New upstream snapshot

[bcachefs-tools-debian] / rust-src / mount / src / key.rs

diff --git a/rust-src/mount/src/key.rs b/rust-src/mount/src/key.rs
new file mode 100644 (file)
index 0000000..91c92d1
--- /dev/null
+++ b/rust-src/mount/src/key.rs
@@ -0,0 +1,97 @@
+use tracing::info;
+
+fn check_for_key(key_name: &std::ffi::CStr) -> anyhow::Result<bool> {
+       use bch_bindgen::keyutils::{self, keyctl_search};
+       let key_name = key_name.to_bytes_with_nul().as_ptr() as *const _;
+       let key_type = c_str!("logon");
+
+       let key_id = unsafe { keyctl_search(keyutils::KEY_SPEC_USER_KEYRING, key_type, key_name, 0) };
+       if key_id > 0 {
+               info!("Key has became avaiable");
+               Ok(true)
+       } else if errno::errno().0 != libc::ENOKEY {
+               Err(crate::ErrnoError(errno::errno()).into())
+       } else {
+               Ok(false)
+       }
+}
+
+fn wait_for_key(uuid: &uuid::Uuid) -> anyhow::Result<()> {
+       let key_name = std::ffi::CString::new(format!("bcachefs:{}", uuid)).unwrap();
+       loop {
+               if check_for_key(&key_name)? {
+                       break Ok(());
+               }
+
+               std::thread::sleep(std::time::Duration::from_secs(1));
+       }
+}
+
+const BCH_KEY_MAGIC: &str = "bch**key";
+use crate::filesystem::FileSystem;
+fn ask_for_key(fs: &FileSystem) -> anyhow::Result<()> {
+       use anyhow::anyhow;
+       use byteorder::{LittleEndian, ReadBytesExt};
+       use bch_bindgen::bcachefs::{self, bch2_chacha_encrypt_key, bch_encrypted_key, bch_key};
+       use std::os::raw::c_char;
+
+       let key_name = std::ffi::CString::new(format!("bcachefs:{}", fs.uuid())).unwrap();
+       if check_for_key(&key_name)? {
+               return Ok(());
+       }
+
+       let bch_key_magic = BCH_KEY_MAGIC.as_bytes().read_u64::<LittleEndian>().unwrap();
+       let crypt = fs.sb().sb().crypt().unwrap();
+       let pass = rpassword::read_password_from_tty(Some("Enter passphrase: "))?;
+       let pass = std::ffi::CString::new(pass.trim_end())?; // bind to keep the CString alive
+       let mut output: bch_key = unsafe {
+               bcachefs::derive_passphrase(
+                       crypt as *const _ as *mut _,
+                       pass.as_c_str().to_bytes_with_nul().as_ptr() as *const _,
+               )
+       };
+
+       let mut key = crypt.key().clone();
+       let ret = unsafe {
+               bch2_chacha_encrypt_key(
+                       &mut output as *mut _,
+                       fs.sb().sb().nonce(),
+                       &mut key as *mut _ as *mut _,
+                       std::mem::size_of::<bch_encrypted_key>() as u64,
+               )
+       };
+       if ret != 0 {
+               Err(anyhow!("chacha decryption failure"))
+       } else if key.magic != bch_key_magic {
+               Err(anyhow!("failed to verify the password"))
+       } else {
+               let key_type = c_str!("logon");
+               let ret = unsafe {
+                       bch_bindgen::keyutils::add_key(
+                               key_type,
+                               key_name.as_c_str().to_bytes_with_nul() as *const _ as *const c_char,
+                               &output as *const _ as *const _,
+                               std::mem::size_of::<bch_key>() as u64,
+                               bch_bindgen::keyutils::KEY_SPEC_USER_KEYRING,
+                       )
+               };
+               if ret == -1 {
+                       Err(anyhow!("failed to add key to keyring: {}", errno::errno()))
+               } else {
+                       Ok(())
+               }
+       }
+}
+
+#[tracing_attributes::instrument]
+pub fn prepare_key(fs: &FileSystem, password: crate::KeyLocation) -> anyhow::Result<()> {
+       use crate::KeyLocation::*;
+       use anyhow::anyhow;
+
+       tracing::info!(msg = "checking if key exists for filesystem");
+       match password {
+               Fail => Err(anyhow!("no key available")),
+               Wait => Ok(wait_for_key(fs.uuid())?),
+               Ask => ask_for_key(fs),
+       }
+}