canvas: auth-gate state-changing POSTs, cap request bodies, restrict tmux sends (security trio)#143
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…rict tmux sends to claude panes Three contained security fixes to the visual canvas server: - #138: /show, /ctl, /say, /play changed state with no auth and were CSRF-able. Route all four through the same _authorized() gate as /input, returning 401 when unauthorized. Read-only GET endpoints and /input's own gate are unchanged. - #139: _read_json read Content-Length bytes uncapped — one POST with a 5 GB Content-Length forced a multi-GB alloc (remote OOM on a RAM-tight host). Reject bodies over 64 KiB with 413 before reading; _read_json also caps its read as defence in depth. - #140: send_input resolved tmux:<target> via raw `tmux display-message` against any session, so text+Enter could land in a bare shell = host command execution. Validate the target against _tmux_cc_panes() (which filters cmd=="claude") and reject anything that isn't a live claude pane. Closes #138, #139, #140
davidj4tech
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…ion) PR #143 auth-gated the state-changing POSTs (incl. /say and /play) for CSRF safety, but the play-turn / play-last-clip client calls still used a plain fetch — so on the merged branch they 401'd and the spinner hung. Route both through authed() (X-Auth-Token, prompt-on-401), same as /input, and drop the spinner on a non-ok response. Verified: /say is 401 without a token, 200 with.
davidj4tech
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Canvas: vim-key navigation for the agent tree + peek panel, play-load spinner, edge-tts PATH fixes, and the auth-gated /say · /play client integration. Bundles the #143 security trio merged into this branch.
This was referenced Jul 11, 2026
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Three contained security fixes to the visual canvas server (
packages/visual/src/agent_media_visual/canvas.py), one per issue. Only this file is touched.#138 — /show /ctl /say /play were unauthenticated & CSRF-able
These state-changing POSTs changed state with no auth, unlike
/input. Any web page the user visited could POST atext/plainJSON body and speak text aloud, play an attacker URL on the house speakers, or spoof images onto every screen. Now all four route through the same_authorized(self)gate as/input, returning 401 when unauthorized./input's own gate is unchanged; read-only GET endpoints (/events,/pair,/agents, …) stay open by design.#139 — unbounded request body → remote OOM
_read_jsonreadContent-Lengthbytes with no cap, so a single POST withContent-Length: 5000000000forced a multi-GB allocation (remote OOM on a RAM-tight host).do_POSTnow rejects bodies over 64 KiB with 413 before reading a byte;_read_jsonadditionally caps its read (min(clen, _MAX_BODY)) as defence in depth.#140 — send-to-pane not restricted to Claude panes → RCE
send_inputresolved atmux:<target>via rawtmux display-messageagainst any session and never verified it was a Claude-Code pane — text+Enter into a bare shell is host command execution. The target is now validated against_tmux_cc_panes()(which already filterspane_current_command == "claude"); anything that isn't a live claude pane is rejected. The legitimate "reply to an agent pane" path still works.Verification
python3 -m py_compilepasses; module imports cleanly.do_POSTwith a fake handler: oversized/show→ 413 with zero bytes read; unauthorized/say,/ctl,/play→ 401; with auth present/saypasses the gate and executes.Closes #138, #139, #140