Programmatically read root CA certificates in iOS

Question

The following code reads out the root certificates in macOS.

I just wonder what are the equivalent code in iOS?

https://github.com/HaxeFoundation/hxcpp/blob/7bd5ff3/src/hx/libs/ssl/SSL.cpp#L455-L491

CFMutableDictionaryRef search;
CFArrayRef result;
SecKeychainRef keychain;
SecCertificateRef item;
CFDataRef dat;
sslcert *chain = NULL;

// Load keychain
if( SecKeychainOpen("/System/Library/Keychains/SystemRootCertificates.keychain",&keychain) != errSecSuccess )
    return null();

// Search for certificates
search = CFDictionaryCreateMutable( NULL, 0, NULL, NULL );
CFDictionarySetValue( search, kSecClass, kSecClassCertificate );
CFDictionarySetValue( search, kSecMatchLimit, kSecMatchLimitAll );
CFDictionarySetValue( search, kSecReturnRef, kCFBooleanTrue );
CFDictionarySetValue( search, kSecMatchSearchList, CFArrayCreate(NULL, (const void **)&keychain, 1, NULL) );
if( SecItemCopyMatching( search, (CFTypeRef *)&result ) == errSecSuccess ){
    CFIndex n = CFArrayGetCount( result );
    for( CFIndex i = 0; i < n; i++ ){
        item = (SecCertificateRef)CFArrayGetValueAtIndex( result, i );

        // Get certificate in DER format
        dat = SecCertificateCopyData( item );
        if( dat ){
            if( chain == NULL ){
                chain = new sslcert();
                chain->create( NULL );
            }
            mbedtls_x509_crt_parse_der( chain->c, (unsigned char *)CFDataGetBytePtr(dat), CFDataGetLength(dat) );
            CFRelease( dat );
        }
    }
}
CFRelease(keychain);
if( chain != NULL )
    return chain;

Answer 1

I'm afraid it won't be possible to do an equivalent in iOS given the app ecosystem is sandboxed.

Without knowing your purposes, the usual approach for tackling this is downloading the apple root certificate from apple.com/certificateauthority and then storing it in your app for reading it.

Take a look this article for inspiring you as well.

PS: It might be possible to do this in an iOS device if it's jailbroken.

Answer 2

The function SecTrustCopyAnchorCertificates from Security.framework that lets you retrieve root certificates stored in the system is only available on macOS. Curiously, it is one of the few functions (from set of related functions) that is not available on iOS. Deliberate, who knows?