Skip to content

πŸ›‘οΈ Sentinel: Fix insecure file permissions in backup script#41

Open
kidchenko wants to merge 1 commit intomainfrom
sentinel/fix-backup-permissions-6173289691338400290
Open

πŸ›‘οΈ Sentinel: Fix insecure file permissions in backup script#41
kidchenko wants to merge 1 commit intomainfrom
sentinel/fix-backup-permissions-6173289691338400290

Conversation

@kidchenko
Copy link
Owner

@kidchenko kidchenko commented Feb 25, 2026

πŸ›‘οΈ Sentinel: [CRITICAL/HIGH] Fix Insecure File Permissions in Backup Script

🚨 Severity: HIGH
πŸ’‘ Vulnerability: Backup archives containing potentially sensitive project code were created with default umask permissions (often 0644 or 0664), making them readable by other users on the system.
🎯 Impact: Unauthorized users could access project source code, secrets, and configuration files stored in backups.
πŸ”§ Fix:

  • Added chmod 700 to backup and log directories.
  • Set umask 077 within the zip creation subshell.
  • Added explicit chmod 600 to the generated archive file.
    βœ… Verification:
  • Verified that mkdir is followed by chmod 700.
  • Verified that zip runs under umask 077.
  • Verified that the resulting archive is chmod 600.

PR created automatically by Jules for task 6173289691338400290 started by @kidchenko

Summary by CodeRabbit

  • Bug Fixes

    • Fixed a security vulnerability where backup archives and directories could be created with overly permissive access rights on multi-user systems, potentially exposing sensitive backup data.
  • Documentation

    • Added documentation describing the file permission security issue and recommended preventive measures for backup operations.

- Restrict backup directory permissions to 0700 (owner only)
- Create backup archives with umask 077 and chmod 0600
- Ensure logs are stored in a 0700 directory

This prevents potential information disclosure on multi-user systems.

Co-authored-by: kidchenko <5432753+kidchenko@users.noreply.github.com>
@google-labs-jules
Copy link
Contributor

πŸ‘‹ Jules, reporting for duty! I'm here to lend a hand with this pull request.

When you start a review, I'll add a πŸ‘€ emoji to each comment to let you know I've read it. I'll focus on feedback directed at me and will do my best to stay out of conversations between you and other bots or reviewers to keep the noise down.

I'll push a commit with your requested changes shortly after. Please note there might be a delay between these steps, but rest assured I'm on the job!

For more direct control, you can switch me to Reactive Mode. When this mode is on, I will only act on comments where you specifically mention me with @jules. You can find this option in the Pull Request section of your global Jules UI settings. You can always switch back!

New to Jules? Learn more at jules.google/docs.


For security, I will only act on instructions from the user who triggered this task.

@coderabbitai
Copy link

coderabbitai bot commented Feb 25, 2026

πŸ“ Walkthrough

Walkthrough

Introduces file permission security hardening to the backup script by documenting an insecure permissions vulnerability and implementing preventive measures: setting explicit directory permissions (700), applying strict umask (077) during archive creation, and restricting archive files to 600 permissions.

Changes

Cohort / File(s) Summary
Security Documentation
.jules/sentinel.md
New documentation entry describing the file permission vulnerability in backup scripts, explaining exposure risks on multi-user systems, and prescribing concrete preventive measures including umask and chmod configurations.
Backup Script Hardening
tools/backup-projects.sh
Added explicit permission controls: directories set to 700, strict umask 077 applied during archive creation in a subshell, and archive files explicitly restricted to 600 permissions in non-dry-run paths.

Estimated Code Review Effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐰 Our burrows were exposed, a careless oversight!
But now with umask charms and permissions tight,
No curious whiskers peek at secrets storedβ€”
Each archive locked, each directory floored! ✨

πŸš₯ Pre-merge checks | βœ… 3
βœ… Passed checks (3 passed)
Check name Status Explanation
Description Check βœ… Passed Check skipped - CodeRabbit’s high-level summary is enabled.
Title check βœ… Passed The PR title accurately describes the main change: fixing insecure file permissions in the backup script, which is the core objective of adding chmod/umask controls.
Docstring Coverage βœ… Passed Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

✏️ Tip: You can configure your own custom pre-merge checks in the settings.

✨ Finishing Touches
  • πŸ“ Generate docstrings (stacked PR)
  • πŸ“ Generate docstrings (commit on current branch)
πŸ§ͺ Generate unit tests (beta)
  • Create PR with unit tests
  • Post copyable unit tests in a comment
  • Commit unit tests in branch sentinel/fix-backup-permissions-6173289691338400290

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❀️ Share

Comment @coderabbitai help to get the list of available commands and usage tips.

Copy link

@coderabbitai coderabbitai bot left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Actionable comments posted: 1

🧹 Nitpick comments (1)
tools/backup-projects.sh (1)

353-356: Consider mkdir -m 700 to eliminate the TOCTOU gap and make intent explicit.

chmod 700 applied after mkdir -p leaves a brief window where the directory exists with default-umask permissions. While low-risk in this single-user context, using -m 700 is the idiomatic way to set the mode atomically at creation time.

♻️ Proposed refactor
-        mkdir -p "$BACKUP_TEMP_DIR"
-        chmod 700 "$BACKUP_TEMP_DIR"
-        mkdir -p "$LOG_DIR"
-        chmod 700 "$LOG_DIR"
+        mkdir -m 700 -p "$BACKUP_TEMP_DIR"
+        mkdir -m 700 -p "$LOG_DIR"

Note: mkdir -m 700 -p sets the mode on the final path component only; any intermediate directories created by -p still inherit the umask. If $BACKUP_BASE_DIR or parent paths of $LOG_DIR are expected to be newly created, add explicit chmod 700 calls for those parents as well.

πŸ€– Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.

In `@tools/backup-projects.sh` around lines 353 - 356, Replace the two-step
create-then-chmod for BACKUP_TEMP_DIR and LOG_DIR with atomic creation using
mkdir -m 700 -p to avoid the TOCTOU window: change the mkdir/ chmod sequence
that references "$BACKUP_TEMP_DIR" and "$LOG_DIR" so the directory is created
with mode 700 in one call, and if you expect intermediate parent directories
(e.g., parents of "$BACKUP_BASE_DIR" or parents of "$LOG_DIR") to be newly
created by -p, retain explicit chmod 700 calls for those parent paths since -m
on mkdir -p only applies to the final path component.
πŸ€– 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 top heading "2025-02-25 - Insecure File
Permissions in Backup Script" to an H1 and correct the year to 2026 (e.g., "#
2026-02-25 - Insecure File Permissions in Backup Script"), ensure there is a
blank line immediately after that heading to satisfy MD022, and reflow/wrap the
following paragraph lines to at most 80 characters to fix MD013 so the
description lines (the text under the heading) are split into shorter lines;
after these edits verify markdownlint no longer reports MD041, MD022, or MD013
failures.

---

Nitpick comments:
In `@tools/backup-projects.sh`:
- Around line 353-356: Replace the two-step create-then-chmod for
BACKUP_TEMP_DIR and LOG_DIR with atomic creation using mkdir -m 700 -p to avoid
the TOCTOU window: change the mkdir/ chmod sequence that references
"$BACKUP_TEMP_DIR" and "$LOG_DIR" so the directory is created with mode 700 in
one call, and if you expect intermediate parent directories (e.g., parents of
"$BACKUP_BASE_DIR" or parents of "$LOG_DIR") to be newly created by -p, retain
explicit chmod 700 calls for those parent paths since -m on mkdir -p only
applies to the final path component.

ℹ️ Review info

Configuration used: defaults

Review profile: CHILL

Plan: Pro

πŸ“₯ Commits

Reviewing files that changed from the base of the PR and between cb5949a and a22a4c4.

πŸ“’ Files selected for processing (2)
  • .jules/sentinel.md
  • tools/backup-projects.sh

Comment on lines +1 to +4
## 2025-02-25 - Insecure File Permissions in Backup Script
**Vulnerability:** The `tools/backup-projects.sh` script created backup archives and log directories without explicitly setting restrictive permissions. This meant that on multi-user systems (or even locally if shared), backup archives containing potentially sensitive project code and secrets were readable by other users (group/world readable depending on umask).
**Learning:** Default umask settings (often 022) are insufficient for security-critical operations like backups. Relying on default permissions assumes a secure environment, which is not always true.
**Prevention:** Always use `umask 077` in subshells when creating sensitive files or directories. Explicitly `chmod 700` directories and `chmod 600` files after creation to enforce defense-in-depth.
Copy link

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

⚠️ Potential issue | 🟑 Minor

Fix markdown lint failures (pipeline broken) and correct the year in the heading date.

Five markdownlint failures are blocking the Lint Documentation check:

Line Rule Fix
1 MD041 – first line must be h1 (#, not ##) Change ## β†’ #
1 MD022 – heading must be surrounded by blank lines Add a blank line after the heading
2–4 MD013 – lines exceed 80 chars Wrap long sentences at ≀80 chars

Additionally, the heading date reads 2025-02-25 but the PR was opened on 2026-02-25.

πŸ“ Proposed fix
-## 2025-02-25 - Insecure File Permissions in Backup Script
-**Vulnerability:** The `tools/backup-projects.sh` script created backup archives and log directories without explicitly setting restrictive permissions. This meant that on multi-user systems (or even locally if shared), backup archives containing potentially sensitive project code and secrets were readable by other users (group/world readable depending on umask).
-**Learning:** Default umask settings (often 022) are insufficient for security-critical operations like backups. Relying on default permissions assumes a secure environment, which is not always true.
-**Prevention:** Always use `umask 077` in subshells when creating sensitive files or directories. Explicitly `chmod 700` directories and `chmod 600` files after creation to enforce defense-in-depth.
+# 2026-02-25 - Insecure File Permissions in Backup Script
+
+**Vulnerability:** The `tools/backup-projects.sh` script created backup archives and log
+directories without explicitly setting restrictive permissions. On multi-user systems,
+backup archives containing potentially sensitive project code and secrets were readable
+by other users (group/world readable depending on umask).
+
+**Learning:** Default umask settings (often 022) are insufficient for security-critical
+operations like backups. Relying on default permissions assumes a secure environment,
+which is not always true.
+
+**Prevention:** Always use `umask 077` in subshells when creating sensitive files or
+directories. Explicitly `chmod 700` directories and `chmod 600` files after creation
+to enforce defense-in-depth.
πŸ“ 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.

Suggested change
## 2025-02-25 - Insecure File Permissions in Backup Script
**Vulnerability:** The `tools/backup-projects.sh` script created backup archives and log directories without explicitly setting restrictive permissions. This meant that on multi-user systems (or even locally if shared), backup archives containing potentially sensitive project code and secrets were readable by other users (group/world readable depending on umask).
**Learning:** Default umask settings (often 022) are insufficient for security-critical operations like backups. Relying on default permissions assumes a secure environment, which is not always true.
**Prevention:** Always use `umask 077` in subshells when creating sensitive files or directories. Explicitly `chmod 700` directories and `chmod 600` files after creation to enforce defense-in-depth.
# 2026-02-25 - Insecure File Permissions in Backup Script
**Vulnerability:** The `tools/backup-projects.sh` script created backup archives and log
directories without explicitly setting restrictive permissions. On multi-user systems,
backup archives containing potentially sensitive project code and secrets were readable
by other users (group/world readable depending on umask).
**Learning:** Default umask settings (often 022) are insufficient for security-critical
operations like backups. Relying on default permissions assumes a secure environment,
which is not always true.
**Prevention:** Always use `umask 077` in subshells when creating sensitive files or
directories. Explicitly `chmod 700` directories and `chmod 600` files after creation
to enforce defense-in-depth.
🧰 Tools
πŸͺ› GitHub Check: Lint Documentation

[failure] 4-4: Line length
.jules/sentinel.md:4:81 MD013/line-length Line length [Expected: 80; Actual: 198] 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: 199] 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: 365] 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: "## 2025-02-25 - Insecure File ..."] 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: "## 2025-02-25 - Insecure File Permissions in Backup Script"] https://github.com/DavidAnson/markdownlint/blob/v0.34.0/doc/md022.md

πŸ€– 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 top heading "2025-02-25 -
Insecure File Permissions in Backup Script" to an H1 and correct the year to
2026 (e.g., "# 2026-02-25 - Insecure File Permissions in Backup Script"), ensure
there is a blank line immediately after that heading to satisfy MD022, and
reflow/wrap the following paragraph lines to at most 80 characters to fix MD013
so the description lines (the text under the heading) are split into shorter
lines; after these edits verify markdownlint no longer reports MD041, MD022, or
MD013 failures.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

None yet

Projects

None yet

Development

Successfully merging this pull request may close these issues.

1 participant