- Credential callbacks (SecretFn) now return Zeroizing<String>, as do the
session-only/pending caches they read and the RDP client's password,
so Nexus's own copies are wiped; a plain String copy is made only
where a library API needs one (SSH password auth, IRC, VNC, CredSSP).
- Release builds disable core dumps (RLIMIT_CORE 0) and, on Linux, mark
the process non-dumpable (PR_SET_DUMPABLE 0), which also blocks ptrace
attach and /proc/<pid>/mem reads by other processes of the same user.
Debug builds are unchanged so they stay debuggable. Verified on the
release binary: core limit 0, /proc/<pid>/{environ,mem} root-owned and
unreadable, local shells (including cwd capture) still work.
Closes the remaining parts of SEC-20261012-007 that the app controls;
egui's internal text buffers remain outside its reach.
The app now writes a diagnostic log to nexus.log in the data directory
(0600, rotated at 5 MiB): connection attempts and results, remote
closes, reconnect scheduling, host-key/certificate checks with the
policy applied, and credentials that couldn't be stored (kind only).
Credentials and terminal data are never logged. RUST_LOG sets the level
and also mirrors the log to stderr. The remaining eprintln! diagnostics
in storage and URL handling go through it too.
Andy Dixon