ffdhe.h

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#ifndef _IPXE_FFDHE_H
#define _IPXE_FFDHE_H
 
/** @file
 *
 * Finite Field Diffie-Hellman Ephemeral key exchange
 *
 */
 
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
FILE_SECBOOT ( PERMITTED );
 
#include <stddef.h>
#include <byteswap.h>
#include <ipxe/bigint.h>
#include <ipxe/crypto.h>
 
/** A finite field DHE group */
struct ffdhe_group {
        /** Group name */
        const char *name;
        /** Group constant */
        const uint8_t *constant;
        /** Length of raw scalar values */
        size_t len;
        /** Number of elements in scalar values */
        unsigned int size;
        /** Length of (short) exponents */
        size_t explen;
        /** Number of elements in exponent values */
        unsigned int expsize;
        /** Least significant interesting bits of modulus (big-endian) */
        uint32_t lsb32;
};
 
extern int ffdhe_share ( struct exchange_algorithm *exchange,
                         const void *private, void *public );
extern int ffdhe_agree ( struct exchange_algorithm *exchange,
                         const void *private, const void *partner,
                         void *shared );
extern int ffdhe_has_params ( struct exchange_algorithm *exchange,
                              const void *modulus, size_t len,
                              const void *generator, size_t generator_len );
 
/**
 * Check if key exchange algorithm is a finite field DHE group
 *
 * @v exchange          Key exchange algorithm
 * @ret is_ffdhe        Key exchange algorithm is a finite field DHE group
 */
static inline __attribute__ (( always_inline )) int
is_ffdhe ( struct exchange_algorithm *exchange ) {
 
        return ( exchange->share == ffdhe_share );
}
 
/** Define a finite field DHE group */
#define FFDHE_GROUP( _name, _exchange, _constant, _bits, _expbits, _lsb ) \
        static struct ffdhe_group _name ## _group = {                     \
                .name = #_name,                                           \
                .constant = (_constant),                                  \
                .len = ( _bits / 8 ),                                     \
                .size = bigint_required_size ( _bits / 8 ),               \
                .explen = ( ( _expbits + 7 ) / 8 ),                       \
                .expsize = bigint_required_size ( ( _expbits + 7 ) / 8 ), \
                .lsb32 = cpu_to_be32 ( _lsb ),                            \
        };                                                                \
        struct exchange_algorithm _exchange = {                           \
                .name = #_name,                                           \
                .privsize = ( ( _expbits + 7 ) / 8 ),                     \
                .pubsize = ( _bits / 8 ),                                 \
                .sharedsize = ( _bits / 8 ),                              \
                .share = ffdhe_share,                                     \
                .agree = ffdhe_agree,                                     \
                .priv = &_name ## _group,                                 \
        }
 
extern struct exchange_algorithm ffdhe2048_algorithm;
extern struct exchange_algorithm ffdhe3072_algorithm;
extern struct exchange_algorithm ffdhe4096_algorithm;
extern struct exchange_algorithm modp2048_algorithm;
extern struct exchange_algorithm modp3072_algorithm;
extern struct exchange_algorithm modp4096_algorithm;
 
#endif /* _IPXE_FFDHE_H */