secure-code-review

Secure Code Review

Rules (for AI agents)

ALWAYS

• Validate input at every trust boundary, not only the HTTP one. A CLI argument, an environment variable, a queue message, a filename, a parsed config or spreadsheet cell all arrive from outside and none of them pass through the request-validation layer. Check type, length, allowed characters and allowed range, and reject before processing. api-security owns the HTTP request body and its schema; this rule is every other way input gets in.
• Build a command as an argument vector, never as a string a shell will parse: subprocess.run([...]) without shell=True, execFile/spawn with an array, exec.Command(name, args...). Passing an array is what removes the shell, and removing the shell is what removes the injection — quoting and escaping are the fallback for when you cannot.
• Canonicalize then check any path built from input: resolve it to an absolute real path, then confirm it is inside the intended directory. Checking the raw string first misses .., symlinks, absolute-path replacement, and encoded separators. file-upload-security owns stored uploads and archive extraction; this rule covers a static-file handler, a template loader, a log path, an export filename.
• Tag any function or module handling PII, PHI or cardholder data with an explicit classification comment (// classification: PII), and keep that handling in clearly-named modules rather than in general utility code. An untagged helper is how regulated data spreads into paths nobody reviews for it, and the tag is what makes the later review possible.
• Consult the owner for anything with one: database-security when code builds a query, crypto-misuse when it hashes, encrypts, signs or compares a secret, frontend-security for output encoding and response headers, auth-security for who the caller is, iam-best-practices for the privileges a process runs with. Each of those states its rule with the API names and the false positives this skill would have to leave out.