feat(pageserver): support kms

Signed-off-by: Alex Chi Z <chi@neon.tech>

libs/remote_storage/Cargo.toml

@@ -18,6 +18,7 @@ camino = { workspace = true, features = ["serde1"] }
 humantime-serde.workspace = true
 hyper = { workspace = true, features = ["client"] }
 futures.workspace = true
+rand.workspace = true
 reqwest.workspace = true
 serde.workspace = true
 serde_json.workspace = true

libs/remote_storage/src/kms.rs

@@ -0,0 +1,50 @@
+//! A module that provides a KMS implementation that generates and unwraps the keys.
+//!
+
+#![allow(dead_code)]
+
+/// A KMS implementation that does static wrapping and unwrapping of the keys.
+pub struct NaiveKms {
+    account_id: String,
+}
+
+pub struct KeyPair {
+    pub wrapped: Vec<u8>,
+    pub plain: Vec<u8>,
+}
+
+impl NaiveKms {
+    pub fn new(account_id: String) -> Self {
+        Self { account_id }
+    }
+
+    /// Generate a new key in the KMS. Returns the plain and wrapped keys.
+    pub fn generate_key(&self) -> anyhow::Result<KeyPair> {
+        // TODO: use a proper library for generating the key (i.e., ring).
+        let plain = rand::random::<[u8; 32]>().to_vec();
+        let wrapped = [self.account_id.as_bytes(), "-wrapped-".as_bytes(), &plain].concat();
+        Ok(KeyPair { wrapped, plain })
+    }
+
+    pub fn unwrap_key(&self, wrapped: &[u8]) -> anyhow::Result<Vec<u8>> {
+        let Some(wrapped) = wrapped.strip_prefix(self.account_id.as_bytes()) else {
+            return Err(anyhow::anyhow!("invalid key"));
+        };
+        let Some(plain) = wrapped.strip_prefix(b"-wrapped-") else {
+            return Err(anyhow::anyhow!("invalid key"));
+        };
+        Ok(plain.to_vec())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_generate_key() {
+        let kms = NaiveKms::new("test-tenant".to_string());
+        let key_pair = kms.generate_key().unwrap();
+        assert_eq!(kms.unwrap_key(&key_pair.wrapped).unwrap(), key_pair.plain);
+    }
+}

libs/remote_storage/src/lib.rs

@@ -17,6 +17,7 @@ mod metrics;
 mod s3_bucket;
 mod simulate_failures;
 mod support;
+mod kms;
 
 use std::collections::HashMap;
 use std::fmt::Debug;