7 ms·

Fun with macOS's Sip

88 points by signa11 4y ago

cobbal 4y ago
There are few miseries I deal with regularly that compare to SIP or the hardened runtime telling me I may not debug processes on a computer where I have root. If anything is going to make me abandon macOS (I've been using it since I was a child) it's the "security and privacy" features.
- aviramha 4y ago
  I totally feel you though I can understand that for Apple the average consumer's security > hackers :) I think Apple should remember that people debugging and working is important too, and make the documentation around the security features less obscure. (Attaching a debugger/ptrace on macOS is really evil to implement)
- sbuk 4y ago
  The security and privacy features benefit the majority, of which you clearly are not, so there is an escape hatch for you; turn off SIP. Just don't disable it for typical users.
  - justsomeadvice0 4y ago
    Yea, I'm really not sure how this is a "misery". System processes are protected for typical users to limit the blast radius of malware, among other reasons. If you are capable of debugging system processes you should be able to manage to: Restart macOS, holding ⌘+R. Open Terminal. Type `csrutil disable`. Restart macOS again.
    - derbOac 4y ago
      For some things though that's just Step 1 of many. Still doable but too much of a pain.
  - aviramha 4y ago
    Why not enable easier override for specific scenarios? Turning off completely feels like a bad outcome
    - galad87 4y ago
      It already allows to turn off only a part of it.
      - aviramha 4y ago
        But I don't want that. That's like taking the gate instead of adding a configurable ACL.
      - saagarjha 4y ago
        Turning off any of SIP is largely isomorphic to turning it all off
  - chongli 4y ago
    That’s like telling me to remove the front door of my house rather than letting me have a key to unlock it.
    - tempodox 4y ago
      True, but giving us a key might jeopardize future revenue streams where we have to pay for the privilege of developing software on Apple platforms. You already get a degraded developer experience for iOS if you don't bribe Apple with a Developer Program subscription.
      - rogual 4y ago
        Not just iOS. Notarizing apps for macOS requires payment too.
      - scarface74 4y ago
        HN has been predicting a future that you could only install apps through the Mac App Store since it was introduced in 2011. Any day now…
        Gigachad 4y ago
        We will see alt app stores on the iphone before we see macOS match those predictions.
    - jabedude 4y ago
      What would be a suitable key in your analogy?
      - solarkraft 4y ago
        Super-root? But as far as I'm aware the reasoning is that if there's a way to access something from a normal user account (with admin privileges) it can be abused somehow. Maybe a "key" would be the ability to boot/log in to a special mode with SIP enabled. Disabling/enabling it approximates this, but as far as I know an update will generally destroy your changes because Apple will just overwrite everything.
  - howinteresting 4y ago
    Then iOS apps stop working, right? The DRM regime requires SIP to be enabled. Stallman was right about "treacherous computing".
    - sbuk 4y ago
      This has nothing to do with iOS.
      - howinteresting 4y ago
        macOS now has support for iOS apps, but only if SIP is enabled and their DRM/"trusted" computing regime is active. https://forums.macrumors.com/threads/if-you-disable-sip-all-you-ios-apps-will-stop-working-on-your-m1.2269661 https://forums.macrumors.com/threads/if-you-disable-sip-all-...
  - vaughan 4y ago
    Turning off SIP means you can’t run iOS apps on macOS. This sucks.
- madeofpalk 4y ago
  You can just disable SIP, no?
  - Gigachad 4y ago
    Yes, the "locked down dictatorship macos" is surprisingly permissive. Impressively you can even dual boot linux on Apple Silicon completely unrestricted without having to turn on off the boot chain security features of macOS.
- lloeki 4y ago
  Under "Security and Privacy" there's been "Developer Tools" for a while, within which I only ever saw Terminal.app (but any app could be added) I'm not sure what it really does (could not find any docs, maybe someone can enlighten?) but the text made me think it could allow stuff like running unsigned debuggers: Allow the applications below to run software locally that does not meet the system's security policies Again I'm really not sure, but maybe it can cover some use cases without going the nuclear route of fully disabling SIP?
  - memco 4y ago
    I Would be interested to know more about it too. I have been interested in running a piece of software that needs SIP partially disabled, but I’d I could just grant it exemption I would prefer that to a blanket removal. Funny thing is all computers used to run without SIP, but since they added it I’m now hesitant to turn it off even though I’m not any worse off than I used to be.
  - macshome 4y ago
    It relaxes the signing requirements and malware signature checks for binaries run in the Terminal. This way you can build and test stuff without needing to relax the security posture of the entire Mac.
- scarface74 4y ago
  Yes because it’s not like bad things can happen when SIP is turned off. Not always malicious, it’s often ineptness https://appleinsider.com/articles/19/09/25/google-chrome-update-corrupting-some-macos-installs----but-theres-a-fix https://appleinsider.com/articles/19/09/25/google-chrome-upd...
antihero 4y ago
This is interesting. I’m guessing just having a patched shell binary and forking stuff from within that wouldn’t work.
- aviramha 4y ago
  You could patch a shell binary, but you'd ultimately want to use other binaries as well. The most common example we had is when people tried to run our software with `pyenv` which was a shell script that used other system binaries + shell scripts
WirelessGigabit 4y ago
While the explanation is super cool it makes me feel nervous. None of this did supported. APIs change without notice, as you don't have a contract. You're relying on the fact that there is an x64 version available.
- aviramha 4y ago
  Most odds is when x64 binary will stop shipping, arm64e won't be in preview mode anymore and we will be able to just do the re-signing part. (Which is supported)
- ghostpepper 4y ago
  It's pretty much expected that if you publish a method for working around a security feature it will be patched quickly. Cool research if that was the intention but if you're building a product around this... you're going to have a bad time.
  - eyalbukchin 4y ago
    This is detailed in the post, but the security feature i.e. preventing injected libraries access to entitlements isn't actually bypassed here. Rather the binary is run without these entitlements (which aren't required anyway for mirrord's use case).
pseufaux 4y ago
> Killed! And it was so young. This got far more of a chuckle from me than it should have. Must have had a long day or far to little sleep.
pedrow 4y ago
Would it be an option to compile your own versions of `ls` et al., maybe from the Darwin source (if available, I don't know) or one of the BSDs? Does what you're trying to do depend on the specific implementation of Apple's utilities?
- eyalbukchin 4y ago
  Maybe, we haven't looked into that option for the following reasons: a. It would require that we maintain a potentially pretty big list of self-compiled binaries b. It would be an alteration of what the user's running, which we try to keep to a minimum, as mirrord's commonly used as a testing tool
david2ndaccount 4y ago
This is a strange product they’re selling. You run your binary on on macOS but presumably your server is running linux. Why are you trying to run Darwin executables as if they were in the cloud when that is not what will actually be deployed? Shouldn’t the testing at least be done from a linux machine?
- eyalbukchin 4y ago
  Ideally! And it can be run on a Linux machine if the user prefers. But if you code on a Mac, mirrord still lets you go through a good number of test iterations (by letting your process run with network input/output, file content and environment variables from the cloud) before having to deploy your code to a Linux machine for that (hopefully) final round of testing.
jbverschoor 4y ago
I have no clue what this mirrord does. Is it some kind of API proxy? What if I don't have 'pods', also, shouldn't it be called redirect_api? mirror sounds like it's mirrorring. Why would I need this? or whatever this does?
- aviramha 4y ago
  mirrord is a tool for backend engineers that enables them to work on a remote environment without needing to deploy there or actually run there. It makes the iteration time (code -> test -> [review] -> deploy) faster since you don't replace the remote service also, which means many devs can work the same time. You can read more about it here https://metalbear.co/blog/mirrord-3.0-is-out/ https://metalbear.co/blog/mirrord-3.0-is-out/

88 points by signa11 4y ago

There are few miseries I deal with regularly that compare to SIP or the hardened runtime telling me I may not debug processes on a computer where I have root. If anything is going to make me abandon macOS (I've been using it since I was a child) it's the "security and privacy" features.

aviramha 4y ago
I totally feel you though I can understand that for Apple the average consumer's security > hackers :) I think Apple should remember that people debugging and working is important too, and make the documentation around the security features less obscure. (Attaching a debugger/ptrace on macOS is really evil to implement)
sbuk 4y ago
The security and privacy features benefit the majority, of which you clearly are not, so there is an escape hatch for you; turn off SIP. Just don't disable it for typical users.
- justsomeadvice0 4y ago
  Yea, I'm really not sure how this is a "misery". System processes are protected for typical users to limit the blast radius of malware, among other reasons. If you are capable of debugging system processes you should be able to manage to: Restart macOS, holding ⌘+R. Open Terminal. Type `csrutil disable`. Restart macOS again.
  - derbOac 4y ago
    For some things though that's just Step 1 of many. Still doable but too much of a pain.
- aviramha 4y ago
  Why not enable easier override for specific scenarios? Turning off completely feels like a bad outcome
  - galad87 4y ago
    It already allows to turn off only a part of it.
    - aviramha 4y ago
      But I don't want that. That's like taking the gate instead of adding a configurable ACL.
    - saagarjha 4y ago
      Turning off any of SIP is largely isomorphic to turning it all off
- chongli 4y ago
  That’s like telling me to remove the front door of my house rather than letting me have a key to unlock it.
  - tempodox 4y ago
    True, but giving us a key might jeopardize future revenue streams where we have to pay for the privilege of developing software on Apple platforms. You already get a degraded developer experience for iOS if you don't bribe Apple with a Developer Program subscription.
    - rogual 4y ago
      Not just iOS. Notarizing apps for macOS requires payment too.
    - scarface74 4y ago
      HN has been predicting a future that you could only install apps through the Mac App Store since it was introduced in 2011. Any day now…
      - Gigachad 4y ago
        We will see alt app stores on the iphone before we see macOS match those predictions.
  - jabedude 4y ago
    What would be a suitable key in your analogy?
    - solarkraft 4y ago
      Super-root? But as far as I'm aware the reasoning is that if there's a way to access something from a normal user account (with admin privileges) it can be abused somehow. Maybe a "key" would be the ability to boot/log in to a special mode with SIP enabled. Disabling/enabling it approximates this, but as far as I know an update will generally destroy your changes because Apple will just overwrite everything.
- howinteresting 4y ago
  Then iOS apps stop working, right? The DRM regime requires SIP to be enabled. Stallman was right about "treacherous computing".
  - sbuk 4y ago
    This has nothing to do with iOS.
    - howinteresting 4y ago
      macOS now has support for iOS apps, but only if SIP is enabled and their DRM/"trusted" computing regime is active. https://forums.macrumors.com/threads/if-you-disable-sip-all-you-ios-apps-will-stop-working-on-your-m1.2269661 https://forums.macrumors.com/threads/if-you-disable-sip-all-...
- vaughan 4y ago
  Turning off SIP means you can’t run iOS apps on macOS. This sucks.
madeofpalk 4y ago
You can just disable SIP, no?
- Gigachad 4y ago
  Yes, the "locked down dictatorship macos" is surprisingly permissive. Impressively you can even dual boot linux on Apple Silicon completely unrestricted without having to turn on off the boot chain security features of macOS.
lloeki 4y ago
Under "Security and Privacy" there's been "Developer Tools" for a while, within which I only ever saw Terminal.app (but any app could be added) I'm not sure what it really does (could not find any docs, maybe someone can enlighten?) but the text made me think it could allow stuff like running unsigned debuggers: Allow the applications below to run software locally that does not meet the system's security policies Again I'm really not sure, but maybe it can cover some use cases without going the nuclear route of fully disabling SIP?
- memco 4y ago
  I Would be interested to know more about it too. I have been interested in running a piece of software that needs SIP partially disabled, but I’d I could just grant it exemption I would prefer that to a blanket removal. Funny thing is all computers used to run without SIP, but since they added it I’m now hesitant to turn it off even though I’m not any worse off than I used to be.
- macshome 4y ago
  It relaxes the signing requirements and malware signature checks for binaries run in the Terminal. This way you can build and test stuff without needing to relax the security posture of the entire Mac.
scarface74 4y ago
Yes because it’s not like bad things can happen when SIP is turned off. Not always malicious, it’s often ineptness https://appleinsider.com/articles/19/09/25/google-chrome-update-corrupting-some-macos-installs----but-theres-a-fix https://appleinsider.com/articles/19/09/25/google-chrome-upd...

antihero 4y ago

This is interesting. I’m guessing just having a patched shell binary and forking stuff from within that wouldn’t work.

aviramha 4y ago
You could patch a shell binary, but you'd ultimately want to use other binaries as well. The most common example we had is when people tried to run our software with `pyenv` which was a shell script that used other system binaries + shell scripts

WirelessGigabit 4y ago

While the explanation is super cool it makes me feel nervous. None of this did supported. APIs change without notice, as you don't have a contract. You're relying on the fact that there is an x64 version available.

aviramha 4y ago
Most odds is when x64 binary will stop shipping, arm64e won't be in preview mode anymore and we will be able to just do the re-signing part. (Which is supported)
ghostpepper 4y ago
It's pretty much expected that if you publish a method for working around a security feature it will be patched quickly. Cool research if that was the intention but if you're building a product around this... you're going to have a bad time.
- eyalbukchin 4y ago
  This is detailed in the post, but the security feature i.e. preventing injected libraries access to entitlements isn't actually bypassed here. Rather the binary is run without these entitlements (which aren't required anyway for mirrord's use case).

pseufaux 4y ago

> Killed! And it was so young. This got far more of a chuckle from me than it should have. Must have had a long day or far to little sleep.

pedrow 4y ago

Would it be an option to compile your own versions of `ls` et al., maybe from the Darwin source (if available, I don't know) or one of the BSDs? Does what you're trying to do depend on the specific implementation of Apple's utilities?

eyalbukchin 4y ago
Maybe, we haven't looked into that option for the following reasons: a. It would require that we maintain a potentially pretty big list of self-compiled binaries b. It would be an alteration of what the user's running, which we try to keep to a minimum, as mirrord's commonly used as a testing tool

david2ndaccount 4y ago

This is a strange product they’re selling. You run your binary on on macOS but presumably your server is running linux. Why are you trying to run Darwin executables as if they were in the cloud when that is not what will actually be deployed? Shouldn’t the testing at least be done from a linux machine?

eyalbukchin 4y ago
Ideally! And it can be run on a Linux machine if the user prefers. But if you code on a Mac, mirrord still lets you go through a good number of test iterations (by letting your process run with network input/output, file content and environment variables from the cloud) before having to deploy your code to a Linux machine for that (hopefully) final round of testing.

jbverschoor 4y ago

I have no clue what this mirrord does. Is it some kind of API proxy? What if I don't have 'pods', also, shouldn't it be called redirect_api? mirror sounds like it's mirrorring. Why would I need this? or whatever this does?

aviramha 4y ago
mirrord is a tool for backend engineers that enables them to work on a remote environment without needing to deploy there or actually run there. It makes the iteration time (code -> test -> [review] -> deploy) faster since you don't replace the remote service also, which means many devs can work the same time. You can read more about it here https://metalbear.co/blog/mirrord-3.0-is-out/ https://metalbear.co/blog/mirrord-3.0-is-out/