Re: Enable the FIPS mode in the library level

["Dr. Matthias St. Pierre" <Matthias.St.Pierre@xxxxxxxxx>]

On 05.03.2018 10:46, Alan Dean wrote:

Question 1: Is it even feasible to make the FIPS mode always enabled for the whole OpenSSL library (i.e. for both libcrypto and libssl), so that most the applications which dynamically linked to libcrypto and libssl will be automatically use OpenSSL FIPS mode without the need of changes to add the FIPS_mode_set invocation (with some exception such as OpenSSH which may still need some fixes). (Assuming from certification's perspective we are ok if we may these changes)

Question 2: If the above idea is feasible, where in the OpenSSL library will be the best entry to invoke FIPS_mode_set API, so that we can make the whole OpenSSL library always in FIPS mode? Any potebtial issues for this solution?

Any suggestions will be greatly appreciated.

The optimal location for inserting the FIPS_mode_set(1) call is probably OPENSSL_init()  (openssl-1.0.2/crypto/o_fips.c), see code snippet below.

void OPENSSL_init(void)
{
    static int done = 0;
    if (done)
        return;
    done = 1;
#ifdef OPENSSL_FIPS
    FIPS_set_locking_callbacks(CRYPTO_lock, CRYPTO_add_lock);
# ifndef OPENSSL_NO_DEPRECATED
    FIPS_crypto_set_id_callback(CRYPTO_thread_id);
# endif
    FIPS_set_error_callbacks(ERR_put_error, ERR_add_error_vdata);
    FIPS_set_malloc_callbacks(CRYPTO_malloc, CRYPTO_free);
    RAND_init_fips();
    FIPS_mode_set(1);   <<< ENABLE FIPS MODE HERE <<<
#endif
#if 0
    fprintf(stderr, "Called OPENSSL_init\n");
#endif


However, I am sceptical whether this approach will be accepted, because there are (at least) two potential problems:

* Normally, it is mandatory to check the result of FIPS_mode_set() or FIPS_mode() to ensure that the FIPS initialization succeeded. However, an application which is not FIPS-aware won't check the result.
* It can happen that applications which have their own configuration and enable/disable FIPS mode explicitely, call FIPS_mode_set(0) afterwards.


HTH,
Matthias

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