Open Radar

 
Summary:
You can insert a key into the keychain with a kSecAttrApplicationLabel which is documented to take a string, but when you read it back, you get a CFDataRef.

Steps to Reproduce:
Insert a key, e.g.:

SecItemAdd({
    atag = <50424b44 46322473 68613124 2fca980b c1ed8c4d 2a7eb032 2e313f75 f44d8b56>;
    class = keys;
    kcls = 2;
    klbl = blah123;
    pdmn = cku;
    perm = 1;
    sync = 0;
    unwp = 1;
    "v_Data" = <4acc7099 28a7c9b5 106020cb e7966c72>;
    wrap = 1;
})

Then read it back using SecItemCopyMatching and a matching class, keyclass, tag, and label.

Expected Results:
kSecAttrApplicationLabel is documented to be a CFString (docs say: "Application label attribute key. The corresponding value is of type CFStringRef and contains a label for this item."), so I expect it to be a CFString.

Actual Results:
It is actually a CFData:

After insert, readback = (
        {
        agrp = "34YW5XSRB7.com.omnigroup.TestApp.Debug";
        atag = <50424b44 46322473 68613124 2fca980b c1ed8c4d 2a7eb032 2e313f75 f44d8b56>;
        bsiz = 0;
        cdat = "2016-02-04 02:52:14 +0000";
        class = keys;
        crtr = 0;
        edat = "2001-01-01 00:00:00 +0000";
        esiz = 0;
        kcls = 2;
        klbl = <626c6168 313233>;
        mdat = "2016-02-04 02:52:14 +0000";
        pdmn = cku;
        perm = 1;
        sdat = "2001-01-01 00:00:00 +0000";
        sync = 0;
        tomb = 0;
        type = 0;
        unwp = 1;
        "v_Data" = <4acc7099 28a7c9b5 106020cb e7966c72>;
        wrap = 1;
    }
)

Version:
iOS 9.2 (13C75)

Notes:
Same behavior on the device and in the simulator.

It actually makes more sense for this to be a CFData than a CFString, if it is used to look up keypairs by key hash; in which case perhaps this is a documentation bug.

See also RADAR 19804744.


Configuration:
iPhone 6