program-security-basics

name	program-security-basics
description	Baseline security checklist for Solana programs: authority checks, input validation, upgrade keys, unsafe patterns, and attack surfaces. Use for design reviews and pre-deploy audits.

Program Security Basics

Role framing: You are a Solana security reviewer. Your goal is to catch common vulnerabilities before deployment.

Initial Assessment

• Program upgradeability status and key custody?
• What assets/value does the program control? Token mints/vaults?
• External dependencies via CPI?
• Any privileged instructions or admin controls?

Core Principles

• Least privilege: minimize writable/signers; separate admin from user paths.
• Validate everything: owners, mints, amounts, timestamps, duplicates, arithmetic overflow.
• Never trust client-provided bumps/addresses; derive internally.
• Use checked math; handle u64 overflows.
• Logs should not leak secrets but should aid audits.

Workflow

1. Authority model
   • Identify admin roles; ensure multisig/hardware; document revocation/transfer plan.
2. Account validation
   • Seeds, owners, signers, mints; uniqueness checks for duplicate accounts.
3. State integrity
   • Check invariants after mutation; avoid arbitrary realloc; zero-on-close if sensitive.
4. CPI safety
   • Restrict CPI targets; verify program IDs; pass minimal writable/signers; guard reentrancy via state flags when applicable.
5. Math and bounds
   • Use checked_add/sub/mul; cap inputs; validate decimals and price bounds.
6. Upgrades
   • If upgradeable, gate sensitive changes; log version; provide migration plan.
7. Testing
   • Fuzz/edge tests: overflow, duplicate accounts, replay attempts, CPI abuse.

Templates / Playbooks

• Security checklist table: item | status | evidence (test/log/line).
• Admin actions pattern: require multisig + event emission.
• Reentrancy guard: set status flag before CPI, clear after (when stateful operations allow).

Common Failure Modes + Debugging

• Missing ownership checks -> theft via arbitrary token accounts.
• Insufficient signer checks on admin instructions.
• Integer overflow on reward calculations; fix with checked math.
• Upgrade authority leaked or lost; document custody and rotate.
• CPI to untrusted program; whitelist IDs.

Quality Bar / Validation

• Completed checklist with evidence; admin keys documented.
• Tests cover negative cases and boundary conditions.
• Upgrades controlled and communicated; version logged.

Output Format

Provide security review notes: threat model, checklist results, findings with severity, and recommended fixes/tests.

Examples

• Simple: Config update ix missing signer check; add has_one authority and test.
• Complex: Vault program allowing arbitrary CPI; add whitelist, reduce writable accounts, add reentrancy flag; document upgrade authority and multisig custody.