hmac.c File Reference

Keyed-Hashing for Message Authentication. More...

#include <string.h>
#include <assert.h>
#include <ipxe/crypto.h>
#include <ipxe/hmac.h>

Go to the source code of this file.

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
void	hmac_init (struct digest_algorithm *digest, void *ctx, const void *key, size_t key_len)
	Initialise HMAC. More...
void	hmac_final (struct digest_algorithm *digest, void *ctx, void *hmac)
	Finalise HMAC. More...

Detailed Description

Keyed-Hashing for Message Authentication.

Definition in file hmac.c.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

hmac_init()

void hmac_init	(	struct digest_algorithm *	digest,
		void *	ctx,
		const void *	key,
		size_t	key_len
	)

Initialise HMAC.

Parameters

digest	Digest algorithm to use
ctx	HMAC context
key	Key
key_len	Length of key

Definition at line 57 of file hmac.c.

                                  {
        hmac_context_t ( digest ) *hctx = ctx;
        unsigned int i;

        /* Construct input pad */
        memset ( hctx->pad, 0, sizeof ( hctx->pad ) );
        if ( key_len <= sizeof ( hctx->pad ) ) {
                memcpy ( hctx->pad, key, key_len );
        } else {
                digest_init ( digest, hctx->ctx );
                digest_update ( digest, hctx->ctx, key, key_len );
                digest_final ( digest, hctx->ctx, hctx->pad );
        }
        for ( i = 0 ; i < sizeof ( hctx->pad ) ; i++ ) {
                hctx->pad[i] ^= 0x36;
        }

        /* Start inner hash */
        digest_init ( digest, hctx->ctx );
        digest_update ( digest, hctx->ctx, hctx->pad, sizeof ( hctx->pad ) );
}

References ctx, digest, hmac_context_t, key, key_len, memcpy(), and memset().

Referenced by ccmp_kie_mic(), hmac_drbg_update_key(), hmac_drbg_update_value(), hmac_okx(), ntlm_key(), ntlm_response(), pbkdf2_sha1_f(), peerdist_info_passphrase_okx(), peerdist_info_segment_hash(), prf_sha1(), tkip_kie_mic(), tls_hmac_init(), and tls_p_hash_va().

hmac_final()

void hmac_final	(	struct digest_algorithm *	digest,
		void *	ctx,
		void *	hmac
	)

Finalise HMAC.

Parameters

digest	Digest algorithm to use
ctx	HMAC context
hmac	HMAC digest to fill in

Definition at line 87 of file hmac.c.

                                                                           {
        hmac_context_t ( digest ) *hctx = ctx;
        unsigned int i;

        /* Construct output pad from input pad */
        for ( i = 0 ; i < sizeof ( hctx->pad ) ; i++ ) {
                hctx->pad[i] ^= 0x6a;
        }

        /* Finish inner hash */
        digest_final ( digest, hctx->ctx, hmac );

        /* Perform outer hash */
        digest_init ( digest, hctx->ctx );
        digest_update ( digest, hctx->ctx, hctx->pad, sizeof ( hctx->pad ) );
        digest_update ( digest, hctx->ctx, hmac, digest->digestsize );
        digest_final ( digest, hctx->ctx, hmac );

        /* Erase output pad (from which the key may be derivable) */
        memset ( hctx->pad, 0, sizeof ( hctx->pad ) );
}

References ctx, digest, digest_algorithm::digestsize, hmac_context_t, and memset().

Referenced by ccmp_kie_mic(), hmac_drbg_update_key(), hmac_drbg_update_value(), hmac_okx(), ntlm_key(), ntlm_response(), pbkdf2_sha1_f(), peerdist_info_passphrase_okx(), peerdist_info_segment_hash(), prf_sha1(), tkip_kie_mic(), tls_hmac_final(), and tls_p_hash_va().