/*- * SPDX-License-Identifier: BSD-2-Clause-FreeBSD * * Copyright (c) 2005-2011 Pawel Jakub Dawidek * All rights reserved. * * 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 __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * The data layout description when integrity verification is configured. * * One of the most important assumption here is that authenticated data and its * HMAC has to be stored in the same place (namely in the same sector) to make * it work reliable. * The problem is that file systems work only with sectors that are multiple of * 512 bytes and a power of two number. * My idea to implement it is as follows. * Let's store HMAC in sector. This is a must. This leaves us 480 bytes for * data. We can't use that directly (ie. we can't create provider with 480 bytes * sector size). We need another sector from where we take only 32 bytes of data * and we store HMAC of this data as well. This takes two sectors from the * original provider at the input and leaves us one sector of authenticated data * at the output. Not very efficient, but you got the idea. * Now, let's assume, we want to create provider with 4096 bytes sector. * To output 4096 bytes of authenticated data we need 8x480 plus 1x256, so we * need nine 512-bytes sectors at the input to get one 4096-bytes sector at the * output. That's better. With 4096 bytes sector we can use 89% of size of the * original provider. I find it as an acceptable cost. * The reliability comes from the fact, that every HMAC stored inside the sector * is calculated only for the data in the same sector, so its impossible to * write new data and leave old HMAC or vice versa. * * And here is the picture: * * da0: +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+-----+ * |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |256b | * |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data | * +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+-----+ * |512 bytes| |512 bytes| |512 bytes| |512 bytes| |512 bytes| |512 bytes| |512 bytes| |512 bytes| |288 bytes | * +---------+ +---------+ +---------+ +---------+ +---------+ +---------+ +---------+ +---------+ |224 unused| * +----------+ * da0.eli: +----+----+----+----+----+----+----+----+----+ * |480b|480b|480b|480b|480b|480b|480b|480b|256b| * +----+----+----+----+----+----+----+----+----+ * | 4096 bytes | * +--------------------------------------------+ * * PS. You can use any sector size with geli(8). My example is using 4kB, * because it's most efficient. For 8kB sectors you need 2 extra sectors, * so the cost is the same as for 4kB sectors. */ /* * Code paths: * BIO_READ: * g_eli_start -> g_eli_auth_read -> g_io_request -> g_eli_read_done -> g_eli_auth_run -> g_eli_auth_read_done -> g_io_deliver * BIO_WRITE: * g_eli_start -> g_eli_auth_run -> g_eli_auth_write_done -> g_io_request -> g_eli_write_done -> g_io_deliver */ /* * Here we generate key for HMAC. Every sector has its own HMAC key, so it is * not possible to copy sectors. * We cannot depend on fact, that every sector has its own IV, because different * IV doesn't change HMAC, when we use encrypt-then-authenticate method. */ static void g_eli_auth_keygen(struct g_eli_softc *sc, off_t offset, u_char *key) { SHA256_CTX ctx; /* Copy precalculated SHA256 context. */ bcopy(&sc->sc_akeyctx, &ctx, sizeof(ctx)); SHA256_Update(&ctx, (uint8_t *)&offset, sizeof(offset)); SHA256_Final(key, &ctx); } /* * The function is called after we read and decrypt data. * * g_eli_start -> g_eli_auth_read -> g_io_request -> g_eli_read_done -> g_eli_auth_run -> G_ELI_AUTH_READ_DONE -> g_io_deliver */ static int g_eli_auth_read_done(struct cryptop *crp) { struct g_eli_softc *sc; struct bio *bp; if (crp->crp_etype == EAGAIN) { if (g_eli_crypto_rerun(crp) == 0) return (0); } bp = (struct bio *)crp->crp_opaque; bp->bio_inbed++; sc = bp->bio_to->geom->softc; if (crp->crp_etype == 0) { bp->bio_completed += crp->crp_payload_length; G_ELI_DEBUG(3, "Crypto READ request done (%d/%d) (add=%d completed=%jd).", bp->bio_inbed, bp->bio_children, crp->crp_payload_length, (intmax_t)bp->bio_completed); } else { u_int nsec, decr_secsize, encr_secsize, rel_sec; int *errorp; /* Sectorsize of decrypted provider eg. 4096. */ decr_secsize = bp->bio_to->sectorsize; /* The real sectorsize of encrypted provider, eg. 512. */ encr_secsize = LIST_FIRST(&sc->sc_geom->consumer)->provider->sectorsize; /* Number of sectors from decrypted provider, eg. 2. */ nsec = bp->bio_length / decr_secsize; /* Number of sectors from encrypted provider, eg. 18. */ nsec = (nsec * sc->sc_bytes_per_sector) / encr_secsize; /* Which relative sector this request decrypted. */ rel_sec = ((crp->crp_buf.cb_buf + crp->crp_payload_start) - (char *)bp->bio_driver2) / encr_secsize; errorp = (int *)((char *)bp->bio_driver2 + encr_secsize * nsec + sizeof(int) * rel_sec); *errorp = crp->crp_etype; G_ELI_DEBUG(1, "Crypto READ request failed (%d/%d) error=%d.", bp->bio_inbed, bp->bio_children, crp->crp_etype); if (bp->bio_error == 0 || bp->bio_error == EINTEGRITY) bp->bio_error = crp->crp_etype == EBADMSG ? EINTEGRITY : crp->crp_etype; } if (crp->crp_cipher_key != NULL) g_eli_key_drop(sc, __DECONST(void *, crp->crp_cipher_key)); crypto_freereq(crp); /* * Do we have all sectors already? */ if (bp->bio_inbed < bp->bio_children) return (0); if (bp->bio_error == 0) { u_int i, lsec, nsec, data_secsize, decr_secsize, encr_secsize; u_char *srcdata, *dstdata; /* Sectorsize of decrypted provider eg. 4096. */ decr_secsize = bp->bio_to->sectorsize; /* The real sectorsize of encrypted provider, eg. 512. */ encr_secsize = LIST_FIRST(&sc->sc_geom->consumer)->provider->sectorsize; /* Number of data bytes in one encrypted sector, eg. 480. */ data_secsize = sc->sc_data_per_sector; /* Number of sectors from decrypted provider, eg. 2. */ nsec = bp->bio_length / decr_secsize; /* Number of sectors from encrypted provider, eg. 18. */ nsec = (nsec * sc->sc_bytes_per_sector) / encr_secsize; /* Last sector number in every big sector, eg. 9. */ lsec = sc->sc_bytes_per_sector / encr_secsize; srcdata = bp->bio_driver2; dstdata = bp->bio_data; for (i = 1; i <= nsec; i++) { data_secsize = sc->sc_data_per_sector; if ((i % lsec) == 0) data_secsize = decr_secsize % data_secsize; bcopy(srcdata + sc->sc_alen, dstdata, data_secsize); srcdata += encr_secsize; dstdata += data_secsize; } } else if (bp->bio_error == EINTEGRITY) { u_int i, lsec, nsec, data_secsize, decr_secsize, encr_secsize; int *errorp; off_t coroff, corsize, dstoff; /* Sectorsize of decrypted provider eg. 4096. */ decr_secsize = bp->bio_to->sectorsize; /* The real sectorsize of encrypted provider, eg. 512. */ encr_secsize = LIST_FIRST(&sc->sc_geom->consumer)->provider->sectorsize; /* Number of data bytes in one encrypted sector, eg. 480. */ data_secsize = sc->sc_data_per_sector; /* Number of sectors from decrypted provider, eg. 2. */ nsec = bp->bio_length / decr_secsize; /* Number of sectors from encrypted provider, eg. 18. */ nsec = (nsec * sc->sc_bytes_per_sector) / encr_secsize; /* Last sector number in every big sector, eg. 9. */ lsec = sc->sc_bytes_per_sector / encr_secsize; errorp = (int *)((char *)bp->bio_driver2 + encr_secsize * nsec); coroff = -1; corsize = 0; dstoff = bp->bio_offset; for (i = 1; i <= nsec; i++) { data_secsize = sc->sc_data_per_sector; if ((i % lsec) == 0) data_secsize = decr_secsize % data_secsize; if (errorp[i - 1] == EBADMSG) { /* * Corruption detected, remember the offset if * this is the first corrupted sector and * increase size. */ if (coroff == -1) coroff = dstoff; corsize += data_secsize; } else { /* * No corruption, good. * Report previous corruption if there was one. */ if (coroff != -1) { G_ELI_DEBUG(0, "%s: Failed to authenticate %jd " "bytes of data at offset %jd.", sc->sc_name, (intmax_t)corsize, (intmax_t)coroff); coroff = -1; corsize = 0; } } dstoff += data_secsize; } /* Report previous corruption if there was one. */ if (coroff != -1) { G_ELI_DEBUG(0, "%s: Failed to authenticate %jd " "bytes of data at offset %jd.", sc->sc_name, (intmax_t)corsize, (intmax_t)coroff); } } g_eli_free_data(bp); if (bp->bio_error != 0) { if (bp->bio_error != EINTEGRITY) { G_ELI_LOGREQ(0, bp, "Crypto READ request failed (error=%d).", bp->bio_error); } bp->bio_completed = 0; } /* * Read is finished, send it up. */ g_io_deliver(bp, bp->bio_error); atomic_subtract_int(&sc->sc_inflight, 1); return (0); } /* * The function is called after data encryption. * * g_eli_start -> g_eli_auth_run -> G_ELI_AUTH_WRITE_DONE -> g_io_request -> g_eli_write_done -> g_io_deliver */ static int g_eli_auth_write_done(struct cryptop *crp) { struct g_eli_softc *sc; struct g_consumer *cp; struct bio *bp, *cbp, *cbp2; u_int nsec; if (crp->crp_etype == EAGAIN) { if (g_eli_crypto_rerun(crp) == 0) return (0); } bp = (struct bio *)crp->crp_opaque; bp->bio_inbed++; if (crp->crp_etype == 0) { G_ELI_DEBUG(3, "Crypto WRITE request done (%d/%d).", bp->bio_inbed, bp->bio_children); } else { G_ELI_DEBUG(1, "Crypto WRITE request failed (%d/%d) error=%d.", bp->bio_inbed, bp->bio_children, crp->crp_etype); if (bp->bio_error == 0) bp->bio_error = crp->crp_etype; } sc = bp->bio_to->geom->softc; if (crp->crp_cipher_key != NULL) g_eli_key_drop(sc, __DECONST(void *, crp->crp_cipher_key)); crypto_freereq(crp); /* * All sectors are already encrypted? */ if (bp->bio_inbed < bp->bio_children) return (0); if (bp->bio_error != 0) { G_ELI_LOGREQ(0, bp, "Crypto WRITE request failed (error=%d).", bp->bio_error); g_eli_free_data(bp); cbp = bp->bio_driver1; bp->bio_driver1 = NULL; g_destroy_bio(cbp); g_io_deliver(bp, bp->bio_error); atomic_subtract_int(&sc->sc_inflight, 1); return (0); } cp = LIST_FIRST(&sc->sc_geom->consumer); cbp = bp->bio_driver1; bp->bio_driver1 = NULL; cbp->bio_to = cp->provider; cbp->bio_done = g_eli_write_done; /* Number of sectors from decrypted provider, eg. 1. */ nsec = bp->bio_length / bp->bio_to->sectorsize; /* Number of sectors from encrypted provider, eg. 9. */ nsec = (nsec * sc->sc_bytes_per_sector) / cp->provider->sectorsize; cbp->bio_length = cp->provider->sectorsize * nsec; cbp->bio_offset = (bp->bio_offset / bp->bio_to->sectorsize) * sc->sc_bytes_per_sector; cbp->bio_data = bp->bio_driver2; /* * We write more than what is requested, so we have to be ready to write * more than maxphys. */ cbp2 = NULL; if (cbp->bio_length > maxphys) { cbp2 = g_duplicate_bio(bp); cbp2->bio_length = cbp->bio_length - maxphys; cbp2->bio_data = cbp->bio_data + maxphys; cbp2->bio_offset = cbp->bio_offset + maxphys; cbp2->bio_to = cp->provider; cbp2->bio_done = g_eli_write_done; cbp->bio_length = maxphys; } /* * Send encrypted data to the provider. */ G_ELI_LOGREQ(2, cbp, "Sending request."); bp->bio_inbed = 0; bp->bio_children = (cbp2 != NULL ? 2 : 1); g_io_request(cbp, cp); if (cbp2 != NULL) { G_ELI_LOGREQ(2, cbp2, "Sending request."); g_io_request(cbp2, cp); } return (0); } void g_eli_auth_read(struct g_eli_softc *sc, struct bio *bp) { struct g_consumer *cp; struct bio *cbp, *cbp2; size_t size; off_t nsec; G_ELI_SETWORKER(bp->bio_pflags, 0); cp = LIST_FIRST(&sc->sc_geom->consumer); cbp = bp->bio_driver1; bp->bio_driver1 = NULL; cbp->bio_to = cp->provider; cbp->bio_done = g_eli_read_done; /* Number of sectors from decrypted provider, eg. 1. */ nsec = bp->bio_length / bp->bio_to->sectorsize; /* Number of sectors from encrypted provider, eg. 9. */ nsec = (nsec * sc->sc_bytes_per_sector) / cp->provider->sectorsize; cbp->bio_length = cp->provider->sectorsize * nsec; size = cbp->bio_length; size += sizeof(int) * nsec; size += G_ELI_AUTH_SECKEYLEN * nsec; cbp->bio_offset = (bp->bio_offset / bp->bio_to->sectorsize) * sc->sc_bytes_per_sector; if (!g_eli_alloc_data(bp, size)) { G_ELI_LOGREQ(0, bp, "Crypto auth read request failed (ENOMEM)"); g_destroy_bio(cbp); bp->bio_error = ENOMEM; g_io_deliver(bp, bp->bio_error); atomic_subtract_int(&sc->sc_inflight, 1); return; } cbp->bio_data = bp->bio_driver2; /* Clear the error array. */ memset((char *)bp->bio_driver2 + cbp->bio_length, 0, sizeof(int) * nsec); /* * We read more than what is requested, so we have to be ready to read * more than maxphys. */ cbp2 = NULL; if (cbp->bio_length > maxphys) { cbp2 = g_duplicate_bio(bp); cbp2->bio_length = cbp->bio_length - maxphys; cbp2->bio_data = cbp->bio_data + maxphys; cbp2->bio_offset = cbp->bio_offset + maxphys; cbp2->bio_to = cp->provider; cbp2->bio_done = g_eli_read_done; cbp->bio_length = maxphys; } /* * Read encrypted data from provider. */ G_ELI_LOGREQ(2, cbp, "Sending request."); g_io_request(cbp, cp); if (cbp2 != NULL) { G_ELI_LOGREQ(2, cbp2, "Sending request."); g_io_request(cbp2, cp); } } /* * This is the main function responsible for cryptography (ie. communication * with crypto(9) subsystem). * * BIO_READ: * g_eli_start -> g_eli_auth_read -> g_io_request -> g_eli_read_done -> G_ELI_AUTH_RUN -> g_eli_auth_read_done -> g_io_deliver * BIO_WRITE: * g_eli_start -> G_ELI_AUTH_RUN -> g_eli_auth_write_done -> g_io_request -> g_eli_write_done -> g_io_deliver */ void g_eli_auth_run(struct g_eli_worker *wr, struct bio *bp) { struct g_eli_softc *sc; struct cryptopq crpq; struct cryptop *crp; u_int i, lsec, nsec, data_secsize, decr_secsize, encr_secsize; off_t dstoff; u_char *p, *data, *authkey, *plaindata; int error; bool batch; G_ELI_LOGREQ(3, bp, "%s", __func__); G_ELI_SETWORKER(bp->bio_pflags, wr->w_number); sc = wr->w_softc; /* Sectorsize of decrypted provider eg. 4096. */ decr_secsize = bp->bio_to->sectorsize; /* The real sectorsize of encrypted provider, eg. 512. */ encr_secsize = LIST_FIRST(&sc->sc_geom->consumer)->provider->sectorsize; /* Number of data bytes in one encrypted sector, eg. 480. */ data_secsize = sc->sc_data_per_sector; /* Number of sectors from decrypted provider, eg. 2. */ nsec = bp->bio_length / decr_secsize; /* Number of sectors from encrypted provider, eg. 18. */ nsec = (nsec * sc->sc_bytes_per_sector) / encr_secsize; /* Last sector number in every big sector, eg. 9. */ lsec = sc->sc_bytes_per_sector / encr_secsize; /* Destination offset, used for IV generation. */ dstoff = (bp->bio_offset / bp->bio_to->sectorsize) * sc->sc_bytes_per_sector; plaindata = bp->bio_data; if (bp->bio_cmd == BIO_READ) { data = bp->bio_driver2; p = data + encr_secsize * nsec; p += sizeof(int) * nsec; } else { size_t size; size = encr_secsize * nsec; size += G_ELI_AUTH_SECKEYLEN * nsec; size += sizeof(uintptr_t); /* Space for alignment. */ if (!g_eli_alloc_data(bp, size)) { G_ELI_LOGREQ(0, bp, "Crypto request failed (ENOMEM)"); if (bp->bio_driver1 != NULL) { g_destroy_bio(bp->bio_driver1); bp->bio_driver1 = NULL; } bp->bio_error = ENOMEM; g_io_deliver(bp, bp->bio_error); if (sc != NULL) atomic_subtract_int(&sc->sc_inflight, 1); return; } data = bp->bio_driver2; p = data + encr_secsize * nsec; } bp->bio_inbed = 0; bp->bio_children = nsec; #if defined(__mips_n64) || defined(__mips_o64) p = (char *)roundup((uintptr_t)p, sizeof(uintptr_t)); #endif TAILQ_INIT(&crpq); batch = atomic_load_int(&g_eli_batch) != 0; for (i = 1; i <= nsec; i++, dstoff += encr_secsize) { crp = crypto_getreq(wr->w_sid, M_WAITOK); authkey = (u_char *)p; p += G_ELI_AUTH_SECKEYLEN; data_secsize = sc->sc_data_per_sector; if ((i % lsec) == 0) { data_secsize = decr_secsize % data_secsize; /* * Last encrypted sector of each decrypted sector is * only partially filled. */ if (bp->bio_cmd == BIO_WRITE) memset(data + sc->sc_alen + data_secsize, 0, encr_secsize - sc->sc_alen - data_secsize); } else if (data_secsize + sc->sc_alen != encr_secsize) { /* * If the HMAC size is not a multiple of 128 bits, the * per-sector data size is rounded down to ensure that * encryption can be performed without requiring any * padding. In this case, each sector contains unused * bytes. */ if (bp->bio_cmd == BIO_WRITE) memset(data + sc->sc_alen + data_secsize, 0, encr_secsize - sc->sc_alen - data_secsize); } if (bp->bio_cmd == BIO_WRITE) { bcopy(plaindata, data + sc->sc_alen, data_secsize); plaindata += data_secsize; } crypto_use_buf(crp, data, sc->sc_alen + data_secsize); crp->crp_opaque = (void *)bp; data += encr_secsize; crp->crp_flags = CRYPTO_F_CBIFSYNC; if (bp->bio_cmd == BIO_WRITE) { crp->crp_callback = g_eli_auth_write_done; crp->crp_op = CRYPTO_OP_ENCRYPT | CRYPTO_OP_COMPUTE_DIGEST; } else { crp->crp_callback = g_eli_auth_read_done; crp->crp_op = CRYPTO_OP_DECRYPT | CRYPTO_OP_VERIFY_DIGEST; } crp->crp_digest_start = 0; crp->crp_payload_start = sc->sc_alen; crp->crp_payload_length = data_secsize; if ((sc->sc_flags & G_ELI_FLAG_FIRST_KEY) == 0) { crp->crp_cipher_key = g_eli_key_hold(sc, dstoff, encr_secsize); } if (g_eli_ivlen(sc->sc_ealgo) != 0) { crp->crp_flags |= CRYPTO_F_IV_SEPARATE; g_eli_crypto_ivgen(sc, dstoff, crp->crp_iv, sizeof(crp->crp_iv)); } g_eli_auth_keygen(sc, dstoff, authkey); crp->crp_auth_key = authkey; if (batch) { TAILQ_INSERT_TAIL(&crpq, crp, crp_next); } else { error = crypto_dispatch(crp); KASSERT(error == 0, ("crypto_dispatch() failed (error=%d)", error)); } } if (batch) crypto_dispatch_batch(&crpq, 0); }