/*- * Copyright (c) 2005-2008 Pawel Jakub Dawidek * Copyright (c) 2010 Konstantin Belousov * Copyright (c) 2014-2021 The FreeBSD Foundation * Copyright (c) 2017 Conrad Meyer * All rights reserved. * * Portions of this software were developed by John-Mark Gurney * under sponsorship of the FreeBSD Foundation and * Rubicon Communications, LLC (Netgate). * * Portions of this software were developed by Ararat River * Consulting, LLC under sponsorship of the FreeBSD Foundation. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include struct aesni_softc { int32_t cid; bool has_aes; bool has_sha; }; static int aesni_cipher_setup(struct aesni_session *ses, const struct crypto_session_params *csp); static int aesni_cipher_process(struct aesni_session *ses, struct cryptop *crp); static int aesni_cipher_crypt(struct aesni_session *ses, struct cryptop *crp, const struct crypto_session_params *csp); static int aesni_cipher_mac(struct aesni_session *ses, struct cryptop *crp, const struct crypto_session_params *csp); MALLOC_DEFINE(M_AESNI, "aesni_data", "AESNI Data"); static void aesni_identify(driver_t *drv, device_t parent) { /* NB: order 10 is so we get attached after h/w devices */ if (device_find_child(parent, "aesni", -1) == NULL && BUS_ADD_CHILD(parent, 10, "aesni", -1) == 0) panic("aesni: could not attach"); } static void detect_cpu_features(bool *has_aes, bool *has_sha) { *has_aes = ((cpu_feature2 & CPUID2_AESNI) != 0 && (cpu_feature2 & CPUID2_SSE41) != 0); *has_sha = ((cpu_stdext_feature & CPUID_STDEXT_SHA) != 0 && (cpu_feature2 & CPUID2_SSSE3) != 0); } static int aesni_probe(device_t dev) { bool has_aes, has_sha; detect_cpu_features(&has_aes, &has_sha); if (!has_aes && !has_sha) { device_printf(dev, "No AES or SHA support.\n"); return (EINVAL); } else if (has_aes && has_sha) device_set_desc(dev, "AES-CBC,AES-CCM,AES-GCM,AES-ICM,AES-XTS,SHA1,SHA256"); else if (has_aes) device_set_desc(dev, "AES-CBC,AES-CCM,AES-GCM,AES-ICM,AES-XTS"); else device_set_desc(dev, "SHA1,SHA256"); return (0); } static int aesni_attach(device_t dev) { struct aesni_softc *sc; sc = device_get_softc(dev); sc->cid = crypto_get_driverid(dev, sizeof(struct aesni_session), CRYPTOCAP_F_SOFTWARE | CRYPTOCAP_F_SYNC | CRYPTOCAP_F_ACCEL_SOFTWARE); if (sc->cid < 0) { device_printf(dev, "Could not get crypto driver id.\n"); return (ENOMEM); } detect_cpu_features(&sc->has_aes, &sc->has_sha); return (0); } static int aesni_detach(device_t dev) { struct aesni_softc *sc; sc = device_get_softc(dev); crypto_unregister_all(sc->cid); return (0); } static bool aesni_auth_supported(struct aesni_softc *sc, const struct crypto_session_params *csp) { if (!sc->has_sha) return (false); switch (csp->csp_auth_alg) { case CRYPTO_SHA1: case CRYPTO_SHA2_224: case CRYPTO_SHA2_256: case CRYPTO_SHA1_HMAC: case CRYPTO_SHA2_224_HMAC: case CRYPTO_SHA2_256_HMAC: break; default: return (false); } return (true); } static bool aesni_cipher_supported(struct aesni_softc *sc, const struct crypto_session_params *csp) { if (!sc->has_aes) return (false); switch (csp->csp_cipher_alg) { case CRYPTO_AES_CBC: case CRYPTO_AES_ICM: switch (csp->csp_cipher_klen * 8) { case 128: case 192: case 256: break; default: CRYPTDEB("invalid CBC/ICM key length"); return (false); } if (csp->csp_ivlen != AES_BLOCK_LEN) return (false); break; case CRYPTO_AES_XTS: switch (csp->csp_cipher_klen * 8) { case 256: case 512: break; default: CRYPTDEB("invalid XTS key length"); return (false); } if (csp->csp_ivlen != AES_XTS_IV_LEN) return (false); break; default: return (false); } return (true); } #define SUPPORTED_SES (CSP_F_SEPARATE_OUTPUT | CSP_F_SEPARATE_AAD | CSP_F_ESN) static int aesni_probesession(device_t dev, const struct crypto_session_params *csp) { struct aesni_softc *sc; sc = device_get_softc(dev); if ((csp->csp_flags & ~(SUPPORTED_SES)) != 0) return (EINVAL); switch (csp->csp_mode) { case CSP_MODE_DIGEST: if (!aesni_auth_supported(sc, csp)) return (EINVAL); break; case CSP_MODE_CIPHER: if (!aesni_cipher_supported(sc, csp)) return (EINVAL); break; case CSP_MODE_AEAD: switch (csp->csp_cipher_alg) { case CRYPTO_AES_NIST_GCM_16: switch (csp->csp_cipher_klen * 8) { case 128: case 192: case 256: break; default: CRYPTDEB("invalid GCM key length"); return (EINVAL); } if (csp->csp_auth_mlen != 0 && csp->csp_auth_mlen != GMAC_DIGEST_LEN) return (EINVAL); if (!sc->has_aes) return (EINVAL); break; case CRYPTO_AES_CCM_16: switch (csp->csp_cipher_klen * 8) { case 128: case 192: case 256: break; default: CRYPTDEB("invalid CCM key length"); return (EINVAL); } if (!sc->has_aes) return (EINVAL); break; default: return (EINVAL); } break; case CSP_MODE_ETA: if (!aesni_auth_supported(sc, csp) || !aesni_cipher_supported(sc, csp)) return (EINVAL); break; default: return (EINVAL); } return (CRYPTODEV_PROBE_ACCEL_SOFTWARE); } static int aesni_newsession(device_t dev, crypto_session_t cses, const struct crypto_session_params *csp) { struct aesni_session *ses; int error; ses = crypto_get_driver_session(cses); switch (csp->csp_mode) { case CSP_MODE_DIGEST: case CSP_MODE_CIPHER: case CSP_MODE_AEAD: case CSP_MODE_ETA: break; default: return (EINVAL); } error = aesni_cipher_setup(ses, csp); if (error != 0) { CRYPTDEB("setup failed"); return (error); } return (0); } static int aesni_process(device_t dev, struct cryptop *crp, int hint __unused) { struct aesni_session *ses; int error; ses = crypto_get_driver_session(crp->crp_session); error = aesni_cipher_process(ses, crp); crp->crp_etype = error; crypto_done(crp); return (0); } static uint8_t * aesni_cipher_alloc(struct cryptop *crp, int start, int length, bool *allocated) { uint8_t *addr; addr = crypto_contiguous_subsegment(crp, start, length); if (addr != NULL) { *allocated = false; return (addr); } addr = malloc(length, M_AESNI, M_NOWAIT); if (addr != NULL) { *allocated = true; crypto_copydata(crp, start, length, addr); } else *allocated = false; return (addr); } static device_method_t aesni_methods[] = { DEVMETHOD(device_identify, aesni_identify), DEVMETHOD(device_probe, aesni_probe), DEVMETHOD(device_attach, aesni_attach), DEVMETHOD(device_detach, aesni_detach), DEVMETHOD(cryptodev_probesession, aesni_probesession), DEVMETHOD(cryptodev_newsession, aesni_newsession), DEVMETHOD(cryptodev_process, aesni_process), DEVMETHOD_END }; static driver_t aesni_driver = { "aesni", aesni_methods, sizeof(struct aesni_softc), }; DRIVER_MODULE(aesni, nexus, aesni_driver, 0, 0); MODULE_VERSION(aesni, 1); MODULE_DEPEND(aesni, crypto, 1, 1, 1); static int intel_sha1_update(void *vctx, const void *vdata, u_int datalen) { struct sha1_ctxt *ctx = vctx; const char *data = vdata; size_t gaplen; size_t gapstart; size_t off; size_t copysiz; u_int blocks; off = 0; /* Do any aligned blocks without redundant copying. */ if (datalen >= 64 && ctx->count % 64 == 0) { blocks = datalen / 64; ctx->c.b64[0] += blocks * 64 * 8; intel_sha1_step(ctx->h.b32, data + off, blocks); off += blocks * 64; } while (off < datalen) { gapstart = ctx->count % 64; gaplen = 64 - gapstart; copysiz = (gaplen < datalen - off) ? gaplen : datalen - off; bcopy(&data[off], &ctx->m.b8[gapstart], copysiz); ctx->count += copysiz; ctx->count %= 64; ctx->c.b64[0] += copysiz * 8; if (ctx->count % 64 == 0) intel_sha1_step(ctx->h.b32, (void *)ctx->m.b8, 1); off += copysiz; } return (0); } static void SHA1_Init_fn(void *ctx) { sha1_init(ctx); } static void SHA1_Finalize_fn(void *digest, void *ctx) { sha1_result(ctx, digest); } static int intel_sha256_update(void *vctx, const void *vdata, u_int len) { SHA256_CTX *ctx = vctx; uint64_t bitlen; uint32_t r; u_int blocks; const unsigned char *src = vdata; /* Number of bytes left in the buffer from previous updates */ r = (ctx->count >> 3) & 0x3f; /* Convert the length into a number of bits */ bitlen = len << 3; /* Update number of bits */ ctx->count += bitlen; /* Handle the case where we don't need to perform any transforms */ if (len < 64 - r) { memcpy(&ctx->buf[r], src, len); return (0); } /* Finish the current block */ memcpy(&ctx->buf[r], src, 64 - r); intel_sha256_step(ctx->state, ctx->buf, 1); src += 64 - r; len -= 64 - r; /* Perform complete blocks */ if (len >= 64) { blocks = len / 64; intel_sha256_step(ctx->state, src, blocks); src += blocks * 64; len -= blocks * 64; } /* Copy left over data into buffer */ memcpy(ctx->buf, src, len); return (0); } static void SHA224_Init_fn(void *ctx) { SHA224_Init(ctx); } static void SHA224_Finalize_fn(void *digest, void *ctx) { SHA224_Final(digest, ctx); } static void SHA256_Init_fn(void *ctx) { SHA256_Init(ctx); } static void SHA256_Finalize_fn(void *digest, void *ctx) { SHA256_Final(digest, ctx); } static int aesni_authprepare(struct aesni_session *ses, int klen) { if (klen > SHA1_BLOCK_LEN) return (EINVAL); if ((ses->hmac && klen == 0) || (!ses->hmac && klen != 0)) return (EINVAL); return (0); } static int aesni_cipher_setup(struct aesni_session *ses, const struct crypto_session_params *csp) { uint8_t *schedbase; int error; bool kt; schedbase = (uint8_t *)roundup2((uintptr_t)ses->schedules, AES_SCHED_ALIGN); ses->enc_schedule = schedbase; ses->dec_schedule = schedbase + AES_SCHED_LEN; ses->xts_schedule = schedbase + AES_SCHED_LEN * 2; switch (csp->csp_auth_alg) { case CRYPTO_SHA1_HMAC: ses->hmac = true; /* FALLTHROUGH */ case CRYPTO_SHA1: ses->hash_len = SHA1_HASH_LEN; ses->hash_init = SHA1_Init_fn; ses->hash_update = intel_sha1_update; ses->hash_finalize = SHA1_Finalize_fn; break; case CRYPTO_SHA2_224_HMAC: ses->hmac = true; /* FALLTHROUGH */ case CRYPTO_SHA2_224: ses->hash_len = SHA2_224_HASH_LEN; ses->hash_init = SHA224_Init_fn; ses->hash_update = intel_sha256_update; ses->hash_finalize = SHA224_Finalize_fn; break; case CRYPTO_SHA2_256_HMAC: ses->hmac = true; /* FALLTHROUGH */ case CRYPTO_SHA2_256: ses->hash_len = SHA2_256_HASH_LEN; ses->hash_init = SHA256_Init_fn; ses->hash_update = intel_sha256_update; ses->hash_finalize = SHA256_Finalize_fn; break; } if (ses->hash_len != 0) { if (csp->csp_auth_mlen == 0) ses->mlen = ses->hash_len; else ses->mlen = csp->csp_auth_mlen; error = aesni_authprepare(ses, csp->csp_auth_klen); if (error != 0) return (error); } else if (csp->csp_cipher_alg == CRYPTO_AES_CCM_16) { if (csp->csp_auth_mlen == 0) ses->mlen = AES_CBC_MAC_HASH_LEN; else ses->mlen = csp->csp_auth_mlen; } kt = (csp->csp_cipher_alg == 0); if (!kt) { fpu_kern_enter(curthread, NULL, FPU_KERN_NORMAL | FPU_KERN_NOCTX); } error = 0; if (csp->csp_cipher_key != NULL) aesni_cipher_setup_common(ses, csp, csp->csp_cipher_key, csp->csp_cipher_klen); if (!kt) { fpu_kern_leave(curthread, NULL); } return (error); } static int aesni_cipher_process(struct aesni_session *ses, struct cryptop *crp) { const struct crypto_session_params *csp; int error; csp = crypto_get_params(crp->crp_session); switch (csp->csp_cipher_alg) { case CRYPTO_AES_CCM_16: if (crp->crp_payload_length > ccm_max_payload_length(csp)) return (EMSGSIZE); /* FALLTHROUGH */ case CRYPTO_AES_ICM: case CRYPTO_AES_NIST_GCM_16: if ((crp->crp_flags & CRYPTO_F_IV_SEPARATE) == 0) return (EINVAL); break; case CRYPTO_AES_CBC: case CRYPTO_AES_XTS: /* CBC & XTS can only handle full blocks for now */ if ((crp->crp_payload_length % AES_BLOCK_LEN) != 0) return (EINVAL); break; } /* Do work */ if (csp->csp_mode == CSP_MODE_ETA) { if (CRYPTO_OP_IS_ENCRYPT(crp->crp_op)) { error = aesni_cipher_crypt(ses, crp, csp); if (error == 0) error = aesni_cipher_mac(ses, crp, csp); } else { error = aesni_cipher_mac(ses, crp, csp); if (error == 0) error = aesni_cipher_crypt(ses, crp, csp); } } else if (csp->csp_mode == CSP_MODE_DIGEST) error = aesni_cipher_mac(ses, crp, csp); else error = aesni_cipher_crypt(ses, crp, csp); return (error); } static int aesni_cipher_crypt(struct aesni_session *ses, struct cryptop *crp, const struct crypto_session_params *csp) { uint8_t iv[AES_BLOCK_LEN], tag[GMAC_DIGEST_LEN]; uint8_t *authbuf, *buf, *outbuf; int error; bool encflag, allocated, authallocated, outallocated, outcopy; if (crp->crp_payload_length == 0) { buf = NULL; allocated = false; } else { buf = aesni_cipher_alloc(crp, crp->crp_payload_start, crp->crp_payload_length, &allocated); if (buf == NULL) return (ENOMEM); } outallocated = false; authallocated = false; authbuf = NULL; if (csp->csp_cipher_alg == CRYPTO_AES_NIST_GCM_16 || csp->csp_cipher_alg == CRYPTO_AES_CCM_16) { if (crp->crp_aad_length == 0) { authbuf = NULL; } else if (crp->crp_aad != NULL) { authbuf = crp->crp_aad; } else { authbuf = aesni_cipher_alloc(crp, crp->crp_aad_start, crp->crp_aad_length, &authallocated); if (authbuf == NULL) { error = ENOMEM; goto out; } } } if (CRYPTO_HAS_OUTPUT_BUFFER(crp) && crp->crp_payload_length > 0) { outbuf = crypto_buffer_contiguous_subsegment(&crp->crp_obuf, crp->crp_payload_output_start, crp->crp_payload_length); if (outbuf == NULL) { outcopy = true; if (allocated) outbuf = buf; else { outbuf = malloc(crp->crp_payload_length, M_AESNI, M_NOWAIT); if (outbuf == NULL) { error = ENOMEM; goto out; } outallocated = true; } } else outcopy = false; } else { outbuf = buf; outcopy = allocated; } fpu_kern_enter(curthread, NULL, FPU_KERN_NORMAL | FPU_KERN_NOCTX); error = 0; encflag = CRYPTO_OP_IS_ENCRYPT(crp->crp_op); if (crp->crp_cipher_key != NULL) aesni_cipher_setup_common(ses, csp, crp->crp_cipher_key, csp->csp_cipher_klen); crypto_read_iv(crp, iv); switch (csp->csp_cipher_alg) { case CRYPTO_AES_CBC: if (encflag) aesni_encrypt_cbc(ses->rounds, ses->enc_schedule, crp->crp_payload_length, buf, outbuf, iv); else { if (buf != outbuf) memcpy(outbuf, buf, crp->crp_payload_length); aesni_decrypt_cbc(ses->rounds, ses->dec_schedule, crp->crp_payload_length, outbuf, iv); } break; case CRYPTO_AES_ICM: /* encryption & decryption are the same */ aesni_encrypt_icm(ses->rounds, ses->enc_schedule, crp->crp_payload_length, buf, outbuf, iv); break; case CRYPTO_AES_XTS: if (encflag) aesni_encrypt_xts(ses->rounds, ses->enc_schedule, ses->xts_schedule, crp->crp_payload_length, buf, outbuf, iv); else aesni_decrypt_xts(ses->rounds, ses->dec_schedule, ses->xts_schedule, crp->crp_payload_length, buf, outbuf, iv); break; case CRYPTO_AES_NIST_GCM_16: if (encflag) { memset(tag, 0, sizeof(tag)); AES_GCM_encrypt(buf, outbuf, authbuf, iv, tag, crp->crp_payload_length, crp->crp_aad_length, csp->csp_ivlen, ses->enc_schedule, ses->rounds); crypto_copyback(crp, crp->crp_digest_start, sizeof(tag), tag); } else { crypto_copydata(crp, crp->crp_digest_start, sizeof(tag), tag); if (!AES_GCM_decrypt(buf, outbuf, authbuf, iv, tag, crp->crp_payload_length, crp->crp_aad_length, csp->csp_ivlen, ses->enc_schedule, ses->rounds)) error = EBADMSG; } break; case CRYPTO_AES_CCM_16: if (encflag) { memset(tag, 0, sizeof(tag)); AES_CCM_encrypt(buf, outbuf, authbuf, iv, tag, crp->crp_payload_length, crp->crp_aad_length, csp->csp_ivlen, ses->mlen, ses->enc_schedule, ses->rounds); crypto_copyback(crp, crp->crp_digest_start, ses->mlen, tag); } else { crypto_copydata(crp, crp->crp_digest_start, ses->mlen, tag); if (!AES_CCM_decrypt(buf, outbuf, authbuf, iv, tag, crp->crp_payload_length, crp->crp_aad_length, csp->csp_ivlen, ses->mlen, ses->enc_schedule, ses->rounds)) error = EBADMSG; } break; } fpu_kern_leave(curthread, NULL); if (outcopy && error == 0) crypto_copyback(crp, CRYPTO_HAS_OUTPUT_BUFFER(crp) ? crp->crp_payload_output_start : crp->crp_payload_start, crp->crp_payload_length, outbuf); out: if (allocated) zfree(buf, M_AESNI); if (authallocated) zfree(authbuf, M_AESNI); if (outallocated) zfree(outbuf, M_AESNI); explicit_bzero(iv, sizeof(iv)); explicit_bzero(tag, sizeof(tag)); return (error); } static int aesni_cipher_mac(struct aesni_session *ses, struct cryptop *crp, const struct crypto_session_params *csp) { union { struct SHA256Context sha2 __aligned(16); struct sha1_ctxt sha1 __aligned(16); } sctx; uint32_t res[SHA2_256_HASH_LEN / sizeof(uint32_t)]; const uint8_t *key; int i, keylen; if (crp->crp_auth_key != NULL) key = crp->crp_auth_key; else key = csp->csp_auth_key; keylen = csp->csp_auth_klen; fpu_kern_enter(curthread, NULL, FPU_KERN_NORMAL | FPU_KERN_NOCTX); if (ses->hmac) { uint8_t hmac_key[SHA1_BLOCK_LEN] __aligned(16); /* Inner hash: (K ^ IPAD) || data */ ses->hash_init(&sctx); for (i = 0; i < keylen; i++) hmac_key[i] = key[i] ^ HMAC_IPAD_VAL; for (i = keylen; i < sizeof(hmac_key); i++) hmac_key[i] = 0 ^ HMAC_IPAD_VAL; ses->hash_update(&sctx, hmac_key, sizeof(hmac_key)); if (crp->crp_aad != NULL) ses->hash_update(&sctx, crp->crp_aad, crp->crp_aad_length); else crypto_apply(crp, crp->crp_aad_start, crp->crp_aad_length, ses->hash_update, &sctx); if (CRYPTO_HAS_OUTPUT_BUFFER(crp) && CRYPTO_OP_IS_ENCRYPT(crp->crp_op)) crypto_apply_buf(&crp->crp_obuf, crp->crp_payload_output_start, crp->crp_payload_length, ses->hash_update, &sctx); else crypto_apply(crp, crp->crp_payload_start, crp->crp_payload_length, ses->hash_update, &sctx); if (csp->csp_flags & CSP_F_ESN) ses->hash_update(&sctx, crp->crp_esn, 4); ses->hash_finalize(res, &sctx); /* Outer hash: (K ^ OPAD) || inner hash */ ses->hash_init(&sctx); for (i = 0; i < keylen; i++) hmac_key[i] = key[i] ^ HMAC_OPAD_VAL; for (i = keylen; i < sizeof(hmac_key); i++) hmac_key[i] = 0 ^ HMAC_OPAD_VAL; ses->hash_update(&sctx, hmac_key, sizeof(hmac_key)); ses->hash_update(&sctx, res, ses->hash_len); ses->hash_finalize(res, &sctx); explicit_bzero(hmac_key, sizeof(hmac_key)); } else { ses->hash_init(&sctx); if (crp->crp_aad != NULL) ses->hash_update(&sctx, crp->crp_aad, crp->crp_aad_length); else crypto_apply(crp, crp->crp_aad_start, crp->crp_aad_length, ses->hash_update, &sctx); if (CRYPTO_HAS_OUTPUT_BUFFER(crp) && CRYPTO_OP_IS_ENCRYPT(crp->crp_op)) crypto_apply_buf(&crp->crp_obuf, crp->crp_payload_output_start, crp->crp_payload_length, ses->hash_update, &sctx); else crypto_apply(crp, crp->crp_payload_start, crp->crp_payload_length, ses->hash_update, &sctx); ses->hash_finalize(res, &sctx); } fpu_kern_leave(curthread, NULL); if (crp->crp_op & CRYPTO_OP_VERIFY_DIGEST) { uint32_t res2[SHA2_256_HASH_LEN / sizeof(uint32_t)]; crypto_copydata(crp, crp->crp_digest_start, ses->mlen, res2); if (timingsafe_bcmp(res, res2, ses->mlen) != 0) return (EBADMSG); explicit_bzero(res2, sizeof(res2)); } else crypto_copyback(crp, crp->crp_digest_start, ses->mlen, res); explicit_bzero(res, sizeof(res)); return (0); }