static int crypt(struct blkcipher_desc *d, struct blkcipher_walk *w, struct priv *ctx, void (*tw)(struct crypto_tfm *, u8 *, const u8 *), void (*fn)(struct crypto_tfm *, u8 *, const u8 *)) { int err; unsigned int avail; const int bs = XTS_BLOCK_SIZE; struct sinfo s = { .tfm = crypto_cipher_tfm(ctx->child), .fn = fn }; u8 *wsrc; u8 *wdst; err = blkcipher_walk_virt(d, w); if (!w->nbytes) return err; s.t = (be128 *)w->iv; avail = w->nbytes; wsrc = w->src.virt.addr; wdst = w->dst.virt.addr; tw(crypto_cipher_tfm(ctx->tweak), w->iv, w->iv); goto first; for (;;) { do { gf128mul_x_ble(s.t, s.t); first: xts_round(&s, wdst, wsrc); wsrc += bs; wdst += bs; } while ((avail -= bs) >= bs); err = blkcipher_walk_done(d, w, avail); if (!w->nbytes) break; avail = w->nbytes; wsrc = w->src.virt.addr; wdst = w->dst.virt.addr; } return err; } static int encrypt(struct blkcipher_desc *desc, struct scatterlist *dst, struct scatterlist *src, unsigned int nbytes) { struct priv *ctx = crypto_blkcipher_ctx(desc->tfm); struct blkcipher_walk w; blkcipher_walk_init(&w, dst, src, nbytes); return crypt(desc, &w, ctx, crypto_cipher_alg(ctx->tweak)->cia_encrypt, crypto_cipher_alg(ctx->child)->cia_encrypt); } static int decrypt(struct blkcipher_desc *desc, struct scatterlist *dst, struct scatterlist *src, unsigned int nbytes) { struct priv *ctx = crypto_blkcipher_ctx(desc->tfm); struct blkcipher_walk w; blkcipher_walk_init(&w, dst, src, nbytes); return crypt(desc, &w, ctx, crypto_cipher_alg(ctx->tweak)->cia_encrypt, crypto_cipher_alg(ctx->child)->cia_decrypt); } int xts_crypt(struct blkcipher_desc *desc, struct scatterlist *sdst, struct scatterlist *ssrc, unsigned int nbytes, struct xts_crypt_req *req) { const unsigned int bsize = XTS_BLOCK_SIZE; const unsigned int max_blks = req->tbuflen / bsize; struct blkcipher_walk walk={}; unsigned int nblocks; be128 *src, *dst, *t; be128 *t_buf = req->tbuf; int err, i; BUG_ON(max_blks < 1); blkcipher_walk_init(&walk, sdst, ssrc, nbytes); err = blkcipher_walk_virt(desc, &walk); nbytes = walk.nbytes; if (!nbytes) return err; nblocks = min(nbytes / bsize, max_blks); src = (be128 *)walk.src.virt.addr; dst = (be128 *)walk.dst.virt.addr; req->tweak_fn(req->tweak_ctx, (u8 *)&t_buf[0], walk.iv); i = 0; goto first; for (;;) { do { for (i = 0; i < nblocks; i++) { gf128mul_x_ble(&t_buf[i], t); first: t = &t_buf[i]; be128_xor(dst + i, t, src + i); } req->crypt_fn(req->crypt_ctx, (u8 *)dst, nblocks * bsize); for (i = 0; i < nblocks; i++) be128_xor(dst + i, dst + i, &t_buf[i]); src += nblocks; dst += nblocks; nbytes -= nblocks * bsize; nblocks = min(nbytes / bsize, max_blks); } while (nblocks > 0); *(be128 *)walk.iv = *t; err = blkcipher_walk_done(desc, &walk, nbytes); nbytes = walk.nbytes; if (!nbytes) break; nblocks = min(nbytes / bsize, max_blks); src = (be128 *)walk.src.virt.addr; dst = (be128 *)walk.dst.virt.addr; } return err; } EXPORT_SYMBOL_GPL(xts_crypt); static int init_tfm(struct crypto_tfm *tfm) { struct crypto_cipher *cipher; struct crypto_instance *inst = (void *)tfm->__crt_alg; struct crypto_spawn *spawn = crypto_instance_ctx(inst); struct priv *ctx = crypto_tfm_ctx(tfm); u32 *flags = &tfm->crt_flags; cipher = crypto_spawn_cipher(spawn); if (IS_ERR(cipher)) return PTR_ERR(cipher); if (crypto_cipher_blocksize(cipher) != XTS_BLOCK_SIZE) { *flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN; crypto_free_cipher(cipher); return -EINVAL; } ctx->child = cipher; cipher = crypto_spawn_cipher(spawn); if (IS_ERR(cipher)) { crypto_free_cipher(ctx->child); return PTR_ERR(cipher); } if (crypto_cipher_blocksize(cipher) != XTS_BLOCK_SIZE) { crypto_free_cipher(cipher); crypto_free_cipher(ctx->child); *flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN; return -EINVAL; } ctx->tweak = cipher; return 0; } static void exit_tfm(struct crypto_tfm *tfm) { struct priv *ctx = crypto_tfm_ctx(tfm); crypto_free_cipher(ctx->child); crypto_free_cipher(ctx->tweak); } static struct crypto_instance *alloc(struct rtattr **tb) { struct crypto_instance *inst; struct crypto_alg *alg; int err; err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER); if (err) return ERR_PTR(err); alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER, CRYPTO_ALG_TYPE_MASK); if (IS_ERR(alg)) return ERR_CAST(alg); inst = crypto_alloc_instance("xts", alg); if (IS_ERR(inst)) goto out_put_alg; inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER; inst->alg.cra_priority = alg->cra_priority; inst->alg.cra_blocksize = alg->cra_blocksize; if (alg->cra_alignmask < 7) inst->alg.cra_alignmask = 7; else inst->alg.cra_alignmask = alg->cra_alignmask; inst->alg.cra_type = &crypto_blkcipher_type; inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize; inst->alg.cra_blkcipher.min_keysize = 2 * alg->cra_cipher.cia_min_keysize; inst->alg.cra_blkcipher.max_keysize = 2 * alg->cra_cipher.cia_max_keysize; inst->alg.cra_ctxsize = sizeof(struct priv); inst->alg.cra_init = init_tfm; inst->alg.cra_exit = exit_tfm; inst->alg.cra_blkcipher.setkey = setkey; inst->alg.cra_blkcipher.encrypt = encrypt; inst->alg.cra_blkcipher.decrypt = decrypt; out_put_alg: crypto_mod_put(alg); return inst; } static void free(struct crypto_instance *inst) { crypto_drop_spawn(crypto_instance_ctx(inst)); kfree(inst); }
static int crypt(struct blkcipher_desc *d, struct blkcipher_walk *w, struct priv *ctx, void (*tw)(struct crypto_tfm *, u8 *, const u8 *), void (*fn)(struct crypto_tfm *, u8 *, const u8 *)) { int err; unsigned int avail; const int bs = crypto_cipher_blocksize(ctx->child); struct sinfo s = { .tfm = crypto_cipher_tfm(ctx->child), .fn = fn }; u8 *wsrc; u8 *wdst; err = blkcipher_walk_virt(d, w); if (!w->nbytes) return err; s.t = (be128 *)w->iv; avail = w->nbytes; wsrc = w->src.virt.addr; wdst = w->dst.virt.addr; /* calculate first value of T */ tw(crypto_cipher_tfm(ctx->tweak), w->iv, w->iv); goto first; for (;;) { do { gf128mul_x_ble(s.t, s.t); first: xts_round(&s, wdst, wsrc); wsrc += bs; wdst += bs; } while ((avail -= bs) >= bs); err = blkcipher_walk_done(d, w, avail); if (!w->nbytes) break; avail = w->nbytes; wsrc = w->src.virt.addr; wdst = w->dst.virt.addr; } return err; } static int encrypt(struct blkcipher_desc *desc, struct scatterlist *dst, struct scatterlist *src, unsigned int nbytes) { struct priv *ctx = crypto_blkcipher_ctx(desc->tfm); struct blkcipher_walk w; blkcipher_walk_init(&w, dst, src, nbytes); return crypt(desc, &w, ctx, crypto_cipher_alg(ctx->tweak)->cia_encrypt, crypto_cipher_alg(ctx->child)->cia_encrypt); } static int decrypt(struct blkcipher_desc *desc, struct scatterlist *dst, struct scatterlist *src, unsigned int nbytes) { struct priv *ctx = crypto_blkcipher_ctx(desc->tfm); struct blkcipher_walk w; blkcipher_walk_init(&w, dst, src, nbytes); return crypt(desc, &w, ctx, crypto_cipher_alg(ctx->tweak)->cia_encrypt, crypto_cipher_alg(ctx->child)->cia_decrypt); } static int init_tfm(struct crypto_tfm *tfm) { struct crypto_cipher *cipher; struct crypto_instance *inst = (void *)tfm->__crt_alg; struct crypto_spawn *spawn = crypto_instance_ctx(inst); struct priv *ctx = crypto_tfm_ctx(tfm); u32 *flags = &tfm->crt_flags; cipher = crypto_spawn_cipher(spawn); if (IS_ERR(cipher)) return PTR_ERR(cipher); if (crypto_cipher_blocksize(cipher) != 16) { *flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN; crypto_free_cipher(cipher); return -EINVAL; } ctx->child = cipher; cipher = crypto_spawn_cipher(spawn); if (IS_ERR(cipher)) { crypto_free_cipher(ctx->child); return PTR_ERR(cipher); } /* this check isn't really needed, leave it here just in case */ if (crypto_cipher_blocksize(cipher) != 16) { crypto_free_cipher(cipher); crypto_free_cipher(ctx->child); *flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN; return -EINVAL; } ctx->tweak = cipher; return 0; } static void exit_tfm(struct crypto_tfm *tfm) { struct priv *ctx = crypto_tfm_ctx(tfm); crypto_free_cipher(ctx->child); crypto_free_cipher(ctx->tweak); } static struct crypto_instance *alloc(struct rtattr **tb) { struct crypto_instance *inst; struct crypto_alg *alg; int err; err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER); if (err) return ERR_PTR(err); alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER, CRYPTO_ALG_TYPE_MASK); if (IS_ERR(alg)) return ERR_PTR(PTR_ERR(alg)); inst = crypto_alloc_instance("xts", alg); if (IS_ERR(inst)) goto out_put_alg; inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER; inst->alg.cra_priority = alg->cra_priority; inst->alg.cra_blocksize = alg->cra_blocksize; if (alg->cra_alignmask < 7) inst->alg.cra_alignmask = 7; else inst->alg.cra_alignmask = alg->cra_alignmask; inst->alg.cra_type = &crypto_blkcipher_type; inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize; inst->alg.cra_blkcipher.min_keysize = 2 * alg->cra_cipher.cia_min_keysize; inst->alg.cra_blkcipher.max_keysize = 2 * alg->cra_cipher.cia_max_keysize; inst->alg.cra_ctxsize = sizeof(struct priv); inst->alg.cra_init = init_tfm; inst->alg.cra_exit = exit_tfm; inst->alg.cra_blkcipher.setkey = setkey; inst->alg.cra_blkcipher.encrypt = encrypt; inst->alg.cra_blkcipher.decrypt = decrypt; out_put_alg: crypto_mod_put(alg); return inst; } static void free(struct crypto_instance *inst) { crypto_drop_spawn(crypto_instance_ctx(inst)); kfree(inst); }