Hello Apple Developer Community,
We have been experiencing a persistent notification issue in our application, Flowace, after updating to macOS 15 and above. The issue is affecting our customers but does not occur on our internal test machines.
Issue Description
When users share their screen using Flowace, they receive a repetitive system notification stating:
"Flowace has accessed your screen and system audio XX times in the past 30 days. You can manage this in settings."
This pop-up appears approximately every minute, even though screen sharing and audio access work correctly. This behavior was not present in macOS 15.1.1 or earlier versions and appears to be related to recent privacy enhancements in macOS.
Impact on Users
The frequent pop-ups disrupt workflows, making it difficult for users to focus while using screen-sharing features.
No issues are detected in Privacy & Security Settings, where Flowace has the necessary permissions.
The issue is not reproducible on our internal test machines, making troubleshooting difficult.
Our application is enterprise level and works all the time, so technically this pop only comes after a period of not using the app.
Request for Assistance
We would like to understand:
Has anyone else encountered a similar issue in macOS 15+?
Is there official Apple documentation explaining this new privacy behavior?
Are there any interim fixes to suppress or manage these notifications?
What are Apple's prospects regarding this feature in upcoming macOS updates?
A demonstration of the issue can be seen in the following video: https://youtu.be/njA6mam_Bgw
Any insights, workarounds, or recommendations would be highly appreciated!
Thank you in advance for your help.
Best,
Anuj Patil
Flowace Team
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Hi,
Xcode Instruments shows multiple Points of Interest with the information that the framework is not listed in my Privacy Manifest.
However, I have already included them in the Privacy Manifest under the privacy tracking domains.
I have this problem with every tracking domain i listed in the Privacy Manifest's Privacy Tracking Domains.
Did I make a mistake in my Privacy Manifest declaration?
I would like to confirm about fraud prevention using Device Check when publishing multiple apps.
If the Team ID and Key ID are the same, will the values be shared across all apps with Device Check?
With Device Check, only two keys can be created per developer account, and these two are primarily intended for key renewal in case of a leak, rather than for assigning different keys to each app, correct?
If both 1 and 2 are correct, does that mean that Device Check should not be used to manage "one-time-only rewards per device" when offering them across multiple apps?
Thank you very much for your confirmation.
I regularly help developers with keychain problems, both here on DevForums and for my Day Job™ in DTS. Many of these problems are caused by a fundamental misunderstanding of how the keychain works. This post is my attempt to explain that. I wrote it primarily so that Future Quinn™ can direct folks here rather than explain everything from scratch (-:
If you have questions or comments about any of this, put them in a new thread and apply the Security tag so that I see it.
Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"
SecItem: Fundamentals
or How I Learned to Stop Worrying and Love the SecItem API
The SecItem API seems very simple. After all, it only has four function calls, how hard can it be? In reality, things are not that easy. Various factors contribute to making this API much trickier than it might seem at first glance.
This post explains the fundamental underpinnings of the keychain. For information about specific issues, see its companion post, SecItem: Pitfalls and Best Practices.
Keychain Documentation
Your basic starting point should be Keychain Items.
If your code runs on the Mac, also read TN3137 On Mac keychain APIs and implementations.
Read the doc comments in <Security/SecItem.h>. In many cases those doc comments contain critical tidbits.
When you read keychain documentation [1] and doc comments, keep in mind that statements specific to iOS typically apply to iPadOS, tvOS, and watchOS as well (r. 102786959). Also, they typically apply to macOS when you target the data protection keychain. Conversely, statements specific to macOS may not apply when you target the data protection keychain.
[1] Except TN3137, which is very clear about this (-:
Caveat Mac Developer
macOS supports two different keychain implementations: the original file-based keychain and the iOS-style data protection keychain.
IMPORTANT If you’re able to use the data protection keychain, do so. It’ll make your life easier. See the Careful With that Shim, Mac Developer section of SecItem: Pitfalls and Best Practices for more about this.
TN3137 On Mac keychain APIs and implementations explains this distinction. It also says:
The file-based keychain is on the road to deprecation.
This is talking about the implementation, not any specific API. The SecItem API can’t be deprecated because it works with both the data protection keychain and the file-based keychain. However, Apple has deprecated many APIs that are specific to the file-based keychain, for example, SecKeychainCreate.
TN3137 also notes that some programs, like launchd daemons, can’t use the file-based keychain. If you’re working on such a program then you don’t have to worry about the deprecation of these file-based keychain APIs. You’re already stuck with the file-based keychain implementation, so using a deprecated file-based keychain API doesn’t make things worse.
The Four Freedoms^H^H^H^H^H^H^H^H Functions
The SecItem API contains just four functions:
SecItemAdd(_:_:)
SecItemCopyMatching(_:_:)
SecItemUpdate(_:_:)
SecItemDelete(_:)
These directly map to standard SQL database operations:
SecItemAdd(_:_:) maps to INSERT.
SecItemCopyMatching(_:_:) maps to SELECT.
SecItemUpdate(_:_:) maps to UPDATE.
SecItemDelete(_:) maps to DELETE.
You can think of each keychain item class (generic password, certificate, and so on) as a separate SQL table within the database. The rows of that table are the individual keychain items for that class and the columns are the attributes of those items.
Note Except for the digital identity class, kSecClassIdentity, where the values are split across the certificate and key tables. See Digital Identities Aren’t Real in SecItem: Pitfalls and Best Practices.
This is not an accident. The data protection keychain is actually implemented as an SQLite database. If you’re curious about its structure, examine it on the Mac by pointing your favourite SQLite inspection tool — for example, the sqlite3 command-line tool — at the keychain database in ~/Library/Keychains/UUU/keychain-2.db, where UUU is a UUID.
WARNING Do not depend on the location and structure of this file. These have changed in the past and are likely to change again in the future. If you embed knowledge of them into a shipping product, it’s likely that your product will have binary compatibility problems at some point in the future. The only reason I’m mentioning them here is because I find it helpful to poke around in the file to get a better understanding of how the API works.
For information about which attributes are supported by each keychain item class — that is, what columns are in each table — see the Note box at the top of Item Attribute Keys and Values. Alternatively, look at the Attribute Key Constants doc comment in <Security/SecItem.h>.
Uniqueness
A critical part of the keychain model is uniqueness. How does the keychain determine if item A is the same as item B? It turns out that this is class dependent. For each keychain item class there is a set of attributes that form the uniqueness constraint for items of that class. That is, if you try to add item A where all of its attributes are the same as item B, the add fails with errSecDuplicateItem. For more information, see the errSecDuplicateItem page. It has lists of attributes that make up this uniqueness constraint, one for each class.
These uniqueness constraints are a major source of confusion, as discussed in the Queries and the Uniqueness Constraints section of SecItem: Pitfalls and Best Practices.
Parameter Blocks Understanding
The SecItem API is a classic ‘parameter block’ API. All of its inputs are dictionaries, and you have to know which properties to set in each dictionary to achieve your desired result. Likewise for when you read properties in output dictionaries.
There are five different property groups:
The item class property, kSecClass, determines the class of item you’re operating on: kSecClassGenericPassword, kSecClassCertificate, and so on.
The item attribute properties, like kSecAttrAccessGroup, map directly to keychain item attributes.
The search properties, like kSecMatchLimit, control how the system runs a query.
The return type properties, like kSecReturnAttributes, determine what values the query returns.
The value type properties, like kSecValueRef perform multiple duties, as explained below.
There are other properties that perform a variety of specific functions. For example, kSecUseDataProtectionKeychain tells macOS to use the data protection keychain instead of the file-based keychain. These properties are hard to describe in general; for the details, see the documentation for each such property.
Inputs
Each of the four SecItem functions take dictionary input parameters of the same type, CFDictionary, but these dictionaries are not the same. Different dictionaries support different property groups:
The first parameter of SecItemAdd(_:_:) is an add dictionary. It supports all property groups except the search properties.
The first parameter of SecItemCopyMatching(_:_:) is a query and return dictionary. It supports all property groups.
The first parameter of SecItemUpdate(_:_:) is a pure query dictionary. It supports all property groups except the return type properties.
Likewise for the only parameter of SecItemDelete(_:).
The second parameter of SecItemUpdate(_:_:) is an update dictionary. It supports the item attribute and value type property groups.
Outputs
Two of the SecItem functions, SecItemAdd(_:_:) and SecItemCopyMatching(_:_:), return values. These output parameters are of type CFTypeRef because the type of value you get back depends on the return type properties you supply in the input dictionary:
If you supply a single return type property, except kSecReturnAttributes, you get back a value appropriate for that return type.
If you supply multiple return type properties or kSecReturnAttributes, you get back a dictionary. This supports the item attribute and value type property groups. To get a non-attribute value from this dictionary, use the value type property that corresponds to its return type property. For example, if you set kSecReturnPersistentRef in the input dictionary, use kSecValuePersistentRef to get the persistent reference from the output dictionary.
In the single item case, the type of value you get back depends on the return type property and the keychain item class:
For kSecReturnData you get back the keychain item’s data. This makes most sense for password items, where the data holds the password. It also works for certificate items, where you get back the DER-encoded certificate. Using this for key items is kinda sketchy. If you want to export a key, called SecKeyCopyExternalRepresentation. Using this for digital identity items is nonsensical.
For kSecReturnRef you get back an object reference. This only works for keychain item classes that have an object representation, namely certificates, keys, and digital identities. You get back a SecCertificate, a SecKey, or a SecIdentity, respectively.
For kSecReturnPersistentRef you get back a data value that holds the persistent reference.
Value Type Subtleties
There are three properties in the value type property group:
kSecValueData
kSecValueRef
kSecValuePersistentRef
Their semantics vary based on the dictionary type.
For kSecValueData:
In an add dictionary, this is the value of the item to add. For example, when adding a generic password item (kSecClassGenericPassword), the value of this key is a Data value containing the password.
This is not supported in a query dictionary.
In an update dictionary, this is the new value for the item.
For kSecValueRef:
In add and query dictionaries, the system infers the class property and attribute properties from the supplied object. For example, if you supply a certificate object (SecCertificate, created using SecCertificateCreateWithData), the system will infer a kSecClass value of kSecClassCertificate and various attribute values, like kSecAttrSerialNumber, from that certificate object.
This is not supported in an update dictionary.
For kSecValuePersistentRef:
For query dictionaries, this uniquely identifies the item to operate on.
This is not supported in add and update dictionaries.
Revision History
2025-05-28 Expanded the Caveat Mac Developer section to cover some subtleties associated with the deprecation of the file-based keychain.
2023-09-12 Fixed various bugs in the revision history. Added a paragraph explaining how to determine which attributes are supported by each keychain item class.
2023-02-22 Made minor editorial changes.
2023-01-28 First posted.
I modified the system.login.screensaver rule in the authorization database to use "authenticate" instead of "use-login-window-ui" to display a custom authentication plugin view when the screensaver starts or the screen locks.
However, I noticed an issue when the "Require Password after Display is Turned Off" setting is set to 5 minutes in lock screen settings:
If I close my Mac’s lid and reopen it within 5 minutes, my authentication plugin view is displayed as expected.
However, the screen is not in a locked state—the desktop remains accessible, and the black background that typically appears behind the lock screen is missing.
This behavior differs from the default lock screen behavior, where the screen remains fully locked, and the desktop is hidden.
Has anyone encountered this issue before? Is there a way to ensure the screen properly locks when using authenticate in the screensaver rule?
I am experiencing an issue with Apple Sign-In on Vision Pro. When I build and run the app from Xcode, everything works fine—after signing in, the app returns to the foreground as expected.
However, when I launch the app directly on Vision Pro (not from Xcode), after completing the sign-in process, the app does not reopen from the background automatically. Instead, it closes, and I have to manually tap the app icon to reopen it.
Has anyone else encountered this issue? Is there a way to ensure the app properly resumes after sign-in without requiring manual intervention?
override func prepareInterface(forPasskeyRegistration registrationRequest: any ASCredentialRequest)
int this function how can i get the "challenge" from user agent, the params "challenge" need to be used in webauthn navigator.credentials.create
I've come across strange behavior with the userID property on the returned credential from a passkey attestation.
When performing a cross-device passkey assertion between iOS and Android by scanning the generated QR code on my iPhone with an Android device the returned credential object contains an empty userID.
This does not happen when performing an on device or cross-device assertion using two iPhones.
Is this expected behavior, or is there something I'm missing here? I couldn't find any more information on this in the documentation.
iOS Version: 26.0.1, Android Version: 13
Topic:
Privacy & Security
SubTopic:
General
Tags:
Passkeys in iCloud Keychain
Authentication Services
Greetings,
We are struggling to implement device binding according to your documentation. We are generation a nonce value in backend like this:
public static String generateNonce(int byteLength) {
byte[] randomBytes = new byte[byteLength];
new SecureRandom().nextBytes(randomBytes);
return Base64.getUrlEncoder().withoutPadding().encodeToString(randomBytes);
}
And our mobile client implement the attestation flow like this:
@implementation AppAttestModule
- (NSData *)sha256FromString:(NSString *)input {
const char *str = [input UTF8String];
unsigned char result[CC_SHA256_DIGEST_LENGTH];
CC_SHA256(str, (CC_LONG)strlen(str), result);
return [NSData dataWithBytes:result length:CC_SHA256_DIGEST_LENGTH];
}
RCT_EXPORT_MODULE();
RCT_EXPORT_METHOD(generateAttestation:(NSString *)nonce
resolver:(RCTPromiseResolveBlock)resolve
rejecter:(RCTPromiseRejectBlock)reject)
{
if (@available(iOS 14.0, *)) {
DCAppAttestService *service = [DCAppAttestService sharedService];
if (![service isSupported]) {
reject(@"not_supported", @"App Attest is not supported on this device.", nil);
return;
}
NSData *nonceData = [self sha256FromString:nonce];
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSString *savedKeyId = [defaults stringForKey:@"AppAttestKeyId"];
NSString *savedAttestation = [defaults stringForKey:@"AppAttestAttestationData"];
void (^resolveWithValues)(NSString *keyId, NSData *assertion, NSString *attestationB64) = ^(NSString *keyId, NSData *assertion, NSString *attestationB64) {
NSString *assertionB64 = [assertion base64EncodedStringWithOptions:0];
resolve(@{
@"nonce": nonce,
@"signature": assertionB64,
@"deviceType": @"IOS",
@"attestationData": attestationB64 ?: @"",
@"keyId": keyId
});
};
void (^handleAssertion)(NSString *keyId, NSString *attestationB64) = ^(NSString *keyId, NSString *attestationB64) {
[service generateAssertion:keyId clientDataHash:nonceData completionHandler:^(NSData *assertion, NSError *assertError) {
if (!assertion) {
reject(@"assertion_error", @"Failed to generate assertion", assertError);
return;
}
resolveWithValues(keyId, assertion, attestationB64);
}];
};
if (savedKeyId && savedAttestation) {
handleAssertion(savedKeyId, savedAttestation);
} else {
[service generateKeyWithCompletionHandler:^(NSString *keyId, NSError *keyError) {
if (!keyId) {
reject(@"keygen_error", @"Failed to generate key", keyError);
return;
}
[service attestKey:keyId clientDataHash:nonceData completionHandler:^(NSData *attestation, NSError *attestError) {
if (!attestation) {
reject(@"attestation_error", @"Failed to generate attestation", attestError);
return;
}
NSString *attestationB64 = [attestation base64EncodedStringWithOptions:0];
[defaults setObject:keyId forKey:@"AppAttestKeyId"];
[defaults setObject:attestationB64 forKey:@"AppAttestAttestationData"];
[defaults synchronize];
handleAssertion(keyId, attestationB64);
}];
}];
}
} else {
reject(@"ios_version", @"App Attest requires iOS 14+", nil);
}
}
@end
For validation we are extracting the nonce from the certificate like this:
private static byte[] extractNonceFromAttestationCert(X509Certificate certificate) throws IOException {
byte[] extensionValue = certificate.getExtensionValue("1.2.840.113635.100.8.2");
if (Objects.isNull(extensionValue)) {
throw new IllegalArgumentException("Apple App Attest nonce extension not found in certificate.");
}
ASN1Primitive extensionPrimitive = ASN1Primitive.fromByteArray(extensionValue);
ASN1OctetString outerOctet = ASN1OctetString.getInstance(extensionPrimitive);
ASN1Sequence sequence = (ASN1Sequence) ASN1Primitive.fromByteArray(outerOctet.getOctets());
ASN1TaggedObject taggedObject = (ASN1TaggedObject) sequence.getObjectAt(0);
ASN1OctetString nonceOctet = ASN1OctetString.getInstance(taggedObject.getObject());
return nonceOctet.getOctets();
}
And for the verification we are using this method:
private OptionalMethodResult<Void> verifyNonce(X509Certificate certificate, String expectedNonce, byte[] authData) {
byte[] expectedNonceHash;
try {
byte[] nonceBytes = MessageDigest.getInstance("SHA-256").digest(expectedNonce.getBytes());
byte[] combined = ByteBuffer.allocate(authData.length + nonceBytes.length).put(authData).put(nonceBytes).array();
expectedNonceHash = MessageDigest.getInstance("SHA-256").digest(combined);
} catch (NoSuchAlgorithmException e) {
log.error("Error while validations iOS attestation: {}", e.getMessage(), e);
return OptionalMethodResult.ofError(deviceBindError.getChallengeNotMatchedError());
}
byte[] actualNonceFromCert;
try {
actualNonceFromCert = extractNonceFromAttestationCert(certificate);
} catch (Exception e) {
log.error("Error while extracting nonce from certificate: {}", e.getMessage(), e);
return OptionalMethodResult.ofError(deviceBindError.getChallengeNotMatchedError());
}
if (!Arrays.equals(expectedNonceHash, actualNonceFromCert)) {
return OptionalMethodResult.ofError(deviceBindError.getChallengeNotMatchedError());
}
return OptionalMethodResult.empty();
}
But the values did not matched. What are we doing wrong here?
Thanks.
Is there a way (in code or on the OAuth2 server/webpage) to specify the desired window size when using ASWebAuthenticationSession on macOS? I haven't found anything, and we would prefer the window to be narrower. For one of our users, the window is even stretched to the full screen width which looks completely broken…
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!
this is my monitor image that shows DeviceCheck api responding very slowly.
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 all,
I’m building a macOS-native C++ trading bot, compiled via Xcode. It sends REST API requests to a crypto exchange (Bitvavo) that require HMAC-SHA256 signatures using a pre-sign string (timestamp + method + path + body) and an API secret.
Here’s the issue:
• The exact same pre-sign string and API secret produce valid responses when signed using Python (hmac.new(secret, msg, hashlib.sha256)),
• But when I generate the HMAC signature using C++ (HMAC(EVP_sha256, ...) via OpenSSL), the exchange returns an invalid signature error.
Environment:
• Xcode 15.3 / macOS 14.x
• OpenSSL installed via Homebrew
• HMAC test vectors match Python’s output for basic strings (so HMAC lib seems correct)
Yet when using the real API keys and dynamic timestamped messages, something differs enough to break verification — possibly due to UTF-8 encoding, memory alignment, or newline handling differences in the Xcode C++ runtime?
Has anyone experienced subtle differences between Python and C++ HMAC-SHA256 behavior when compiled in Xcode?
I’ve published a GitHub repo for reproducibility:
🔗 https://github.com/vanBaardewijk/bitvavo-cpp-signature-test
Thanks in advance for any suggestions or insights.
Sascha
Quinn, you've often suggested that to validate the other side of an XPC connection, we should use the audit token. But that's not available from the XPC object, whereas the PID is. So everyone uses the PID.
While looking for something completely unrelated, I found this in the SecCode.h file
OSStatus SecCodeCreateWithXPCMessage(xpc_object_t message, SecCSFlags flags,
SecCodeRef * __nonnull CF_RETURNS_RETAINED target);
Would this be the preferred way to do this now? At least from 11.0 and up.
Like I said, I was looking for something completely unrelated and found this and don't have the cycles right now to try it. But it looks promising from the description and I wanted to check in with you about it in case you can say yes or no before I get a chance to test it.
Thanks
I have a sandboxed Mac app which I can grant access to a folder using an NSOpenPanel. Once it’s been granted access it can enumerate the contents of the folder just fine. If I rename the folder while the app is open and then make the app enumerate the folder’s contents again, though, it seems to have lost access.
What’s the recommended way to have an app’s sandbox “track” files as they’re moved around the filesystem? (NSDocument handles this for you, from what I can tell.) I’ve managed to hack something together with a combination of Dispatch sources and security-scoped bookmarks, but it feels like there must be an easier solution …
I need to open p12 file from other iOS applications to import private key to my application. My app is set up to be able to open nay file with following plist
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>CFBundleDocumentTypes</key>
<array>
<dict>
<key>CFBundleTypeName</key>
<string>Files</string>
<key>LSHandlerRank</key>
<string>Default</string>
<key>LSItemContentTypes</key>
<array>
<string>public.item</string>
<string>public.data</string>
<string>public.content</string>
</array>
</dict>
</array>
</dict>
</plist>
But my don't appear in share dialog from Files or Mail app for example. There are however other third party apps that can accept this file. Some of them use Share extension which I don't have, but some of them don't have it as far as I can understand. At least they don't present any UI and open apps directly.
Also I've tried to specify com.rsa.pkcs-12 UTI directly but it didn't help. Also noticed that *.crt files have similar behaviour.
Am I missing something about this specific file type?
Hi everyone,
I’m working an Objective-C lib that performs Keychain operations, such as generating cryptographic keys and signing data. The lib will be used by my team in a Java program for macOS via JNI.
When working with the traditional file-based Keychain (i.e., without access control flags), everything works smoothly, no issues at all.
However, as soon as I try to generate a key using access control flags SecAccessControlCreateWithFlags, the Data Protection Keychain returns error -34018 (errSecMissingEntitlement) during SecKeyCreateRandomKey. This behavior is expected.
To address this, I attempted to codesign my native dynamic library (.dylib) with an entitlement plist specifying various combinations of:
keychain-access-groups
com.apple.security.keychain
etc.
with:
My Apple Development certificate
Developer ID Application certificate
Apple Distribution certificate
None of these combinations made a difference, the error persists.
I’d love to clarify:
Is it supported to access Data Protection Keychain / Secure Enclave Keys in this type of use case?
If so, what exact entitlements does macOS expect when calling SecKeyCreateRandomKey from a native library?
I’d really appreciate any guidance or clarification. Thanks in advance!
Best regards,
Neil
I work for Brave, a browser with ~80M users. We want to introduce a new system for automatic updates called Omaha 4 (O4). It's the same system that powers automatic updates in Chrome.
O4 runs as a separate application on users' systems. For Chrome, this works as follows: An app called GoogleUpdater.app regularly checks for updates in the background. When a new version is found, then GoogleUpdater.app installs it into Chrome's installation directory /Applications/Google Chrome.app.
But consider what this means: A separate application, GoogleUpdater.app, is able to modify Google Chrome.app.
This is especially surprising because, for example, the built-in Terminal.app is not able to modify Google Chrome.app. Here's how you can check this for yourself:
(Re-)install Chrome with its DMG installer.
Run the following command in Terminal: mkdir /Applications/Google\ Chrome.app/test. This works.
Undo the command: rm -rf /Applications/Google\ Chrome.app/test
Start Chrome and close it again.
mkdir /Applications/Google\ Chrome.app/test now fails with "Operation not permitted".
(These steps assume that Terminal does not have Full Disk Access and System Integrity Protection is enabled.)
In other words, once Chrome was started at least once, another application (Terminal in this case) is no longer allowed to modify it.
But at the same time, GoogleUpdater.app is able to modify Chrome. It regularly applies updates to the browser. For each update, this process begins with an mkdir call similarly to the one shown above.
How is this possible? What is it in macOS that lets GoogleUpdater.app modify Chrome, but not another app such as Terminal? Note that Terminal is not sandboxed.
I've checked that it's not related to codesigning or notarization issues. In our case, the main application (Brave) and the updater (BraveUpdater) are signed and notarized with the same certificate and have equivalent requirements, entitlements and provisioning profiles as Chrome and GoogleUpdater.
The error that shows up in the Console for the disallowed mkdir call is:
kernel (Sandbox)
System Policy: mkdir(8917) deny(1) file-write-create /Applications/Google Chrome.app/foo
(It's a similar error when BraveUpdater tries to install a new version into /Applications/Brave Browser.app.)
The error goes away when I disable System Integrity Protection. But of course, we cannot ask users to do that.
Any help would be greatly appreciated.
I am working on adding RFC4217 Secure FTP with TLS by extending Mike Gleason's classic libncftp client library. I refactored the code to include an FTP channel abstraction with FTP channel abstraction types for TCP, TLS, and TCP with Opportunistic TLS types. The first implementation of those included BSD sockets that libncftp has always supported with the clear TCP channel type.
I first embarked on extending the sockets implementation by adding TCP, TLS, and TCP with Opportunistic TLS channel abstraction types against the new, modern Network.framework C-based APIs, including using the “tricky” framer technique to employ a TCP with Opportunistic TLS FTP channel abstraction type to support explicit FTPS as specified by RFC4217 where you have to connect first in the clear with TCP, request AUTH TLS, and then start TLS after receiving positive confirmation. That all worked great.
Unfortunately, at the end of that effort, I discovered that many modern FTPS server implementations (vsftpd, pure-ftpd, proftpd) mandate TLS session reuse / resumption across the control and data channels, specifying the identical session ID and cipher suites across the control and data channels. Since Network.framework lacked a necessary and equivalent to the Secure Transport SSLSetPeerID, I retrenched and rewrote the necessary TLS and TCP with Opportunistic TLS FTP channel abstraction types using the now-deprecated Secure Transport APIs atop the Network.framework-based TCP clear FTP channel type abstraction I had just written.
Using the canonical test server I had been using throughout development, test.rebex.net, this Secure Transport solution seemed to work perfectly, working in clear, secure-control-only, and secure-control+data explicit FTPS operation.
I then proceeded to expand testing to include a broad set of Microsoft FTP Service, pure-ftpd, vsftpd, proftpd, and other FTP servers identified on the Internet (a subset from this list: https://gist.github.com/mnjstwins/85ac8348d6faeb32b25908d447943300).
In doing that testing, beyond test.rebex.net, I was unable to identify a single (among hundreds), that successfully work with secure-control+data explicit FTPS operation even though nearly all of them work with secure-control-only explicit FTPS operation.
So, I started regressing my libncftp + Network.framework + Secure Transport implementation against curl 8.7.1 on macOS 14.7.2 “Sonoma":
% which curl; `which curl` --version
/usr/bin/curl
curl 8.7.1 (x86_64-apple-darwin23.0) libcurl/8.7.1 (SecureTransport) LibreSSL/3.3.6 zlib/1.2.12 nghttp2/1.61.0
Release-Date: 2024-03-27
Protocols: dict file ftp ftps gopher gophers http https imap imaps ipfs ipns ldap ldaps mqtt pop3 pop3s rtsp smb smbs smtp smtps telnet tftp
Features: alt-svc AsynchDNS GSS-API HSTS HTTP2 HTTPS-proxy IPv6 Kerberos Largefile libz MultiSSL NTLM SPNEGO SSL threadsafe UnixSockets
I find that curl (also apparently written against Secure Transport) works in almost all of the cases my libncftp does not. This is a representative example:
% ./samples/misc/ncftpgetbytes -d stderr --secure --explicit --secure-both ftps://ftp.sjtu.edu.cn:21/pub/README.NetInstall
which fails in the secure-control+data case with errSSLClosedAbort on the data channel TLS handshake, just after ClientHello, attempts whereas:
% curl -4 --verbose --ftp-pasv --ftp-ssl-reqd ftp://ftp.sjtu.edu.cn:21/pub/README.NetInstall
succeeds.
I took an in-depth look at the implementation of github.com/apple-oss-distributions/curl/ and git/github.com/apple-oss-distributions/Security/ to identify areas where my implementation was, perhaps, deficient relative to curl and its curl/lib/vtls/sectransp.c Secure Transport implementation. As far as I can tell, I am doing everything consistently with what the Apple OSS implementation of curl is doing. The analysis included:
SSLSetALPNProtocols
Not applicable for FTP; only used for HTTP/2 and HTTP/3.
SSLSetCertificate
Should only be relevant when a custom, non-Keychain-based certificate is used.
SSLSetEnabledCiphers
This could be an issue; however, the cipher suite used for the data channel should be the same as that used for the control channel. curl talks about disabling "weak" cipher suites that are known-insecure even though the default suites macOS enables are unlikely to enable them.
SSLSetProtocolVersionEnabled
We do not appear to be getting a protocol version negotiation error, so this seems unlikely, but possible.
SSLSetProtocolVersionMax
We do not appear to be getting a protocol version negotiation error, so this seems unlikely, but possible.
SSLSetProtocolVersionMin
We do not appear to be getting a protocol version negotiation error, so this seems unlikely, but possible.
SSLSetSessionOption( , kSSLSessionOptionFalseStart)
curl does seem to enable this for certain versions of macOS and disables it for others. Possible.
Running curl with the --false-start option does not seem to make a difference.
SSLSetSessionOption( , kSSLSessionOptionSendOneByteRecord)
Corresponds to "*****" which seems defaulted and is related to an SSL security flaw when using CBC-based block encryption ciphers, which is not applicable here.
Based on that, further experiments I attempted included:
Disable use of kSSLSessionOptionBreakOnServerAuth: No impact
Assert use of kSSLSessionOptionFalseStart: No impact
Assert use of kSSLSessionOptionSendOneByteRecord: No impact
Use SSLSetProtocolVersionMin and SSLSetProtocolVersionMax in various combinations: No impact
Use SSLSetProtocolVersionEnabled in various combinations: No impact
Forcibly set a single cipher suite (TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, known to work with a given server): No impact
Employ a SetDefaultCipherSuites function similar to what curl does (filtering out “weak” cipher suites): No impact
Notably, I can never coax a similar set of cipher suites that macOS curl does with that technique. In fact, it publishes ciphers that aren’t even in <Security/CipherSuite.h> nor referenced by github.com/apple-oss-distributions/curl/curl/lib/vtls/sectransp.c.
Assert use of kSSLSessionOptionAllowRenegotiation: No impact
Assert use of kSSLSessionOptionEnableSessionTickets: No impact
Looking at Wireshark, my ClientHello includes status_request, signed_certificate_timestamp, and extended_master_secret extensions whereas macOS curl's never do--same Secure Transport APIs. None of the above API experiments seem to influence the inclusion / exclusion of those three ClientHello additions.
Any suggestions are welcomed that might shine a light on what native curl has access to that allows it to work with ST for these FTP secure-control+data use cases.