security: Fix critical & high-risk vulnerabilities

[realmrhigh]

Security: Fix Critical & High-Risk Vulnerabilities

Overview

This PR addresses 4 critical/high-risk security issues identified during a security audit of the Rotunda browser. These fixes are essential for personal/production use and prevent token theft, binary compromise, MITM attacks, and arbitrary file writes.

Changes

C1: Auth Token Storage (Critical)

Issue: Session tokens stored plaintext in ~/.rotunda/agent/sessions/ with default permissions
Fix:

• Session directories created with 0o700 (owner-only access)
• All token files written with 0o600 permissions via atomic writes
• Prevents unauthorized token access via symlink/permission races

Files: src/agent/session_manager.py

C2: Binary Integrity (Critical)

Issue: Downloaded browser binaries never verified; vulnerable to MITM/compromised releases
Fix:

• SHA-256 checksum verification on all browser downloads
• Checksums can be pinned in code; fails loudly if mismatch
• Falls back to warning with computed hash if no pin exists

Files: src/browser/downloader.py

C3: SSL Verification (Critical)

Issue: verify=False in HTTP requests to geolocation/IP endpoints; vulnerable to MITM
Fix:

• Removed all verify=False parameters
• Enabled proper SSL verification using system CA bundle
• Geolocation/fingerprint data now protected

Files: src/utils/ip_utils.py, src/api/endpoints.py

H2: Path Traversal (High)

Issue: No sanitization on screenshot/download file paths; allows arbitrary file writes
Fix:

• New _safe_output_path() helper using os.path.normpath() + .resolve()
• All file writes sandboxed to ROTUNDA_OUTPUT_DIR
• Traversal attempts (../, symlinks) fail safely

Files: src/api/endpoints.py

Testing

• All syntax checks pass ✅
• No breaking changes to the API ✅
• Session creation still works with new permissions ✅
• Binary download with checksum verification tested ✅

Impact

• For users: Tokens, binaries, and network traffic are now protected
• For production: Eliminates the top 4 security attack vectors
• Backwards compatible: No API changes, just stricter security enforcement

Commits

9aeb360 security: fix C1 token storage - restrictive 0o600/0o700 permissions
8d428a5 security: fix C2 binary integrity - SHA-256 checksum verification
593a67c security: fix C3 SSL verification - enable verify=True for geolocation
d938f1d security: fix H2 path traversal - sandbox screenshot and download paths

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Signed-off-by: Stanton High stantonhigh@gmail.com