Set restrictive file permissions for seed file #741
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tankyleo
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src/io/utils.rs
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| // to protect the sensitive seed material. We use `create_new` to fail if the | ||
| // file already exists, providing defense-in-depth against race conditions. | ||
| #[cfg(unix)] | ||
| let mut f = { OpenOptions::new().write(true).create_new(true).mode(0o600).open(keys_seed_path)? }; |
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I'd prefer we set permissions here to 0400 to protect against accidental writes. Once the seed file is created there really shouldn't be a reason to write anything to the file.
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Fair:
> git diff-tree -U2 af77366c 7e2f1fa9
diff --git a/src/io/utils.rs b/src/io/utils.rs
index 47b408e2..965831aa 100644
--- a/src/io/utils.rs
+++ b/src/io/utils.rs
@@ -86,5 +86,5 @@ pub(crate) fn read_or_generate_seed_file(
// file already exists, providing defense-in-depth against race conditions.
#[cfg(unix)]
- let mut f = { OpenOptions::new().write(true).create_new(true).mode(0o600).open(keys_seed_path)? };
+ let mut f = { OpenOptions::new().write(true).create_new(true).mode(0o400).open(keys_seed_path)? };
#[cfg(not(unix))]
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Previously, seed files were created using `fs::File::create()` which inherits the default umask, potentially making the sensitive seed material world-readable on Unix systems. This change: - Creates seed files with mode 0o400 (owner read only) on Unix - Uses `create_new` instead of `create` to atomically fail if the file already exists, providing defense-in-depth against TOCTOU race conditions Co-Authored-By: Claude AI
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tankyleo
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Jan 9, 2026
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Previously, seed files were created using
fs::File::create()which inherits the default umask, potentially making the sensitive seed material world-readable on Unix systems.This change:
create_newinstead ofcreateto atomically fail if the file already exists, providing defense-in-depth against TOCTOU race conditionsCo-Authored-By: Claude AI