| 1 | //! Shared file-store write lock. Native uses the same fd-lock 4.0.4 and |
| 2 | //! persistent `<filename>.lock` protocol. Never delete or replace that inode. |
| 3 | //! Older writers bypassing this protocol cannot participate safely. |
| 4 | use crate::SecretsError; |
| 5 | use std::{fs, path::Path}; |
| 6 | |
| 7 | pub(crate) fn open_private(path: &Path, create: bool) -> Result<fs::File, SecretsError> { |
| 8 | match fs::symlink_metadata(path) { |
| 9 | Ok(meta) if meta.file_type().is_symlink() || !meta.is_file() => { |
| 10 | return Err(std::io::Error::other("The secret store must be a regular file.").into()); |
| 11 | } |
| 12 | Ok(_) => {} |
| 13 | Err(error) if error.kind() == std::io::ErrorKind::NotFound => {} |
| 14 | Err(error) => return Err(error.into()), |
| 15 | } |
| 16 | let mut options = fs::OpenOptions::new(); |
| 17 | options |
| 18 | .read(true) |
| 19 | .write(create) |
| 20 | .create(create) |
| 21 | .truncate(false); |
| 22 | #[cfg(unix)] |
| 23 | { |
| 24 | use std::os::unix::fs::OpenOptionsExt; |
| 25 | options.mode(0o600).custom_flags(libc::O_NOFOLLOW); |
| 26 | } |
| 27 | #[cfg(windows)] |
| 28 | { |
| 29 | use std::os::windows::fs::OpenOptionsExt; |
| 30 | options.custom_flags(0x0020_0000); // FILE_FLAG_OPEN_REPARSE_POINT |
| 31 | } |
| 32 | let file = options.open(path)?; |
| 33 | let meta = file.metadata()?; |
| 34 | if !meta.is_file() { |
| 35 | return Err(std::io::Error::other("The secret store must be a regular file.").into()); |
| 36 | } |
| 37 | #[cfg(unix)] |
| 38 | { |
| 39 | use std::os::unix::fs::PermissionsExt; |
| 40 | let mode = meta.permissions().mode() & 0o777; |
| 41 | if mode & 0o077 != 0 { |
| 42 | return Err(SecretsError::InsecurePermissions { |
| 43 | path: path.into(), |
| 44 | mode, |
| 45 | }); |
| 46 | } |
| 47 | } |
| 48 | #[cfg(windows)] |
| 49 | { |
| 50 | use std::os::windows::fs::MetadataExt; |
| 51 | if meta.file_attributes() & 0x400 != 0 { |
| 52 | return Err( |
| 53 | std::io::Error::other("The secret store cannot be a reparse point.").into(), |
| 54 | ); |
| 55 | } |
| 56 | } |
| 57 | Ok(file) |
| 58 | } |
| 59 | |
| 60 | pub(crate) fn with_write_lock<T>( |
| 61 | path: &Path, |
| 62 | operation: impl FnOnce(&Path) -> Result<T, SecretsError>, |
| 63 | ) -> Result<T, SecretsError> { |
| 64 | let parent = path |
| 65 | .parent() |
| 66 | .filter(|p| !p.as_os_str().is_empty()) |
| 67 | .unwrap_or(Path::new(".")); |
| 68 | let mut directory = fs::DirBuilder::new(); |
| 69 | directory.recursive(true); |
| 70 | #[cfg(unix)] |
| 71 | { |
| 72 | use std::os::unix::fs::DirBuilderExt; |
| 73 | directory.mode(0o700); |
| 74 | } |
| 75 | directory.create(parent)?; |
| 76 | let filename = path |
| 77 | .file_name() |
| 78 | .ok_or_else(|| std::io::Error::other("Invalid secret store path."))?; |
| 79 | let path = parent.canonicalize()?.join(filename); |
| 80 | let mut lock_name = path.as_os_str().to_os_string(); |
| 81 | lock_name.push(".lock"); |
| 82 | let mut lock = fd_lock::RwLock::new(open_private(Path::new(&lock_name), true)?); |
| 83 | let _guard = lock.write()?; |
| 84 | operation(&path) |
| 85 | } |
| 86 |