The reading of the full reading's fixes found that writePrivately made
the file, then set it to 0600: another local user could open it in that
window and keep reading what was written after; and that where the path
was a link or another user's file, chmod failed and the secret was
written into it anyway.
On Linux and macOS it now makes a new file beside the one chosen, 0600
as it is created (O_EXCL, O_NOFOLLOW), writes through the descriptor that
made it, and renames it over the chosen path, so the old file is never
written into; a symbolic link or another user's file is refused, with
nothing written (lstat through FFI, by each system's layout). Windows
writes in place, with its folder's rights.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
On the desktop a saved file (a recovery phrase, recovery codes, an
archive with progress) is made the own user's alone (0600, chmod(2)
through the C library already in the process) on the emptied file before
anything is written, so no other user of the machine reads it; Windows'
files keep their folder's rights. On iOS, file_picker (darwin v2.1.2)
writes a copy into the app's temporary folder for the system's picker and
never removes it, saved or cancelled: it goes once the picker is done.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
