| 1 | |
| 2 | |
| 3 | * ESSIV skcipher and aead template for block encryption
|
| 4 | *
|
| 5 | * This template encapsulates the ESSIV IV generation algorithm used by
|
| 6 | * dm-crypt and fscrypt, which converts the initial vector for the skcipher
|
| 7 | * used for block encryption, by encrypting it using the hash of the
|
| 8 | * skcipher key as encryption key. Usually, the input IV is a 64-bit sector
|
| 9 | * number in LE representation zero-padded to the size of the IV, but this
|
| 10 | * is not assumed by this driver.
|
| 11 | *
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| 12 | * The typical use of this template is to instantiate the skcipher
|
| 13 | * 'essiv(cbc(aes),sha256)', which is the only instantiation used by
|
| 14 | * fscrypt, and the most relevant one for dm-crypt. However, dm-crypt
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| 15 | * also permits ESSIV to be used in combination with the authenc template,
|
| 16 | * e.g., 'essiv(authenc(hmac(sha256),cbc(aes)),sha256)', in which case
|
| 17 | * we need to instantiate an aead that accepts the same special key format
|
| 18 | * as the authenc template, and deals with the way the encrypted IV is
|
| 19 | * embedded into the AAD area of the aead request. This means the AEAD
|
| 20 | * flavor produced by this template is tightly coupled to the way dm-crypt
|
| 21 | * happens to use it.
|
| 22 | *
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| 23 | * Copyright (c) 2019 Linaro, Ltd. <[email protected]>
|
| 24 | *
|
| 25 | * Heavily based on:
|
| 26 | * adiantum length-preserving encryption mode
|
| 27 | *
|
| 28 | * Copyright 2018 Google LLC
|
| 29 |
|
| 30 |
|
| 31 | #include <crypto/authenc.h>
|
| 32 | #include <crypto/internal/aead.h>
|
| 33 | #include <crypto/internal/cipher.h>
|
| 34 | #include <crypto/internal/hash.h>
|
| 35 | #include <crypto/internal/skcipher.h>
|
| 36 | #include <crypto/scatterwalk.h>
|
| 37 | #include <linux/module.h>
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| 38 |
|
| 39 | #include "internal.h"
|
| 40 |
|
| 41 | struct essiv_instance_ctx {
|
| 42 | union {
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| 43 | struct crypto_skcipher_spawn skcipher_spawn;
|
| 44 | struct crypto_aead_spawn aead_spawn;
|
| 45 | } u;
|
| 46 | char essiv_cipher_name[CRYPTO_MAX_ALG_NAME];
|
| 47 | char shash_driver_name[CRYPTO_MAX_ALG_NAME];
|
| 48 | };
|
| 49 |
|
| 50 | struct essiv_tfm_ctx {
|
| 51 | union {
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| 52 | struct crypto_skcipher *skcipher;
|
| 53 | struct crypto_aead *aead;
|
| 54 | } u;
|
| 55 | struct crypto_cipher *essiv_cipher;
|
| 56 | struct crypto_shash *hash;
|
| 57 | int ivoffset;
|
| 58 | };
|
| 59 |
|
| 60 | struct essiv_aead_request_ctx {
|
| 61 | struct scatterlist sg[4];
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| 62 | u8 *assoc;
|
| 63 | struct aead_request aead_req;
|
| 64 | };
|
| 65 |
|
| 66 | static int essiv_skcipher_setkey(struct crypto_skcipher *tfm,
|
| 67 | const u8 *key, unsigned int keylen)
|
| 68 | {
|
| 69 | struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
|
| 70 | u8 salt[HASH_MAX_DIGESTSIZE];
|
| 71 | int err;
|
| 72 |
|
| 73 | crypto_skcipher_clear_flags(tctx->u.skcipher, CRYPTO_TFM_REQ_MASK);
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| 74 | crypto_skcipher_set_flags(tctx->u.skcipher,
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| 75 | crypto_skcipher_get_flags(tfm) &
|
| 76 | CRYPTO_TFM_REQ_MASK);
|
| 77 | err = crypto_skcipher_setkey(tctx->u.skcipher, key, keylen);
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| 78 | if (err)
|
| 79 | return err;
|
| 80 |
|
| 81 | err = crypto_shash_tfm_digest(tctx->hash, key, keylen, salt);
|
| 82 | if (err)
|
| 83 | return err;
|
| 84 |
|
| 85 | crypto_cipher_clear_flags(tctx->essiv_cipher, CRYPTO_TFM_REQ_MASK);
|
| 86 | crypto_cipher_set_flags(tctx->essiv_cipher,
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| 87 | crypto_skcipher_get_flags(tfm) &
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| 88 | CRYPTO_TFM_REQ_MASK);
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| 89 | return crypto_cipher_setkey(tctx->essiv_cipher, salt,
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| 90 | crypto_shash_digestsize(tctx->hash));
|
| 91 | }
|
| 92 |
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| 93 | static int essiv_aead_setkey(struct crypto_aead *tfm, const u8 *key,
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| 94 | unsigned int keylen)
|
| 95 | {
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| 96 | struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
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| 97 | SHASH_DESC_ON_STACK(desc, tctx->hash);
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| 98 | struct crypto_authenc_keys keys;
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| 99 | u8 salt[HASH_MAX_DIGESTSIZE];
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| 100 | int err;
|
| 101 |
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| 102 | crypto_aead_clear_flags(tctx->u.aead, CRYPTO_TFM_REQ_MASK);
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| 103 | crypto_aead_set_flags(tctx->u.aead, crypto_aead_get_flags(tfm) &
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| 104 | CRYPTO_TFM_REQ_MASK);
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| 105 | err = crypto_aead_setkey(tctx->u.aead, key, keylen);
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| 106 | if (err)
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| 107 | return err;
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| 108 |
|
| 109 | if (crypto_authenc_extractkeys(&keys, key, keylen) != 0)
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| 110 | return -EINVAL;
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| 111 |
|
| 112 | desc->tfm = tctx->hash;
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| 113 | err = crypto_shash_init(desc) ?:
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| 114 | crypto_shash_update(desc, keys.enckey, keys.enckeylen) ?:
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| 115 | crypto_shash_finup(desc, keys.authkey, keys.authkeylen, salt);
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| 116 | if (err)
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| 117 | return err;
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| 118 |
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| 119 | crypto_cipher_clear_flags(tctx->essiv_cipher, CRYPTO_TFM_REQ_MASK);
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| 120 | crypto_cipher_set_flags(tctx->essiv_cipher, crypto_aead_get_flags(tfm) &
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| 121 | CRYPTO_TFM_REQ_MASK);
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| 122 | return crypto_cipher_setkey(tctx->essiv_cipher, salt,
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| 123 | crypto_shash_digestsize(tctx->hash));
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| 124 | }
|
| 125 |
|
| 126 | static int essiv_aead_setauthsize(struct crypto_aead *tfm,
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| 127 | unsigned int authsize)
|
| 128 | {
|
| 129 | struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
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| 130 |
|
| 131 | return crypto_aead_setauthsize(tctx->u.aead, authsize);
|
| 132 | }
|
| 133 |
|
| 134 | static void essiv_skcipher_done(void *data, int err)
|
| 135 | {
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| 136 | struct skcipher_request *req = data;
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| 137 |
|
| 138 | skcipher_request_complete(req, err);
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| 139 | }
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| 140 |
|
| 141 | static int essiv_skcipher_crypt(struct skcipher_request *req, bool enc)
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| 142 | {
|
| 143 | struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
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| 144 | const struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
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| 145 | struct skcipher_request *subreq = skcipher_request_ctx(req);
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| 146 |
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| 147 | crypto_cipher_encrypt_one(tctx->essiv_cipher, req->iv, req->iv);
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| 148 |
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| 149 | skcipher_request_set_tfm(subreq, tctx->u.skcipher);
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| 150 | skcipher_request_set_crypt(subreq, req->src, req->dst, req->cryptlen,
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| 151 | req->iv);
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| 152 | skcipher_request_set_callback(subreq, skcipher_request_flags(req),
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| 153 | essiv_skcipher_done, req);
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| 154 |
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| 155 | return enc ? crypto_skcipher_encrypt(subreq) :
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| 156 | crypto_skcipher_decrypt(subreq);
|
| 157 | }
|
| 158 |
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| 159 | static int essiv_skcipher_encrypt(struct skcipher_request *req)
|
| 160 | {
|
| 161 | return essiv_skcipher_crypt(req, true);
|
| 162 | }
|
| 163 |
|
| 164 | static int essiv_skcipher_decrypt(struct skcipher_request *req)
|
| 165 | {
|
| 166 | return essiv_skcipher_crypt(req, false);
|
| 167 | }
|
| 168 |
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| 169 | static void essiv_aead_done(void *data, int err)
|
| 170 | {
|
| 171 | struct aead_request *req = data;
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| 172 | struct essiv_aead_request_ctx *rctx = aead_request_ctx(req);
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| 173 |
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| 174 | if (err == -EINPROGRESS)
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| 175 | goto out;
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| 176 |
|
| 177 | kfree(rctx->assoc);
|
| 178 |
|
| 179 | out:
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| 180 | aead_request_complete(req, err);
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| 181 | }
|
| 182 |
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| 183 | static int essiv_aead_crypt(struct aead_request *req, bool enc)
|
| 184 | {
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| 185 | struct crypto_aead *tfm = crypto_aead_reqtfm(req);
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| 186 | const struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
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| 187 | struct essiv_aead_request_ctx *rctx = aead_request_ctx(req);
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| 188 | struct aead_request *subreq = &rctx->aead_req;
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| 189 | int ivsize = crypto_aead_ivsize(tfm);
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| 190 | int ssize = req->assoclen - ivsize;
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| 191 | struct scatterlist *src = req->src;
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| 192 | int err;
|
| 193 |
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| 194 | if (ssize < 0)
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| 195 | return -EINVAL;
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| 196 |
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| 197 | crypto_cipher_encrypt_one(tctx->essiv_cipher, req->iv, req->iv);
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| 198 |
|
| 199 | |
| 200 | * dm-crypt embeds the sector number and the IV in the AAD region, so
|
| 201 | * we have to copy the converted IV into the right scatterlist before
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| 202 | * we pass it on.
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| 203 |
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| 204 | rctx->assoc = NULL;
|
| 205 | if (req->src == req->dst || !enc) {
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| 206 | scatterwalk_map_and_copy(req->iv, req->dst, ssize, ivsize, 1);
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| 207 | } else {
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| 208 | u8 *iv = (u8 *)aead_request_ctx(req) + tctx->ivoffset;
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| 209 | struct scatterlist *sg;
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| 210 | int nents;
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| 211 |
|
| 212 | nents = sg_nents_for_len(req->src, ssize);
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| 213 | if (nents < 0)
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| 214 | return -EINVAL;
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| 215 |
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| 216 | memcpy(iv, req->iv, ivsize);
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| 217 | sg_init_table(rctx->sg, 4);
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| 218 |
|
| 219 | if (unlikely(nents > 1)) {
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| 220 | |
| 221 | * This is a case that rarely occurs in practice, but
|
| 222 | * for correctness, we have to deal with it nonetheless.
|
| 223 |
|
| 224 | rctx->assoc = kmalloc(ssize, GFP_ATOMIC);
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| 225 | if (!rctx->assoc)
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| 226 | return -ENOMEM;
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| 227 |
|
| 228 | scatterwalk_map_and_copy(rctx->assoc, req->src, 0,
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| 229 | ssize, 0);
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| 230 | sg_set_buf(rctx->sg, rctx->assoc, ssize);
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| 231 | } else {
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| 232 | sg_set_page(rctx->sg, sg_page(req->src), ssize,
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| 233 | req->src->offset);
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| 234 | }
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| 235 |
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| 236 | sg_set_buf(rctx->sg + 1, iv, ivsize);
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| 237 | sg = scatterwalk_ffwd(rctx->sg + 2, req->src, req->assoclen);
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| 238 | if (sg != rctx->sg + 2)
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| 239 | sg_chain(rctx->sg, 3, sg);
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| 240 |
|
| 241 | src = rctx->sg;
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| 242 | }
|
| 243 |
|
| 244 | aead_request_set_tfm(subreq, tctx->u.aead);
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| 245 | aead_request_set_ad(subreq, req->assoclen);
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| 246 | aead_request_set_callback(subreq, aead_request_flags(req),
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| 247 | essiv_aead_done, req);
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| 248 | aead_request_set_crypt(subreq, src, req->dst, req->cryptlen, req->iv);
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| 249 |
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| 250 | err = enc ? crypto_aead_encrypt(subreq) :
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| 251 | crypto_aead_decrypt(subreq);
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| 252 |
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| 253 | if (rctx->assoc && err != -EINPROGRESS && err != -EBUSY)
|
| 254 | kfree(rctx->assoc);
|
| 255 | return err;
|
| 256 | }
|
| 257 |
|
| 258 | static int essiv_aead_encrypt(struct aead_request *req)
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| 259 | {
|
| 260 | return essiv_aead_crypt(req, true);
|
| 261 | }
|
| 262 |
|
| 263 | static int essiv_aead_decrypt(struct aead_request *req)
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| 264 | {
|
| 265 | return essiv_aead_crypt(req, false);
|
| 266 | }
|
| 267 |
|
| 268 | static int essiv_init_tfm(struct essiv_instance_ctx *ictx,
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| 269 | struct essiv_tfm_ctx *tctx)
|
| 270 | {
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| 271 | struct crypto_cipher *essiv_cipher;
|
| 272 | struct crypto_shash *hash;
|
| 273 | int err;
|
| 274 |
|
| 275 | essiv_cipher = crypto_alloc_cipher(ictx->essiv_cipher_name, 0, 0);
|
| 276 | if (IS_ERR(essiv_cipher))
|
| 277 | return PTR_ERR(essiv_cipher);
|
| 278 |
|
| 279 | hash = crypto_alloc_shash(ictx->shash_driver_name, 0, 0);
|
| 280 | if (IS_ERR(hash)) {
|
| 281 | err = PTR_ERR(hash);
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| 282 | goto err_free_essiv_cipher;
|
| 283 | }
|
| 284 |
|
| 285 | tctx->essiv_cipher = essiv_cipher;
|
| 286 | tctx->hash = hash;
|
| 287 |
|
| 288 | return 0;
|
| 289 |
|
| 290 | err_free_essiv_cipher:
|
| 291 | crypto_free_cipher(essiv_cipher);
|
| 292 | return err;
|
| 293 | }
|
| 294 |
|
| 295 | static int essiv_skcipher_init_tfm(struct crypto_skcipher *tfm)
|
| 296 | {
|
| 297 | struct skcipher_instance *inst = skcipher_alg_instance(tfm);
|
| 298 | struct essiv_instance_ctx *ictx = skcipher_instance_ctx(inst);
|
| 299 | struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
|
| 300 | struct crypto_skcipher *skcipher;
|
| 301 | int err;
|
| 302 |
|
| 303 | skcipher = crypto_spawn_skcipher(&ictx->u.skcipher_spawn);
|
| 304 | if (IS_ERR(skcipher))
|
| 305 | return PTR_ERR(skcipher);
|
| 306 |
|
| 307 | crypto_skcipher_set_reqsize(tfm, sizeof(struct skcipher_request) +
|
| 308 | crypto_skcipher_reqsize(skcipher));
|
| 309 |
|
| 310 | err = essiv_init_tfm(ictx, tctx);
|
| 311 | if (err) {
|
| 312 | crypto_free_skcipher(skcipher);
|
| 313 | return err;
|
| 314 | }
|
| 315 |
|
| 316 | tctx->u.skcipher = skcipher;
|
| 317 | return 0;
|
| 318 | }
|
| 319 |
|
| 320 | static int essiv_aead_init_tfm(struct crypto_aead *tfm)
|
| 321 | {
|
| 322 | struct aead_instance *inst = aead_alg_instance(tfm);
|
| 323 | struct essiv_instance_ctx *ictx = aead_instance_ctx(inst);
|
| 324 | struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
|
| 325 | struct crypto_aead *aead;
|
| 326 | unsigned int subreq_size;
|
| 327 | int err;
|
| 328 |
|
| 329 | BUILD_BUG_ON(offsetofend(struct essiv_aead_request_ctx, aead_req) !=
|
| 330 | sizeof(struct essiv_aead_request_ctx));
|
| 331 |
|
| 332 | aead = crypto_spawn_aead(&ictx->u.aead_spawn);
|
| 333 | if (IS_ERR(aead))
|
| 334 | return PTR_ERR(aead);
|
| 335 |
|
| 336 | subreq_size = sizeof_field(struct essiv_aead_request_ctx, aead_req) +
|
| 337 | crypto_aead_reqsize(aead);
|
| 338 |
|
| 339 | tctx->ivoffset = offsetof(struct essiv_aead_request_ctx, aead_req) +
|
| 340 | subreq_size;
|
| 341 | crypto_aead_set_reqsize(tfm, tctx->ivoffset + crypto_aead_ivsize(aead));
|
| 342 |
|
| 343 | err = essiv_init_tfm(ictx, tctx);
|
| 344 | if (err) {
|
| 345 | crypto_free_aead(aead);
|
| 346 | return err;
|
| 347 | }
|
| 348 |
|
| 349 | tctx->u.aead = aead;
|
| 350 | return 0;
|
| 351 | }
|
| 352 |
|
| 353 | static void essiv_skcipher_exit_tfm(struct crypto_skcipher *tfm)
|
| 354 | {
|
| 355 | struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
|
| 356 |
|
| 357 | crypto_free_skcipher(tctx->u.skcipher);
|
| 358 | crypto_free_cipher(tctx->essiv_cipher);
|
| 359 | crypto_free_shash(tctx->hash);
|
| 360 | }
|
| 361 |
|
| 362 | static void essiv_aead_exit_tfm(struct crypto_aead *tfm)
|
| 363 | {
|
| 364 | struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
|
| 365 |
|
| 366 | crypto_free_aead(tctx->u.aead);
|
| 367 | crypto_free_cipher(tctx->essiv_cipher);
|
| 368 | crypto_free_shash(tctx->hash);
|
| 369 | }
|
| 370 |
|
| 371 | static void essiv_skcipher_free_instance(struct skcipher_instance *inst)
|
| 372 | {
|
| 373 | struct essiv_instance_ctx *ictx = skcipher_instance_ctx(inst);
|
| 374 |
|
| 375 | crypto_drop_skcipher(&ictx->u.skcipher_spawn);
|
| 376 | kfree(inst);
|
| 377 | }
|
| 378 |
|
| 379 | static void essiv_aead_free_instance(struct aead_instance *inst)
|
| 380 | {
|
| 381 | struct essiv_instance_ctx *ictx = aead_instance_ctx(inst);
|
| 382 |
|
| 383 | crypto_drop_aead(&ictx->u.aead_spawn);
|
| 384 | kfree(inst);
|
| 385 | }
|
| 386 |
|
| 387 | static bool parse_cipher_name(char *essiv_cipher_name, const char *cra_name)
|
| 388 | {
|
| 389 | const char *p, *q;
|
| 390 | int len;
|
| 391 |
|
| 392 |
|
| 393 | p = strrchr(cra_name, '(');
|
| 394 | if (!p++)
|
| 395 | return false;
|
| 396 |
|
| 397 |
|
| 398 | q = strchr(p, ')');
|
| 399 | if (!q)
|
| 400 | return false;
|
| 401 |
|
| 402 | len = q - p;
|
| 403 | if (len >= CRYPTO_MAX_ALG_NAME)
|
| 404 | return false;
|
| 405 |
|
| 406 | strscpy(essiv_cipher_name, p, len + 1);
|
| 407 | return true;
|
| 408 | }
|
| 409 |
|
| 410 | static bool essiv_supported_algorithms(const char *essiv_cipher_name,
|
| 411 | struct shash_alg *hash_alg,
|
| 412 | int ivsize)
|
| 413 | {
|
| 414 | struct crypto_alg *alg;
|
| 415 | bool ret = false;
|
| 416 |
|
| 417 | alg = crypto_alg_mod_lookup(essiv_cipher_name,
|
| 418 | CRYPTO_ALG_TYPE_CIPHER,
|
| 419 | CRYPTO_ALG_TYPE_MASK);
|
| 420 | if (IS_ERR(alg))
|
| 421 | return false;
|
| 422 |
|
| 423 | if (hash_alg->digestsize < alg->cra_cipher.cia_min_keysize ||
|
| 424 | hash_alg->digestsize > alg->cra_cipher.cia_max_keysize)
|
| 425 | goto out;
|
| 426 |
|
| 427 | if (ivsize != alg->cra_blocksize)
|
| 428 | goto out;
|
| 429 |
|
| 430 | if (crypto_shash_alg_needs_key(hash_alg))
|
| 431 | goto out;
|
| 432 |
|
| 433 | ret = true;
|
| 434 |
|
| 435 | out:
|
| 436 | crypto_mod_put(alg);
|
| 437 | return ret;
|
| 438 | }
|
| 439 |
|
| 440 | static int essiv_create(struct crypto_template *tmpl, struct rtattr **tb)
|
| 441 | {
|
| 442 | struct skcipher_alg_common *skcipher_alg = NULL;
|
| 443 | struct crypto_attr_type *algt;
|
| 444 | const char *inner_cipher_name;
|
| 445 | const char *shash_name;
|
| 446 | struct skcipher_instance *skcipher_inst = NULL;
|
| 447 | struct aead_instance *aead_inst = NULL;
|
| 448 | struct crypto_instance *inst;
|
| 449 | struct crypto_alg *base, *block_base;
|
| 450 | struct essiv_instance_ctx *ictx;
|
| 451 | struct aead_alg *aead_alg = NULL;
|
| 452 | struct crypto_alg *_hash_alg;
|
| 453 | struct shash_alg *hash_alg;
|
| 454 | int ivsize;
|
| 455 | u32 type;
|
| 456 | u32 mask;
|
| 457 | int err;
|
| 458 |
|
| 459 | algt = crypto_get_attr_type(tb);
|
| 460 | if (IS_ERR(algt))
|
| 461 | return PTR_ERR(algt);
|
| 462 |
|
| 463 | inner_cipher_name = crypto_attr_alg_name(tb[1]);
|
| 464 | if (IS_ERR(inner_cipher_name))
|
| 465 | return PTR_ERR(inner_cipher_name);
|
| 466 |
|
| 467 | shash_name = crypto_attr_alg_name(tb[2]);
|
| 468 | if (IS_ERR(shash_name))
|
| 469 | return PTR_ERR(shash_name);
|
| 470 |
|
| 471 | type = algt->type & algt->mask;
|
| 472 | mask = crypto_algt_inherited_mask(algt);
|
| 473 |
|
| 474 | switch (type) {
|
| 475 | case CRYPTO_ALG_TYPE_LSKCIPHER:
|
| 476 | skcipher_inst = kzalloc(sizeof(*skcipher_inst) +
|
| 477 | sizeof(*ictx), GFP_KERNEL);
|
| 478 | if (!skcipher_inst)
|
| 479 | return -ENOMEM;
|
| 480 | inst = skcipher_crypto_instance(skcipher_inst);
|
| 481 | base = &skcipher_inst->alg.base;
|
| 482 | ictx = crypto_instance_ctx(inst);
|
| 483 |
|
| 484 |
|
| 485 | err = crypto_grab_skcipher(&ictx->u.skcipher_spawn, inst,
|
| 486 | inner_cipher_name, 0, mask);
|
| 487 | if (err)
|
| 488 | goto out_free_inst;
|
| 489 | skcipher_alg = crypto_spawn_skcipher_alg_common(
|
| 490 | &ictx->u.skcipher_spawn);
|
| 491 | block_base = &skcipher_alg->base;
|
| 492 | ivsize = skcipher_alg->ivsize;
|
| 493 | break;
|
| 494 |
|
| 495 | case CRYPTO_ALG_TYPE_AEAD:
|
| 496 | aead_inst = kzalloc(sizeof(*aead_inst) +
|
| 497 | sizeof(*ictx), GFP_KERNEL);
|
| 498 | if (!aead_inst)
|
| 499 | return -ENOMEM;
|
| 500 | inst = aead_crypto_instance(aead_inst);
|
| 501 | base = &aead_inst->alg.base;
|
| 502 | ictx = crypto_instance_ctx(inst);
|
| 503 |
|
| 504 |
|
| 505 | err = crypto_grab_aead(&ictx->u.aead_spawn, inst,
|
| 506 | inner_cipher_name, 0, mask);
|
| 507 | if (err)
|
| 508 | goto out_free_inst;
|
| 509 | aead_alg = crypto_spawn_aead_alg(&ictx->u.aead_spawn);
|
| 510 | block_base = &aead_alg->base;
|
| 511 | if (!strstarts(block_base->cra_name, "authenc(")) {
|
| 512 | pr_warn("Only authenc() type AEADs are supported by ESSIV\n");
|
| 513 | err = -EINVAL;
|
| 514 | goto out_drop_skcipher;
|
| 515 | }
|
| 516 | ivsize = aead_alg->ivsize;
|
| 517 | break;
|
| 518 |
|
| 519 | default:
|
| 520 | return -EINVAL;
|
| 521 | }
|
| 522 |
|
| 523 | if (!parse_cipher_name(ictx->essiv_cipher_name, block_base->cra_name)) {
|
| 524 | pr_warn("Failed to parse ESSIV cipher name from skcipher cra_name\n");
|
| 525 | err = -EINVAL;
|
| 526 | goto out_drop_skcipher;
|
| 527 | }
|
| 528 |
|
| 529 |
|
| 530 | _hash_alg = crypto_alg_mod_lookup(shash_name,
|
| 531 | CRYPTO_ALG_TYPE_SHASH,
|
| 532 | CRYPTO_ALG_TYPE_MASK | mask);
|
| 533 | if (IS_ERR(_hash_alg)) {
|
| 534 | err = PTR_ERR(_hash_alg);
|
| 535 | goto out_drop_skcipher;
|
| 536 | }
|
| 537 | hash_alg = __crypto_shash_alg(_hash_alg);
|
| 538 |
|
| 539 |
|
| 540 | if (!essiv_supported_algorithms(ictx->essiv_cipher_name, hash_alg,
|
| 541 | ivsize)) {
|
| 542 | pr_warn("Unsupported essiv instantiation: essiv(%s,%s)\n",
|
| 543 | block_base->cra_name, hash_alg->base.cra_name);
|
| 544 | err = -EINVAL;
|
| 545 | goto out_free_hash;
|
| 546 | }
|
| 547 |
|
| 548 |
|
| 549 | strscpy(ictx->shash_driver_name, hash_alg->base.cra_driver_name);
|
| 550 |
|
| 551 |
|
| 552 |
|
| 553 | err = -ENAMETOOLONG;
|
| 554 | if (snprintf(base->cra_name, CRYPTO_MAX_ALG_NAME,
|
| 555 | "essiv(%s,%s)", block_base->cra_name,
|
| 556 | hash_alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
|
| 557 | goto out_free_hash;
|
| 558 | if (snprintf(base->cra_driver_name, CRYPTO_MAX_ALG_NAME,
|
| 559 | "essiv(%s,%s)", block_base->cra_driver_name,
|
| 560 | hash_alg->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
|
| 561 | goto out_free_hash;
|
| 562 |
|
| 563 | |
| 564 | * hash_alg wasn't gotten via crypto_grab*(), so we need to inherit its
|
| 565 | * flags manually.
|
| 566 |
|
| 567 | base->cra_flags |= (hash_alg->base.cra_flags &
|
| 568 | CRYPTO_ALG_INHERITED_FLAGS);
|
| 569 | base->cra_blocksize = block_base->cra_blocksize;
|
| 570 | base->cra_ctxsize = sizeof(struct essiv_tfm_ctx);
|
| 571 | base->cra_alignmask = block_base->cra_alignmask;
|
| 572 | base->cra_priority = block_base->cra_priority;
|
| 573 |
|
| 574 | if (type == CRYPTO_ALG_TYPE_LSKCIPHER) {
|
| 575 | skcipher_inst->alg.setkey = essiv_skcipher_setkey;
|
| 576 | skcipher_inst->alg.encrypt = essiv_skcipher_encrypt;
|
| 577 | skcipher_inst->alg.decrypt = essiv_skcipher_decrypt;
|
| 578 | skcipher_inst->alg.init = essiv_skcipher_init_tfm;
|
| 579 | skcipher_inst->alg.exit = essiv_skcipher_exit_tfm;
|
| 580 |
|
| 581 | skcipher_inst->alg.min_keysize = skcipher_alg->min_keysize;
|
| 582 | skcipher_inst->alg.max_keysize = skcipher_alg->max_keysize;
|
| 583 | skcipher_inst->alg.ivsize = ivsize;
|
| 584 | skcipher_inst->alg.chunksize = skcipher_alg->chunksize;
|
| 585 |
|
| 586 | skcipher_inst->free = essiv_skcipher_free_instance;
|
| 587 |
|
| 588 | err = skcipher_register_instance(tmpl, skcipher_inst);
|
| 589 | } else {
|
| 590 | aead_inst->alg.setkey = essiv_aead_setkey;
|
| 591 | aead_inst->alg.setauthsize = essiv_aead_setauthsize;
|
| 592 | aead_inst->alg.encrypt = essiv_aead_encrypt;
|
| 593 | aead_inst->alg.decrypt = essiv_aead_decrypt;
|
| 594 | aead_inst->alg.init = essiv_aead_init_tfm;
|
| 595 | aead_inst->alg.exit = essiv_aead_exit_tfm;
|
| 596 |
|
| 597 | aead_inst->alg.ivsize = ivsize;
|
| 598 | aead_inst->alg.maxauthsize = crypto_aead_alg_maxauthsize(aead_alg);
|
| 599 | aead_inst->alg.chunksize = crypto_aead_alg_chunksize(aead_alg);
|
| 600 |
|
| 601 | aead_inst->free = essiv_aead_free_instance;
|
| 602 |
|
| 603 | err = aead_register_instance(tmpl, aead_inst);
|
| 604 | }
|
| 605 |
|
| 606 | if (err)
|
| 607 | goto out_free_hash;
|
| 608 |
|
| 609 | crypto_mod_put(_hash_alg);
|
| 610 | return 0;
|
| 611 |
|
| 612 | out_free_hash:
|
| 613 | crypto_mod_put(_hash_alg);
|
| 614 | out_drop_skcipher:
|
| 615 | if (type == CRYPTO_ALG_TYPE_LSKCIPHER)
|
| 616 | crypto_drop_skcipher(&ictx->u.skcipher_spawn);
|
| 617 | else
|
| 618 | crypto_drop_aead(&ictx->u.aead_spawn);
|
| 619 | out_free_inst:
|
| 620 | kfree(skcipher_inst);
|
| 621 | kfree(aead_inst);
|
| 622 | return err;
|
| 623 | }
|
| 624 |
|
| 625 |
|
| 626 | static struct crypto_template essiv_tmpl = {
|
| 627 | .name = "essiv",
|
| 628 | .create = essiv_create,
|
| 629 | .module = THIS_MODULE,
|
| 630 | };
|
| 631 |
|
| 632 | static int __init essiv_module_init(void)
|
| 633 | {
|
| 634 | return crypto_register_template(&essiv_tmpl);
|
| 635 | }
|
| 636 |
|
| 637 | static void __exit essiv_module_exit(void)
|
| 638 | {
|
| 639 | crypto_unregister_template(&essiv_tmpl);
|
| 640 | }
|
| 641 |
|
| 642 | module_init(essiv_module_init);
|
| 643 | module_exit(essiv_module_exit);
|
| 644 |
|
| 645 | MODULE_DESCRIPTION("ESSIV skcipher/aead wrapper for block encryption");
|
| 646 | MODULE_LICENSE("GPL v2");
|
| 647 | MODULE_ALIAS_CRYPTO("essiv");
|
| 648 | MODULE_IMPORT_NS("CRYPTO_INTERNAL");
|