diff options
Diffstat (limited to 'src/crypto/rbg.c')
| -rw-r--r-- | src/crypto/rbg.c | 43 |
1 files changed, 39 insertions, 4 deletions
diff --git a/src/crypto/rbg.c b/src/crypto/rbg.c index 4b45b3474..5e1c25f53 100644 --- a/src/crypto/rbg.c +++ b/src/crypto/rbg.c @@ -75,6 +75,9 @@ static int rbg_startup ( void ) { int len; int rc; + /* Record that startup has been attempted (even if unsuccessful) */ + rbg.started = 1; + /* Try to obtain system UUID for use as personalisation * string, in accordance with ANS X9.82 Part 3-2007 Section * 8.5.2. If no UUID is available, proceed without a @@ -98,6 +101,33 @@ static int rbg_startup ( void ) { } /** + * Generate bits using RBG + * + * @v additional Additional input + * @v additional_len Length of additional input + * @v prediction_resist Prediction resistance is required + * @v data Output buffer + * @v len Length of output buffer + * @ret rc Return status code + * + * This is the RBG_Generate function defined in ANS X9.82 Part 4 + * (April 2011 Draft) Section 9.1.2.2. + */ +int rbg_generate ( const void *additional, size_t additional_len, + int prediction_resist, void *data, size_t len ) { + + /* Attempt startup, if not already attempted */ + if ( ! rbg.started ) + rbg_startup(); + + /* Generate bits. The DRBG will itself return an error if it + * is not valid (e.g. due to an instantiation failure). + */ + return drbg_generate ( &rbg.state, additional, additional_len, + prediction_resist, data, len ); +} + +/** * Shut down RBG * */ @@ -105,16 +135,21 @@ static void rbg_shutdown ( void ) { /* Uninstantiate DRBG */ drbg_uninstantiate ( &rbg.state ); + + /* Clear startup attempted flag */ + rbg.started = 0; } /** RBG startup function */ static void rbg_startup_fn ( void ) { - /* Start up RBG. There is no way to report an error at this - * stage, but a failed startup will result in an invalid DRBG - * that refuses to generate bits. + /* Start up RBG (if not already started on demand). There is + * no way to report an error at this stage, but a failed + * startup will result in an invalid DRBG that refuses to + * generate bits. */ - rbg_startup(); + if ( ! rbg.started ) + rbg_startup(); } /** RBG shutdown function */ |