IMSCryptoUtils.m plaintext memory leaking?

[olavandrade]

Running clang on SecureFoundation found a possible memory leak?

SecureFoundation/IMSCryptoUtils.m:303:5: Potential leak of memory pointed to by 'plaintext'
SecureFoundation/IMSCryptoUtils.m:260:7: Assuming 'ciphertext' is not equal to nil
SecureFoundation/IMSCryptoUtils.m:260:26: Assuming 'key' is not equal to nil
SecureFoundation/IMSCryptoUtils.m:278:21: Memory is allocated
SecureFoundation/IMSCryptoUtils.m:279:7: Assuming 'plaintext' is not equal to null
SecureFoundation/IMSCryptoUtils.m:290:7: Assuming 'status' is not equal to kCCSuccess
SecureFoundation/IMSCryptoUtils.m:303:5: Potential leak of memory pointed to by 'plaintext'