Add `change password` UI + API.

The protocol here re-checks the caller's password, as a "I left myself logged in" anti-pranking check.

1 files changed, 42 insertions, 1 deletions

diff --git a/src/token/app.rs b/src/token/app.rs
index c19d6a0..5c0aeb0 100644
--- a/src/token/app.rs
+++ b/src/token/app.rs
@@ -13,7 +13,7 @@ use super::{
 use crate::{
     clock::DateTime,
     db::NotFound as _,
-    login::{Login, Password},
+    login::{repo::Provider as _, Login, Password},
     name::{self, Name},
 };
 
@@ -61,6 +61,47 @@ impl<'a> Tokens<'a> {
         Ok((snapshot, token))
     }
 
+    pub async fn change_password(
+        &self,
+        login: &Login,
+        password: &Password,
+        to: &Password,
+        changed_at: &DateTime,
+    ) -> Result<(Login, Secret), LoginError> {
+        let mut tx = self.db.begin().await?;
+        let (login, stored_hash) = tx
+            .auth()
+            .for_login(login)
+            .await
+            .optional()?
+            .ok_or(LoginError::Rejected)?;
+        // Split the transaction here to avoid holding the tx open (potentially blocking
+        // other writes) while we do the fairly expensive task of verifying the
+        // password. It's okay if the token issuance transaction happens some notional
+        // amount of time after retrieving the login, as inserting the token will fail
+        // if the account is deleted during that time.
+        tx.commit().await?;
+
+        if !stored_hash.verify(password)? {
+            return Err(LoginError::Rejected);
+        }
+
+        let snapshot = login.as_snapshot().ok_or(LoginError::Rejected)?;
+        let to_hash = to.hash()?;
+
+        let mut tx = self.db.begin().await?;
+        let tokens = tx.tokens().revoke_all(&login).await?;
+        tx.logins().set_password(&login, &to_hash).await?;
+        let secret = tx.tokens().issue(&login, changed_at).await?;
+        tx.commit().await?;
+
+        for event in tokens.into_iter().map(TokenEvent::Revoked) {
+            self.token_events.broadcast(event);
+        }
+
+        Ok((snapshot, secret))
+    }
+
     pub async fn validate(
         &self,
         secret: &Secret,