wolfsftp: apply the attributes SETSTAT and FSETSTAT acknowledge

[yosuke-wolfssl]

Problem

SFTP_SetFileAttributes() and SFTP_SetFileAttributesHandle() left the SIZE
and UIDGID operations as @TODO no-ops yet returned WS_SUCCESS, so
wolfSSH_SFTP_RecvSetSTAT() and wolfSSH_SFTP_RecvFSetSTAT() replied
SSH_FX_OK for truncate and chown requests that never happened. A client that
truncates a file and gets OK back reasonably believes the file is that length.

The same defect covered timestamps: WSETTIME/WFSETTIME existed only as (0)
stubs on every port, so TIME was silently discarded too.

Closes f-11658.

Fix (src/wolfsftp.c)

Every requested attribute is now applied or reported:

• WTRUNCATE/WFTRUNCATE and WCHOWN/WFCHOWN carry out size and
  ownership changes; the 64-bit size is bounds-checked by the existing
  wResolveOffset() against WOLFSSH_MAX_FILE_OFFSET.
• WSETTIME/WFSETTIME are real implementations built on the existing
  WUTIMES_NOFOLLOW/WFUTIMES helpers, inheriting their symlink hardening.
• WS_UNIMPLEMENTED_E where a port defines no wrapper, which the handlers
  answer as SSH_FX_OP_UNSUPPORTED.

Flag	POSIX	Windows
SIZE	truncate / ftruncate	unsupported
UIDGID	chown / fchown	unsupported
PERM	chmod / fchmod	_wchmod via new WS_ChmodA()
TIME	futimens / utimensat	unsupported

Windows permissions needed more than the guard change. SFTP paths arrive as
/C:/..., which _chmod() rejects — every other Windows file routine in
port.c already strips that leading root via TrimFileName(). WS_ChmodA()
follows the same pattern, so WCHMOD works on Windows for the first time.

Client companion fix (required). wolfSSH_SFTP_CHMOD() STATs the target and
echoed the entire reply back, and the server's STAT sets every flag — so once the
server honours SIZE, a chmod asks it to truncate() the target, which fails on a
directory. It now sends only WOLFSSH_FILEATRB_PERM, matching OpenSSH's client.

Tests

• TestSftpSetStatAttributes() drives both handlers for size, timestamp and
  ownership, asserting the on-disk result via WSTAT rather than the status
  alone, with separate root and non-root ownership paths.
• tests/sftp.c adds an end-to-end chmod of a directory, guarding the client fix.

Verification

• Negative controls fail first: pre-fix the status is OK while the file is
  unchanged; without the client fix the directory chmod fails; stubbing
  WFCHOWN fails the give-away-chown case.
• regress.test passes as an ordinary user and under sudo, so both ownership
  branches execute. make check: 9 pass, 1 skip, 2 fail — both
  scripts/{sftp,scp}.test, which pass on serial re-run (known parallel flake).
• GCC preflight clean across 6 configs; ASan + UBSan clean.
• Windows MSVC: builds with SFTP enabled, api-test/unit-test pass, and an
  end-to-end chmod 400/chmod 600 over SFTP toggles the read-only attribute.
• OpenSSH client interop: chmod on a directory and put -p both correct.

[Copilot]

Pull request overview

Fixes SFTP SETSTAT/FSETSTAT so the server only acknowledges attributes it actually applies (size/uid-gid/timestamps), returning SSH_FX_OP_UNSUPPORTED when a port lacks the needed wrappers. Also adjusts the built-in SFTP client’s chmod behavior to avoid unintentionally requesting unrelated attribute changes.

Changes:

• Implement SIZE, UIDGID, and TIME application in SFTP_SetFileAttributes() / SFTP_SetFileAttributesHandle(), with WS_UNIMPLEMENTED_E mapped to SSH_FX_OP_UNSUPPORTED.
• Add portable wrappers in port.h for truncate/chown and real WSETTIME/WFSETTIME implementations when supported.
• Add regression and end-to-end tests covering SETSTAT/FSETSTAT attribute application and directory chmod behavior.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
wolfssh/port.h	Adds WTRUNCATE/WFTRUNCATE, WCHOWN/WFCHOWN, and functional WSETTIME/WFSETTIME wrappers where supported.
src/wolfsftp.c	Applies SETSTAT/FSETSTAT attributes (or reports unsupported), and fixes client-side chmod to send only PERM.
tests/regress.c	Adds a regression test ensuring SETSTAT/FSETSTAT really change size/time/ownership on disk.
tests/sftp.c	Adds an end-to-end chmod-directory test to guard the client fix.

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[wolfSSL-Fenrir-bot]

Fenrir Automated Review — PR #1197

Scan targets checked: wolfssh-bugs, wolfssh-src

Findings: 2
2 finding(s) posted as inline comments (see file-level comments below)

This review was generated automatically by Fenrir. Reported findings require changes before merge.

[wolfSSL-Fenrir-bot]

Fenrir Automated Review — PR #1197

Scan targets checked: wolfssh-bugs, wolfssh-src

Findings: 1
1 finding(s) posted as inline comments (see file-level comments below)

This review was generated automatically by Fenrir. Reported findings require changes before merge.