server: Add a check for a changing private key

This checks that the private key used to encode the passwords has not
changed since last successful startup, leading to a corruption of all
the passwords. Lots of common scenario are covered, with various
combinations of key in a file or from a seed, set in the config file or
in an env variable or through CLI, and so on.

server/src/domain/sql_tables.rs

@@ -1,12 +1,47 @@
-use super::sql_migrations::{get_schema_version, migrate_from_version, upgrade_to_v1};
-use sea_orm::{DeriveValueType, QueryResult, Value};
+use crate::domain::sql_migrations::{
+    get_schema_version, migrate_from_version, upgrade_to_v1, Metadata,
+};
+use sea_orm::{
+    sea_query::Query, ConnectionTrait, DeriveValueType, Iden, QueryResult, TryGetable, Value,
+};
+use serde::{Deserialize, Serialize};
 
 pub type DbConnection = sea_orm::DatabaseConnection;
 
 #[derive(Copy, PartialEq, Eq, Debug, Clone, PartialOrd, Ord, DeriveValueType)]
 pub struct SchemaVersion(pub i16);
 
-pub const LAST_SCHEMA_VERSION: SchemaVersion = SchemaVersion(6);
+pub const LAST_SCHEMA_VERSION: SchemaVersion = SchemaVersion(7);
+
+#[derive(Copy, PartialEq, Eq, Debug, Clone, PartialOrd, Ord)]
+pub struct PrivateKeyHash(pub [u8; 32]);
+
+impl TryGetable for PrivateKeyHash {
+    fn try_get(res: &QueryResult, pre: &str, col: &str) -> Result<Self, sea_orm::TryGetError> {
+        let index = format!("{pre}{col}");
+        Self::try_get_by(res, index.as_str())
+    }
+
+    fn try_get_by_index(res: &QueryResult, index: usize) -> Result<Self, sea_orm::TryGetError> {
+        Self::try_get_by(res, index)
+    }
+
+    fn try_get_by<I: sea_orm::ColIdx>(
+        res: &QueryResult,
+        index: I,
+    ) -> Result<Self, sea_orm::TryGetError> {
+        Ok(PrivateKeyHash(
+            std::convert::TryInto::<[u8; 32]>::try_into(res.try_get_by::<Vec<u8>, I>(index)?)
+                .unwrap(),
+        ))
+    }
+}
+
+impl From<PrivateKeyHash> for Value {
+    fn from(val: PrivateKeyHash) -> Self {
+        Self::from(val.0.to_vec())
+    }
+}
 
 pub async fn init_table(pool: &DbConnection) -> anyhow::Result<()> {
     let version = {
@@ -21,6 +56,71 @@ pub async fn init_table(pool: &DbConnection) -> anyhow::Result<()> {
     Ok(())
 }
 
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq)]
+pub enum ConfigLocation {
+    ConfigFile(String),
+    EnvironmentVariable(String),
+    CommandLine,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq)]
+pub enum PrivateKeyLocation {
+    KeySeed(ConfigLocation),
+    KeyFile(ConfigLocation, std::ffi::OsString),
+    Default,
+    #[cfg(test)]
+    Tests,
+}
+
+#[derive(Debug)]
+pub struct PrivateKeyInfo {
+    pub private_key_hash: PrivateKeyHash,
+    pub private_key_location: PrivateKeyLocation,
+}
+
+pub async fn get_private_key_info(pool: &DbConnection) -> anyhow::Result<Option<PrivateKeyInfo>> {
+    let result = pool
+        .query_one(
+            pool.get_database_backend().build(
+                Query::select()
+                    .column(Metadata::PrivateKeyHash)
+                    .column(Metadata::PrivateKeyLocation)
+                    .from(Metadata::Table),
+            ),
+        )
+        .await?;
+    let result = match result {
+        None => return Ok(None),
+        Some(r) => r,
+    };
+    if let Ok(hash) = result.try_get("", &Metadata::PrivateKeyHash.to_string()) {
+        Ok(Some(PrivateKeyInfo {
+            private_key_hash: hash,
+            private_key_location: serde_json::from_str(
+                &result.try_get::<String>("", &Metadata::PrivateKeyLocation.to_string())?,
+            )?,
+        }))
+    } else {
+        Ok(None)
+    }
+}
+
+pub async fn set_private_key_info(pool: &DbConnection, info: PrivateKeyInfo) -> anyhow::Result<()> {
+    pool.execute(
+        pool.get_database_backend().build(
+            Query::update()
+                .table(Metadata::Table)
+                .value(Metadata::PrivateKeyHash, Value::from(info.private_key_hash))
+                .value(
+                    Metadata::PrivateKeyLocation,
+                    Value::from(serde_json::to_string(&info.private_key_location).unwrap()),
+                ),
+        ),
+    )
+    .await?;
+    Ok(())
+}
+
 #[cfg(test)]
 mod tests {
     use crate::domain::{