From c2668b61ea5ac01279929be6be86cc04fd342ab5 Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Mon, 20 Feb 2012 21:24:30 +0000 Subject: [PATCH] [rng] Record validity within DRBG state Treat an empty (zeroed) DRBG as invalid. This ensures that a DRBG that has not yet been instantiated (or that has been uninstantiated) will refuse to attempt to generate random bits. Signed-off-by: Michael Brown --- src/crypto/drbg.c | 17 +++++++++++++---- src/include/ipxe/drbg.h | 2 ++ 2 files changed, 15 insertions(+), 4 deletions(-) diff --git a/src/crypto/drbg.c b/src/crypto/drbg.c index 58e8fa7b..88cf3acd 100644 --- a/src/crypto/drbg.c +++ b/src/crypto/drbg.c @@ -151,6 +151,7 @@ int drbg_instantiate ( struct drbg_state *state, const void *personal, * in-situ.) */ state->reseed_required = 0; + state->valid = 1; /* 12. Return SUCCESS and state_handle. */ return 0; @@ -187,9 +188,13 @@ int drbg_reseed ( struct drbg_state *state, const void *additional, * If state_handle indicates an invalid or empty internal * state, return an ERROR_FLAG. * - * (Nothing to do since the memory holding the internal state - * was passed in by the caller.) + * (Almost nothing to do since the memory holding the internal + * state was passed in by the caller.) */ + if ( ! state->valid ) { + DBGC ( state, "DRBG %p not valid\n", state ); + return -EINVAL; + } /* 2. If prediction_resistance_request is set, and * prediction_resistance_flag is not set, then return an @@ -273,9 +278,13 @@ int drbg_generate ( struct drbg_state *state, const void *additional, * for the instantiation. If state_handle indicates an * invalid or empty internal state, then return an ERROR_FLAG. * - * (Nothing to do since the memory holding the internal state - * was passed in by the caller.) + * (Almost nothing to do since the memory holding the internal + * state was passed in by the caller.) */ + if ( ! state->valid ) { + DBGC ( state, "DRBG %p not valid\n", state ); + return -EINVAL; + } /* 2. If requested_number_of_bits > * max_number_of_bits_per_request, then return an diff --git a/src/include/ipxe/drbg.h b/src/include/ipxe/drbg.h index a09d136d..3cf4584a 100644 --- a/src/include/ipxe/drbg.h +++ b/src/include/ipxe/drbg.h @@ -39,6 +39,8 @@ struct drbg_state { struct hmac_drbg_state internal; /** Reseed required flag */ int reseed_required; + /** State is valid */ + int valid; }; /**