Add secrets.keys_dir config option.

crates/config/src/sections/secrets.rs

@@ -244,6 +244,86 @@ impl From<Encryption> for EncryptionRaw {
     }
 }
 
+/// Description of signing keys.
+///
+/// It either holds the key config values directly or references a directory
+/// where each file contains a key.
+#[derive(Debug, Clone)]
+pub enum Keys {
+    Values(Vec<KeyConfig>),
+    Directory(Utf8PathBuf),
+}
+
+impl Keys {
+    /// Returns a list of key configs.
+    ///
+    /// If `keys_dir` was given, the keys are read from file.
+    async fn key_configs(&self) -> anyhow::Result<Vec<KeyConfig>> {
+        match self {
+            Keys::Values(key_configs) => Ok(key_configs.clone()),
+            Keys::Directory(path) => key_configs_from_path(path).await,
+        }
+    }
+}
+
+/// Reads all keys from the given directory.
+async fn key_configs_from_path(path: &Utf8PathBuf) -> anyhow::Result<Vec<KeyConfig>> {
+    let mut result = vec![];
+    let mut read_dir = tokio::fs::read_dir(path).await?;
+    while let Some(dir_entry) = read_dir.next_entry().await? {
+        if !dir_entry.path().is_file() {
+            continue;
+        }
+        result.push(KeyConfig {
+            kid: None,
+            password: None,
+            key: Key::File(dir_entry.path().try_into()?),
+        });
+    }
+    Ok(result)
+}
+
+#[serde_as]
+#[derive(JsonSchema, Serialize, Deserialize, Debug, Clone)]
+struct KeysRaw {
+    /// List of private keys to use for signing and encrypting payloads.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    keys: Option<Vec<KeyConfig>>,
+
+    /// Directory of private keys to use for signing and encrypting payloads.
+    #[schemars(with = "Option<String>")]
+    #[serde(skip_serializing_if = "Option::is_none")]
+    keys_dir: Option<Utf8PathBuf>,
+}
+
+impl TryFrom<KeysRaw> for Keys {
+    type Error = anyhow::Error;
+
+    fn try_from(value: KeysRaw) -> Result<Keys, Self::Error> {
+        match (value.keys, value.keys_dir) {
+            (None, None) => bail!("Missing `keys` or `keys_dir`"),
+            (None, Some(path)) => Ok(Keys::Directory(path)),
+            (Some(keys), None) => Ok(Keys::Values(keys)),
+            (Some(_), Some(_)) => bail!("Cannot specify both `keys` and `keys_dir`"),
+        }
+    }
+}
+
+impl From<Keys> for KeysRaw {
+    fn from(value: Keys) -> Self {
+        match value {
+            Keys::Directory(path) => KeysRaw {
+                keys_dir: Some(path),
+                keys: None,
+            },
+            Keys::Values(keys) => KeysRaw {
+                keys_dir: None,
+                keys: Some(keys),
+            },
+        }
+    }
+}
+
 /// Application secrets
 #[serde_as]
 #[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
@@ -255,8 +335,10 @@ pub struct SecretsConfig {
     encryption: Encryption,
 
     /// List of private keys to use for signing and encrypting payloads
-    #[serde(default)]
-    keys: Vec<KeyConfig>,
+    #[schemars(with = "KeysRaw")]
+    #[serde_as(as = "serde_with::TryFromInto<KeysRaw>")]
+    #[serde(flatten)]
+    keys: Keys,
 }
 
 impl SecretsConfig {
@@ -267,7 +349,8 @@ impl SecretsConfig {
     /// Returns an error when a key could not be imported
     #[tracing::instrument(name = "secrets.load", skip_all)]
     pub async fn key_store(&self) -> anyhow::Result<Keystore> {
-        let web_keys = try_join_all(self.keys.iter().map(KeyConfig::json_web_key)).await?;
+        let key_configs = self.keys.key_configs().await?;
+        let web_keys = try_join_all(key_configs.iter().map(KeyConfig::json_web_key)).await?;
 
         Ok(Keystore::new(JsonWebKeySet::new(web_keys)))
     }
@@ -382,7 +465,7 @@ impl SecretsConfig {
 
         Ok(Self {
             encryption: Encryption::Value(Standard.sample(&mut rng)),
-            keys: vec![rsa_key, ec_p256_key, ec_p384_key, ec_k256_key],
+            keys: Keys::Values(vec![rsa_key, ec_p256_key, ec_p384_key, ec_k256_key]),
         })
     }
 
@@ -423,7 +506,7 @@ impl SecretsConfig {
 
         Self {
             encryption: Encryption::Value([0xEA; 32]),
-            keys: vec![rsa_key, ecdsa_key],
+            keys: Keys::Values(vec![rsa_key, ecdsa_key]),
         }
     }
 }
@@ -439,6 +522,129 @@ mod tests {
 
     use super::*;
 
+    #[tokio::test]
+    async fn load_config() {
+        task::spawn_blocking(|| {
+            Jail::expect_with(|jail| {
+                jail.create_file(
+                    "config.yaml",
+                    indoc::indoc! {r"
+                        secrets:
+                          encryption_file: encryption
+                          keys_dir: keys
+                    "},
+                )?;
+                jail.create_file("encryption", example_secret())?;
+                jail.create_dir("keys")?;
+                jail.create_file(
+                    "keys/key1",
+                    indoc::indoc! {r"
+                        -----BEGIN RSA PRIVATE KEY-----
+                        MIIJKQIBAAKCAgEA6oR6LXzJOziUxcRryonLTM5Xkfr9cYPCKvnwsWoAHfd2MC6Q
+                        OCAWSQnNcNz5RTeQUcLEaA8sxQi64zpCwO9iH8y8COCaO8u9qGkOOuJwWnmPfeLs
+                        cEwALEp0LZ67eSUPsMaz533bs4C8p+2UPMd+v7Td8TkkYoqgUrfYuT0bDTMYVsSe
+                        wcNB5qsI7hDLf1t5FX6KU79/Asn1K3UYHTdN83mghOlM4zh1l1CJdtgaE1jAg4Ml
+                        1X8yG+cT+Ks8gCSGQfIAlVFV4fvvzmpokNKfwAI/b3LS2/ft4ZrK+RCTsWsjUu38
+                        Zr8jbQMtDznzBHMw1LoaHpwRNjbJZ7uA6x5ikbwz5NAlfCITTta6xYn8qvaBfiYJ
+                        YyUFl0kIHm9Kh9V9p54WPMCFCcQx12deovKV82S6zxTeMflDdosJDB/uG9dT2qPt
+                        wkpTD6xAOx5h59IhfiY0j4ScTl725GygVzyK378soP3LQ/vBixQLpheALViotodH
+                        fJknsrelaISNkrnapZL3QE5C1SUoaUtMG9ovRz5HDpMx5ooElEklq7shFWDhZXbp
+                        2ndU5RPRCZO3Szop/Xhn2mNWQoEontFh79WIf+wS8TkJIRXhjtYBt3+s96z0iqSg
+                        gDmE8BcP4lP1+TAUY1d7+QEhGCsTJa9TYtfDtNNfuYI9e3mq6LEpHYKWOvECAwEA
+                        AQKCAgAlF60HaCGf50lzT6eePQCAdnEtWrMeyDCRgZTLStvCjEhk7d3LssTeP9mp
+                        oe8fPomUv6c3BOds2/5LQFockABHd/y/CV9RA973NclAEQlPlhiBrb793Vd4VJJe
+                        6331dveDW0+ggVdFjfVzjhqQfnE9ZcsQ2JvjpiTI0Iv2cy7F01tke0GCSMgx8W1p
+                        J2jjDOxwNOKGGoIT8S4roHVJnFy3nM4sbNtyDj+zHimP4uBE8m2zSgQAP60E8sia
+                        3+Ki1flnkXJRgQWCHR9cg5dkXfFRz56JmcdgxAHGWX2vD9XRuFi5nitPc6iTw8PV
+                        u7GvS3+MC0oO+1pRkTAhOGv3RDK3Uqmy2zrMUuWkEsz6TVId6gPl7+biRJcP+aER
+                        plJkeC9J9nSizbQPwErGByzoHGLjADgBs9hwqYkPcN38b6jR5S/VDQ+RncCyI87h
+                        s/0pIs/fNlfw4LtpBrolP6g++vo6KUufmE3kRNN9dN4lNOoKjUGkcmX6MGnwxiw6
+                        NN/uEqf9+CKQele1XeUhRPNJc9Gv+3Ly5y/wEi6FjfVQmCK4hNrl3tvuZw+qkGbq
+                        Au9Jhk7wV81An7fbhBRIXrwOY9AbOKNqUfY+wpKi5vyJFS1yzkFaYSTKTBspkuHW
+                        pWbohO+KreREwaR5HOMK8tQMTLEAeE3taXGsQMJSJ15lRrLc7QKCAQEA68TV/R8O
+                        C4p+vnGJyhcfDJt6+KBKWlroBy75BG7Dg7/rUXaj+MXcqHi+whRNXMqZchSwzUfS
+                        B2WK/HrOBye8JLKDeA3B5TumJaF19vV7EY/nBF2QdRmI1r33Cp+RWUvAcjKa/v2u
+                        KksV3btnJKXCu/stdAyTK7nU0on4qBzm5WZxuIJv6VMHLDNPFdCk+4gM8LuJ3ITU
+                        l7XuZd4gXccPNj0VTeOYiMjIwxtNmE9RpCkTLm92Z7MI+htciGk1xvV0N4m1BXwA
+                        7qhl1nBgVuJyux4dEYFIeQNhLpHozkEz913QK2gDAHL9pAeiUYJntq4p8HNvfHiQ
+                        vE3wTzil3aUFnwKCAQEA/qQm1Nx5By6an5UunrOvltbTMjsZSDnWspSQbX//j6mL
+                        2atQLe3y/Nr7E5SGZ1kFD9tgAHTuTGVqjvTqp5dBPw4uo146K2RJwuvaYUzNK26c
+                        VoGfMfsI+/bfMfjFnEmGRARZdMr8cvhU+2m04hglsSnNGxsvvPdsiIbRaVDx+JvN
+                        C5C281WlN0WeVd7zNTZkdyUARNXfCxBHQPuYkP5Mz2roZeYlJMWU04i8Cx0/SEuu
+                        bhZQDaNTccSdPDFYcyDDlpqp+mN+U7m+yUPOkVpaxQiSYJZ+NOQsNcAVYfjzyY0E
+                        /VP3s2GddjCJs0amf9SeW0LiMAHPgTp8vbMSRPVVbwKCAQEAmZsSd+llsys2TEmY
+                        pivONN6PjbCRALE9foCiCLtJcmr1m4uaZRg0HScd0UB87rmoo2TLk9L5CYyksr4n
+                        wQ2oTJhpgywjaYAlTVsWiiGBXv3MW1HCLijGuHHno+o2PmFWLpC93ufUMwXcZywT
+                        lRLR/rs07+jJcbGO8OSnNpAt9sN5z+Zblz5a6/c5zVK0SpRnKehld2CrSXRkr8W6
+                        fJ6WUJYXbTmdRXDbLBJ7yYHUBQolzxkboZBJhvmQnec9/DQq1YxIfhw+Vz8rqjxo
+                        5/J9IWALPD5owz7qb/bsIITmoIFkgQMxAXfpvJaksEov3Bs4g8oRlpzOX4C/0j1s
+                        Ay3irQKCAQEAwRJ/qufcEFkCvjsj1QsS+MC785shyUSpiE/izlO91xTLx+f/7EM9
+                        +QCkXK1B1zyE/Qft24rNYDmJOQl0nkuuGfxL2mzImDv7PYMM2reb3PGKMoEnzoKz
+                        xi/h/YbNdnm9BvdxSH/cN+QYs2Pr1X5Pneu+622KnbHQphfq0fqg7Upchwdb4Faw
+                        5Z6wthVMvK0YMcppUMgEzOOz0w6xGEbowGAkA5cj1KTG+jjzs02ivNM9V5Utb5nF
+                        3D4iphAYK3rNMfTlKsejciIlCX+TMVyb9EdSjU+uM7ZJ2xtgWx+i4NA+10GCT42V
+                        EZct4TORbN0ukK2+yH2m8yoAiOks0gJemwKCAQAMGROGt8O4HfhpUdOq01J2qvQL
+                        m5oUXX8w1I95XcoAwCqb+dIan8UbCyl/79lbqNpQlHbRy3wlXzWwH9aHKsfPlCvk
+                        5dE1qrdMdQhLXwP109bRmTiScuU4zfFgHw3XgQhMFXxNp9pze197amLws0TyuBW3
+                        fupS4kM5u6HKCeBYcw2WP5ukxf8jtn29tohLBiA2A7NYtml9xTer6BBP0DTh+QUn
+                        IJL6jSpuCNxBPKIK7p6tZZ0nMBEdAWMxglYm0bmHpTSd3pgu3ltCkYtDlDcTIaF0
+                        Q4k44lxUTZQYwtKUVQXBe4ZvaT/jIEMS7K5bsAy7URv/toaTaiEh1hguwSmf
+                        -----END RSA PRIVATE KEY-----
+                    "},
+                )?;
+                jail.create_file(
+                    "keys/key2",
+                    indoc::indoc! {r"
+                        -----BEGIN EC PRIVATE KEY-----
+                        MHcCAQEEIKlZz/GnH0idVH1PnAF4HQNwRafgBaE2tmyN1wjfdOQqoAoGCCqGSM49
+                        AwEHoUQDQgAEHrgPeG+Mt8eahih1h4qaPjhl7jT25cdzBkg3dbVks6gBR2Rx4ug9
+                        h27LAir5RqxByHvua2XsP46rSTChof78uw==
+                        -----END EC PRIVATE KEY-----
+                    "},
+                )?;
+
+                let config = Figment::new()
+                    .merge(Yaml::file("config.yaml"))
+                    .extract_inner::<SecretsConfig>("secrets")?;
+
+                Handle::current().block_on(async move {
+                    assert!(
+                        matches!(config.encryption, Encryption::File(ref p) if p == "encryption")
+                    );
+                    assert_eq!(
+                        config.encryption().await.unwrap(),
+                        [
+                            0, 0, 17, 17, 34, 34, 51, 51, 68, 68, 85, 85, 102, 102, 119, 119, 136,
+                            136, 153, 153, 170, 170, 187, 187, 204, 204, 221, 221, 238, 238, 255,
+                            255
+                        ]
+                    );
+
+                    let mut key_config = config.keys.key_configs().await.unwrap();
+                    key_config.sort_by_key(|a| {
+                        if let Key::File(p) = &a.key {
+                            Some(p.clone())
+                        } else {
+                            None
+                        }
+                    });
+                    let key_store = config.key_store().await.unwrap();
+
+                    assert!(key_config[0].kid.is_none());
+                    assert!(matches!(&key_config[0].key, Key::File(p) if p == "keys/key1"));
+                    assert!(key_store.iter().any(|k| k.kid() == Some("xmgGCzGtQFmhEOP0YAqBt-oZyVauSVMXcf4kwcgGZLc")));
+                    assert!(key_config[1].kid.is_none());
+                    assert!(matches!(&key_config[1].key, Key::File(p) if p == "keys/key2"));
+                    assert!(key_store.iter().any(|k| k.kid() == Some("ONUCn80fsiISFWKrVMEiirNVr-QEvi7uQI0QH9q9q4o")));
+                });
+
+                Ok(())
+            });
+        })
+        .await
+        .unwrap();
+    }
+
     #[tokio::test]
     async fn load_config_inline_secrets() {
         task::spawn_blocking(|| {

docs/config.schema.json

@@ -1528,14 +1528,6 @@
       "description": "Application secrets",
       "type": "object",
       "properties": {
-        "keys": {
-          "description": "List of private keys to use for signing and encrypting payloads",
-          "default": [],
-          "type": "array",
-          "items": {
-            "$ref": "#/definitions/KeyConfig"
-          }
-        },
         "encryption_file": {
           "description": "File containing the encryption key for secure cookies.",
           "type": "string"
@@ -1547,6 +1539,17 @@
           ],
           "type": "string",
           "pattern": "[0-9a-fA-F]{64}"
+        },
+        "keys": {
+          "description": "List of private keys to use for signing and encrypting payloads.",
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/KeyConfig"
+          }
+        },
+        "keys_dir": {
+          "description": "Directory of private keys to use for signing and encrypting payloads.",
+          "type": "string"
         }
       }
     },

docs/reference/configuration.md

@@ -222,7 +222,7 @@ The secret is not updated when the content of the file changes.
 > Changing the encryption secret afterwards will lead to a loss of all encrypted
 > information in the database.
 
-### `secrets.keys`
+### Singing Keys
 
 The service can use a number of key types for signing.
 The following key types are supported:
@@ -232,15 +232,26 @@ The following key types are supported:
 - ECDSA with the P-384 (`secp384r1`) curve
 - ECDSA with the K-256 (`secp256k1`) curve
 
-Each entry in the list corresponds to one signing key used by MAS.
-The key can either be specified inline (with the `key` property),
-or loaded from a file (with the `key_file` property).
 The following key formats are supported:
 
 - PKCS#1 PEM or DER-encoded RSA private key
 - PKCS#8 PEM or DER-encoded RSA or ECDSA private key, encrypted or not
 - SEC1 PEM or DER-encoded ECDSA private key
 
+The keys can be given as a directory path via `secrets.keys_dir`
+or, alternatively, as an inline configuration list via `secrets.keys`.
+
+#### `secrets.keys_dir`
+
+Path to the directory containing MAS signing key files.
+Only keys that don’t require a password are supported.
+
+#### `secrets.keys`
+
+Each entry in the list corresponds to one signing key used by MAS.
+The key can either be specified inline (with the `key` property),
+or loaded from a file (with the `key_file` property).
+
 A [JWK Key ID] is automatically derived from each key.
 To override this default, set `kid` to a custom value.
 The `kid` can be any case-sensitive string value as long as it is unique to this list;