Post #2882123

A while back I stumbled on this nice description of a surprising feature of Linux: you can sometimes use /proc/<pid>/mem to write to memory that is mapped read-only. https://offlinemark.com/an-obscure-quirk-of-proc/ What I had not understood is: "sometimes" means *when*, and "write to memory" means *which copy* of that memory? Clearly not "always" "the mapped physical memory"... this would be a gaping security problem if an unprivileged sure could write to literally any physical frame mapped by their process. So...