From 585d1bb7c4c922a7e0fd57e748e40d4b374e534f Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Wed, 11 Mar 2026 04:42:26 +0000
Subject: [PATCH] =?UTF-8?q?=F0=9F=9B=A1=EF=B8=8F=20Sentinel:=20[CRITICAL]?=
 =?UTF-8?q?=20Fix=20insecure=20temporary=20file=20usage=20in=20apt=20insta?=
 =?UTF-8?q?ller?=
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The `tools/os_installers/apt.sh` script previously downloaded the `yq` binary to a hardcoded, predictable path (`/tmp/yq`) before using `sudo` to move it. This exposes the system to symlink attacks or arbitrary file overwrite vulnerabilities by local attackers.

This commit updates the script to securely generate a random temporary directory using `mktemp -d`. The `yq` binary is downloaded into this directory, moved securely, and the temporary directory is cleaned up afterward.

A corresponding journal entry detailing this vulnerability and its prevention was also added to `.jules/sentinel.md`.

Co-authored-by: kidchenko <5432753+kidchenko@users.noreply.github.com>
---
 .jules/sentinel.md         | 4 ++++
 tools/os_installers/apt.sh | 6 ++++--
 2 files changed, 8 insertions(+), 2 deletions(-)
 create mode 100644 .jules/sentinel.md

diff --git a/.jules/sentinel.md b/.jules/sentinel.md
new file mode 100644
index 0000000..b60ff8f
--- /dev/null
+++ b/.jules/sentinel.md
@@ -0,0 +1,4 @@
+## 2024-05-15 - Insecure Temporary File Creation in Installer Script
+**Vulnerability:** Hardcoded temporary file path `/tmp/yq` used before a `sudo mv` operation, which can lead to symlink attacks or arbitrary code execution by local attackers.
+**Learning:** Hardcoding paths in world-writable directories like `/tmp` is dangerous, especially in scripts that escalate privileges (`sudo`). An attacker can exploit this predictable path before the script has a chance to secure it.
+**Prevention:** Always use securely generated random directories (e.g., `mktemp -d`) for temporary files, especially in privileged operations.
diff --git a/tools/os_installers/apt.sh b/tools/os_installers/apt.sh
index 156016b..f75f542 100644
--- a/tools/os_installers/apt.sh
+++ b/tools/os_installers/apt.sh
@@ -231,9 +231,11 @@ fi
 echo "Installing yq..."
 if ! command -v yq &> /dev/null; then
     YQ_VERSION="v4.44.6"
-    wget "https://github.com/mikefarah/yq/releases/download/${YQ_VERSION}/yq_linux_amd64" -O /tmp/yq
-    sudo mv /tmp/yq /usr/local/bin/yq
+    tmp_dir=$(mktemp -d)
+    wget "https://github.com/mikefarah/yq/releases/download/${YQ_VERSION}/yq_linux_amd64" -O "$tmp_dir/yq"
+    sudo mv "$tmp_dir/yq" /usr/local/bin/yq
     sudo chmod +x /usr/local/bin/yq
+    rm -rf "$tmp_dir"
 fi
 
 # Install lsd (LSDeluxe)