SFTP path confinement and status-reply refactor#1000
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Fenrir Automated Review — PR #1000
Scan targets checked: wolfssh-bugs, wolfssh-src
Findings: 3
3 finding(s) posted as inline comments (see file-level comments below)
This review was generated automatically by Fenrir. Findings are non-blocking.
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Fenrir Automated Review — PR #1000
Scan targets checked: wolfssh-bugs, wolfssh-src
Findings: 3
3 finding(s) posted as inline comments (see file-level comments below)
This review was generated automatically by Fenrir. Findings are non-blocking.
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Fenrir Automated Review — PR #1000
Scan targets checked: wolfssh-bugs, wolfssh-src
Findings: 3
3 finding(s) posted as inline comments (see file-level comments below)
This review was generated automatically by Fenrir. Findings are non-blocking.
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Background
The SFTP server resolved client request paths but did not verify the result stayed inside the configured default/home directory, so a client could reach absolute or ..-laden paths outside its intended jail.
This adds a confinement check that rejects any resolved path outside the canonical default path, and hardens the surrounding status-reply handling.
Changes
Confinement check in GetAndCleanPath — after wolfSSH_RealPath resolves a request, the canonical result is prefix-compared against the stored canonical default path (with a /-boundary check so /jaildir can't match /jaildirX). Out-of-jail requests return WS_PERMISSIONS. The "/" default (no confinement) and trailing-separator cases are handled explicitly. On Windows (USE_WINDOWS_API) the compare is case-insensitive to match the case-insensitive filesystem.
wolfSSH_SFTP_SetDefaultPath rewritten — stores the default path in canonical form (resolving relative paths against the cwd) so the per-request confinement compare is a cheap prefix match with no re-canonicalization. Also frees any previously-stored default path to avoid a leak on reassignment (reachable from wolfsshd's chroot setup).
New SFTP_SendStatus helper — consolidates the build-status-packet-and-queue boilerplate; 14 call sites across the Recv* handlers (RMDIR/MKDIR/Open/OpenDir/Write/Close/Remove/Rename/STAT/LSTAT/SetSTAT/FSetSTAT) refactored to use it, replacing repeated inline blocks.
New tests to exercise new code path
Updated the SFTP CI tests to read/write within the echoserver's working directory (its jail) rather than /tmp, since out-of-jail absolute paths are now correctly rejected.
Addressed by f_4720, f_4791, f_4796, f_4942, f_5111, f_5134, f_5725, f_5828.