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)
	FILE_SECBOOT (PERMITTED)
void	hmac_key (struct digest_algorithm *digest, void *ctx, const void *secret, size_t len, void *key)
	Construct HMAC reduced key.
void	hmac_init_key (struct digest_algorithm *digest, void *ctx, const void *key)
	Initialise HMAC from reduced key.
void	hmac_init (struct digest_algorithm *digest, void *ctx, const void *secret, size_t len)
	Initialise HMAC.
void	hmac_final (struct digest_algorithm *digest, void *ctx, void *hmac)
	Finalise HMAC.

Detailed Description

Keyed-Hashing for Message Authentication.

Definition in file hmac.c.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

FILE_SECBOOT()

FILE_SECBOOT

(

PERMITTED

)

hmac_key()

void hmac_key	(	struct digest_algorithm *	digest,
		void *	ctx,
		const void *	secret,
		size_t	len,
		void *	key )

Construct HMAC reduced key.

Parameters

digest	Digest algorithm to use
ctx	HMAC context
secret	Secret key
len	Length of secret key
key	HMAC reduced key to fill in

Definition at line 59 of file hmac.c.

                                        {
        hmac_context_t ( digest ) *hctx = ctx;
        hmac_key_t ( digest ) *hkey = key;
 
        /* Reduce key (if applicable) and zero-pad to block size */
        memset ( hkey->pad, 0, sizeof ( hkey->pad ) );
        if ( len <= sizeof ( hkey->pad ) ) {
                memcpy ( hkey->pad, secret, len );
        } else {
                digest_init ( digest, hctx->ctx );
                digest_update ( digest, hctx->ctx, secret, len );
                digest_final ( digest, hctx->ctx, hkey->pad );
        }
}

References ctx, digest_final(), digest_init(), digest_update(), hmac_context_t, hmac_key_t, key, len, memcpy(), and memset().

Referenced by hmac_init(), hmac_okx(), and tls_set_kdf_master().

hmac_init_key()

void hmac_init_key	(	struct digest_algorithm *	digest,
		void *	ctx,
		const void *	key )

Initialise HMAC from reduced key.

Parameters

digest	Digest algorithm
ctx	HMAC context
hkey	HMAC key

Definition at line 82 of file hmac.c.

                                       {
        hmac_context_t ( digest ) *hctx = ctx;
        const hmac_key_t ( digest ) *hkey = key;
        unsigned int i;
 
        /* Construct input pad */
        for ( i = 0 ; i < sizeof ( hkey->pad ) ; i++ ) {
                hctx->pad[i] = ( hkey->pad[i] ^ 0x36 );
        }
 
        /* Start inner hash */
        digest_init ( digest, hctx->ctx );
        digest_update ( digest, hctx->ctx, hctx->pad, sizeof ( hctx->pad ) );
}

References ctx, digest_init(), digest_update(), hmac_context_t, hmac_key_t, and key.

Referenced by hmac_init(), hmac_okx(), and tls_p_hash_va().

hmac_init()

void hmac_init	(	struct digest_algorithm *	digest,
		void *	ctx,
		const void *	secret,
		size_t	len )

Initialise HMAC.

Parameters

digest	Digest algorithm to use
ctx	HMAC context
secret	Secret key
len	Length of secret key

Definition at line 106 of file hmac.c.

                                                  {
        hmac_context_t ( digest ) *hctx = ctx;
 
        /* Construct reduced key (in input pad) */
        hmac_key ( digest, hctx->ctx, secret, len, hctx->pad );
 
        /* Initialise HMAC */
        hmac_init_key ( digest, hctx->ctx, hctx->pad );
}

References ctx, hmac_context_t, hmac_init_key(), hmac_key(), and len.

Referenced by ccmp_kie_mic(), hkdf_expand(), hkdf_extract(), 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(), and tls_hmac_init().

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 124 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_final(), digest_init(), digest_update(), digest_algorithm::digestsize, hmac_context_t, and memset().

Referenced by ccmp_kie_mic(), hkdf_expand(), hkdf_extract(), 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().