I have an app that runs on macOS Monterey.
For various reasons, I have to externally add a sandbox entitlement (externally, as in using codesign, rather than rebuilding it)
After adding the sandbox entitlement, and resigning appropriately, the app crashes on launch with the following error :
ERROR:process_singleton_posix.cc(1186)] Failed to bind() /var/folders/s2/j0z79krx321qg318das1r95_zc0000gn/T/com.funkyapp/S/SingletonSocket
So I assumed I needed to give access to this file.
So I added the following entitlements to the app, via codesign :
<key>com.apple.security.temporary-exception.files.absolute-path.read-write</key> <array> <string>/var</string> <string>/var/folders/s2/j0z79krx321qg318das1r95_zc0000gn/T/com.funkyapp/S/SingletonSocket</string> </array>
and also
<key>com.apple.security.network.client</key> <true/>
<key>com.apple.security.network.server</key> <true/>
Unfortunately, it still crashes on load, with the same error.
Does anyone know why that is? From my perspective, I gave the appropriate entitlements to bind a socket at that path, what am I missing?
Thanks !
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I’ve got a run of the mill Drag&Drop DMG installer. It works as expected when the drop target is /Applications. However I deliver plugins which I want to be copy to somewhere below /Library/Aplication Support/. Here too, everything works fine until I upload and download the dmg to my webserver. Now when dropping the plugins onto the target alias they just slide back. No error, no dialog asking for permissions, no nothing… just silently sliding back. And I haven’t the faintest idea how to address this. Would somebody please be my hero of the day and point me into the right direction, pretty please?
The plugins and the dmg are codesigned and notarized. They work as expected when moving them to the plugins folder directly. It’s only the alias that will not work. The alias btw. is a soft link created using ln - s.
Not sure this is the right category to post in. But it feels like it’s a probably a permission/entitlements issue.
One code signing issue I commonly see, both here on DevForums and in my Day Job™ with DTS, is that the codesign command fails with errSecInternalComponent. This issue crops up in a wide variety of circumstances and the correct fix depends on the specific problem. This post is my attempt to clarify the potential causes of this error and help folks resolve it.
If you have any questions or comments about this, please start a new thread, tagging it with Code Signing so that I see it.
Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"
Resolving errSecInternalComponent errors during code signing
In some circumstances the codesign command might fail with the error errSecInternalComponent. For example:
% codesign -s "Apple Development" "MyTrue"
MyTrue: errSecInternalComponent
This typically affects folks who are signing code in a nonstandard environment, for example, when logged into a Mac via SSH or when signing code on a continuous integration (CI) server. This post explains how to resolve such issues, starting in the simplest case, signing from Terminal app, and then going on to discuss SSH and other contexts.
IMPORTANT Before going further, make sure you understand the difference between a digital identity and a certificate. See TN3161 Inside Code Signing: Certificates for the details.
Test from Terminal
Code signing makes extensive use of the keychain, and that’s sensitive to the execution context in which it’s running. So, the first step in resolving this problem is to test your code signing from Terminal. To start, log in to the Mac using the GUI.
Note If you don’t have access to the GUI, see Working without the GUI, below.
Check that Keychain Access shows that your code signing identity’s certificate is trusted. Select the certificate and look for a green checkmark with the text “This certificate is valid”. If you see a red cross with an explanatory text like “… certificate is not trusted”, follow the instructions in Fixing an untrusted code signing certificate.
Note macOS 15 moved Keychain Access out of the Utilities folder. The easiest way to find and launch Keychain Access is to use Spotlight.
In Terminal, run the security tool to check that your code signing identity is available:
% security find-identity -p codesigning
Policy: Code Signing
Matching identities
1) 4E587951B705280CBB8086325CD134D4CDA04977 "Apple Development: …"
1 identities found
Valid identities only
1) 4E587951B705280CBB8086325CD134D4CDA04977 "Apple Development: …"
1 valid identities found
If the identity is missing from the Matching identities list, you don’t have a code signing identity to sign with. If you see your code signing identity’s certificate in the keychain, it’s possible that you’re missing its private key. See Certificate Signing Requests Explained for more about that issue.
If the identity is shown in the Matching identities list but not in the Valid identities only list, see Fixing an untrusted code signing certificate.
This example assumes that you’re testing with an Apple Development signing identity. If you’re using something else, you’ll see a different identity name in this list. Use that identity name in the codesign command below.
Still in Terminal, make a copy of the true tool to use for this test:
% cp "/usr/bin/true" "MyTrue"
Try to sign it:
% codesign -s "Apple Development" -f "MyTrue"
MyTrue: replacing existing signature
The -f flag tells codesign to replace the existing signature.
This command may display one or more keychain dialogs but, once you respond to those, it should correctly sign MyTrue. If it doesn’t, skip down to the Terminal failure section at the end of this post.
Eliminate keychain alerts
When you signed your code in the previous section, you may have seen one of two different types of keychain alerts:
Keychain unlock dialog
Access control list (ACL) dialog
The keychain unlock dialog looks like this:
codesign wants to use the … keychain.
Please enter the keychain password.
Password: [ ]
[Cancel] [[OK]]
The keychain containing your code signing identity is locked, and you must enter the keychain password to unlock it. You rarely see this dialog when logged in via the GUI because the system automatically unlocks the login keychain when you log in. However, the underlying cause of this alert will become relevant in the next section, when you log in via SSH.
The ACL dialog looks like this:
codesign wants to sign using key … in your keychain.
To allow this, enter the … keychain password.
Password: [ ]
[Always Allow] [Deny] [[Allow]]
The ACL for the your code signing identity’s private key prevents codesign from using the private key without your explicit approval. If you enter your password and click Allow, codesign can use the private key once. If you click Always Allow, the system adds codesign to the private key’s ACL so that it doesn’t have to ask again.
To avoid this alert in the future, enter your keychain password and click Always Allow. Now repeat the codesign command from the previous section. It will sign the code without presenting any dialogs.
Test over SSH
Once you can sign your code in Terminal without seeing any dialogs, it’s time to repeat that process over SSH. To start, log out of the GUI and then log in via SSH.
If you’re testing on a CI system, log in to that system by running ssh from Terminal on your Mac. If you want to test on your local Mac, choose one of these options
If you have a second Mac, log in to that second Mac using the GUI, launch Terminal, and then run ssh to log in to your main Mac from there.
If you have an iPad, use a third-party iPad SSH app to log in to your main Mac over SSH.
Use a virtualisation app to run a macOS guest that you can treat like your CI system.
Once you’re logged in over SSH, repeat the signing command from the earlier section:
% codesign -s "Apple Development" -f "MyTrue"
MyTrue: replacing existing signature
MyTrue: errSecInternalComponent
This fails because:
The system locked the keychain when you logged out of the GUI.
Logging in via SSH does not unlock the keychain.
When codesign tries to use your code signing identity, the system attempts to present the keychain unlock dialog.
That fails because you’re logged in via SSH and thus don’t have access to the GUI.
The system returns the errSecInternalComponent error to codesign, which reports it to you.
To fix this, unlock your keychain using the security tool:
% security unlock-keychain
password to unlock default: KEYCHAIN_PASSWORD
% codesign -s "Apple Development" -f "MyTrue"
MyTrue: replacing existing signature
IMPORTANT This assumes that your code signing identity is in your login keychain. If it’s in some other keychain, read the security man page to learn how to unlock a specific keychain.
Best practice is to store both parts of your code signing identity (the certificate and the private key) in the same keychain. If you split the identity across two keychains, unlock the keychain that contains the private key.
Test your CI job
Once you have everything working on your CI system over SSH, try running exactly the same commands in your CI job. If your CI system manages user contexts correctly, those commands should just work. If they don’t, discuss this with your CI vendor.
Note macOS has a complex execution context model. For background on this, see the Execution Contexts section of Technote 2083 Daemons and Agents. Some CI systems don’t correctly establish a user context when running jobs. For example, they might switch the traditional Unix execution context — the EUID, RUID, and so on — but not the security context. This mixed execution context causes problems for the keychain, which relies on the security context.
Avoid doing code signing work as root. Some folks run everything as root because they think it’ll avoid problems. When working with the keychain the opposite is true: Running as root often causes more problems than it solves. These problems are most likely to show up when you use sudo, which creates a mixed execution context.
Working without the GUI
The instructions above assume you have access to the GUI so that you can test and resolve issues using GUI tools like Keychain Access. However, many CI systems don’t give you access to the GUI; at best you might have interactive access using SSH.
Note If you CI system allows remote access using a screen sharing protocol, use that rather than messing around with the instructions here.
If you don’t have access to the GUI of the machine on which you’re signing code, there are three issues to deal with:
Avoiding the keychain unlock dialog
Avoiding the ACL dialog
Investigating an untrusted code signing certificate issue
To unlock the keychain, use the unlock-keychain subcommand of the security tool, discussed in the Test over SSH section earlier.
When logged in with the GUI, you can respond to ACL dialog by clicking Always Allow. This prevents that dialog showing up again. However, if you don’t have GUI access there’s no way to click that button. To get around this, import your signing identity and set its ACL to allow codesign to use it without extra authorisation. To do this, first unlock the keychain:
% security unlock-keychain
password to unlock default: KEYCHAIN_PASSWORD
Then use the security tool to import the PKCS#12 file:
% security import IDENTITY.p12 -T /usr/bin/codesign -P P12_PASSWORD
1 identity imported.
Note the -T option, which adds codesign to the private key’s ACL.
Finally, modify the partition list to allow access by Apple code:
% security set-key-partition-list -S "apple:" -l "Apple Development: …"
This example assumes you’re using an Apple Development signing identity to test with. If you’re using something else, replace Apple Development: … with that identity name.
Finally, investigating an untrusted code signing certificate issue remotely is quite challenging. Your best option here is to set up a local test environment, run your investigation in that environment, and then apply the results to your CI environment.
There are two good choices for your local test environment:
Use a virtualisation app to create a ‘clean’ macOS guest, one that’s never seen your code signing setup before.
Use System Settings > Users & Groups to create a new local user account and do your testing there.
The first option is best because you can easily restore your VM to a clean state between tests.
When running through the process described in Fixing an untrusted code signing certificate, you might end up performing two different remedial actions:
Importing an intermediate
Reseting trust settings.
Once you understand these remediations, you need to apply them to your CI system. The first one is easy: To import an intermediate, run security with the import subcommand:
% security import INTERMEDIATE.cer
1 certificate imported.
Resetting trust settings is more of a challenge. It’s probably possible to do this with the security tool but, honestly, if you think that your CI system has messed up trust settings it’s easiest to throw it away and start again from scratch.
Terminal failure
The bulk of this post assumes that the process described in the Test from Terminal section works. If it doesn’t, something weird is happening and you should apply the following diagnostic suggestions.
The first is to create a new local user account on your Mac — using System Settings > Users & Groups — and then retry there. The goal of this test is to isolate:
A problem that affects your Mac as a whole
From a problem that’s tied to your user account
If the problem is with your user account, switch back to your original account and run:
% security dump-trust-settings
SecTrustSettingsCopyCertificates: No Trust Settings were found.
In most cases this should report that no trust settings were found. If it report trust setting overrides, remove them. See Check for a trust settings override in Fixing an untrusted code signing certificate.
If that doesn’t resolve the issue, something else is afoot and I recommend that you seek dedicated help per the start of this post.
Revision History
2024-10-05 Added the Terminal failure section. Made other minor editorial changes.
2022-08-12 Extended the unlock-keychain explanation to cover the split identity issue.
2022-08-11 First posted.
General:
DevForums tag: App Sandbox
App Sandbox documentation
App Sandbox Design Guide documentation — This is no longer available from Apple. There’s still some info in there that isn’t covered by the current docs but, with the latest updates, it’s pretty minimal (r. 110052019). Still, if you’re curious, you can consult an old copy [1].
App Sandbox Temporary Exception Entitlements archived documentation — To better understand the role of temporary exception entitlements, see this post.
Embedding a Command-Line Tool in a Sandboxed App documentation
Discovering and diagnosing App Sandbox violations (replaces the Viewing Sandbox Violation Reports DevForums post)
Resolving App Sandbox Inheritance Problems DevForums post
The Case for Sandboxing a Directly Distributed App DevForums post
Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"
[1] For example, this one archived by the Wayback Machine.
This post is part of a cluster of posts related to the trusted execution system. If you found your way here directly, I recommend that you start at the top.
Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"
Resolving Gatekeeper Problems
Gatekeeper strives to ensure that only trusted software runs on a user’s Mac. It’s important that your code pass Gatekeeper. If not, you’re likely to lose a lot of customers, and your users’ hard-won trust.
There are four common Gatekeeper problems:
App blocked by a dangling load command path
Broken code signature
Lack of notarisation
Command-line tool blocked by Gatekeeper
The first problem is by far the most common. For the details, see Resolving Gatekeeper Problems Caused by Dangling Load Command Paths.
For general information about Gatekeeper, read Apple > Developer > Signing Mac Software with Developer ID and Apple > Support > Safely open apps on your Mac.
IMPORTANT This post focuses on Developer ID-signed code. Gatekeeper should not block App Store apps. If an app downloaded from the App Store fails to run, it’s likely to be some other trusted execution issue. For more about this, read Resolving Trusted Execution Problems.
macOS 14 introduced gktool, a very minimal interface to Gatekeeper. Run the tool with the help argument to learn more:
% gktool help
Verify Your Signature
A good first step in any Gatekeeper investigation is to verify that your code is signed correctly. Use the codesign tool for this:
% codesign -v -vvv --strict --deep MyApp.app
The -vvv options increase verbosity to the point where codesign will give you useful diagnostics. For example:
% codesign -v -vvv --strict --deep "Munged.app"
Munged.app: a sealed resource is missing or invalid
file added: …/Munged.app/Contents/Resources/names/Adam.txt
file modified: …/Munged.app/Contents/Resources/names/Morgan.txt
file missing: …/Munged.app/Contents/Resources/names/Rhonda.txt
This app was changed after it was signed in three different ways:
Adam.txt was added.
Morgan.txt was modified.
Rhonda.txt was removed.
You might see some results that make no sense. For example:
Start with an app with a valid code signature:
% codesign -v -vvv --strict --deep "NotNormal.app"
NotNormal.app: valid on disk
NotNormal.app: satisfies its Designated Requirement
Use the Finder to create a zip archive (File > Compress).
Use the Finder to unpack that archive.
Check the code signature of the unpacked file:
% codesign -v -vvv --strict --deep "NotNormal 2.app"
NotNormal 2.app: a sealed resource is missing or invalid
file added: …/NotNormal 2.app/Contents/Resources/names/Zoë Schrödinger.txt
file missing: …/NotNormal 2.app/Contents/Resources/names/Zoë Schrödinger.txt
There are two things to note here. First, just compressing and decompressing the app broke its code signature. Weird! Second, look at the error messages. It seems that the Zoë Schrödinger.txt file is was both added and removed. Weirder!
To see what’s going on here you have to look at a hex dump of the file name:
% ls "NotNormal.app/Contents/Resources/names" | xxd
00000000: 5a6f c3ab 2053 6368 726f cc88 6469 6e67 Zo.. Schro..ding
00000010: 6572 2e74 7874 0a er.txt.
% ls "NotNormal 2.app/Contents/Resources/names" | xxd
00000000: 5a6f 65cc 8820 5363 6872 6fcc 8864 696e Zoe.. Schro..din
00000010: 6765 722e 7478 740a ger.txt.
The names are not the same! The app started out with the ë in precomposed form and the ö in decomposed form. Compressing and decompressing the app converted the ë to its decomposed form, and that change broke the code signature.
Programs that deal with Unicode are expected to ignore differences in normalisation. Sadly, Apple’s code signing implementation missed that memo (r. 68829319). For more details see this post but the executive summary is that it’s best to stick to ASCII when naming files in a bundle.
Identify a Notarisation Problem
Gatekeeper requires that your app be notarised. If not, it will block the execution of your app with a generic, user-level message. If you find your app blocked by Gatekeeper, check if this is a notarisation issue by looking in the system log for an entry like this:
type: info
time: 2022-05-11 14:57:21.812176 -0700
process: syspolicyd
subsystem: com.apple.syspolicy
category: default
message: ticket not available: 2/2/8b7410713591e6c79ea98f0132136f0faa55d22a
Note If the ticket details show as <private>, enable private data in the system log. For information on how to do that, see Recording Private Data in the System Log. For general information about the system log, see Your Friend the System Log.
The long hex number is the code directory hash, or cdhash, of the offending code. In this example, it’s the cdhash of the app itself:
% codesign -d -vvv /Applications/NotNotarised.app
…
CDHash=8b7410713591e6c79ea98f0132136f0faa55d22a
…
However, in some cases it may be the cdhash of some library referenced by the app.
For more information about cdhashes, see TN3126 Inside Code Signing: Hashes.
Resolve a Notarisation Problem
The obvious cause of this problem is that you haven’t notarised your app. For information on how to do that, see Notarizing macOS Software Before Distribution.
If you have notarised your app and yet you still see this problem, something more subtle is happening. For example, your app might reference a dynamic library that wasn’t seen by the notary service.
To investigate this:
Fetch the notary log for your app. For advice on that, see Fetching the Notary Log.
Confirm that the notary log matches the app you installed. Look in the notary log for the sha256 property. Its value is a SHA-256 hash of the file received by the notary service. Check that this matches the SHA-256 hash of the file you used to install your app. If not, see Hash Mismatch, below.
Search the notary log for the cdhash value from the Gatekeeper log message.
If the notary log doesn’t contain that cdhash, that code wasn’t included in the notarised ticket. It’s possible that you failed to submit the code to the notary service, that it was switched out with a different version after you notarised your app, that it was package in some way that the notary service couldn’t see it, or that something went wrong within the notary service.
Hash Mismatch
If you stapled your notarised ticket to the file used to install your app then the hashes in step 2 of the previous section won’t match. What to do depends on the file type:
If the file used to install your app was a zip archive (.zip), you definitely have the wrong file. Zip archives don’t support stapling.
If the file used to install your app was a signed disk image (.dmg), compare the disk image’s cdhash with the cdhash for the disk image in the notary log. If those match, you know you’re working with the same disk image.
To dump a disk image’s cdhash, run the codesign tool as follows:
% codesign -d -vvv DISK_IMAGE
…
CDHash=d963af703ac2e54af6609e9ad309abee7b66fae2
…
Replace DISK_IMAGE with the path to your disk image.
If the file used to install your app was a disk image but it wasn’t signed, switch to a signed disk image. It’s generally a better option.
If the file used to install your app was an installer package (.pkg), there’s no good way to know if this is the correct package. In this case, modify your notarisation workflow to retain a copy of the file before it was modified by stapler.
Tool Blocked by Gatekeeper
If your product includes a command-line tool, you might notice this behaviour:
When you double click the tool in Finder, it’s blocked by Gatekeeper.
When you run the tool from within Terminal, it works.
This is a known bug in macOS (r. 58097824). The issue is that, when you double click a tool in the Finder, it doesn’t run Gatekeeper’s standard execution logic. Rather, the Finder passes the tool to Terminal as a document and that opens a window (and associated shell) in which to run that document. This triggers Gatekeeper’s document logic, and that logic always blocks the tool.
There are two ways around this:
Embed your tool in an application. If the user runs the application first, Gatekeeper runs its normal application check. If the user allows the app to run, Gatekeeper records that decision and applies it to the app and any code within the app, including your tool.
Install your tool using an installer package. When the user goes to install the package, Gatekeeper checks it. Assuming that check passes, Gatekeeper does no further checks on the content it installed.
Revision History
2024-11-11 Added a mention of gktool.
2022-05-20 Added the Verify Your Signature section. Made other minor editorial changes.
I help a lot of developers with macOS trusted execution problems. For example, they might have an app being blocked by Gatekeeper, or an app that crashes on launch with a code signing error.
If you encounter a problem that’s not explained here, start a new thread with the details. Make sure to add relevant tags — like Gatekeeper, Code Signing, and Notarization — so that I see your post.
IMPORTANT macOS 14 has a new tool, syspolicy_check, that was specifically designed to help diagnose problems like this. I plan to update this post once I have more experience with it. In the meantime, however, if you hit a trusted execution problem and it reproduces on macOS 14, please try out syspolicy_check and let us know how that pans out.
Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"
Resolving Trusted Execution Problems
macOS supports three software distribution channels:
The user downloads an app from the App Store.
The user gets a Developer ID-signed program directly from its developer.
The user builds programs locally using Apple or third-party developer tools.
The trusted execution system aims to protect users from malicious code. It’s comprised of a number of different subsystems. For example, Gatekeeper strives to ensure that only trusted software runs on a user’s Mac, while XProtect is the platform’s built-in anti-malware technology.
Note To learn more about these technologies, see Apple Platform Security.
If you’re developing software for macOS your goal is to avoid trusted execution entanglements. You want users to install and use your product without taking any special steps. If, for example, you ship an app that’s blocked by Gatekeeper, you’re likely to lose a lot of customers, and your users’ hard-won trust.
Trusted execution problems are rare with Mac App Store apps because the Mac App Store validation process tends to catch things early. This post is primarily focused on Developer ID-signed programs.
Developers who use Xcode encounter fewer trusted execution problems because Xcode takes care of many code signing and packaging chores. If you’re not using Xcode, consider making the switch. If you can’t, consult the following for information on how to structure, sign, and package your code:
Placing Content in a Bundle
Embedding Nonstandard Code Structures in a Bundle
Embedding a Command-Line Tool in a Sandboxed App
Creating distribution-signed code for macOS
Packaging Mac software for distribution
Gatekeeper Basics
User-level apps on macOS implement a quarantine system for new downloads. For example, if Safari downloads a zip archive, it quarantines that archive. This involves setting the com.apple.quarantine extended attribute on the file.
Note The com.apple.quarantine extended attribute is not documented as API. If you need to add, check, or remove quarantine from a file programmatically, use the quarantinePropertiesKey property.
User-level unarchiving tools preserve quarantine. To continue the above example, if you double click the quarantined zip archive in the Finder, Archive Utility will unpack the archive and quarantine the resulting files.
If you launch a quarantined app, the system invokes Gatekeeper. Gatekeeper checks the app for problems. If it finds no problems, it asks the user to confirm the launch, just to be sure. If it finds a problem, it displays an alert to the user and prevents them from launching it. The exact wording of this alert varies depending on the specific problem, and from release to release of macOS, but it generally looks like the ones shown in Apple > Support > Safely open apps on your Mac.
The system may run Gatekeeper at other times as well. The exact circumstances under which it runs Gatekeeper is not documented and changes over time. However, running a quarantined app always invokes Gatekeeper.
Unix-y networking tools, like curl and scp, don’t quarantine the files they download. Unix-y unarchiving tools, like tar and unzip, don’t propagate quarantine to the unarchived files.
Confirm the Problem
Trusted execution problems can be tricky to reproduce:
You may encounter false negatives, that is, you have a trusted execution problem but you don’t see it during development.
You may also encounter false positives, that is, things fail on one specific Mac but otherwise work.
To avoid chasing your own tail, test your product on a fresh Mac, one that’s never seen your product before. The best way to do this is using a VM, restoring to a snapshot between runs. For a concrete example of this, see Testing a Notarised Product.
The most common cause of problems is a Gatekeeper alert saying that it’s blocked your product from running. However, that’s not the only possibility. Before going further, confirm that Gatekeeper is the problem by running your product without quarantine. That is, repeat the steps in Testing a Notarised Product except, in step 2, download your product in a way that doesn’t set quarantine. Then try launching your app. If that launch fails then Gatekeeper is not the problem, or it’s not the only problem!
Note The easiest way to download your app to your test environment without setting quarantine is curl or scp. Alternatively, use xattr to remove the com.apple.quarantine extended attribute from the download before you unpack it. For more information about the xattr tool, see the xattr man page.
Trusted execution problems come in all shapes and sizes. The remaining sections address the most common ones.
App Blocked by Gatekeeper
If your product is an app and it works correctly when not quarantined but is blocked by Gatekeeper when it is, you have a Gatekeeper problem. For advice on how to investigate such issues, see Resolving Gatekeeper Problems.
App Can’t Be Opened
Not all failures to launch are Gatekeeper errors. In some cases the app is just broken. For example:
The app’s executable might be missing the x bit set in its file permissions.
The app’s executable might be subtly incompatible with the current system. A classic example of this is trying to run a third-party app that contains arm64e code.
macOS requires that third-party kernel extensions use the arm64e architecture. In other circumstances, stick to arm64 for your shipping products. If you want to test arm64e code locally, see Preparing Your App to Work with Pointer Authentication.
The app’s executable might claim restricted entitlements that aren’t authorised by a provisioning profile.
Or the app might have some other code signing problem.
Note For more information about provisioning profiles, see TN3125 Inside Code Signing: Provisioning Profiles.
In such cases the system displays an alert saying:
The application “NoExec” can’t
be opened.
[[OK]]
Note In macOS 11 this alert was:
You do not have permission to
open the application “NoExec”.
Contact your computer or network
administrator for assistance.
[[OK]]
which was much more confusing.
A good diagnostic here is to run the app’s executable from Terminal. For example, an app with a missing x bit will fail to run like so:
% NoExec.app/Contents/MacOS/NoExec
zsh: permission denied: NoExec.app/Contents/MacOS/NoExec
And an app with unauthorised entitlements will be killed by the trusted execution system:
% OverClaim.app/Contents/MacOS/OverClaim
zsh: killed OverClaim.app/Contents/MacOS/OverClaim
In some cases running the executable from Terminal will reveal useful diagnostics. For example, if the app references a library that’s not available, the dynamic linker will print a helpful diagnostic:
% MissingLibrary.app/Contents/MacOS/MissingLibrary
dyld[88394]: Library not loaded: @rpath/CoreWaffleVarnishing.framework/Versions/A/CoreWaffleVarnishing
…
zsh: abort MissingLibrary.app/Contents/MacOS/MissingLibrary
Code Signing Crashes on Launch
A code signing crash has the following exception information:
Exception Type: EXC_CRASH (SIGKILL (Code Signature Invalid))
The most common such crash is a crash on launch. To confirm that, look at the thread backtraces:
Backtrace not available
For steps to debug this, see Resolving Code Signing Crashes on Launch.
One common cause of this problem is running distribution-signed code. Don’t do that! For details on why that’s a bad idea, see Don’t Run App Store Distribution-Signed Code.
Code Signing Crashes After Launch
If your program crashes due to a code signing problem after launch, you might have encountered the issue discussed in Updating Mac Software.
Non-Code Signing Failures After Launch
The hardened runtime enables a number of security checks within a process. Some coding techniques are incompatible with the hardened runtime. If you suspect that your code is incompatible with the hardened runtime, see Resolving Hardened Runtime Incompatibilities.
App Sandbox Inheritance
If you’re creating a product with the App Sandbox enabled and it crashes with a trap within _libsecinit_appsandbox, it’s likely that you’re having App Sandbox inheritance problems. For the details, see Resolving App Sandbox Inheritance Problems.
Library Loading Problem
Most library loading problems have an obvious cause. For example, the library might not be where you expect it, or it might be built with the wrong platform or architecture. However, some library loading problems are caused by the trusted execution system. For the details, see Resolving Library Loading Problems.
Explore the System Log
If none of the above resolves your issue, look in the system log for clues as to what’s gone wrong. Some good keywords to search for include:
gk, for Gatekeeper
xprotect
syspolicy, per the syspolicyd man page
cmd, for Mach-O load command oddities
amfi, for Apple mobile file integrity, per the amfid man page
taskgated, see its taskgated man page
yara, discussed in Apple Platform Security
ProvisioningProfiles
You may be able to get more useful logging with this command:
% sudo sysctl -w security.mac.amfi.verbose_logging=1
Here’s a log command that I often use when I’m investigating a trusted execution problem and I don’t know here to start:
% log stream --predicate "sender == 'AppleMobileFileIntegrity' or sender == 'AppleSystemPolicy' or process == 'amfid' or process == 'taskgated-helper' or process == 'syspolicyd'"
For general information the system log, see Your Friend the System Log.
Revision History
2024-10-11 Added info about the security.mac.amfi.verbose_logging option. Updated some links to point to official documentation that replaces some older DevForums posts.
2024-01-12 Added a specific command to the Explore the System Log section. Change the syspolicy_check callout to reflect that macOS 14 is no longer in beta. Made minor editorial changes.
2023-06-14 Added a quick call-out to the new syspolicy_check tool.
2022-06-09 Added the Non-Code Signing Failures After Launch section.
2022-06-03 Added a link to Don’t Run App Store Distribution-Signed Code. Fixed the link to TN3125.
2022-05-20 First posted.
I have been working with a framework to add multiplayer support to my app. The app runs on test devices, simulators, and archives perfectly fine and the app is fine without the framework. But when I go to distribute the app, I see get this error related to the multiplayer framework I have added. I have tried updating the minimumOSVersion to 9.0, 10.0, 12.0, and 13.0 everywhere (info.plist, deployment info, build settings, etc) and they all match with each build/archive but no matter what I can't get fix this error. This error only shows up when I go to distribute the app to the store. Any ideas on what to try or how to fix this issue? I've attached a screenshot of the issue below.
IMPORTANT The underlying issue here (FB8830007) was fixed in macOS 11.3, so the advice in this post is irrelevant if you’re building on that release or later.
Note This content is a repost of info from another thread because that thread is not world readable (it’s tied to the DTK programme).
A number of folks have reported problems where:
They have a product that supports older versions of macOS (anything prior to 10.11).
If they build their product on Intel, everything works.
If they build their product on Apple Silicon, it fails on those older versions of macOS.
A developer filed a bug about this (FB8830007) and, based on the diagnosis of that bug, I have some info to share as to what’s going wrong and how you can prevent it. Let’s start with some background.
macOS’s code signing architecture supports two different hash formats:
sha1, the original hash format, which is now deprecated
sha256, the new format, support for which was added in macOS 10.11
codesign should choose the signing format based on the deployment target:
If your deployment target is 10.11 or later, you get sha256.
If your deployment target is earlier, you get both sha1 and sha256.
This problem crops up because, when building for both Intel and Apple Silicon, your deployment targets are different. You might set the deployment target to 10.9 but, on Apple Silicon, that’s raised to the minimum Apple Silicon system, 11.0. So, which deployment target does it choose?
Well, the full answer to that is complex but the executive summary is that it chooses the deployment target of the current architecture, that is, Intel if you’re building on Intel and Apple Silicon if you’re building on Apple Silicon. For example:
intel% codesign -d --arch x86_64 -vvv Test664892.app
…
Hash choices=sha1,sha256
…
intel% codesign -d --arch arm64 -vvv Test664892.app
…
Hash choices=sha1,sha256
…
arm% codesign -d --arch x86_64 -vvv Test664892.app
…
Hash choices=sha256
…
arm% codesign -d --arch arm64 -vvv Test664892.app
…
Hash choices=sha256
…
The upshot is that you have problems if your deployment target is less than 10.11 and you sign on Apple Silicon. When you run on, say, macOS 10.10, the system looks for a sha1 hash, doesn’t find it, and complains.
The workaround is to supply the --digest-algorithm=sha1,sha256, which overrides the hash choice logic in codesign and causes it to include both hashes:
arm% codesign -s - --digest-algorithm=sha1,sha256 Test664892.app
arm% codesign -d --arch x86_64 -vvv Test664892.app
…
Hash choices=sha1,sha256
…
% codesign -d --arch arm64 -vvv Test664892.app
…
Hash choices=sha1,sha256
…
Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"
To ship a product outside of the Mac App Store, you must notarise it. The notary service issues a notarised ticket, and the ultimate consumer of that ticket is Gatekeeper. However, Gatekeeper does not just check the ticket; it also applies a variety of other checks, and it’s possible for those checks to fail even if your notarised ticket is just fine. To avoid such problems showing up in the field, test your product’s compatibility with Gatekeeper before shipping it.
To do this:
Set up a fresh machine, one that’s never seen your product before. If your product supports macOS 10.15.x, x < 4, the best OS version to test with is 10.15.3 [1].
Download your product in a way that quarantines it (for example, using Safari).
Disconnect the machine from the network. It might make sense to skip this step. See the discussion below.
Install and use your product as your users would.
If the product is signed, notarised, and stapled correctly, everything should work. If not, you’ll need to investigate what’s making Gatekeeper unhappy, fix that, and then retest. For detailed advice on that topic, see Resolving Trusted Execution Problems.
Run this test on a fresh machine each time. This is necessary because Gatekeeper caches information about your product and it’s not easy to reset that cache. Your best option is to do this testing on a virtual machine (VM). Take a snapshot of the VM before the first test, and then restore to that snapshot when you want to retest.
Also, by using a VM you can disable networking in step 3 without disrupting other work on your machine.
The reason why you should disable networking in step 3 is to test that you’ve correctly stapled the notarised ticket on to your product. If, for some reason, you’re unable to do that stapling, it’s fine to skip step 3. However, be aware that this may cause problems for a user if they try to deploy your product to a Mac that does not have access to the wider Internet. For more background on this, see The Pros and Cons of Stapling.
[1] macOS 10.15.4 fixes a bug that made Gatekeeper unnecessarily strict (r. 57278824), so by testing on 10.15.3 you’re exercising the worst case.
The process described above is by far the best way to test your Gatekeeper compatibility because it accurately tests how your users run your product. However, you can also run a quick, albeit less accurate test, using various command-line tools. The exact process depends on the type of product you’re trying to check:
App — Run syspolicy_check like this:
% syspolicy_check distribution WaffleVarnish.app
This tool was introduced in macOS 14. On older systems, use the older spctl tool. Run it like this:
% spctl -a -t exec -vvv WaffleVarnish.app
Be aware, however, that this check is much less accurate.
Disk image — Run spctl like this:
% spctl -a -t open -vvv --context context:primary-signature WaffleVarnish.dmg
Installer package — Run spctl like this:
% spctl -a -t install -vvv WaffleVarnish.pkg
Other code — Run codesign like this:
% codesign -vvvv -R="notarized" --check-notarization WaffleVarnish.bundle
This command requires macOS 10.15 or later.
Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"
Revision history:
2024-12-05 Added instructions for using syspolicy_check. Made other minor editorial changes.
2023-10-20 Added links to Resolving Trusted Execution Problems and The Pros and Cons of Stapling. Made other minor editorial changes.
2021-02-26 Fixed the formatting.
2020-04-17 Added the section discussing spctl.
2020-03-25 First version.