Also, /proc/<pid>/environ. There are rules on who owns this file (root, or the executing user) based on the suid bit. Regardless, you are now depending on linux permissions to protect your secrets, which begs the question: Why not just trust the filesystem? Even if /proc/<pid>/environ didn't exist, you could go through /proc/<pid>/mem to find secrets.

It seems that this is designed to protect you from untrusted execution environments, which I don't see as feasible. What am I missing?