From 46821fe6d86a1f1a338a9fa4da87ab698cb4fb1b Mon Sep 17 00:00:00 2001
From: RagavRida <ragavrida@gmail.com>
Date: Fri, 24 Apr 2026 00:06:39 +0530
Subject: [PATCH] fix(telemetry-sync): drop predictable $$ tmp-file fallback
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gstack-telemetry-sync tried 'mktemp /tmp/gstack-sync-XXXXXX' and on
failure fell back to '/tmp/gstack-sync-$$'. $$ is the PID — predictable
and reusable, so on shared hosts another user can pre-create or symlink
the path and either steal the response body or clobber an unrelated
file when curl writes through it.

Drop the fallback. If mktemp cannot produce a unique file we just skip
this sync cycle — the events stay on disk and the next run picks them
up. Also install an EXIT trap so the response file is cleaned up on
unexpected exit, not just on the happy path.
---
 bin/gstack-telemetry-sync | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/bin/gstack-telemetry-sync b/bin/gstack-telemetry-sync
index 93cf2707a..20f322043 100755
--- a/bin/gstack-telemetry-sync
+++ b/bin/gstack-telemetry-sync
@@ -107,7 +107,13 @@ BATCH="$BATCH]"
 [ "$COUNT" -eq 0 ] && exit 0
 
 # ─── POST to edge function ───────────────────────────────────
-RESP_FILE="$(mktemp /tmp/gstack-sync-XXXXXX 2>/dev/null || echo "/tmp/gstack-sync-$$")"
+# Create response file atomically. If mktemp fails, refuse to continue rather
+# than fall back to a predictable $$-based path (race + overwrite footgun).
+RESP_FILE="$(mktemp "${TMPDIR:-/tmp}/gstack-sync-XXXXXX")" || {
+  echo "gstack-telemetry-sync: mktemp failed — skipping this run" >&2
+  exit 0
+}
+trap 'rm -f "$RESP_FILE"' EXIT
 HTTP_CODE="$(curl -s -w '%{http_code}' --max-time 10 \
   -X POST "${SUPABASE_URL}/functions/v1/telemetry-ingest" \
   -H "Content-Type: application/json" \