5 ms·

> Really? Is that a serious reason? Key-loggers are still very much possible because any program can read the memory of all other running programs of the same u

> Really? Is that a serious reason? Key-loggers are still very much possible because any program can read the memory of all other running programs of the same user. That's not true. Reading other processes memory requires root even for processes of the same user.

enriquto 4y ago
I was going to reply in an impulsive manner (saying, derisively "so how does strace work, then? and why can you attach gdb to already running processes?"). But it turns out that you are right! Well, at least in modern ubuntu/fedora desktop installs, a few years ago they disabled the ptrace(2) system call. ("The maniacs! They did it!", I'm tempted to cry in anger.) You can still read children processes, but unless you change the yama defaults in the kernel, ptrace(2) no longer works for processes that are not children. I didn't notice because I surely have changed this default in my old laptop because I use ptrace daily. But you are right that modern linuxes are likely thus crippled. Still, it seems that an attack model based on defending against a rogue user process is quite doomed. Can't this process change the init files of other programs that will run, even if they aren't its children?
- seba_dos1 4y ago
  > Still, it seems that an attack model based on defending against a rogue user process is quite doomed. Can't this process change the init files of other programs that will run, even if they aren't its children? No, they often can't. Things like Flatpak make it so apps have no unnecessary access to the filesystem.
  - enriquto 4y ago
    Fortunately, things like snap and flatpak are still fringe projects with no realistic perspectives for a widespread adoption. Which would be ridiculous, anyway: why would you want all the programs in /usr/bin to be isolated "apps"?
    - klooney 4y ago
      I run most of my GUI stuff out of flatpaks now, it's pretty great. Run the latest releases on a stable LTS with no dependency problems.

enriquto 4y ago

I was going to reply in an impulsive manner (saying, derisively "so how does strace work, then? and why can you attach gdb to already running processes?"). But it turns out that you are right! Well, at least in modern ubuntu/fedora desktop installs, a few years ago they disabled the ptrace(2) system call. ("The maniacs! They did it!", I'm tempted to cry in anger.) You can still read children processes, but unless you change the yama defaults in the kernel, ptrace(2) no longer works for processes that are not children. I didn't notice because I surely have changed this default in my old laptop because I use ptrace daily. But you are right that modern linuxes are likely thus crippled. Still, it seems that an attack model based on defending against a rogue user process is quite doomed. Can't this process change the init files of other programs that will run, even if they aren't its children?

seba_dos1 4y ago
> Still, it seems that an attack model based on defending against a rogue user process is quite doomed. Can't this process change the init files of other programs that will run, even if they aren't its children? No, they often can't. Things like Flatpak make it so apps have no unnecessary access to the filesystem.
- enriquto 4y ago
  Fortunately, things like snap and flatpak are still fringe projects with no realistic perspectives for a widespread adoption. Which would be ridiculous, anyway: why would you want all the programs in /usr/bin to be isolated "apps"?
  - klooney 4y ago
    I run most of my GUI stuff out of flatpaks now, it's pretty great. Run the latest releases on a stable LTS with no dependency problems.