/*      $OpenBSD: via.c,v 1.50 2021/10/24 10:26:22 patrick Exp $        */
/*      $NetBSD: machdep.c,v 1.214 1996/11/10 03:16:17 thorpej Exp $    */

/*-
 * Copyright (c) 2003 Jason Wright
 * Copyright (c) 2003, 2004 Theo de Raadt
 * All rights reserved.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/timeout.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>

#ifdef CRYPTO
#include <crypto/cryptodev.h>
#include <crypto/aes.h>
#include <crypto/xform.h>
#include <crypto/cryptosoft.h>
#endif

#include <machine/cpufunc.h>
#include <machine/specialreg.h>

void    viac3_rnd(void *);


#ifdef CRYPTO

struct viac3_session {
        u_int32_t       ses_ekey[4 * (AES_MAXROUNDS + 1) + 4];  /* 128 bit aligned */
        u_int32_t       ses_dkey[4 * (AES_MAXROUNDS + 1) + 4];  /* 128 bit aligned */
        u_int32_t       ses_cw0;
        struct swcr_data *swd;
        int             ses_klen;
        int             ses_used;
};

struct viac3_softc {
        u_int32_t               op_cw[4];               /* 128 bit aligned */
        u_int8_t                op_iv[16];              /* 128 bit aligned */
        void                    *op_buf;

        /* normal softc stuff */
        int32_t                 sc_cid;
        int                     sc_nsessions;
        struct viac3_session    *sc_sessions;
};

#define VIAC3_SESSION(sid)              ((sid) & 0x0fffffff)
#define VIAC3_SID(crd,ses)              (((crd) << 28) | ((ses) & 0x0fffffff))

static struct viac3_softc *vc3_sc;
extern int i386_has_xcrypt;

extern const u_int8_t hmac_ipad_buffer[HMAC_MAX_BLOCK_LEN];
extern const u_int8_t hmac_opad_buffer[HMAC_MAX_BLOCK_LEN];

void viac3_crypto_setup(void);
int viac3_crypto_newsession(u_int32_t *, struct cryptoini *);
int viac3_crypto_process(struct cryptop *);
int viac3_crypto_swauth(struct cryptop *, struct cryptodesc *,
    struct swcr_data *, caddr_t);
int viac3_crypto_encdec(struct cryptop *, struct cryptodesc *,
    struct viac3_session *, struct viac3_softc *, caddr_t);
int viac3_crypto_freesession(u_int64_t);
static __inline void viac3_cbc(void *, void *, void *, void *, int, void *);

void
viac3_crypto_setup(void)
{
        int algs[CRYPTO_ALGORITHM_MAX + 1];

        vc3_sc = malloc(sizeof(*vc3_sc), M_DEVBUF, M_NOWAIT|M_ZERO);
        if (vc3_sc == NULL)
                return;

        bzero(algs, sizeof(algs));
        algs[CRYPTO_AES_CBC] = CRYPTO_ALG_FLAG_SUPPORTED;
        algs[CRYPTO_MD5_HMAC] = CRYPTO_ALG_FLAG_SUPPORTED;
        algs[CRYPTO_SHA1_HMAC] = CRYPTO_ALG_FLAG_SUPPORTED;
        algs[CRYPTO_RIPEMD160_HMAC] = CRYPTO_ALG_FLAG_SUPPORTED;
        algs[CRYPTO_SHA2_256_HMAC] = CRYPTO_ALG_FLAG_SUPPORTED;
        algs[CRYPTO_SHA2_384_HMAC] = CRYPTO_ALG_FLAG_SUPPORTED;
        algs[CRYPTO_SHA2_512_HMAC] = CRYPTO_ALG_FLAG_SUPPORTED;
        algs[CRYPTO_ESN] = CRYPTO_ALG_FLAG_SUPPORTED;

        vc3_sc->sc_cid = crypto_get_driverid(0);
        if (vc3_sc->sc_cid < 0) {
                free(vc3_sc, M_DEVBUF, sizeof(*vc3_sc));
                vc3_sc = NULL;
                return;
        }

        crypto_register(vc3_sc->sc_cid, algs, viac3_crypto_newsession,
            viac3_crypto_freesession, viac3_crypto_process);
}

int
viac3_crypto_newsession(u_int32_t *sidp, struct cryptoini *cri)
{
        struct cryptoini        *c;
        struct viac3_softc      *sc = vc3_sc;
        struct viac3_session    *ses = NULL;
        const struct auth_hash  *axf;
        struct swcr_data        *swd;
        int                      sesn, i, cw0;

        if (sc == NULL || sidp == NULL || cri == NULL)
                return (EINVAL);

        if (sc->sc_sessions == NULL) {
                ses = sc->sc_sessions = malloc(sizeof(*ses), M_DEVBUF,
                    M_NOWAIT);
                if (ses == NULL)
                        return (ENOMEM);
                sesn = 0;
                sc->sc_nsessions = 1;
        } else {
                for (sesn = 0; sesn < sc->sc_nsessions; sesn++) {
                        if (sc->sc_sessions[sesn].ses_used == 0) {
                                ses = &sc->sc_sessions[sesn];
                                break;
                        }
                }

                if (ses == NULL) {
                        sesn = sc->sc_nsessions;
                        ses = mallocarray(sesn + 1, sizeof(*ses), M_DEVBUF,
                            M_NOWAIT);
                        if (ses == NULL)
                                return (ENOMEM);
                        memcpy(ses, sc->sc_sessions, sesn * sizeof(*ses));
                        explicit_bzero(sc->sc_sessions, sesn * sizeof(*ses));
                        free(sc->sc_sessions, M_DEVBUF, sesn * sizeof(*ses));
                        sc->sc_sessions = ses;
                        ses = &sc->sc_sessions[sesn];
                        sc->sc_nsessions++;
                }
        }

        bzero(ses, sizeof(*ses));
        ses->ses_used = 1;

        for (c = cri; c != NULL; c = c->cri_next) {
                switch (c->cri_alg) {
                case CRYPTO_AES_CBC:
                        switch (c->cri_klen) {
                        case 128:
                                cw0 = C3_CRYPT_CWLO_KEY128;
                                break;
                        case 192:
                                cw0 = C3_CRYPT_CWLO_KEY192;
                                break;
                        case 256:
                                cw0 = C3_CRYPT_CWLO_KEY256;
                                break;
                        default:
                                viac3_crypto_freesession(sesn);
                                return (EINVAL);
                        }
                        cw0 |= C3_CRYPT_CWLO_ALG_AES | C3_CRYPT_CWLO_KEYGEN_SW |
                            C3_CRYPT_CWLO_NORMAL;

                        ses->ses_klen = c->cri_klen;
                        ses->ses_cw0 = cw0;

                        /* Build expanded keys for both directions */
                        AES_KeySetup_Encrypt(ses->ses_ekey, c->cri_key,
                            c->cri_klen / 8);
                        AES_KeySetup_Decrypt(ses->ses_dkey, c->cri_key,
                            c->cri_klen / 8);
                        for (i = 0; i < 4 * (AES_MAXROUNDS + 1); i++) {
                                ses->ses_ekey[i] = ntohl(ses->ses_ekey[i]);
                                ses->ses_dkey[i] = ntohl(ses->ses_dkey[i]);
                        }

                        break;

                case CRYPTO_MD5_HMAC:
                        axf = &auth_hash_hmac_md5_96;
                        goto authcommon;
                case CRYPTO_SHA1_HMAC:
                        axf = &auth_hash_hmac_sha1_96;
                        goto authcommon;
                case CRYPTO_RIPEMD160_HMAC:
                        axf = &auth_hash_hmac_ripemd_160_96;
                        goto authcommon;
                case CRYPTO_SHA2_256_HMAC:
                        axf = &auth_hash_hmac_sha2_256_128;
                        goto authcommon;
                case CRYPTO_SHA2_384_HMAC:
                        axf = &auth_hash_hmac_sha2_384_192;
                        goto authcommon;
                case CRYPTO_SHA2_512_HMAC:
                        axf = &auth_hash_hmac_sha2_512_256;
                authcommon:
                        swd = malloc(sizeof(struct swcr_data), M_CRYPTO_DATA,
                            M_NOWAIT|M_ZERO);
                        if (swd == NULL) {
                                viac3_crypto_freesession(sesn);
                                return (ENOMEM);
                        }
                        ses->swd = swd;

                        swd->sw_ictx = malloc(axf->ctxsize, M_CRYPTO_DATA,
                            M_NOWAIT);
                        if (swd->sw_ictx == NULL) {
                                viac3_crypto_freesession(sesn);
                                return (ENOMEM);
                        }

                        swd->sw_octx = malloc(axf->ctxsize, M_CRYPTO_DATA,
                            M_NOWAIT);
                        if (swd->sw_octx == NULL) {
                                viac3_crypto_freesession(sesn);
                                return (ENOMEM);
                        }

                        for (i = 0; i < c->cri_klen / 8; i++)
                                c->cri_key[i] ^= HMAC_IPAD_VAL;

                        axf->Init(swd->sw_ictx);
                        axf->Update(swd->sw_ictx, c->cri_key, c->cri_klen / 8);
                        axf->Update(swd->sw_ictx, hmac_ipad_buffer,
                            axf->blocksize - (c->cri_klen / 8));

                        for (i = 0; i < c->cri_klen / 8; i++)
                                c->cri_key[i] ^= (HMAC_IPAD_VAL ^
                                    HMAC_OPAD_VAL);

                        axf->Init(swd->sw_octx);
                        axf->Update(swd->sw_octx, c->cri_key, c->cri_klen / 8);
                        axf->Update(swd->sw_octx, hmac_opad_buffer,
                            axf->blocksize - (c->cri_klen / 8));

                        for (i = 0; i < c->cri_klen / 8; i++)
                                c->cri_key[i] ^= HMAC_OPAD_VAL;

                        swd->sw_axf = axf;
                        swd->sw_alg = c->cri_alg;

                        break;
                case CRYPTO_ESN:
                        /* nothing to do */
                        break;
                default:
                        viac3_crypto_freesession(sesn);
                        return (EINVAL);
                }
        }

        *sidp = VIAC3_SID(0, sesn);
        return (0);
}

int
viac3_crypto_freesession(u_int64_t tid)
{
        struct viac3_softc *sc = vc3_sc;
        struct swcr_data *swd;
        const struct auth_hash *axf;
        int sesn;
        u_int32_t sid = ((u_int32_t)tid) & 0xffffffff;

        if (sc == NULL)
                return (EINVAL);
        sesn = VIAC3_SESSION(sid);
        if (sesn >= sc->sc_nsessions)
                return (EINVAL);

        if (sc->sc_sessions[sesn].swd) {
                swd = sc->sc_sessions[sesn].swd;
                axf = swd->sw_axf;

                if (swd->sw_ictx) {
                        explicit_bzero(swd->sw_ictx, axf->ctxsize);
                        free(swd->sw_ictx, M_CRYPTO_DATA, axf->ctxsize);
                }
                if (swd->sw_octx) {
                        explicit_bzero(swd->sw_octx, axf->ctxsize);
                        free(swd->sw_octx, M_CRYPTO_DATA, axf->ctxsize);
                }
                free(swd, M_CRYPTO_DATA, sizeof(*swd));
        }

        explicit_bzero(&sc->sc_sessions[sesn], sizeof(sc->sc_sessions[sesn]));
        return (0);
}

static __inline void
viac3_cbc(void *cw, void *src, void *dst, void *key, int rep,
    void *iv)
{
        unsigned int creg0;

        creg0 = rcr0();         /* Permit access to SIMD/FPU path */
        lcr0(creg0 & ~(CR0_EM|CR0_TS));

        /* Do the deed */
        __asm volatile("pushfl; popfl");
        __asm volatile("rep xcryptcbc" :
            : "a" (iv), "b" (key), "c" (rep), "d" (cw), "S" (src), "D" (dst)
            : "memory", "cc");

        lcr0(creg0);
}

int
viac3_crypto_swauth(struct cryptop *crp, struct cryptodesc *crd,
    struct swcr_data *sw, caddr_t buf)
{
        int     type;

        if (crp->crp_flags & CRYPTO_F_IMBUF)
                type = CRYPTO_BUF_MBUF;
        else
                type= CRYPTO_BUF_IOV;
                
        return (swcr_authcompute(crp, crd, sw, buf, type));
}

int
viac3_crypto_encdec(struct cryptop *crp, struct cryptodesc *crd,
    struct viac3_session *ses, struct viac3_softc *sc, caddr_t buf)
{
        u_int32_t *key;
        int     err = 0;

        if ((crd->crd_len % 16) != 0)
                return (EINVAL);

        sc->op_buf = malloc(crd->crd_len, M_DEVBUF, M_NOWAIT);
        if (sc->op_buf == NULL)
                return (ENOMEM);

        if (crd->crd_flags & CRD_F_ENCRYPT) {
                sc->op_cw[0] = ses->ses_cw0 | C3_CRYPT_CWLO_ENCRYPT;
                key = ses->ses_ekey;
                if (crd->crd_flags & CRD_F_IV_EXPLICIT)
                        memcpy(sc->op_iv, crd->crd_iv, 16);
                else
                        arc4random_buf(sc->op_iv, 16);

                if ((crd->crd_flags & CRD_F_IV_PRESENT) == 0) {
                        if (crp->crp_flags & CRYPTO_F_IMBUF)
                                err = m_copyback((struct mbuf *)crp->crp_buf,
                                    crd->crd_inject, 16, sc->op_iv, M_NOWAIT);
                        else if (crp->crp_flags & CRYPTO_F_IOV)
                                cuio_copyback((struct uio *)crp->crp_buf,
                                    crd->crd_inject, 16, sc->op_iv);
                        else
                                memcpy(crp->crp_buf + crd->crd_inject,
                                    sc->op_iv, 16);
                        if (err)
                                goto errout;
                }
        } else {
                sc->op_cw[0] = ses->ses_cw0 | C3_CRYPT_CWLO_DECRYPT;
                key = ses->ses_dkey;
                if (crd->crd_flags & CRD_F_IV_EXPLICIT)
                        memcpy(sc->op_iv, crd->crd_iv, 16);
                else {
                        if (crp->crp_flags & CRYPTO_F_IMBUF)
                                m_copydata((struct mbuf *)crp->crp_buf,
                                    crd->crd_inject, 16, sc->op_iv);
                        else if (crp->crp_flags & CRYPTO_F_IOV)
                                cuio_copydata((struct uio *)crp->crp_buf,
                                    crd->crd_inject, 16, sc->op_iv);
                        else
                                memcpy(sc->op_iv,
                                    crp->crp_buf + crd->crd_inject, 16);
                }
        }

        if (crp->crp_flags & CRYPTO_F_IMBUF)
                m_copydata((struct mbuf *)crp->crp_buf,
                    crd->crd_skip, crd->crd_len, sc->op_buf);
        else if (crp->crp_flags & CRYPTO_F_IOV)
                cuio_copydata((struct uio *)crp->crp_buf,
                    crd->crd_skip, crd->crd_len, sc->op_buf);
        else
                memcpy(sc->op_buf, crp->crp_buf + crd->crd_skip, crd->crd_len);

        sc->op_cw[1] = sc->op_cw[2] = sc->op_cw[3] = 0;
        viac3_cbc(&sc->op_cw, sc->op_buf, sc->op_buf, key,
            crd->crd_len / 16, sc->op_iv);

        if (crp->crp_flags & CRYPTO_F_IMBUF)
                err = m_copyback((struct mbuf *)crp->crp_buf,
                    crd->crd_skip, crd->crd_len, sc->op_buf, M_NOWAIT);
        else if (crp->crp_flags & CRYPTO_F_IOV)
                cuio_copyback((struct uio *)crp->crp_buf,
                    crd->crd_skip, crd->crd_len, sc->op_buf);
        else
                memcpy(crp->crp_buf + crd->crd_skip, sc->op_buf,
                    crd->crd_len);

 errout:
        if (sc->op_buf != NULL) {
                explicit_bzero(sc->op_buf, crd->crd_len);
                free(sc->op_buf, M_DEVBUF, crd->crd_len);
                sc->op_buf = NULL;
        }

        return (err);
}

int
viac3_crypto_process(struct cryptop *crp)
{
        struct viac3_softc *sc = vc3_sc;
        struct viac3_session *ses;
        struct cryptodesc *crd;
        int sesn, err = 0;
        int i;

        KASSERT(crp->crp_ndesc >= 1);

        sesn = VIAC3_SESSION(crp->crp_sid);
        if (sesn >= sc->sc_nsessions) {
                err = EINVAL;
                goto out;
        }
        ses = &sc->sc_sessions[sesn];
        if (ses->ses_used == 0) {
                err = EINVAL;
                goto out;
        }

        for (i = 0; i < crp->crp_ndesc; i++) {
                crd = &crp->crp_desc[i];
                switch (crd->crd_alg) {
                case CRYPTO_AES_CBC:
                        if ((err = viac3_crypto_encdec(crp, crd, ses, sc,
                            crp->crp_buf)) != 0)
                                goto out;
                        break;

                case CRYPTO_MD5_HMAC:
                case CRYPTO_SHA1_HMAC:
                case CRYPTO_RIPEMD160_HMAC:
                case CRYPTO_SHA2_256_HMAC:
                case CRYPTO_SHA2_384_HMAC:
                case CRYPTO_SHA2_512_HMAC:
                        if ((err = viac3_crypto_swauth(crp, crd, ses->swd,
                            crp->crp_buf)) != 0)
                                goto out;
                        break;

                default:
                        err = EINVAL;
                        goto out;
                }
        }
out:
        return (err);
}

#endif /* CRYPTO */

/*
 * Note, the VIA C3 Nehemiah provides 4 internal 8-byte buffers, which
 * store random data, and can be accessed a lot quicker than waiting
 * for new data to be generated.  As we are using every 8th bit only
 * due to whitening. Since the RNG generates in excess of 21KB/s at
 * its worst, collecting 64 bytes worth of entropy should not affect
 * things significantly.
 *
 * Note, due to some weirdness in the RNG, we need at least 7 bytes
 * extra on the end of our buffer.  Also, there is an outside chance
 * that the VIA RNG can "wedge", as the generated bit-rate is variable.
 * We could do all sorts of startup testing and things, but
 * frankly, I don't really see the point.  If the RNG wedges, then the
 * chances of you having a defective CPU are very high.  Let it wedge.
 *
 * Adding to the whole confusion, in order to access the RNG, we need
 * to have FXSR support enabled, and the correct FPU enable bits must
 * be there to enable the FPU in kernel.  It would be nice if all this
 * mumbo-jumbo was not needed in order to use the RNG.  Oh well, life
 * does go on...
 */
#define VIAC3_RNG_BUFSIZ        16              /* 32bit words */
struct timeout viac3_rnd_tmo;
int viac3_rnd_present;

void
viac3_rnd(void *v)
{
        struct timeout *tmo = v;
        unsigned int *p, i, rv, creg0, len = VIAC3_RNG_BUFSIZ;
        static int buffer[VIAC3_RNG_BUFSIZ + 2];        /* XXX why + 2? */
#ifdef MULTIPROCESSOR
        int s = splipi();
#endif

        creg0 = rcr0();         /* Permit access to SIMD/FPU path */
        lcr0(creg0 & ~(CR0_EM|CR0_TS));

        /*
         * Here we collect the random data from the VIA C3 RNG.  We make
         * sure that we turn on maximum whitening (%edx[0,1] == "11"), so
         * that we get the best random data possible.
         */
        __asm volatile("rep xstorerng"
            : "=a" (rv) : "d" (3), "D" (buffer), "c" (len*sizeof(int))
            : "memory", "cc");

        lcr0(creg0);

#ifdef MULTIPROCESSOR
        splx(s);
#endif

        for (i = 0, p = buffer; i < VIAC3_RNG_BUFSIZ; i++, p++)
                enqueue_randomness(*p);

        timeout_add_msec(tmo, 10);
}