Verified before the fix: `age -d -o <existing>` overwrites without a word
("PRECIOUS EXISTING KEY" became "secret"), and the old `cp` for the public
key did the same. Decrypting a vault entry on top of a newer working key
in ~/.ssh destroyed it with no prompt, no backup and no mention. It is the
only finding in the audit that loses data the user never asked to touch.
Every collision — private and public, both output modes — is now settled
before anything is written, so the questions are asked about files that
still exist. Default is to keep what is there.
cp and chmod are gone. Three spawns per key become one, it works where
those binaries do not, and the chmod happens in-process immediately after
age returns: age creates its output 0644 regardless of umask, so a
plaintext private key was world-readable for the length of two spawns and
stayed 0644 whenever the chmod itself failed. ~/.ssh is created 0700 when
absent rather than assumed.
decrypt.test.ts stops asserting on which binaries were spawned. The age
stand-in now writes its -o file at 0644 the way age does, and the tests
assert the bytes and the mode on disk — the outcome rather than the
mechanism.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Benjamin Diedrichsen
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