTP_FreeHandles)
• Added new file handle tracking system with WS_FILE_LIST structure and helper functions (SFTP_AddFileHandle, SFTP_FindFileHandle, SFTP_RemoveFileHandle, SFTP_FreeAllFileHandles)
• Unified RecvClose implementation across platforms (previously had separate Unix and Windows versions)
• Updated all file operations (Open, Read, Write, Close, FSTAT, FSetSTAT) to use 8-byte handle IDs instead of raw file descriptors

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 14 comments.

File	Description
wolfssh/wolfsftp.h	Removed declarations for old WOLFSSH_STOREHANDLE functions (SFTP_AddHandleNode, SFTP_RemoveHandleNode)
wolfssh/internal.h	Added WOLFSSH_HANDLE_ID_SZ constant, WS_FILE_LIST typedef, and fileIdCount/fileList members to WOLFSSH struct, removed conditional WOLFSSH_STOREHANDLE handleList member
src/wolfsftp.c	Implemented new file handle tracking system, updated all file operations to use 8-byte IDs, unified cross-platform RecvClose implementation, removed old WOLFSSH_STOREHANDLE code, fixed code style (else statement formatting)

Comments suppressed due to low confidence (1)

src/wolfsftp.c:2184

• When SFTP_CreatePacket fails on line 2176, the file is closed (lines 2178-2182), but the file handle is not removed from the tracking list. This creates the same issue as with the malloc failure: the handle remains in ssh->fileList with an invalid file descriptor. SFTP_RemoveFileHandle should be called to clean up the tracking list before returning WS_FATAL_ERROR.

        if (SFTP_CreatePacket(ssh, WOLFSSH_FTP_HANDLE, out, outSz,
            idFlat, sizeof(idFlat)) != WS_SUCCESS) {
        #ifdef MICROCHIP_MPLAB_HARMONY
            WFCLOSE(ssh->fs, &fd);
        #else
            WCLOSE(ssh->fs, fd);
        #endif
            return WS_FATAL_ERROR;
        }

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Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

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[Copilot]

Resource leak: If SFTP_AddFileHandle fails but wolfSSH_SFTP_CreateStatus succeeds (returns WS_SIZE_ONLY), the file descriptor is not closed before returning WS_FATAL_ERROR. The file should be closed unconditionally after SFTP_AddFileHandle failure, similar to how it's handled in the Windows version at line 2322.