🛡️ Sentinel: [CRITICAL] Fix insecure temporary file usage#73
🛡️ Sentinel: [CRITICAL] Fix insecure temporary file usage#73
Conversation
Replaced hardcoded and predictable temporary paths (e.g., /tmp/yq) with securely generated temporary directories using `mktemp -d`. This prevents symlink attacks and arbitrary file overwrites when downloading tools in `apt.sh`. Additionally, encapsulated each download block in a subshell with a localized cleanup trap to ensure directories are removed without affecting global script state. Signed-off-by: Sentinel <sentinel@example.com> Co-authored-by: kidchenko <5432753+kidchenko@users.noreply.github.com>
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📝 WalkthroughWalkthroughA security-focused refactor replaces hardcoded and predictable temporary file paths in installer scripts with securely generated temporary directories, paired with trap handlers to ensure cleanup on exit. Documentation describing the vulnerability is added. Changes
Estimated code review effort🎯 4 (Complex) | ⏱️ ~40 minutes Poem
🚥 Pre-merge checks | ✅ 3✅ Passed checks (3 passed)
✏️ Tip: You can configure your own custom pre-merge checks in the settings. ✨ Finishing Touches📝 Generate docstrings
🧪 Generate unit tests (beta)
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Actionable comments posted: 2
🤖 Prompt for all review comments with AI agents
Verify each finding against the current code and only fix it if needed.
Inline comments:
In @.jules/sentinel.md:
- Around line 1-4: Change the first line to a top-level heading (replace leading
"##" with "#") and insert a blank line after that heading to satisfy MD041 and
MD022; then reflow the subsequent paragraph lines to be <=80 characters each
(wrap the long sentence about vulnerability/learning/prevention into multiple
shorter lines) so MD013 is fixed; reference the heading text "2024-05-24 -
[Avoid predictable temporary paths in shared locations like /tmp]" when updating
.jules/sentinel.md.
In `@tools/os_installers/apt.sh`:
- Around line 272-276: The else branch that handles the checksum mismatch
currently only echoes an error and returns a zero exit status; update the
checksum verification block that compares EXPECTED_CHECKSUM and ACTUAL_CHECKSUM
to terminate the script with a non-zero status on failure by adding an explicit
exit 1 after the error message so the installer does not continue silently
(affecting the branch that would otherwise run sudo php
"$COMPOSER_TMP_DIR/composer-setup.php" --quiet --install-dir=/usr/local/bin
--filename=composer).
🪄 Autofix (Beta)
Fix all unresolved CodeRabbit comments on this PR:
- Push a commit to this branch (recommended)
- Create a new PR with the fixes
ℹ️ Review info
⚙️ Run configuration
Configuration used: defaults
Review profile: CHILL
Plan: Pro
Run ID: e11643a6-d049-4b31-b2c1-7d1dab02a5dd
📒 Files selected for processing (2)
.jules/sentinel.mdtools/os_installers/apt.sh
| ## 2024-05-24 - [Avoid predictable temporary paths in shared locations like /tmp] | ||
| **Vulnerability:** A script uses a hardcoded, predictable path (e.g., `/tmp/yq`) when downloading tools, which could lead to a symlink attack or unauthorized file modification, especially when running with elevated privileges (like `sudo mv /tmp/yq /usr/local/bin/yq`). | ||
| **Learning:** Hardcoding paths in world-writable directories (`/tmp`) makes the script vulnerable to a local attacker pre-creating the file (or a symlink) to perform malicious actions. | ||
| **Prevention:** Always use securely generated temporary directories (e.g., `mktemp -d`) coupled with a cleanup trap to store downloaded files before moving them to their final destination. |
There was a problem hiding this comment.
Fix markdown linting errors to pass CI.
The pipeline reports several markdownlint failures:
- MD041: First line should be a top-level heading (
#instead of##) - MD022: Add a blank line after the heading
- MD013: Lines 2-4 exceed the 80-character limit
Proposed fix
-## 2024-05-24 - [Avoid predictable temporary paths in shared locations like /tmp]
-**Vulnerability:** A script uses a hardcoded, predictable path (e.g., `/tmp/yq`) when downloading tools, which could lead to a symlink attack or unauthorized file modification, especially when running with elevated privileges (like `sudo mv /tmp/yq /usr/local/bin/yq`).
-**Learning:** Hardcoding paths in world-writable directories (`/tmp`) makes the script vulnerable to a local attacker pre-creating the file (or a symlink) to perform malicious actions.
-**Prevention:** Always use securely generated temporary directories (e.g., `mktemp -d`) coupled with a cleanup trap to store downloaded files before moving them to their final destination.
+# Sentinel Security Learnings
+
+## 2024-05-24 - Avoid predictable temporary paths in /tmp
+
+**Vulnerability:** A script uses a hardcoded, predictable path (e.g.,
+`/tmp/yq`) when downloading tools, which could lead to a symlink attack or
+unauthorized file modification, especially when running with elevated
+privileges (like `sudo mv /tmp/yq /usr/local/bin/yq`).
+
+**Learning:** Hardcoding paths in world-writable directories (`/tmp`) makes
+the script vulnerable to a local attacker pre-creating the file (or a
+symlink) to perform malicious actions.
+
+**Prevention:** Always use securely generated temporary directories (e.g.,
+`mktemp -d`) coupled with a cleanup trap to store downloaded files before
+moving them to their final destination.📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| ## 2024-05-24 - [Avoid predictable temporary paths in shared locations like /tmp] | |
| **Vulnerability:** A script uses a hardcoded, predictable path (e.g., `/tmp/yq`) when downloading tools, which could lead to a symlink attack or unauthorized file modification, especially when running with elevated privileges (like `sudo mv /tmp/yq /usr/local/bin/yq`). | |
| **Learning:** Hardcoding paths in world-writable directories (`/tmp`) makes the script vulnerable to a local attacker pre-creating the file (or a symlink) to perform malicious actions. | |
| **Prevention:** Always use securely generated temporary directories (e.g., `mktemp -d`) coupled with a cleanup trap to store downloaded files before moving them to their final destination. | |
| # Sentinel Security Learnings | |
| ## 2024-05-24 - Avoid predictable temporary paths in /tmp | |
| **Vulnerability:** A script uses a hardcoded, predictable path (e.g., | |
| `/tmp/yq`) when downloading tools, which could lead to a symlink attack or | |
| unauthorized file modification, especially when running with elevated | |
| privileges (like `sudo mv /tmp/yq /usr/local/bin/yq`). | |
| **Learning:** Hardcoding paths in world-writable directories (`/tmp`) makes | |
| the script vulnerable to a local attacker pre-creating the file (or a | |
| symlink) to perform malicious actions. | |
| **Prevention:** Always use securely generated temporary directories (e.g., | |
| `mktemp -d`) coupled with a cleanup trap to store downloaded files before | |
| moving them to their final destination. |
🧰 Tools
🪛 GitHub Check: Lint Documentation
[failure] 4-4: Line length
.jules/sentinel.md:4:81 MD013/line-length Line length [Expected: 80; Actual: 188] https://github.com/DavidAnson/markdownlint/blob/v0.34.0/doc/md013.md
[failure] 3-3: Line length
.jules/sentinel.md:3:81 MD013/line-length Line length [Expected: 80; Actual: 184] https://github.com/DavidAnson/markdownlint/blob/v0.34.0/doc/md013.md
[failure] 2-2: Line length
.jules/sentinel.md:2:81 MD013/line-length Line length [Expected: 80; Actual: 269] https://github.com/DavidAnson/markdownlint/blob/v0.34.0/doc/md013.md
[failure] 1-1: First line in a file should be a top-level heading
.jules/sentinel.md:1 MD041/first-line-heading/first-line-h1 First line in a file should be a top-level heading [Context: "## 2024-05-24 - [Avoid predict..."] https://github.com/DavidAnson/markdownlint/blob/v0.34.0/doc/md041.md
[failure] 1-1: Headings should be surrounded by blank lines
.jules/sentinel.md:1 MD022/blanks-around-headings Headings should be surrounded by blank lines [Expected: 1; Actual: 0; Below] [Context: "## 2024-05-24 - [Avoid predictable temporary paths in shared locations like /tmp]"] https://github.com/DavidAnson/markdownlint/blob/v0.34.0/doc/md022.md
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In @.jules/sentinel.md around lines 1 - 4, Change the first line to a top-level
heading (replace leading "##" with "#") and insert a blank line after that
heading to satisfy MD041 and MD022; then reflow the subsequent paragraph lines
to be <=80 characters each (wrap the long sentence about
vulnerability/learning/prevention into multiple shorter lines) so MD013 is
fixed; reference the heading text "2024-05-24 - [Avoid predictable temporary
paths in shared locations like /tmp]" when updating .jules/sentinel.md.
| if [ "$EXPECTED_CHECKSUM" = "$ACTUAL_CHECKSUM" ]; then | ||
| sudo php "$COMPOSER_TMP_DIR/composer-setup.php" --quiet --install-dir=/usr/local/bin --filename=composer | ||
| else | ||
| >&2 echo 'ERROR: Invalid installer checksum for Composer' | ||
| fi |
There was a problem hiding this comment.
Add exit 1 after checksum mismatch error.
When the checksum validation fails, the script prints an error but the subshell exits with code 0 (from the successful echo). This means the overall script continues silently without installing Composer, which could mask a security issue.
Proposed fix
if [ "$EXPECTED_CHECKSUM" = "$ACTUAL_CHECKSUM" ]; then
sudo php "$COMPOSER_TMP_DIR/composer-setup.php" --quiet --install-dir=/usr/local/bin --filename=composer
else
>&2 echo 'ERROR: Invalid installer checksum for Composer'
+ exit 1
fi📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| if [ "$EXPECTED_CHECKSUM" = "$ACTUAL_CHECKSUM" ]; then | |
| sudo php "$COMPOSER_TMP_DIR/composer-setup.php" --quiet --install-dir=/usr/local/bin --filename=composer | |
| else | |
| >&2 echo 'ERROR: Invalid installer checksum for Composer' | |
| fi | |
| if [ "$EXPECTED_CHECKSUM" = "$ACTUAL_CHECKSUM" ]; then | |
| sudo php "$COMPOSER_TMP_DIR/composer-setup.php" --quiet --install-dir=/usr/local/bin --filename=composer | |
| else | |
| >&2 echo 'ERROR: Invalid installer checksum for Composer' | |
| exit 1 | |
| fi |
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In `@tools/os_installers/apt.sh` around lines 272 - 276, The else branch that
handles the checksum mismatch currently only echoes an error and returns a zero
exit status; update the checksum verification block that compares
EXPECTED_CHECKSUM and ACTUAL_CHECKSUM to terminate the script with a non-zero
status on failure by adding an explicit exit 1 after the error message so the
installer does not continue silently (affecting the branch that would otherwise
run sudo php "$COMPOSER_TMP_DIR/composer-setup.php" --quiet
--install-dir=/usr/local/bin --filename=composer).
1 participant
🚨 Severity: CRITICAL
💡 Vulnerability: Insecure temporary file usage (CWE-377/CWE-362). The script
tools/os_installers/apt.shdownloaded files (e.g.,yq) directly to a predictable path in a world-writable directory (/tmp/yq) before executingsudo mvandsudo chmod.🎯 Impact: A local attacker could pre-create the predictable file or create a symlink at
/tmp/yq. When the script executes, it would overwrite the attacker-controlled location or execute malicious code with elevated privileges, leading to local privilege escalation.🔧 Fix: Replaced hardcoded and predictable paths with securely generated temporary directories using
mktemp -d. Each tool installation was wrapped in a subshell(...)with a localtrap 'rm -rf "$TMP_DIR"' EXITto ensure clean up. This was applied toyq,Go,lsd, andComposerdownloads.✅ Verification: Review the changes in
tools/os_installers/apt.shto ensuremktemp -dis used. Run./build.shto verify syntax and linting checks pass.PR created automatically by Jules for task 16156909619627972950 started by @kidchenko
Summary by CodeRabbit
Bug Fixes
Documentation