diff options
-rw-r--r-- | crypto/xts.c | 547 | ||||
-rw-r--r-- | include/crypto/xts.h | 26 |
2 files changed, 416 insertions, 157 deletions
diff --git a/crypto/xts.c b/crypto/xts.c index 305343f..410a2e2 100644 --- a/crypto/xts.c +++ b/crypto/xts.c @@ -13,7 +13,8 @@ * Software Foundation; either version 2 of the License, or (at your option) * any later version. */ -#include <crypto/algapi.h> +#include <crypto/internal/skcipher.h> +#include <crypto/scatterwalk.h> #include <linux/err.h> #include <linux/init.h> #include <linux/kernel.h> @@ -25,140 +26,320 @@ #include <crypto/b128ops.h> #include <crypto/gf128mul.h> +#define XTS_BUFFER_SIZE 128u + struct priv { - struct crypto_cipher *child; + struct crypto_skcipher *child; struct crypto_cipher *tweak; }; -static int setkey(struct crypto_tfm *parent, const u8 *key, +struct xts_instance_ctx { + struct crypto_skcipher_spawn spawn; + char name[CRYPTO_MAX_ALG_NAME]; +}; + +struct rctx { + be128 buf[XTS_BUFFER_SIZE / sizeof(be128)]; + + be128 t; + + be128 *ext; + + struct scatterlist srcbuf[2]; + struct scatterlist dstbuf[2]; + struct scatterlist *src; + struct scatterlist *dst; + + unsigned int left; + + struct skcipher_request subreq; +}; + +static int setkey(struct crypto_skcipher *parent, const u8 *key, unsigned int keylen) { - struct priv *ctx = crypto_tfm_ctx(parent); - struct crypto_cipher *child = ctx->tweak; + struct priv *ctx = crypto_skcipher_ctx(parent); + struct crypto_skcipher *child; + struct crypto_cipher *tweak; int err; - err = xts_check_key(parent, key, keylen); + err = xts_verify_key(parent, key, keylen); if (err) return err; + keylen /= 2; + /* we need two cipher instances: one to compute the initial 'tweak' * by encrypting the IV (usually the 'plain' iv) and the other * one to encrypt and decrypt the data */ /* tweak cipher, uses Key2 i.e. the second half of *key */ - crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK); - crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) & + tweak = ctx->tweak; + crypto_cipher_clear_flags(tweak, CRYPTO_TFM_REQ_MASK); + crypto_cipher_set_flags(tweak, crypto_skcipher_get_flags(parent) & CRYPTO_TFM_REQ_MASK); - err = crypto_cipher_setkey(child, key + keylen/2, keylen/2); + err = crypto_cipher_setkey(tweak, key + keylen, keylen); + crypto_skcipher_set_flags(parent, crypto_cipher_get_flags(tweak) & + CRYPTO_TFM_RES_MASK); if (err) return err; - crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) & - CRYPTO_TFM_RES_MASK); - + /* data cipher, uses Key1 i.e. the first half of *key */ child = ctx->child; + crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK); + crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) & + CRYPTO_TFM_REQ_MASK); + err = crypto_skcipher_setkey(child, key, keylen); + crypto_skcipher_set_flags(parent, crypto_skcipher_get_flags(child) & + CRYPTO_TFM_RES_MASK); - /* data cipher, uses Key1 i.e. the first half of *key */ - crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK); - crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) & - CRYPTO_TFM_REQ_MASK); - err = crypto_cipher_setkey(child, key, keylen/2); - if (err) - return err; + return err; +} - crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) & - CRYPTO_TFM_RES_MASK); +static int post_crypt(struct skcipher_request *req) +{ + struct rctx *rctx = skcipher_request_ctx(req); + be128 *buf = rctx->ext ?: rctx->buf; + struct skcipher_request *subreq; + const int bs = XTS_BLOCK_SIZE; + struct skcipher_walk w; + struct scatterlist *sg; + unsigned offset; + int err; - return 0; -} + subreq = &rctx->subreq; + err = skcipher_walk_virt(&w, subreq, false); -struct sinfo { - be128 *t; - struct crypto_tfm *tfm; - void (*fn)(struct crypto_tfm *, u8 *, const u8 *); -}; + while (w.nbytes) { + unsigned int avail = w.nbytes; + be128 *wdst; -static inline void xts_round(struct sinfo *s, void *dst, const void *src) -{ - be128_xor(dst, s->t, src); /* PP <- T xor P */ - s->fn(s->tfm, dst, dst); /* CC <- E(Key1,PP) */ - be128_xor(dst, dst, s->t); /* C <- T xor CC */ + wdst = w.dst.virt.addr; + + do { + be128_xor(wdst, buf++, wdst); + wdst++; + } while ((avail -= bs) >= bs); + + err = skcipher_walk_done(&w, avail); + } + + rctx->left -= subreq->cryptlen; + + if (err || !rctx->left) + goto out; + + rctx->dst = rctx->dstbuf; + + scatterwalk_done(&w.out, 0, 1); + sg = w.out.sg; + offset = w.out.offset; + + if (rctx->dst != sg) { + rctx->dst[0] = *sg; + sg_unmark_end(rctx->dst); + scatterwalk_crypto_chain(rctx->dst, sg_next(sg), 0, 2); + } + rctx->dst[0].length -= offset - sg->offset; + rctx->dst[0].offset = offset; + +out: + return err; } -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 *)) +static int pre_crypt(struct skcipher_request *req) { - int err; - unsigned int avail; + struct rctx *rctx = skcipher_request_ctx(req); + be128 *buf = rctx->ext ?: rctx->buf; + struct skcipher_request *subreq; 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; + struct skcipher_walk w; + struct scatterlist *sg; + unsigned cryptlen; + unsigned offset; + bool more; + int err; - s.t = (be128 *)w->iv; - avail = w->nbytes; + subreq = &rctx->subreq; + cryptlen = subreq->cryptlen; - wsrc = w->src.virt.addr; - wdst = w->dst.virt.addr; + more = rctx->left > cryptlen; + if (!more) + cryptlen = rctx->left; - /* calculate first value of T */ - tw(crypto_cipher_tfm(ctx->tweak), w->iv, w->iv); + skcipher_request_set_crypt(subreq, rctx->src, rctx->dst, + cryptlen, NULL); - goto first; + err = skcipher_walk_virt(&w, subreq, false); - for (;;) { - do { - gf128mul_x_ble(s.t, s.t); + while (w.nbytes) { + unsigned int avail = w.nbytes; + be128 *wsrc; + be128 *wdst; -first: - xts_round(&s, wdst, wsrc); + wsrc = w.src.virt.addr; + wdst = w.dst.virt.addr; - wsrc += bs; - wdst += bs; + do { + *buf++ = rctx->t; + be128_xor(wdst++, &rctx->t, wsrc++); + gf128mul_x_ble(&rctx->t, &rctx->t); } while ((avail -= bs) >= bs); - err = blkcipher_walk_done(d, w, avail); - if (!w->nbytes) - break; + err = skcipher_walk_done(&w, avail); + } + + skcipher_request_set_crypt(subreq, rctx->dst, rctx->dst, + cryptlen, NULL); - avail = w->nbytes; + if (err || !more) + goto out; - wsrc = w->src.virt.addr; - wdst = w->dst.virt.addr; + rctx->src = rctx->srcbuf; + + scatterwalk_done(&w.in, 0, 1); + sg = w.in.sg; + offset = w.in.offset; + + if (rctx->src != sg) { + rctx->src[0] = *sg; + sg_unmark_end(rctx->src); + scatterwalk_crypto_chain(rctx->src, sg_next(sg), 0, 2); } + rctx->src[0].length -= offset - sg->offset; + rctx->src[0].offset = offset; +out: return err; } -static int encrypt(struct blkcipher_desc *desc, struct scatterlist *dst, - struct scatterlist *src, unsigned int nbytes) +static int init_crypt(struct skcipher_request *req, crypto_completion_t done) { - struct priv *ctx = crypto_blkcipher_ctx(desc->tfm); - struct blkcipher_walk w; + struct priv *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req)); + struct rctx *rctx = skcipher_request_ctx(req); + struct skcipher_request *subreq; + gfp_t gfp; + + subreq = &rctx->subreq; + skcipher_request_set_tfm(subreq, ctx->child); + skcipher_request_set_callback(subreq, req->base.flags, done, req); + + gfp = req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL : + GFP_ATOMIC; + rctx->ext = NULL; + + subreq->cryptlen = XTS_BUFFER_SIZE; + if (req->cryptlen > XTS_BUFFER_SIZE) { + subreq->cryptlen = min(req->cryptlen, (unsigned)PAGE_SIZE); + rctx->ext = kmalloc(subreq->cryptlen, gfp); + } + + rctx->src = req->src; + rctx->dst = req->dst; + rctx->left = req->cryptlen; - 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); + /* calculate first value of T */ + crypto_cipher_encrypt_one(ctx->tweak, (u8 *)&rctx->t, req->iv); + + return 0; } -static int decrypt(struct blkcipher_desc *desc, struct scatterlist *dst, - struct scatterlist *src, unsigned int nbytes) +static void exit_crypt(struct skcipher_request *req) { - struct priv *ctx = crypto_blkcipher_ctx(desc->tfm); - struct blkcipher_walk w; + struct rctx *rctx = skcipher_request_ctx(req); + + rctx->left = 0; - 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); + if (rctx->ext) + kzfree(rctx->ext); +} + +static int do_encrypt(struct skcipher_request *req, int err) +{ + struct rctx *rctx = skcipher_request_ctx(req); + struct skcipher_request *subreq; + + subreq = &rctx->subreq; + + while (!err && rctx->left) { + err = pre_crypt(req) ?: + crypto_skcipher_encrypt(subreq) ?: + post_crypt(req); + + if (err == -EINPROGRESS || + (err == -EBUSY && + req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)) + return err; + } + + exit_crypt(req); + return err; +} + +static void encrypt_done(struct crypto_async_request *areq, int err) +{ + struct skcipher_request *req = areq->data; + struct skcipher_request *subreq; + struct rctx *rctx; + + rctx = skcipher_request_ctx(req); + subreq = &rctx->subreq; + subreq->base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG; + + err = do_encrypt(req, err ?: post_crypt(req)); + if (rctx->left) + return; + + skcipher_request_complete(req, err); +} + +static int encrypt(struct skcipher_request *req) +{ + return do_encrypt(req, init_crypt(req, encrypt_done)); +} + +static int do_decrypt(struct skcipher_request *req, int err) +{ + struct rctx *rctx = skcipher_request_ctx(req); + struct skcipher_request *subreq; + + subreq = &rctx->subreq; + + while (!err && rctx->left) { + err = pre_crypt(req) ?: + crypto_skcipher_decrypt(subreq) ?: + post_crypt(req); + + if (err == -EINPROGRESS || + (err == -EBUSY && + req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)) + return err; + } + + exit_crypt(req); + return err; +} + +static void decrypt_done(struct crypto_async_request *areq, int err) +{ + struct skcipher_request *req = areq->data; + struct skcipher_request *subreq; + struct rctx *rctx; + + rctx = skcipher_request_ctx(req); + subreq = &rctx->subreq; + subreq->base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG; + + err = do_decrypt(req, err ?: post_crypt(req)); + if (rctx->left) + return; + + skcipher_request_complete(req, err); +} + +static int decrypt(struct skcipher_request *req) +{ + return do_decrypt(req, init_crypt(req, decrypt_done)); } int xts_crypt(struct blkcipher_desc *desc, struct scatterlist *sdst, @@ -233,112 +414,168 @@ first: } EXPORT_SYMBOL_GPL(xts_crypt); -static int init_tfm(struct crypto_tfm *tfm) +static int init_tfm(struct crypto_skcipher *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; - } + struct skcipher_instance *inst = skcipher_alg_instance(tfm); + struct xts_instance_ctx *ictx = skcipher_instance_ctx(inst); + struct priv *ctx = crypto_skcipher_ctx(tfm); + struct crypto_skcipher *child; + struct crypto_cipher *tweak; - ctx->child = cipher; + child = crypto_spawn_skcipher(&ictx->spawn); + if (IS_ERR(child)) + return PTR_ERR(child); - cipher = crypto_spawn_cipher(spawn); - if (IS_ERR(cipher)) { - crypto_free_cipher(ctx->child); - return PTR_ERR(cipher); - } + ctx->child = child; - /* this check isn't really needed, leave it here just in case */ - 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; + tweak = crypto_alloc_cipher(ictx->name, 0, 0); + if (IS_ERR(tweak)) { + crypto_free_skcipher(ctx->child); + return PTR_ERR(tweak); } - ctx->tweak = cipher; + ctx->tweak = tweak; + + crypto_skcipher_set_reqsize(tfm, crypto_skcipher_reqsize(child) + + sizeof(struct rctx)); return 0; } -static void exit_tfm(struct crypto_tfm *tfm) +static void exit_tfm(struct crypto_skcipher *tfm) { - struct priv *ctx = crypto_tfm_ctx(tfm); - crypto_free_cipher(ctx->child); + struct priv *ctx = crypto_skcipher_ctx(tfm); + + crypto_free_skcipher(ctx->child); crypto_free_cipher(ctx->tweak); } -static struct crypto_instance *alloc(struct rtattr **tb) +static void free(struct skcipher_instance *inst) +{ + crypto_drop_skcipher(skcipher_instance_ctx(inst)); + kfree(inst); +} + +static int create(struct crypto_template *tmpl, struct rtattr **tb) { - struct crypto_instance *inst; - struct crypto_alg *alg; + struct skcipher_instance *inst; + struct crypto_attr_type *algt; + struct xts_instance_ctx *ctx; + struct skcipher_alg *alg; + const char *cipher_name; int err; - err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER); + algt = crypto_get_attr_type(tb); + if (IS_ERR(algt)) + return PTR_ERR(algt); + + if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask) + return -EINVAL; + + cipher_name = crypto_attr_alg_name(tb[1]); + if (IS_ERR(cipher_name)) + return PTR_ERR(cipher_name); + + inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); + if (!inst) + return -ENOMEM; + + ctx = skcipher_instance_ctx(inst); + + crypto_set_skcipher_spawn(&ctx->spawn, skcipher_crypto_instance(inst)); + err = crypto_grab_skcipher(&ctx->spawn, cipher_name, 0, + crypto_requires_sync(algt->type, + algt->mask)); + if (err == -ENOENT) { + err = -ENAMETOOLONG; + if (snprintf(ctx->name, CRYPTO_MAX_ALG_NAME, "ecb(%s)", + cipher_name) >= CRYPTO_MAX_ALG_NAME) + goto err_free_inst; + + err = crypto_grab_skcipher(&ctx->spawn, ctx->name, 0, + crypto_requires_sync(algt->type, + algt->mask)); + } + if (err) - return ERR_PTR(err); + goto err_free_inst; - alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER, - CRYPTO_ALG_TYPE_MASK); - if (IS_ERR(alg)) - return ERR_CAST(alg); + alg = crypto_skcipher_spawn_alg(&ctx->spawn); - inst = crypto_alloc_instance("xts", alg); - if (IS_ERR(inst)) - goto out_put_alg; + err = -EINVAL; + if (alg->base.cra_blocksize != XTS_BLOCK_SIZE) + goto err_drop_spawn; - inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER; - inst->alg.cra_priority = alg->cra_priority; - inst->alg.cra_blocksize = alg->cra_blocksize; + if (crypto_skcipher_alg_ivsize(alg)) + goto err_drop_spawn; - if (alg->cra_alignmask < 7) - inst->alg.cra_alignmask = 7; - else - inst->alg.cra_alignmask = alg->cra_alignmask; + err = crypto_inst_setname(skcipher_crypto_instance(inst), "xts", + &alg->base); + if (err) + goto err_drop_spawn; - inst->alg.cra_type = &crypto_blkcipher_type; + err = -EINVAL; + cipher_name = alg->base.cra_name; - 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; + /* Alas we screwed up the naming so we have to mangle the + * cipher name. + */ + if (!strncmp(cipher_name, "ecb(", 4)) { + unsigned len; - inst->alg.cra_ctxsize = sizeof(struct priv); + len = strlcpy(ctx->name, cipher_name + 4, sizeof(ctx->name)); + if (len < 2 || len >= sizeof(ctx->name)) + goto err_drop_spawn; - inst->alg.cra_init = init_tfm; - inst->alg.cra_exit = exit_tfm; + if (ctx->name[len - 1] != ')') + goto err_drop_spawn; - inst->alg.cra_blkcipher.setkey = setkey; - inst->alg.cra_blkcipher.encrypt = encrypt; - inst->alg.cra_blkcipher.decrypt = decrypt; + ctx->name[len - 1] = 0; -out_put_alg: - crypto_mod_put(alg); - return inst; -} + if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME, + "xts(%s)", ctx->name) >= CRYPTO_MAX_ALG_NAME) + return -ENAMETOOLONG; + } else + goto err_drop_spawn; -static void free(struct crypto_instance *inst) -{ - crypto_drop_spawn(crypto_instance_ctx(inst)); + inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC; + inst->alg.base.cra_priority = alg->base.cra_priority; + inst->alg.base.cra_blocksize = XTS_BLOCK_SIZE; + inst->alg.base.cra_alignmask = alg->base.cra_alignmask | + (__alignof__(u64) - 1); + + inst->alg.ivsize = XTS_BLOCK_SIZE; + inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) * 2; + inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) * 2; + + inst->alg.base.cra_ctxsize = sizeof(struct priv); + + inst->alg.init = init_tfm; + inst->alg.exit = exit_tfm; + + inst->alg.setkey = setkey; + inst->alg.encrypt = encrypt; + inst->alg.decrypt = decrypt; + + inst->free = free; + + err = skcipher_register_instance(tmpl, inst); + if (err) + goto err_drop_spawn; + +out: + return err; + +err_drop_spawn: + crypto_drop_skcipher(&ctx->spawn); +err_free_inst: kfree(inst); + goto out; } static struct crypto_template crypto_tmpl = { .name = "xts", - .alloc = alloc, - .free = free, + .create = create, .module = THIS_MODULE, }; diff --git a/include/crypto/xts.h b/include/crypto/xts.h index ede6b97..77b6306 100644 --- a/include/crypto/xts.h +++ b/include/crypto/xts.h @@ -2,8 +2,7 @@ #define _CRYPTO_XTS_H #include <crypto/b128ops.h> -#include <linux/crypto.h> -#include <crypto/algapi.h> +#include <crypto/internal/skcipher.h> #include <linux/fips.h> struct scatterlist; @@ -51,4 +50,27 @@ static inline int xts_check_key(struct crypto_tfm *tfm, return 0; } +static inline int xts_verify_key(struct crypto_skcipher *tfm, + const u8 *key, unsigned int keylen) +{ + /* + * key consists of keys of equal size concatenated, therefore + * the length must be even. + */ + if (keylen % 2) { + crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN); + return -EINVAL; + } + + /* ensure that the AES and tweak key are not identical */ + if ((fips_enabled || crypto_skcipher_get_flags(tfm) & + CRYPTO_TFM_REQ_WEAK_KEY) && + !crypto_memneq(key, key + (keylen / 2), keylen / 2)) { + crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_WEAK_KEY); + return -EINVAL; + } + + return 0; +} + #endif /* _CRYPTO_XTS_H */ |