Feedback ticket ID: FB21797397
Summary
When using posix_spawn() with posix_spawnattr_set_uid_np() to spawn a child process with a different UID, the eslogger incorrectly reports a setuid event as an event originating from the parent process instead of the child process.
Steps to Reproduce
Create a binary that do the following:
Configure posix_spawnattr_t that set the process UIDs to some other user ID (I'll use 501 in this example).
Uses posix_spawn() to spawn a child process
Run eslogger with the event types setuid, fork, exec
Execute the binary as root process using sudo or from root owned shell
Terminate the launched eslogger
Observe the process field in the setuid event
Expected behavior
The eslogger will report events indicating a process launch and uid changes so the child process is set to 501. i.e.:
fork
setuid - Done by child process
exec
Actual behavior
The process field in the setuid event is reported as the parent process (that called posix_spawn) - indicating UID change to the parent process.
Attachments
I'm attaching source code for a small project with a 2 binaries:
I'll add the source code for the project at the end of the file + attach filtered eslogger JSONs
One that runs the descirbed posix_spawn flow
One that produces the exact same sequence of events by doing different operation and reaching a different process state:
Parent calls fork()
Parent process calls setuid(501)
Child process calls exec()
Why this is problematic
Both binaries in my attachment do different operations, achieving different process state (1 is parent with UID=0 and child with UID=501 while the other is parent UID=501 and child UID=0), but report the same sequence of events.
Code
#include <cstdio>
#include <spawn.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>
#include <string.h>
// environ contains the current environment variables
extern char **environ;
extern "C" {
int posix_spawnattr_set_uid_np(posix_spawnattr_t *attr, uid_t uid);
int posix_spawnattr_set_gid_np(posix_spawnattr_t *attr, gid_t gid);
}
int main() {
pid_t pid;
int status;
posix_spawnattr_t attr;
// 1. Define the executable path and arguments
const char *path = "/bin/sleep";
char *const argv[] = {(char *)"sleep", (char *)"1", NULL};
// 2. Initialize spawn attributes
if ((status = posix_spawnattr_init(&attr)) != 0) {
fprintf(stderr, "posix_spawnattr_init: %s\n", strerror(status));
return EXIT_FAILURE;
}
// 3. Set the UID for the child process (e.g., UID 501)
// Note: Parent must be root to change to a different user
uid_t target_uid = 501;
if ((status = posix_spawnattr_set_uid_np(&attr, target_uid)) != 0) {
fprintf(stderr, "posix_spawnattr_set_uid_np: %s\n", strerror(status));
posix_spawnattr_destroy(&attr);
return EXIT_FAILURE;
}
// 4. Spawn the process
printf("Spawning /bin/sleep 1 as UID %d...\n", target_uid);
status = posix_spawn(&pid, path, NULL, &attr, argv, environ);
if (status == 0) {
printf("Successfully spawned child with PID: %d\n", pid);
// Wait for the child to finish (will take 63 seconds)
if (waitpid(pid, &status, 0) != -1) {
printf("Child process exited with status %d\n", WEXITSTATUS(status));
} else {
perror("waitpid");
}
} else {
fprintf(stderr, "posix_spawn: %s\n", strerror(status));
}
// 5. Clean up
posix_spawnattr_destroy(&attr);
return (status == 0) ? EXIT_SUCCESS : EXIT_FAILURE;
}
#include <cstdio>
#include <cstdlib>
#include <unistd.h>
#include <sys/wait.h>
#include <errno.h>
#include <string.h>
// This program demonstrates fork + setuid + exec behavior for ES framework bug report
// 1. Parent forks
// 2. Parent does setuid(501)
// 3. Child waits with sleep syscall
// 4. Child performs exec
int main() {
printf("Parent PID: %d, UID: %d, EUID: %d\n", getpid(), getuid(), geteuid());
pid_t pid = fork();
if (pid < 0) {
// Fork failed
perror("fork");
return EXIT_FAILURE;
}
if (pid == 0) {
// Child process
printf("Child PID: %d, UID: %d, EUID: %d\n", getpid(), getuid(), geteuid());
// Child waits for a bit with sleep syscall
printf("Child sleeping for 2 seconds...\n");
sleep(2);
// Child performs exec
printf("Child executing child_exec...\n");
// Get the path to child_exec (same directory as this executable)
char *const argv[] = {(char *)"/bin/sleep", (char *)"2", NULL};
// Try to exec child_exec from current directory first
execv("/bin/sleep", argv);
// If exec fails
perror("execv");
return EXIT_FAILURE;
} else {
// Parent process
printf("Parent forked child with PID: %d\n", pid);
// Parent does setuid(501)
printf("Parent calling setuid(501)...\n");
if (setuid(501) != 0) {
perror("setuid");
// Continue anyway to observe behavior
}
printf("Parent after setuid - UID: %d, EUID: %d\n", getuid(), geteuid());
// Wait for child to finish
int status;
if (waitpid(pid, &status, 0) != -1) {
if (WIFEXITED(status)) {
printf("Child exited with status %d\n", WEXITSTATUS(status));
} else if (WIFSIGNALED(status)) {
printf("Child killed by signal %d\n", WTERMSIG(status));
}
} else {
perror("waitpid");
}
}
return EXIT_SUCCESS;
}
posix_spawn.json
fork_exec.json
General
RSS for tagPrioritize user privacy and data security in your app. Discuss best practices for data handling, user consent, and security measures to protect user information.
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Hi! We are developing an authentication plugin for macOS that integrates with the system's authentication flow. The plugin is designed to prompt the user for approval via a push notification in our app before allowing access. The plugin is added as the first mechanism in the authenticate rule, followed by the default builtin:authenticate as a fallback.
When the system requests authentication (e.g., during screen unlock), our plugin successfully displays the custom UI and sends a push notification to the user's device. However, I've encountered the following issue:
If the user does not approve the push notification within ~30 seconds, the system resets the screen lock (expected behavior).
If the user approves the push notification within approximately 30 seconds but doesn’t start entering their password before the timeout expires, the system still resets the screen lock before they can enter their password, effectively canceling the session.
What I've Tried:
Attempted to imitate mouse movement after the push button was clicked to keep the session active.
Created a display sleep prevention assertion using IOKit to prevent the screen from turning off.
Used the caffeinate command to keep the display and system awake.
Tried setting the result as allow for the authorization request and passing an empty password to prevent the display from turning off.
I also checked the system logs when this issue occurred and found the following messages:
___loginwindow: -[LWScreenLock (Private) askForPasswordSecAgent] | localUser = >timeout
loginwindow: -[LWScreenLock handleUnlockResult:] _block_invoke | ERROR: Unexpected _lockRequestedBy of:7 sleeping screen
loginwindow: SleepDisplay | enter
powerd: Process (loginwindow) is requesting display idle___
These messages suggest that the loginwindow process encounters a timeout condition, followed by the display entering sleep mode. Despite my attempts to prevent this behavior, the screen lock still resets prematurely.
Questions:
Is there a documented (or undocumented) system timeout for the entire authentication flow during screen unlock that I cannot override?
Are there any strategies for pausing or extending the authentication timeout to allow for complex authentication flows like push notifications?
Any guidance or insights would be greatly appreciated. Thank you!
I have been trying to find a way to be able to sign some data with private key of an identity in login keychain without raising any prompts.
I am able to do this with system keychain (obviously with correct permissions and checks) but not with login keychain. It always ends up asking user for their login password.
Here is how the code looks, roughly,
NSDictionary *query = @{
(__bridge id)kSecClass: (__bridge id)kSecClassIdentity,
(__bridge id)kSecReturnRef: @YES,
(__bridge id)kSecMatchLimit: (__bridge id)kSecMatchLimitAll
};
CFTypeRef result = NULL;
OSStatus status = SecItemCopyMatching((__bridge CFDictionaryRef)query, (CFTypeRef *)&amp;result);
NSArray *identities = ( NSArray *)result;
SecIdentityRef identity = NULL;
for (id _ident in identities) {
// pick one as required
}
SecKeyRef privateKey = NULL;
OSStatus status = SecIdentityCopyPrivateKey(identity, &amp;privateKey);
NSData *strData = [string dataUsingEncoding:NSUTF8StringEncoding];
unsigned char hash[CC_SHA256_DIGEST_LENGTH];
CC_SHA256(strData.bytes, (CC_LONG)strData.length, hash);
NSData *digestData = [NSData dataWithBytes:hash length:CC_SHA256_DIGEST_LENGTH];
CFErrorRef cfError = NULL;
NSData *signature = (__bridge_transfer NSData *)SecKeyCreateSignature(privateKey,
kSecKeyAlgorithmRSASignatureDigestPKCS1v15SHA256,
(__bridge CFDataRef)digestData,
&amp;cfError);
Above code raises these system logs in console
default 08:44:52.781024+0000 securityd client is valid, proceeding
default 08:44:52.781172+0000 securityd code requirement check failed (-67050), client is not Apple-signed
default 08:44:52.781233+0000 securityd displaying keychain prompt for /Applications/Demo.app(81692)
If the key is in login keychain, is there any way to do SecKeyCreateSignature without raising prompts? What does client is not Apple-signed mean?
PS: Identities are pre-installed either manually or via some device management solution, the application is not installing them.
Hi,
I am using CryptoKit in my app. I am getting an error sometimes with some users. I log the description to Firebase but I am not sure what is it exactly about.
CryptoKit.CryptoKitError error 2
CryptoKit.CryptoKitError error 3
I receive both of these errors. I also save debug prints to a log file and let users share them with me. Logs are line-by-line encrypted but after getting these errors in the app also decryption of log files doesn't work and it throws these errors too.
I couldn't reproduce the same error by myself, and I can't reach the user's logs so I am a little blind about what triggers this.
It would be helpful to understand what these errors mean.
Thanks
The Core Problem
After Users sign out from the App, the app isn’t properly retrieving the user on second sign in. Instead, it’s treating the user as “Unknown” and saving a new entry in CloudKit and locally. Is there a tutorial aside from 'Juice' that is recent and up to date?
Is there any way for an iOS app to get a log of all Airdrop transfers originating in all apps on the iOS device e.g. from the last week?
Topic:
Privacy & Security
SubTopic:
General
Binary code is associated with the NSUserTrackingUsageDescription deleted at present, but in the revised App privacy will contain NSUserTrackingUsageDescription, I feel very confused, don't know should shouldn't solve.
Can you please give me a hand with importing certificates under MacOS?
I want to connect to Wi-Fi with 802.1X authentication (EAP-TLS) using a certificate that my homebrew application imported into my data protection keychain, but the imported certificate does not show up and I cannot select the certificate.
It also does not show up in the Keychain Access app.
One method I have tried is to import it into the data protection keychain by using the SecItemAdd function and setting kSecUseDataProtectionKeychain to true, but it does not work.
Is there a better way to do this?
ID:
for id in identities {
let identityParams: [String: Any] = [
kSecValueRef as String: id,
kSecReturnPersistentRef as String: true,
kSecUseDataProtectionKeychain as String: true
]
let addIdentityStatus = SecItemAdd(identityParams as CFDictionary, nil)
if addIdentityStatus == errSecSuccess {
print("Successfully added the ID.: \(addIdentityStatus)")
} else {
print("Failed to add the ID.: \(addIdentityStatus)")
}
}
Certificate:
for cert in certificates {
let certParams: [String: Any] = [
kSecValueRef as String: cert,
kSecReturnPersistentRef as String: true,
kSecUseDataProtectionKeychain as String: true
]
let addCertStatus = SecItemAdd(certParams as CFDictionary, nil)
if addCertStatus == errSecSuccess {
print("Successfully added the certificate.: (\(addCertStatus))")
} else {
print("Failed to add the certificate.: (\(addCertStatus))")
}
}
Private key:
for privateKey in keys {
let keyTag = UUID().uuidString.data(using: .utf8)!
let keyParams: [String: Any] = [
kSecAttrApplicationTag as String: keyTag,
kSecValueRef as String: privateKey,
kSecReturnPersistentRef as String: true,
kSecUseDataProtectionKeychain as String: true
]
let addKeyStatus = SecItemAdd(keyParams as CFDictionary, nil)
if addKeyStatus == errSecSuccess {
print("Successfully added the private key.: \(addKeyStatus)")
} else {
print("Failed to add the private key.: \(addKeyStatus)")
}
}
Our background monitoring application uses a Unix executable that requests Screen Recording permission via CGRequestScreenCaptureAccess(). This worked correctly in macOS Tahoe 26.0.1, but broke in 26.1.
Issue:
After calling CGRequestScreenCaptureAccess() in macOS Tahoe 26.1:
System dialog appears and opens System Settings
Our executable does NOT appear in the Screen Recording list
Manually adding via "+" button grants permission internally, but the executable still doesn't show in the UI
Users cannot verify or revoke permissions
Background:
Unix executable runs as a background process (not from Terminal)
Uses Accessibility APIs to retrieve window titles
Same issue occurs with Full Disk Access permissions
Environment:
macOS Tahoe 26.1 (worked in 26.0.1)
Background process (not launched from Terminal)
Questions:
Is this a bug or intentional design change in 26.1?
What's the recommended approach for background executables to properly register with TCC?
Are there specific requirements (Info.plist, etc.) needed?
This significantly impacts user experience as they cannot manage permissions through the UI.
Any guidance would be greatly appreciated. Thank you
Hello,
I’m storing some values in the Keychain with the attribute ‘ksecattraccessibleafterfirstunlockthisdeviceonly’ (https://developer.apple.com/documentation/security/ksecattraccessibleafterfirstunlockthisdeviceonly).
When I migrate user data between iPhones via iCloud, this behaves as expected and the keys are not preserved.
However, when I migrate using a direct connection between two devices, the keys are preserved, which seems to contradict the attribute’s intent.
Is this a known behavior, and if so, is there a workaround?
Topic:
Privacy & Security
SubTopic:
General
Hi Apple Team and Community,
We encountered a sudden and widespread failure related to the App Attest service on Friday, July 25, starting at around 9:22 AM UTC.
After an extended investigation, our network engineers noted that the size of the attestation objects received from the attestKey call grew in size notably starting at that time. As a result, our firewall began blocking the requests from our app made to our servers with the Base64-encoded attestation objects in the payload, as these requests began triggering our firewall's max request length rule.
Could Apple engineers please confirm whether there was any change rolled out by Apple at or around that time that would cause the attestation object size to increase?
Can anyone else confirm seeing this?
Any insights from Apple or others would be appreciated to ensure continued stability.
Thanks!
Issue: Plain Executables Do Not Appear Under “Screen & System Audio Recording” on macOS 26.1 (Tahoe)
Summary
I am investigating a change in macOS 26.1 (Tahoe) where plain (non-bundled) executables that request screen recording access no longer appear under:
System Settings → Privacy & Security → Screen & System Audio Recording
This behavior differs from macOS Sequoia, where these executables did appear in the list and could be managed through the UI. Tahoe still prompts for permission and still allows the executable to capture the screen once permission is granted, but the executable never shows up in the UI list. This breaks user expectations and removes UI-based permission management.
To confirm the behavior, I created a small reproduction project with both:
a plain executable, and
an identical executable packaged inside an .app bundle.
Only the bundled version appears in System Settings.
Observed Behaviour
1. Plain Executable (from my reproduction project)
When running a plain executable that captures the screen:
macOS displays the normal screen-recording permission prompt.
Before granting permission: screenshots show only the desktop background.
After granting permission: screenshots capture the full display.
The executable does not appear under “Screen & System Audio Recording”.
Even when permission is granted manually (e.g., dragging the executable into the pane), the executable still does not appear, which prevents the user from modifying or revoking the permission through the UI.
If the executable is launched from inside another app (e.g., VS Code, Terminal), the parent app appears in the list instead, not the executable itself.
2. Bundled App Version (from the reproduction project)
I packaged the same code into a simple .app bundle (ScreenCaptureApp.app).
When running the app:
The same permission prompt appears.
Pre-permission screenshots show the desktop background.
Post-permission screenshots capture the full display.
The app does appear under “Screen & System Audio Recording”.
This bundle uses the same underlying executable — the only difference is packaging.
Hypothesis
macOS 26.1 (Tahoe) appears to require app bundles for an item to be shown in the Screen Recording privacy UI.
Plain executables:
still request and receive permission,
still function correctly after permission is granted,
but do not appear in the System Settings list.
This may be an intentional change, undocumented behavior, or a regression.
Reproduction Project
The reproduction project includes:
screen_capture.go A simple Go program that captures screenshots in a loop.
screen_capture_executable Plain executable built from the Go source.
ScreenCaptureApp.app/ App bundle containing the same executable.
build.sh Builds both the plain executable and the app bundle.
Permission reset and TCC testing scripts.
The project demonstrates the behavior consistently.
Steps to Reproduce
Plain Executable
Build:
./build.sh
Reset screen capture permissions:
sudo tccutil reset ScreenCapture
Run:
./screen_capture_executable
Before granting: screenshots show desktop only.
Grant permission when prompted.
After granting: full screenshots.
Executable does not appear in “Screen & System Audio Recording”.
Bundled App
Build (if not already built):
./build.sh
Reset permissions (optional):
sudo tccutil reset ScreenCapture
Run:
open ScreenCaptureApp.app
Before granting: screenshots show desktop.
After granting: full screenshots.
App bundle appears in the System Settings list.
Additional Check
I also tested launching the plain executable as a child process of another executable, similar to how some software architectures work.
Result:
Permission prompt appears
Permission can be granted
Executable still does not appear in the UI, even though TCC tracks it internally → consistent with the plain-executable behaviour.
This reinforces that only app bundles are listed.
Questions for Apple
Is the removal of plain executables from “Screen & System Audio Recording” an intentional change in macOS Tahoe?
If so, does Apple now require all screen-recording capable binaries to be packaged as .app bundles for the UI to display them?
Is there a supported method for making a plain executable (launched by a parent process) appear in the list?
If this is not intentional, what is the recommended path for reporting this as a regression?
Files
Unfortunately, I have discovered the zip file that contains my reproduction project can't be directly uploaded here.
Here is a Google Drive link instead: https://drive.google.com/file/d/1sXsr3Q0g6_UzlOIL54P5wbS7yBkpMJ7A/view?usp=sharing
Thank you for taking the time to review this. Any insight into whether this change is intentional or a regression would be very helpful.
WebAuthn Level 3 § 6.3.2 Step 2 states the authenticator must :
Check if at least one of the specified combinations of PublicKeyCredentialType and cryptographic parameters in credTypesAndPubKeyAlgs is supported. If not, return an error code equivalent to "NotSupportedError" and terminate the operation.
On my iPhone 15 Pro Max running iOS 18.5, Safari + Passwords does not exhibit this behavior; instead an error is not reported and an ES256 credential is created when an RP passes a non-empty sequence that does not contain {"type":"public-key","alg":-7} (e.g., [{"type":"public-key","alg":-8}]).
When I use Chromium 138.0.7204.92 on my laptop running Arch Linux in conjunction with the Passwords app (connected via the "hybrid" protocol), a credential is not created and instead an error is reported per the spec.
Has anyone here encountered this? It's driving me crazy.
It appears on launch.
App Sandbox is enabled.
The proper entitlement is selected (com.apple.security.files.user-selected.read-write)
I believe this is causing an issue with app functionality for users on different machines.
There is zero documentation across the internet on this problem.
I am on macOS 26 beta. This error appears in both Xcode and Xcode-beta.
Please help!
Thank you,
Logan
I am developing a macOS application (targeting macOS 13 and later) that is non-sandboxed and needs to install and trust a root certificate by adding it to the System keychain programmatically.
I’m fine with prompting the user for admin privileges or password, if needed.
So far, I have attempted to execute the following command programmatically from both:
A user-level process
A root-level process
sudo security add-trusted-cert -d -r trustRoot -k /Library/Keychains/System.keychain /path/to/cert.pem
While the certificate does get installed, it does not appear as trusted in the Keychain Access app.
One more point:
The app is not distributed via MDM.
App will be distributed out side the app store.
Questions:
What is the correct way to programmatically install and trust a root certificate in the System keychain?
Does this require additional entitlements, signing, or profile configurations?
Is it possible outside of MDM management?
Any guidance or working samples would be greatly appreciated.
Having trouble decrypting a string using an encryption key and an IV.
var key: String
var iv: String
func decryptData(_ encryptedText: String) -> String?
{
if let textData = Data(base64Encoded: iv + encryptedText) {
do {
let sealedBox = try AES.GCM.SealedBox(combined: textData)
let key = SymmetricKey(data: key.data(using: .utf8)!)
let decryptedData = try AES.GCM.open(sealedBox, using: key)
return String(data: decryptedData, encoding: .utf8)
} catch {
print("Decryption failed: \(error)")
return nil
}
}
return nil
}
Proper coding choices aside (I'm just trying anything at this point,) the main problem is opening the SealedBox. If I go to an online decryption site, I can paste in my encrypted text, the encryption key, and the IV as plain text and I can encrypt and decrypt just fine.
But I can't seem to get the right combo in my Swift code. I don't have a "tag" even though I'm using the combined option. How can I make this work when all I will be receiving is the encrypted text, the encryption key, and the IV. (the encryption key is 256 bits)
Try an AES site with a key of 32 digits and an IV of 16 digits and text of your choice. Use the encrypted version of the text and then the key and IV in my code and you'll see the problem. I can make the SealedBox but I can't open it to get the decrypted data. So I'm not combining the right things the right way. Anyone notice the problem?
Topic:
Privacy & Security
SubTopic:
General
Hello, I am currently researching to develop an application where I want to apply the MacOS updates without the password prompt shown to the users.
I did some research on this and understand that an MDM solution can apply these patches without user intervention.
Are there any other ways we can achieve this? Any leads are much appreciated.
Hello,
I'm an application developer related to Apple system extensions. I developed an endpoint security system extension that can run normally before the 14.x system. However, after I upgraded to 15.x, I found that when I uninstalled and reinstalled my system extension, although the system extension was installed successfully, a system warning box would pop up when I clicked enable in the Settings, indicating a failure.
I conducted the following test. I reinstalled a brand-new MAC 15.x system. When I installed my applications, the system extensions could be installed successfully and enabled normally. However, when I uninstalled and reinstalled, my system extension couldn't be enabled properly and a system warning popped up as well. I tried disabling SIP and enabling System Extension Developers, but it still didn't work.
When the system warning box pops up, I can see some error log information through the console application, including an error related to
Failed to authorize right 'com.apple.system-extensions.admin' by client '/System/Library/ExtensionKit/Extensions/SettingsSystemExtensionController.appex' [2256] for authorization created by '/System/Library/ExtensionKit/Extensions/SettingsSystemExtensionController.appex' [2256] (3,0) (-60005) (engine 179)
as shown in the screenshot.
The same problem, mentioned in Cannot approve some extensions in MacOS Sequoia , but there is no solution
I am developing a daemon-based product that needs a cryptographic, non-spoofable proof of machine identity so a remote management server can grant permissions based on the physical machine.
I was thinking to create a signing key in the Secure Enclave and use a certificate signed by that key as the machine identity. The problem is that the Secure Enclave key I can create is only accessible from user context, while my product runs as a system daemon and must not rely on user processes or launchAgents.
Could you please advise on the recommended Apple-supported approaches for this use case ?
Specifically, Is there a supported way for a system daemon to generate and use an unremovable Secure Enclave key during phases like the pre-logon, that doesn't have non user context (only the my application which created this key/certificate will have permission to use/delete it)
If Secure Enclave access from a daemon is not supported, what Apple-recommended alternatives exist for providing a hardware-backed machine identity for system daemons?
I'd rather avoid using system keychain, as its contents may be removed or used by root privileged users.
The ideal solution would be that each Apple product, would come out with a non removable signing certificate, that represent the machine itself (lets say that the cetificate name use to represent the machine ID), and can be validated by verify that the root signer is "Apple Root CA"
I am not very well versed in this area, so I would appreciate some guidance on what should be enabled or disabled. My app is an AppKit app. I have read the documentation and watched the video, but I find it hard to understand.
When I added the Enhanced Security capability in Xcode, the following options were enabled automatically:
Memory Safety
Enable Enhanced Security Typed Allocator
Runtime Protections
Enable Additional Runtime Platform Restrictions
Authenticate Pointers
Enable Read-only Platform Memory
The following options were disabled by default:
Memory Safety
Enable Hardware Memory Tagging
Memory Tag Pure Data
Prevent Receiving Tagged Memory
Enable Soft Mode for Memory Tagging
Should I enable these options? Is there anything I should consider disabling?