8 ms·

"a kernel-mode Adobe Type Manager Font Driver" this is just such a crazy idea.

Someone1234 7y ago
It is an old idea. Back when "put everything in the kernel to make it fast" was the forefront of computing technology. Microsoft obviously still has work to do but they did take a large chunk of sound and graphics code out of kernel space in Vista.
- IshKebab 7y ago
  And to be fair, putting graphics stuff in the kernel allows Windows to do some graphical things properly, like a secure attention key (ctrl-alt-delete to log in) and a proper task manager. Linux can't really do either of those things nicely because graphics is just another program. Although I'm sure you can isolate your don't decoding better than shoving it in the kernel.
  - kohtatsu 7y ago
    Euh, I think a secure attention key is fine; you only have that chord sent to a designated trusted process; preventing other processes from being able to react to it and mimic an auth dialog. Am I missing something?
    - lonelappde 7y ago
      Parent said SAK is good.
      - deleted 7y ago
        [deleted]
      - kohtatsu 7y ago
        Sorry that was ambiguous wording; I was addressing their statement it was harder to do without the graphics being in the kernel.
  - tinus_hn 7y ago
    The secure attention key is handled or if you will caught in the keyboard driver, and then sent to Winlogon, a user space program. How does that relate to graphics being in the Windows kernel?
    - bryanrasmussen 7y ago
      Well kernel development is not my area of expertise, and I haven't done even any Windows development since before 2009 so ancient history in the recesses of my mind, but I would think that since the SAK causes the secure desktop to appear then there needs to be graphical connection there? Probably I'm wrong in that supposition there, but then what happens?
  - paulie_a 7y ago
    The secure attention key is long gone and didn't work anyways.
    - bryanrasmussen 7y ago
      you can enable it, I believe most enterprises have it enabled by default.
  - floatboth 7y ago
    You absolutely can do secure attention key with just another program. If your account does not have /dev/input permissions, only your display server has keyboard access (unless you run stuff as root lol), and handle key combos that force some secure thing to happen.
- DyslexicAtheist 7y ago
  > Back when "put everything in the kernel to make it fast" was the forefront of computing technology. Linux kernel/bpf is getting nervous. joking aside (and sorry for going off on this tangent) under Linux it seems the kernel is eating more of user-space every year. That argument could of course be also turned around by claiming that user-space is eating the kernel. which ever way you look at - systems programming has gotten much more challenging (interesting) in the past years.
  - microcolonel 7y ago
    I guess I don't see it that way. Probably the hairiest things in the kernel that maybe shouldn't be there are boot-time network filesystems, but I think that's kinda the price you pay for that sort of convenience. bpf is a sandbox, and unprivileged processes do not magically gain access to it; anything malicious that could be done with bpf could as easily be done with the coincident root privileges. What is your example of where the Linux kernel is "eating more of user space every year"?
    - blattimwind 7y ago
      > I guess I don't see it that way. Probably the hairiest things in the kernel that maybe shouldn't be there are boot-time network filesystems, but I think that's kinda the price you pay for that sort of convenience. X.509 parsers... or three or so...
    - nneonneo 7y ago
      Unprivileged processes can load bpf filters though - they can attach filters to sockets or load seccomp syscall filters, to name two examples. Just because it is a sandbox doesn’t mean that loading and executing user-supplied code in kernel mode is free from risk! I’m sure the Microsoft engineers thought their code was bulletproof too right until the exploits started showing up. Heck, the entire io_uring system is a prime example of the Linux kernel “eating more of user space” - it’s essentially a programmable syscall pipeline that executes entirely in kernel mode. All to reduce some user/kernel transitions - exactly why ATMFD and http.sys were invented in the Windows kernel.

It is an old idea. Back when "put everything in the kernel to make it fast" was the forefront of computing technology. Microsoft obviously still has work to do but they did take a large chunk of sound and graphics code out of kernel space in Vista.

IshKebab 7y ago
And to be fair, putting graphics stuff in the kernel allows Windows to do some graphical things properly, like a secure attention key (ctrl-alt-delete to log in) and a proper task manager. Linux can't really do either of those things nicely because graphics is just another program. Although I'm sure you can isolate your don't decoding better than shoving it in the kernel.
- kohtatsu 7y ago
  Euh, I think a secure attention key is fine; you only have that chord sent to a designated trusted process; preventing other processes from being able to react to it and mimic an auth dialog. Am I missing something?
  - lonelappde 7y ago
    Parent said SAK is good.
    - deleted 7y ago
      [deleted]
    - kohtatsu 7y ago
      Sorry that was ambiguous wording; I was addressing their statement it was harder to do without the graphics being in the kernel.
- tinus_hn 7y ago
  The secure attention key is handled or if you will caught in the keyboard driver, and then sent to Winlogon, a user space program. How does that relate to graphics being in the Windows kernel?
  - bryanrasmussen 7y ago
    Well kernel development is not my area of expertise, and I haven't done even any Windows development since before 2009 so ancient history in the recesses of my mind, but I would think that since the SAK causes the secure desktop to appear then there needs to be graphical connection there? Probably I'm wrong in that supposition there, but then what happens?
- paulie_a 7y ago
  The secure attention key is long gone and didn't work anyways.
  - bryanrasmussen 7y ago
    you can enable it, I believe most enterprises have it enabled by default.
- floatboth 7y ago
  You absolutely can do secure attention key with just another program. If your account does not have /dev/input permissions, only your display server has keyboard access (unless you run stuff as root lol), and handle key combos that force some secure thing to happen.
DyslexicAtheist 7y ago
> Back when "put everything in the kernel to make it fast" was the forefront of computing technology. Linux kernel/bpf is getting nervous. joking aside (and sorry for going off on this tangent) under Linux it seems the kernel is eating more of user-space every year. That argument could of course be also turned around by claiming that user-space is eating the kernel. which ever way you look at - systems programming has gotten much more challenging (interesting) in the past years.
- microcolonel 7y ago
  I guess I don't see it that way. Probably the hairiest things in the kernel that maybe shouldn't be there are boot-time network filesystems, but I think that's kinda the price you pay for that sort of convenience. bpf is a sandbox, and unprivileged processes do not magically gain access to it; anything malicious that could be done with bpf could as easily be done with the coincident root privileges. What is your example of where the Linux kernel is "eating more of user space every year"?
  - blattimwind 7y ago
    > I guess I don't see it that way. Probably the hairiest things in the kernel that maybe shouldn't be there are boot-time network filesystems, but I think that's kinda the price you pay for that sort of convenience. X.509 parsers... or three or so...
  - nneonneo 7y ago
    Unprivileged processes can load bpf filters though - they can attach filters to sockets or load seccomp syscall filters, to name two examples. Just because it is a sandbox doesn’t mean that loading and executing user-supplied code in kernel mode is free from risk! I’m sure the Microsoft engineers thought their code was bulletproof too right until the exploits started showing up. Heck, the entire io_uring system is a prime example of the Linux kernel “eating more of user space” - it’s essentially a programmable syscall pipeline that executes entirely in kernel mode. All to reduce some user/kernel transitions - exactly why ATMFD and http.sys were invented in the Windows kernel.