gunnar-core 2.0.0

//! **Company single sign-on: the rows** (owner, 2026-10-05: "SSO for
//! companies in gunnar, OIDC and SAML, so a company's people log in with their
//! own identity system" — and SCIM provisioning beside it).
//!
//! The account model is the owner's and does not move:
//!
//! * one account type; its creator is its admin;
//! * an **enterprise** account is an account whose admin enrolled employees,
//!   and an employee is a NEW user, created by and bound to the account
//!   ([`crate::AuthTable::enroll_employee`]) — an existing principal never
//!   becomes one;
//! * private by default; only the account admin makes anything public.
//!
//! SSO changes none of that. An account admin points the account at the
//! company's identity provider; a person the IdP vouches for is mapped to an
//! EMPLOYEE of THAT account — created just in time on the first login (a new
//! employee, never an attached principal), or provisioned beforehand by the
//! company's directory (SCIM, a CSV import) and claimed by its directory user
//! name on its first login. Every row here lives in the identity table
//! (`refs/gunnar/auth`), in the same compare-and-swap as the principal it
//! names, and reaches the twin with it.
//!
//! **No secret is in any row.** The OIDC client secret is sealed in the
//! secret store under [`client_secret_key`] (the box's KEK, replicated sealed);
//! a SCIM bearer is kept only as its SHA-256.

use crate::model::UnixMillis;

/// The protocol an account's identity provider speaks.
#[derive(Clone, Copy, PartialEq, Eq, Debug, serde::Serialize, serde::Deserialize)]
#[serde(rename_all = "lowercase")]
pub enum SsoProtocol {
    /// OpenID Connect.
    Oidc,
    /// SAML 2.0.
    Saml,
}

/// An OIDC identity provider (authorization code + PKCE).
#[derive(Clone, PartialEq, Eq, Debug, Default, serde::Serialize, serde::Deserialize)]
#[serde(deny_unknown_fields)]
pub struct OidcSettings {
    /// The issuer, exactly as its discovery document names it.
    pub issuer: String,
    /// The client id the IdP issued for this account's console.
    pub client_id: String,
    /// Beside `openid`, which is always asked.
    #[serde(default)]
    pub scopes: Vec<String>,
    /// The claim that names the person in the company's directory
    /// (`preferred_username` when empty; `email` when that is absent).
    #[serde(default)]
    pub username_claim: String,
    /// The claim shown as the person's name (`name` when empty).
    #[serde(default)]
    pub display_name_claim: String,
    /// **The IdP's own CA** (DER, base64, standard alphabet): the account
    /// admin's trust anchor for a company IdP behind a private CA — used for
    /// THIS provider's https calls alone (discovery, keys, token), beside the
    /// public roots (`gunnar_grpc::sso::idp_ca::parse_idp_ca` decides what is one). Written only when
    /// set, so a gunnar from before it reads every provider that has none.
    #[serde(default, skip_serializing_if = "Vec::is_empty")]
    pub idp_ca: Vec<String>,
}

/// An IdP CA as the identity table keeps it (base64 DER, [`OidcSettings::idp_ca`]).
pub fn idp_ca_stored(ders: &[Vec<u8>]) -> Vec<String> {
    use base64ct::{Base64, Encoding as _};
    ders.iter().map(|d| Base64::encode_string(d)).collect()
}

/// [`idp_ca_stored`] read back; an entry that does not decode is dropped.
pub fn idp_ca_from_stored(stored: &[String]) -> Vec<Vec<u8>> {
    use base64ct::{Base64, Encoding as _};
    stored.iter().filter_map(|s| Base64::decode_vec(s.trim()).ok()).collect()
}

/// A SAML 2.0 identity provider (HTTP-Redirect out, HTTP-POST back).
#[derive(Clone, PartialEq, Eq, Debug, Default, serde::Serialize, serde::Deserialize)]
#[serde(deny_unknown_fields)]
pub struct SamlSettings {
    /// The IdP's entity id (the assertion's issuer).
    pub idp_entity_id: String,
    /// Where the AuthnRequest goes (HTTP-Redirect binding).
    pub idp_sso_url: String,
    /// The IdP's signing certificates, DER, base64 (standard alphabet). The
    /// ONLY keys a response is verified with — a key in the message is never
    /// trusted.
    pub idp_certificates: Vec<String>,
    /// Where the metadata was read from, when it was (an https URL).
    #[serde(default)]
    pub metadata_url: String,
    /// The attribute that names the person (the NameID when empty).
    #[serde(default)]
    pub username_attribute: String,
    #[serde(default)]
    /// The attribute shown as the person's name.
    pub display_name_attribute: String,
}

/// **An account's identity provider**, as its admin configured it. Keyed by
/// the account.
#[derive(Clone, PartialEq, Eq, Debug, serde::Serialize, serde::Deserialize)]
#[serde(deny_unknown_fields)]
pub struct SsoProvider {
    /// The account (its principal id and namespace).
    pub account: String,
    /// OIDC or SAML.
    pub protocol: SsoProtocol,
    /// "Sign in with <display_name>".
    pub display_name: String,
    /// Email domains that lead the login page to this account (lowercase,
    /// unique on the server: one domain, one company).
    #[serde(default)]
    pub domains: Vec<String>,
    #[serde(default)]
    /// Set when `protocol` is OIDC.
    pub oidc: Option<OidcSettings>,
    #[serde(default)]
    /// Set when `protocol` is SAML.
    pub saml: Option<SamlSettings>,
    /// The account's EMPLOYEES log in through the IdP only: a passkey alone
    /// is refused for them. The account admin is not an employee and keeps
    /// the passkey (the break-glass).
    #[serde(default)]
    pub require_sso: bool,
    /// After the IdP, a passkey of the same person (registered on the first
    /// login when there is none yet).
    #[serde(default)]
    pub require_passkey: bool,
    /// The console the redirect URI and the SAML ACS hang off
    /// (`https://gunnar.example`), as the admin's console named it.
    pub console_origin: String,
    #[serde(default)]
    /// When it was last configured.
    pub updated: UnixMillis,
    #[serde(default)]
    /// Who configured it last.
    pub updated_by: String,
}

impl SsoProvider {
    /// The OIDC redirect URI the admin registers at the IdP.
    pub fn redirect_uri(&self) -> String {
        redirect_uri(&self.console_origin)
    }

    /// The SAML SP entity id (the audience).
    pub fn sp_entity_id(&self) -> String {
        sp_entity_id(&self.console_origin, &self.account)
    }

    /// The SAML Assertion Consumer Service URL.
    pub fn acs_url(&self) -> String {
        acs_url(&self.console_origin)
    }

    /// The issuer a subject is bound under: the OIDC issuer, or the SAML
    /// IdP's entity id.
    pub fn issuer(&self) -> &str {
        match self.protocol {
            SsoProtocol::Oidc => self.oidc.as_ref().map_or("", |o| o.issuer.as_str()),
            SsoProtocol::Saml => self.saml.as_ref().map_or("", |s| s.idp_entity_id.as_str()),
        }
    }
}

/// `<origin>/auth/sso/oidc/callback`.
pub fn redirect_uri(origin: &str) -> String {
    format!("{}/auth/sso/oidc/callback", origin.trim_end_matches('/'))
}

/// `<origin>/auth/sso/saml/<account>` — the SP entity id, one per account so
/// two companies' IdPs never share an audience.
pub fn sp_entity_id(origin: &str, account: &str) -> String {
    format!("{}/auth/sso/saml/{account}", origin.trim_end_matches('/'))
}

/// `<origin>/auth/sso/saml/acs`.
pub fn acs_url(origin: &str) -> String {
    format!("{}/auth/sso/saml/acs", origin.trim_end_matches('/'))
}

/// Where a directory user came from.
#[derive(Clone, Copy, PartialEq, Eq, Debug, serde::Serialize, serde::Deserialize)]
#[serde(rename_all = "lowercase")]
pub enum SsoSource {
    /// Created just in time by its first SSO login.
    Jit,
    /// Provisioned by the company's directory over SCIM.
    Scim,
    /// Provisioned by the account admin's CSV import.
    Csv,
}

impl SsoSource {
    /// The word a listing shows.
    pub fn as_str(self) -> &'static str {
        match self {
            SsoSource::Jit => "jit",
            SsoSource::Scim => "scim",
            SsoSource::Csv => "csv",
        }
    }
}

/// **One person of a company's directory**: an EMPLOYEE of `account`, keyed
/// by its principal id. Written in the same compare-and-swap as the employee
/// it describes, removed with it.
#[derive(Clone, PartialEq, Eq, Debug, serde::Serialize, serde::Deserialize)]
#[serde(deny_unknown_fields)]
pub struct SsoUser {
    /// The employee.
    pub principal_id: String,
    /// The account it is an employee of.
    pub account: String,
    /// The directory's user name, lowercase (SCIM `userName`, the mapped
    /// claim or attribute). Unique within the account.
    pub user_name: String,
    #[serde(default)]
    /// The person's name, as the directory says it.
    pub display_name: String,
    #[serde(default)]
    /// The person's address, as the directory says it (never mailed by gunnar).
    pub email: String,
    /// The directory's own id for the person (SCIM `externalId`).
    #[serde(default)]
    pub external_id: String,
    /// [`subject_key`] of the IdP subject this person logs in as, once bound
    /// (by the first login). `None`: provisioned, never logged in yet.
    #[serde(default)]
    pub subject: Option<String>,
    /// False: deactivated — gated, sessions revoked, data kept.
    pub active: bool,
    /// Where the row came from.
    pub source: SsoSource,
    /// When it was created.
    pub created: UnixMillis,
    #[serde(default)]
    /// When its last SSO login was.
    pub last_login: Option<UnixMillis>,
    /// The web session keys SSO logins enrolled (fingerprints), so a
    /// deactivation ends them. Pruned at each login.
    #[serde(default)]
    pub sessions: Vec<String>,
    /// Removed from the directory (SCIM DELETE): still gated, data kept, no
    /// longer listed or claimable; its user name is free for a NEW person.
    #[serde(default)]
    pub deleted: bool,
}

/// A SCIM bearer, by the SHA-256 of its secret.
#[derive(Clone, PartialEq, Eq, Debug, serde::Serialize, serde::Deserialize)]
#[serde(deny_unknown_fields)]
pub struct ScimToken {
    /// The public id a listing and a revocation name.
    pub id: String,
    /// The account the bearer provisions.
    pub account: String,
    /// Lowercase hex SHA-256 of the secret. Never the secret.
    pub secret_hash: String,
    #[serde(default)]
    /// What the account admin called it.
    pub label: String,
    /// When it was created.
    pub created: UnixMillis,
    /// Who created it.
    pub created_by: String,
    #[serde(default)]
    /// When it was last presented (to a minute).
    pub last_used: Option<UnixMillis>,
}

/// A SCIM group of an account's directory. Kept as the directory sent it;
/// what a group may reach is granted by the account admin.
#[derive(Clone, PartialEq, Eq, Debug, serde::Serialize, serde::Deserialize)]
#[serde(deny_unknown_fields)]
pub struct SsoGroup {
    /// The group's id (SCIM `id`).
    pub id: String,
    /// The account whose directory it is in.
    pub account: String,
    /// The group's name (SCIM `displayName`), unique within the account.
    pub display_name: String,
    #[serde(default)]
    /// The directory's own id for the group (SCIM `externalId`).
    pub external_id: String,
    /// Principal ids (employees of the same account only).
    #[serde(default)]
    pub members: Vec<String>,
    /// When it was created.
    pub created: UnixMillis,
}

/// The secret-store key of an account's OIDC client secret.
pub fn client_secret_key(account: &str) -> String {
    format!("sso/{account}/oidc-client-secret")
}

/// The gate holder a directory deactivation writes, so a reactivation lifts
/// only its own gate and never an operator's suspension.
pub fn gate_holder(account: &str) -> String {
    format!("sso:{account}")
}

/// **The key a subject is bound under**: SHA-256 of `issuer ␟ subject`, hex.
/// Hashed so a listing of the identity table carries no IdP identifiers.
pub fn subject_key(issuer: &str, subject: &str) -> String {
    let mut text = issuer.trim().trim_end_matches('/').to_owned();
    text.push('\u{1f}');
    text.push_str(subject);
    crate::auth::token_hash(&text)
}

/// The longest principal id a console carries in a session.
pub const MAX_ID_LEN: usize = 64;

/// **The ids a NEW employee for `user_name` may take**, in order:
/// `<account>.<local>`, then `-2` … `-9` — the local part of an address (or
/// the whole name) reduced to `[a-z0-9._-]`. Never an existing principal: the
/// caller takes the first one that is free and creates it.
pub fn principal_id_candidates(account: &str, user_name: &str) -> Vec<String> {
    let local = user_name.split('@').next().unwrap_or(user_name);
    let mut cleaned = String::new();
    for c in local.chars() {
        let c = c.to_ascii_lowercase();
        let keep =
            if c.is_ascii_lowercase() || c.is_ascii_digit() || c == '_' || c == '-' || c == '.' {
                c
            } else {
                '-'
            };
        if (keep == '-' || keep == '.') && cleaned.ends_with(['-', '.']) {
            continue;
        }
        cleaned.push(keep);
    }
    let cleaned = cleaned.trim_matches(['-', '.']).to_owned();
    let cleaned = if cleaned.is_empty() {
        "user".to_owned()
    } else {
        cleaned
    };
    let account = account.to_ascii_lowercase();
    let mut out = Vec::new();
    for n in 1..=9 {
        let suffix = if n == 1 {
            String::new()
        } else {
            format!("-{n}")
        };
        let room = MAX_ID_LEN.saturating_sub(account.len() + 1 + suffix.len());
        if room == 0 {
            break;
        }
        let body: String = cleaned.chars().take(room).collect();
        let body = body.trim_end_matches(['-', '.']);
        let id = format!("{account}.{body}{suffix}");
        if crate::sandbox::check_component(&id, &id).is_ok() && id.len() <= MAX_ID_LEN {
            out.push(id);
        }
    }
    out
}

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

    #[test]
    fn candidates_are_the_accounts_and_valid_ids() {
        let ids = principal_id_candidates("acme", "Bob.Smith@ACME.example");
        assert_eq!(ids[0], "acme.bob.smith");
        assert_eq!(ids[1], "acme.bob.smith-2");
        assert_eq!(ids.len(), 9);
        let odd = principal_id_candidates("acme", "  ..--åsa ö'connor--..");
        assert_eq!(odd[0], "acme.sa-connor");
        let empty = principal_id_candidates("acme", "@@@");
        assert_eq!(empty[0], "acme.user");
        let long = principal_id_candidates("acme", &"x".repeat(200));
        assert!(long.iter().all(|id| id.len() <= MAX_ID_LEN));
    }

    /// A provider with no CA is written as before: a gunnar from before the
    /// CA reads it (`deny_unknown_fields`).
    #[test]
    fn a_provider_without_a_ca_is_written_as_before() {
        let o = OidcSettings { issuer: "https://idp.example".into(), client_id: "c".into(), ..Default::default() };
        let text = serde_json::to_string(&o).expect("json");
        assert!(!text.contains("idp_ca"), "{text}");
        let with = OidcSettings { idp_ca: vec!["AAAA".into()], ..o };
        assert!(serde_json::to_string(&with).expect("json").contains("idp_ca"));
    }

    #[test]
    fn subject_keys_bind_the_issuer() {
        assert_ne!(
            subject_key("https://a.example", "1"),
            subject_key("https://b.example", "1")
        );
        assert_eq!(
            subject_key("https://a.example/", "1"),
            subject_key("https://a.example", "1")
        );
        assert_eq!(subject_key("i", "s").len(), 64);
    }
}