[pbs-devel] [RFC v2 proxmox-backup 13/42] config: introduce s3 object store client configuration

[Christian Ebner]

Adds the client configuration for s3 object store as dedicated
configuration files, with secrets being stored separately from the
regular configuration and excluded from api responses for security
reasons.

Signed-off-by: Christian Ebner <c.ebner at proxmox.com>
---
 pbs-config/src/lib.rs |  1 +
 pbs-config/src/s3.rs  | 82 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 83 insertions(+)
 create mode 100644 pbs-config/src/s3.rs

diff --git a/pbs-config/src/lib.rs b/pbs-config/src/lib.rs
index 9c4d77c24..d03c079ab 100644
--- a/pbs-config/src/lib.rs
+++ b/pbs-config/src/lib.rs
@@ -10,6 +10,7 @@ pub mod network;
 pub mod notifications;
 pub mod prune;
 pub mod remote;
+pub mod s3;
 pub mod sync;
 pub mod tape_job;
 pub mod token_shadow;
diff --git a/pbs-config/src/s3.rs b/pbs-config/src/s3.rs
new file mode 100644
index 000000000..5fce5034d
--- /dev/null
+++ b/pbs-config/src/s3.rs
@@ -0,0 +1,82 @@
+use std::collections::HashMap;
+use std::sync::LazyLock;
+
+use anyhow::Error;
+
+use proxmox_schema::*;
+use proxmox_section_config::{SectionConfig, SectionConfigData, SectionConfigPlugin};
+
+use pbs_api_types::{S3ClientConfig, S3ClientSecretsConfig, JOB_ID_SCHEMA};
+
+use crate::{open_backup_lockfile, replace_backup_config, BackupLockGuard};
+
+pub static CONFIG: LazyLock<SectionConfig> = LazyLock::new(init);
+
+fn init() -> SectionConfig {
+    let obj_schema = match S3ClientConfig::API_SCHEMA {
+        Schema::Object(ref obj_schema) => obj_schema,
+        _ => unreachable!(),
+    };
+    let secrets_obj_schema = match S3ClientSecretsConfig::API_SCHEMA {
+        Schema::Object(ref obj_schema) => obj_schema,
+        _ => unreachable!(),
+    };
+
+    let plugin =
+        SectionConfigPlugin::new("s3client".to_string(), Some(String::from("id")), obj_schema);
+    let secrets_plugin = SectionConfigPlugin::new(
+        "s3secrets".to_string(),
+        Some(String::from("secrets-id")),
+        secrets_obj_schema,
+    );
+    let mut config = SectionConfig::new(&JOB_ID_SCHEMA);
+    config.register_plugin(plugin);
+    config.register_plugin(secrets_plugin);
+
+    config
+}
+
+pub const S3_CFG_FILENAME: &str = "/etc/proxmox-backup/s3.cfg";
+pub const S3_SECRETS_CFG_FILENAME: &str = "/etc/proxmox-backup/s3-secrets.cfg";
+pub const S3_CFG_LOCKFILE: &str = "/etc/proxmox-backup/.s3.lck";
+
+/// Get exclusive lock
+pub fn lock_config() -> Result<BackupLockGuard, Error> {
+    open_backup_lockfile(S3_CFG_LOCKFILE, None, true)
+}
+
+pub fn config() -> Result<(SectionConfigData, [u8; 32]), Error> {
+    parse_config(S3_CFG_FILENAME)
+}
+
+pub fn secrets_config() -> Result<(SectionConfigData, [u8; 32]), Error> {
+    parse_config(S3_SECRETS_CFG_FILENAME)
+}
+
+pub fn save_config(config: &SectionConfigData, secrets: &SectionConfigData) -> Result<(), Error> {
+    let raw = CONFIG.write(S3_CFG_FILENAME, config)?;
+    replace_backup_config(S3_CFG_FILENAME, raw.as_bytes())?;
+
+    let secrets_raw = CONFIG.write(S3_SECRETS_CFG_FILENAME, secrets)?;
+    // Secrets are stored with `backup` permissions to allow reading from
+    // not protected api endpoints as well.
+    replace_backup_config(S3_SECRETS_CFG_FILENAME, secrets_raw.as_bytes())?;
+
+    Ok(())
+}
+
+// shell completion helper
+pub fn complete_s3_client_id(_arg: &str, _param: &HashMap<String, String>) -> Vec<String> {
+    match config() {
+        Ok((data, _digest)) => data.sections.keys().map(|id| id.to_string()).collect(),
+        Err(_) => Vec::new(),
+    }
+}
+
+fn parse_config(path: &str) -> Result<(SectionConfigData, [u8; 32]), Error> {
+    let content = proxmox_sys::fs::file_read_optional_string(path)?;
+    let content = content.unwrap_or_default();
+    let digest = openssl::sha::sha256(content.as_bytes());
+    let data = CONFIG.parse(path, &content)?;
+    Ok((data, digest))
+}
-- 
2.39.5