cregit-Linux how code gets into the kernel

Release 4.11 crypto/xts.c

Directory: crypto
/* XTS: as defined in IEEE1619/D16
 *      http://grouper.ieee.org/groups/1619/email/pdf00086.pdf
 *      (sector sizes which are not a multiple of 16 bytes are,
 *      however currently unsupported)
 *
 * Copyright (c) 2007 Rik Snel <rsnel@cube.dyndns.org>
 *
 * Based on ecb.c
 * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 */
#include <crypto/internal/skcipher.h>
#include <crypto/scatterwalk.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>

#include <crypto/xts.h>
#include <crypto/b128ops.h>
#include <crypto/gf128mul.h>


#define XTS_BUFFER_SIZE 128u


struct priv {
	
struct crypto_skcipher *child;
	
struct crypto_cipher *tweak;
};


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_skcipher_ctx(parent); struct crypto_skcipher *child; struct crypto_cipher *tweak; int err; 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 */ 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(tweak, key + keylen, keylen); crypto_skcipher_set_flags(parent, crypto_cipher_get_flags(tweak) & CRYPTO_TFM_RES_MASK); if (err) return err; /* 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); return err; }

Contributors

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Rik Snel12470.45%125.00%
Herbert Xu3922.16%125.00%
Stephan Mueller126.82%125.00%
Lucas De Marchi10.57%125.00%
Total176100.00%4100.00%


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; subreq = &rctx->subreq; err = skcipher_walk_virt(&w, subreq, false); while (w.nbytes) { unsigned int avail = w.nbytes; be128 *wdst; 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; }

Contributors

PersonTokensPropCommitsCommitProp
Herbert Xu25291.30%133.33%
Rik Snel238.33%133.33%
Sebastian Andrzej Siewior10.36%133.33%
Total276100.00%3100.00%


static int pre_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 cryptlen; unsigned offset; bool more; int err; subreq = &rctx->subreq; cryptlen = subreq->cryptlen; more = rctx->left > cryptlen; if (!more) cryptlen = rctx->left; skcipher_request_set_crypt(subreq, rctx->src, rctx->dst, cryptlen, NULL); err = skcipher_walk_virt(&w, subreq, false); while (w.nbytes) { unsigned int avail = w.nbytes; be128 *wsrc; be128 *wdst; wsrc = w.src.virt.addr; wdst = w.dst.virt.addr; do { *buf++ = rctx->t; be128_xor(wdst++, &rctx->t, wsrc++); gf128mul_x_ble(&rctx->t, &rctx->t); } while ((avail -= bs) >= bs); err = skcipher_walk_done(&w, avail); } skcipher_request_set_crypt(subreq, rctx->dst, rctx->dst, cryptlen, NULL); if (err || !more) goto out; 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; }

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Herbert Xu33089.92%125.00%
Rik Snel338.99%125.00%
Sebastian Andrzej Siewior30.82%125.00%
Jussi Kivilinna10.27%125.00%
Total367100.00%4100.00%


static int init_crypt(struct skcipher_request *req, crypto_completion_t done) { 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) { unsigned int n = min(req->cryptlen, (unsigned int)PAGE_SIZE); rctx->ext = kmalloc(n, gfp); if (rctx->ext) subreq->cryptlen = n; } rctx->src = req->src; rctx->dst = req->dst; rctx->left = req->cryptlen; /* calculate first value of T */ crypto_cipher_encrypt_one(ctx->tweak, (u8 *)&rctx->t, req->iv); return 0; }

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Herbert Xu18190.50%150.00%
Eric Biggers199.50%150.00%
Total200100.00%2100.00%


static void exit_crypt(struct skcipher_request *req) { struct rctx *rctx = skcipher_request_ctx(req); rctx->left = 0; if (rctx->ext) kzfree(rctx->ext); }

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Herbert Xu40100.00%1100.00%
Total40100.00%1100.00%


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; }

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Herbert Xu99100.00%1100.00%
Total99100.00%1100.00%


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); if (err == -EINPROGRESS) { if (rctx->left != req->cryptlen) return; goto out; } subreq = &rctx->subreq; subreq->base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG; err = do_encrypt(req, err ?: post_crypt(req)); if (rctx->left) return; out: skcipher_request_complete(req, err); }

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Herbert Xu9587.16%266.67%
Rik Snel1412.84%133.33%
Total109100.00%3100.00%


static int encrypt(struct skcipher_request *req) { return do_encrypt(req, init_crypt(req, encrypt_done)); }

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Herbert Xu1979.17%150.00%
Rik Snel520.83%150.00%
Total24100.00%2100.00%


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; }

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Herbert Xu8282.83%150.00%
Rik Snel1717.17%150.00%
Total99100.00%2100.00%


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); if (err == -EINPROGRESS) { if (rctx->left != req->cryptlen) return; goto out; } subreq = &rctx->subreq; subreq->base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG; err = do_decrypt(req, err ?: post_crypt(req)); if (rctx->left) return; out: skcipher_request_complete(req, err); }

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Herbert Xu8275.23%266.67%
Rik Snel2724.77%133.33%
Total109100.00%3100.00%


static int decrypt(struct skcipher_request *req) { return do_decrypt(req, init_crypt(req, decrypt_done)); }

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Rik Snel1770.83%150.00%
Herbert Xu729.17%150.00%
Total24100.00%2100.00%


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; /* calculate first value of T */ 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]; /* PP <- T xor P */ be128_xor(dst + i, t, src + i); } /* CC <- E(Key2,PP) */ req->crypt_fn(req->crypt_ctx, (u8 *)dst, nblocks * bsize); /* C <- T xor CC */ 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; }

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Jussi Kivilinna40798.79%150.00%
Herbert Xu51.21%150.00%
Total412100.00%2100.00%

EXPORT_SYMBOL_GPL(xts_crypt);
static int init_tfm(struct crypto_skcipher *tfm) { 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; child = crypto_spawn_skcipher(&ictx->spawn); if (IS_ERR(child)) return PTR_ERR(child); ctx->child = child; tweak = crypto_alloc_cipher(ictx->name, 0, 0); if (IS_ERR(tweak)) { crypto_free_skcipher(ctx->child); return PTR_ERR(tweak); } ctx->tweak = tweak; crypto_skcipher_set_reqsize(tfm, crypto_skcipher_reqsize(child) + sizeof(struct rctx)); return 0; }

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Herbert Xu140100.00%1100.00%
Total140100.00%1100.00%


static void exit_tfm(struct crypto_skcipher *tfm) { struct priv *ctx = crypto_skcipher_ctx(tfm); crypto_free_skcipher(ctx->child); crypto_free_cipher(ctx->tweak); }

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Herbert Xu35100.00%1100.00%
Total35100.00%1100.00%


static void free(struct skcipher_instance *inst) { crypto_drop_skcipher(skcipher_instance_ctx(inst)); kfree(inst); }

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Herbert Xu2187.50%150.00%
Jussi Kivilinna312.50%150.00%
Total24100.00%2100.00%


static int create(struct crypto_template *tmpl, struct rtattr **tb) { struct skcipher_instance *inst; struct crypto_attr_type *algt; struct xts_instance_ctx *ctx; struct skcipher_alg *alg; const char *cipher_name; u32 mask; int err; 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)); mask = crypto_requires_off(algt->type, algt->mask, CRYPTO_ALG_NEED_FALLBACK | CRYPTO_ALG_ASYNC); err = crypto_grab_skcipher(&ctx->spawn, cipher_name, 0, 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, mask); } if (err) goto err_free_inst; alg = crypto_skcipher_spawn_alg(&ctx->spawn); err = -EINVAL; if (alg->base.cra_blocksize != XTS_BLOCK_SIZE) goto err_drop_spawn; if (crypto_skcipher_alg_ivsize(alg)) goto err_drop_spawn; err = crypto_inst_setname(skcipher_crypto_instance(inst), "xts", &alg->base); if (err) goto err_drop_spawn; err = -EINVAL; cipher_name = alg->base.cra_name; /* Alas we screwed up the naming so we have to mangle the * cipher name. */ if (!strncmp(cipher_name, "ecb(", 4)) { unsigned len; len = strlcpy(ctx->name, cipher_name + 4, sizeof(ctx->name)); if (len < 2 || len >= sizeof(ctx->name)) goto err_drop_spawn; if (ctx->name[len - 1] != ')') goto err_drop_spawn; ctx->name[len - 1] = 0; 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; 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; }

Contributors

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Herbert Xu39862.58%266.67%
Rik Snel23837.42%133.33%
Total636100.00%3100.00%

static struct crypto_template crypto_tmpl = { .name = "xts", .create = create, .module = THIS_MODULE, };
static int __init crypto_module_init(void) { return crypto_register_template(&crypto_tmpl); }

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Rik Snel16100.00%1100.00%
Total16100.00%1100.00%


static void __exit crypto_module_exit(void) { crypto_unregister_template(&crypto_tmpl); }

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Rik Snel15100.00%1100.00%
Total15100.00%1100.00%

module_init(crypto_module_init); module_exit(crypto_module_exit); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("XTS block cipher mode"); MODULE_ALIAS_CRYPTO("xts");

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Herbert Xu191164.21%325.00%
Rik Snel60920.46%18.33%
Jussi Kivilinna41413.91%216.67%
Eric Biggers190.64%18.33%
Stephan Mueller120.40%18.33%
Kees Cook50.17%18.33%
Sebastian Andrzej Siewior40.13%18.33%
Lucas De Marchi10.03%18.33%
Corentin Labbe10.03%18.33%
Total2976100.00%12100.00%
Directory: crypto
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