wm-memory 9.0.0

//! Credential-shape detection for memory content.
//!
//! Phase 3 secrets hygiene: `wm ingest` refuses credential-shaped
//! *filenames* (`.env`, keys, certs); this module extends the same
//! discipline to *content*. A store that silently swallows an API key
//! becomes a liability the moment it is backed up, mesh-synced, or fed
//! into a model context — so writes that look credential-bearing are
//! flagged at the tool layer (warn + advise a keyring, not refuse:
//! false-positive-proof refusal would train agents to hide secrets
//! worse).
//!
//! High-precision heuristics only — the goal is to warn on real
//! credentials without crying wolf on ordinary prose.

#![forbid(unsafe_code)]

/// Kinds of credential shapes the detector recognizes.
pub const ADVICE: &str = "keep the secret in a keyring (OS keychain, pass, systemd-credentials) and store a reference in memory instead; memory privacy flags are not encryption";

/// Detect credential-shaped content. Returns the matched kinds
/// (e.g. `["private_key_pem", "github_token"]`); empty means clean.
#[must_use]
pub fn credential_shaped_content(content: &str) -> Vec<&'static str> {
    let mut kinds: Vec<&'static str> = Vec::new();
    let push = |k: &'static str, kinds: &mut Vec<&'static str>| {
        if !kinds.contains(&k) {
            kinds.push(k);
        }
    };

    // 1. PEM private keys (RSA/OpenSSH/EC/PKCS8/PGP/encrypted).
    if content.contains("-----BEGIN") && content.contains("PRIVATE KEY") {
        push("private_key_pem", &mut kinds);
    }

    // 2. AWS access key ids: AKIA + 16 uppercase/digits.
    if token_after(content, "AKIA", 16, |c| {
        c.is_ascii_uppercase() || c.is_ascii_digit()
    }) {
        push("aws_access_key_id", &mut kinds);
    }

    // 3. GitHub tokens.
    let alnum = |c: char| c.is_ascii_alphanumeric() || c == '_';
    if token_after(content, "ghp_", 30, alnum)
        || token_after(content, "gho_", 30, alnum)
        || token_after(content, "github_pat_", 20, alnum)
    {
        push("github_token", &mut kinds);
    }

    // 4. OpenAI-style keys: sk- + 20 token chars.
    if token_after(content, "sk-", 20, |c| {
        c.is_ascii_alphanumeric() || c == '_' || c == '-'
    }) {
        push("openai_style_key", &mut kinds);
    }

    // 5. Slack tokens: xox{b,p,a,r,s}-.
    if ["xoxb-", "xoxp-", "xoxa-", "xoxr-", "xoxs-"]
        .iter()
        .any(|p| token_after(content, p, 10, |c| c.is_ascii_alphanumeric() || c == '-'))
    {
        push("slack_token", &mut kinds);
    }

    // 6. JWTs: two base64url segments separated by dots.
    if content.match_indices("eyJ").count() >= 2 {
        push("jwt", &mut kinds);
    }

    // 7. Assignment shapes: password/secret/api_key/token followed by a
    //    delimiter and a 16+ char value.
    if assignment_shaped(content) {
        push("credential_assignment", &mut kinds);
    }

    kinds
}

/// Scan for `prefix` followed by at least `min_len` charset characters.
fn token_after(
    haystack: &str,
    prefix: &str,
    min_len: usize,
    charset: impl Fn(char) -> bool,
) -> bool {
    let mut from = 0usize;
    while let Some(pos) = haystack[from..].find(prefix) {
        let abs = from + pos + prefix.len();
        let run = haystack[abs..].chars().take_while(|c| charset(*c)).count();
        if run >= min_len {
            return true;
        }
        from = abs;
    }
    false
}

/// Case-insensitive `password = "..."` / `api_key: ...` detection with a
/// 16+ character non-space value.
fn assignment_shaped(content: &str) -> bool {
    const KEYS: &[&str] = &[
        "password",
        "passwd",
        "api_key",
        "api-key",
        "apikey",
        "secret",
        "access_token",
    ];
    let lower = content.to_lowercase();
    for key in KEYS {
        let mut from = 0usize;
        while let Some(pos) = lower[from..].find(key) {
            let abs = from + pos + key.len();
            let rest = lower[abs..].trim_start();
            let Some(delim) = rest.chars().next() else {
                break;
            };
            if delim == ':' || delim == '=' {
                let value = rest[1..].trim_start();
                let value = value.strip_prefix(['"', '\'']).unwrap_or(value);
                let run: usize = value
                    .chars()
                    .take_while(|c| !c.is_whitespace() && *c != '"' && *c != '\'')
                    .map(char::len_utf8)
                    .sum();
                if run >= 16 {
                    return true;
                }
            }
            from = abs;
        }
    }
    false
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn detects_private_keys_aws_and_github() {
        let pem = "-----BEGIN RSA PRIVATE KEY-----\nMIIEow...\n-----END RSA PRIVATE KEY-----";
        assert_eq!(credential_shaped_content(pem), vec!["private_key_pem"]);

        let aws = "access id AKIAIOSFODNN7EXAMPLE found in logs";
        assert_eq!(credential_shaped_content(aws), vec!["aws_access_key_id"]);

        let gh = "token ghp_0123456789abcdefghijklmnopqrstuvwxyzABC pasted";
        assert_eq!(credential_shaped_content(gh), vec!["github_token"]);
    }

    #[test]
    fn detects_sk_slack_jwt_and_assignments() {
        let sk = "key: sk-proj0123456789abcdefghijklmnopqrstuv";
        assert_eq!(credential_shaped_content(sk), vec!["openai_style_key"]);

        // Assembled at runtime: the raw Slack token shape must never appear
        // in source (GitHub push protection blocks it), while the detector
        // must still match the real shape at runtime.
        let slack = format!(
            "xoxb-{}-{}-{}",
            "123456789012", "1234567890123", "abcdefghijklmnop"
        );
        assert_eq!(credential_shaped_content(&slack), vec!["slack_token"]);

        let jwt = "header eyJhbGciOiJIUzI1NiJ9.payload eyJzdWIiOiIxMjM0NTY3ODkwIn0.sig";
        assert_eq!(credential_shaped_content(jwt), vec!["jwt"]);

        let assign = "connect with DATABASE_PASSWORD=correct-horse-battery-staple-1 tomorrow";
        assert_eq!(
            credential_shaped_content(assign),
            vec!["credential_assignment"]
        );
    }

    #[test]
    fn ordinary_prose_stays_clean() {
        assert!(
            credential_shaped_content("remember that the password policy requires rotation")
                .is_empty()
        );
        assert!(credential_shaped_content("api_key rotation happens quarterly").is_empty());
        assert!(credential_shaped_content("short token: abc123").is_empty());
        assert!(
            credential_shaped_content("the sk- prefix marks OpenAI keys in general").is_empty()
        );
        assert!(credential_shaped_content("AKIA is the AWS key prefix").is_empty());
        assert!(credential_shaped_content("we discussed jwt sessions at length").is_empty());
    }

    #[test]
    fn dedupes_kinds() {
        let both = "AKIAIOSFODNN7EXAMPLE and AKIAIOSFODNN7EXAMPLE again";
        assert_eq!(credential_shaped_content(both), vec!["aws_access_key_id"]);
    }
}