| 1 | /* |
| 2 | * seqiv: Sequence Number IV Generator |
| 3 | * |
| 4 | * This generator generates an IV based on a sequence number by xoring it |
| 5 | * with a salt. This algorithm is mainly useful for CTR and similar modes. |
| 6 | * |
| 7 | * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au> |
| 8 | * |
| 9 | * This program is free software; you can redistribute it and/or modify it |
| 10 | * under the terms of the GNU General Public License as published by the Free |
| 11 | * Software Foundation; either version 2 of the License, or (at your option) |
| 12 | * any later version. |
| 13 | * |
| 14 | */ |
| 15 | |
| 16 | #include <crypto/internal/aead.h> |
| 17 | #include <crypto/internal/skcipher.h> |
| 18 | #include <crypto/rng.h> |
| 19 | #include <linux/err.h> |
| 20 | #include <linux/init.h> |
| 21 | #include <linux/kernel.h> |
| 22 | #include <linux/module.h> |
| 23 | #include <linux/slab.h> |
| 24 | #include <linux/spinlock.h> |
| 25 | #include <linux/string.h> |
| 26 | |
| 27 | struct seqiv_ctx { |
| 28 | spinlock_t lock; |
| 29 | u8 salt[] __attribute__ ((aligned(__alignof__(u32)))); |
| 30 | }; |
| 31 | |
| 32 | static void seqiv_complete2(struct skcipher_givcrypt_request *req, int err) |
| 33 | { |
| 34 | struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req); |
| 35 | struct crypto_ablkcipher *geniv; |
| 36 | |
| 37 | if (err == -EINPROGRESS) |
| 38 | return; |
| 39 | |
| 40 | if (err) |
| 41 | goto out; |
| 42 | |
| 43 | geniv = skcipher_givcrypt_reqtfm(req); |
| 44 | memcpy(req->creq.info, subreq->info, crypto_ablkcipher_ivsize(geniv)); |
| 45 | |
| 46 | out: |
| 47 | kfree(subreq->info); |
| 48 | } |
| 49 | |
| 50 | static void seqiv_complete(struct crypto_async_request *base, int err) |
| 51 | { |
| 52 | struct skcipher_givcrypt_request *req = base->data; |
| 53 | |
| 54 | seqiv_complete2(req, err); |
| 55 | skcipher_givcrypt_complete(req, err); |
| 56 | } |
| 57 | |
| 58 | static void seqiv_aead_complete2(struct aead_givcrypt_request *req, int err) |
| 59 | { |
| 60 | struct aead_request *subreq = aead_givcrypt_reqctx(req); |
| 61 | struct crypto_aead *geniv; |
| 62 | |
| 63 | if (err == -EINPROGRESS) |
| 64 | return; |
| 65 | |
| 66 | if (err) |
| 67 | goto out; |
| 68 | |
| 69 | geniv = aead_givcrypt_reqtfm(req); |
| 70 | memcpy(req->areq.iv, subreq->iv, crypto_aead_ivsize(geniv)); |
| 71 | |
| 72 | out: |
| 73 | kfree(subreq->iv); |
| 74 | } |
| 75 | |
| 76 | static void seqiv_aead_complete(struct crypto_async_request *base, int err) |
| 77 | { |
| 78 | struct aead_givcrypt_request *req = base->data; |
| 79 | |
| 80 | seqiv_aead_complete2(req, err); |
| 81 | aead_givcrypt_complete(req, err); |
| 82 | } |
| 83 | |
| 84 | static void seqiv_geniv(struct seqiv_ctx *ctx, u8 *info, u64 seq, |
| 85 | unsigned int ivsize) |
| 86 | { |
| 87 | unsigned int len = ivsize; |
| 88 | |
| 89 | if (ivsize > sizeof(u64)) { |
| 90 | memset(info, 0, ivsize - sizeof(u64)); |
| 91 | len = sizeof(u64); |
| 92 | } |
| 93 | seq = cpu_to_be64(seq); |
| 94 | memcpy(info + ivsize - len, &seq, len); |
| 95 | crypto_xor(info, ctx->salt, ivsize); |
| 96 | } |
| 97 | |
| 98 | static int seqiv_givencrypt(struct skcipher_givcrypt_request *req) |
| 99 | { |
| 100 | struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req); |
| 101 | struct seqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv); |
| 102 | struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req); |
| 103 | crypto_completion_t complete; |
| 104 | void *data; |
| 105 | u8 *info; |
| 106 | unsigned int ivsize; |
| 107 | int err; |
| 108 | |
| 109 | ablkcipher_request_set_tfm(subreq, skcipher_geniv_cipher(geniv)); |
| 110 | |
| 111 | complete = req->creq.base.complete; |
| 112 | data = req->creq.base.data; |
| 113 | info = req->creq.info; |
| 114 | |
| 115 | ivsize = crypto_ablkcipher_ivsize(geniv); |
| 116 | |
| 117 | if (unlikely(!IS_ALIGNED((unsigned long)info, |
| 118 | crypto_ablkcipher_alignmask(geniv) + 1))) { |
| 119 | info = kmalloc(ivsize, req->creq.base.flags & |
| 120 | CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL: |
| 121 | GFP_ATOMIC); |
| 122 | if (!info) |
| 123 | return -ENOMEM; |
| 124 | |
| 125 | complete = seqiv_complete; |
| 126 | data = req; |
| 127 | } |
| 128 | |
| 129 | ablkcipher_request_set_callback(subreq, req->creq.base.flags, complete, |
| 130 | data); |
| 131 | ablkcipher_request_set_crypt(subreq, req->creq.src, req->creq.dst, |
| 132 | req->creq.nbytes, info); |
| 133 | |
| 134 | seqiv_geniv(ctx, info, req->seq, ivsize); |
| 135 | memcpy(req->giv, info, ivsize); |
| 136 | |
| 137 | err = crypto_ablkcipher_encrypt(subreq); |
| 138 | if (unlikely(info != req->creq.info)) |
| 139 | seqiv_complete2(req, err); |
| 140 | return err; |
| 141 | } |
| 142 | |
| 143 | static int seqiv_aead_givencrypt(struct aead_givcrypt_request *req) |
| 144 | { |
| 145 | struct crypto_aead *geniv = aead_givcrypt_reqtfm(req); |
| 146 | struct seqiv_ctx *ctx = crypto_aead_ctx(geniv); |
| 147 | struct aead_request *areq = &req->areq; |
| 148 | struct aead_request *subreq = aead_givcrypt_reqctx(req); |
| 149 | crypto_completion_t complete; |
| 150 | void *data; |
| 151 | u8 *info; |
| 152 | unsigned int ivsize; |
| 153 | int err; |
| 154 | |
| 155 | aead_request_set_tfm(subreq, aead_geniv_base(geniv)); |
| 156 | |
| 157 | complete = areq->base.complete; |
| 158 | data = areq->base.data; |
| 159 | info = areq->iv; |
| 160 | |
| 161 | ivsize = crypto_aead_ivsize(geniv); |
| 162 | |
| 163 | if (unlikely(!IS_ALIGNED((unsigned long)info, |
| 164 | crypto_aead_alignmask(geniv) + 1))) { |
| 165 | info = kmalloc(ivsize, areq->base.flags & |
| 166 | CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL: |
| 167 | GFP_ATOMIC); |
| 168 | if (!info) |
| 169 | return -ENOMEM; |
| 170 | |
| 171 | complete = seqiv_aead_complete; |
| 172 | data = req; |
| 173 | } |
| 174 | |
| 175 | aead_request_set_callback(subreq, areq->base.flags, complete, data); |
| 176 | aead_request_set_crypt(subreq, areq->src, areq->dst, areq->cryptlen, |
| 177 | info); |
| 178 | aead_request_set_assoc(subreq, areq->assoc, areq->assoclen); |
| 179 | |
| 180 | seqiv_geniv(ctx, info, req->seq, ivsize); |
| 181 | memcpy(req->giv, info, ivsize); |
| 182 | |
| 183 | err = crypto_aead_encrypt(subreq); |
| 184 | if (unlikely(info != areq->iv)) |
| 185 | seqiv_aead_complete2(req, err); |
| 186 | return err; |
| 187 | } |
| 188 | |
| 189 | static int seqiv_givencrypt_first(struct skcipher_givcrypt_request *req) |
| 190 | { |
| 191 | struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req); |
| 192 | struct seqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv); |
| 193 | int err = 0; |
| 194 | |
| 195 | spin_lock_bh(&ctx->lock); |
| 196 | if (crypto_ablkcipher_crt(geniv)->givencrypt != seqiv_givencrypt_first) |
| 197 | goto unlock; |
| 198 | |
| 199 | crypto_ablkcipher_crt(geniv)->givencrypt = seqiv_givencrypt; |
| 200 | err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt, |
| 201 | crypto_ablkcipher_ivsize(geniv)); |
| 202 | |
| 203 | unlock: |
| 204 | spin_unlock_bh(&ctx->lock); |
| 205 | |
| 206 | if (err) |
| 207 | return err; |
| 208 | |
| 209 | return seqiv_givencrypt(req); |
| 210 | } |
| 211 | |
| 212 | static int seqiv_aead_givencrypt_first(struct aead_givcrypt_request *req) |
| 213 | { |
| 214 | struct crypto_aead *geniv = aead_givcrypt_reqtfm(req); |
| 215 | struct seqiv_ctx *ctx = crypto_aead_ctx(geniv); |
| 216 | int err = 0; |
| 217 | |
| 218 | spin_lock_bh(&ctx->lock); |
| 219 | if (crypto_aead_crt(geniv)->givencrypt != seqiv_aead_givencrypt_first) |
| 220 | goto unlock; |
| 221 | |
| 222 | crypto_aead_crt(geniv)->givencrypt = seqiv_aead_givencrypt; |
| 223 | err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt, |
| 224 | crypto_aead_ivsize(geniv)); |
| 225 | |
| 226 | unlock: |
| 227 | spin_unlock_bh(&ctx->lock); |
| 228 | |
| 229 | if (err) |
| 230 | return err; |
| 231 | |
| 232 | return seqiv_aead_givencrypt(req); |
| 233 | } |
| 234 | |
| 235 | static int seqiv_init(struct crypto_tfm *tfm) |
| 236 | { |
| 237 | struct crypto_ablkcipher *geniv = __crypto_ablkcipher_cast(tfm); |
| 238 | struct seqiv_ctx *ctx = crypto_ablkcipher_ctx(geniv); |
| 239 | |
| 240 | spin_lock_init(&ctx->lock); |
| 241 | |
| 242 | tfm->crt_ablkcipher.reqsize = sizeof(struct ablkcipher_request); |
| 243 | |
| 244 | return skcipher_geniv_init(tfm); |
| 245 | } |
| 246 | |
| 247 | static int seqiv_aead_init(struct crypto_tfm *tfm) |
| 248 | { |
| 249 | struct crypto_aead *geniv = __crypto_aead_cast(tfm); |
| 250 | struct seqiv_ctx *ctx = crypto_aead_ctx(geniv); |
| 251 | |
| 252 | spin_lock_init(&ctx->lock); |
| 253 | |
| 254 | tfm->crt_aead.reqsize = sizeof(struct aead_request); |
| 255 | |
| 256 | return aead_geniv_init(tfm); |
| 257 | } |
| 258 | |
| 259 | static struct crypto_template seqiv_tmpl; |
| 260 | |
| 261 | static struct crypto_instance *seqiv_ablkcipher_alloc(struct rtattr **tb) |
| 262 | { |
| 263 | struct crypto_instance *inst; |
| 264 | |
| 265 | inst = skcipher_geniv_alloc(&seqiv_tmpl, tb, 0, 0); |
| 266 | |
| 267 | if (IS_ERR(inst)) |
| 268 | goto out; |
| 269 | |
| 270 | inst->alg.cra_ablkcipher.givencrypt = seqiv_givencrypt_first; |
| 271 | |
| 272 | inst->alg.cra_init = seqiv_init; |
| 273 | inst->alg.cra_exit = skcipher_geniv_exit; |
| 274 | |
| 275 | inst->alg.cra_ctxsize += inst->alg.cra_ablkcipher.ivsize; |
| 276 | |
| 277 | out: |
| 278 | return inst; |
| 279 | } |
| 280 | |
| 281 | static struct crypto_instance *seqiv_aead_alloc(struct rtattr **tb) |
| 282 | { |
| 283 | struct crypto_instance *inst; |
| 284 | |
| 285 | inst = aead_geniv_alloc(&seqiv_tmpl, tb, 0, 0); |
| 286 | |
| 287 | if (IS_ERR(inst)) |
| 288 | goto out; |
| 289 | |
| 290 | inst->alg.cra_aead.givencrypt = seqiv_aead_givencrypt_first; |
| 291 | |
| 292 | inst->alg.cra_init = seqiv_aead_init; |
| 293 | inst->alg.cra_exit = aead_geniv_exit; |
| 294 | |
| 295 | inst->alg.cra_ctxsize = inst->alg.cra_aead.ivsize; |
| 296 | |
| 297 | out: |
| 298 | return inst; |
| 299 | } |
| 300 | |
| 301 | static struct crypto_instance *seqiv_alloc(struct rtattr **tb) |
| 302 | { |
| 303 | struct crypto_attr_type *algt; |
| 304 | struct crypto_instance *inst; |
| 305 | int err; |
| 306 | |
| 307 | algt = crypto_get_attr_type(tb); |
| 308 | err = PTR_ERR(algt); |
| 309 | if (IS_ERR(algt)) |
| 310 | return ERR_PTR(err); |
| 311 | |
| 312 | err = crypto_get_default_rng(); |
| 313 | if (err) |
| 314 | return ERR_PTR(err); |
| 315 | |
| 316 | if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & CRYPTO_ALG_TYPE_MASK) |
| 317 | inst = seqiv_ablkcipher_alloc(tb); |
| 318 | else |
| 319 | inst = seqiv_aead_alloc(tb); |
| 320 | |
| 321 | if (IS_ERR(inst)) |
| 322 | goto put_rng; |
| 323 | |
| 324 | inst->alg.cra_alignmask |= __alignof__(u32) - 1; |
| 325 | inst->alg.cra_ctxsize += sizeof(struct seqiv_ctx); |
| 326 | |
| 327 | out: |
| 328 | return inst; |
| 329 | |
| 330 | put_rng: |
| 331 | crypto_put_default_rng(); |
| 332 | goto out; |
| 333 | } |
| 334 | |
| 335 | static void seqiv_free(struct crypto_instance *inst) |
| 336 | { |
| 337 | if ((inst->alg.cra_flags ^ CRYPTO_ALG_TYPE_AEAD) & CRYPTO_ALG_TYPE_MASK) |
| 338 | skcipher_geniv_free(inst); |
| 339 | else |
| 340 | aead_geniv_free(inst); |
| 341 | crypto_put_default_rng(); |
| 342 | } |
| 343 | |
| 344 | static struct crypto_template seqiv_tmpl = { |
| 345 | .name = "seqiv", |
| 346 | .alloc = seqiv_alloc, |
| 347 | .free = seqiv_free, |
| 348 | .module = THIS_MODULE, |
| 349 | }; |
| 350 | |
| 351 | static int __init seqiv_module_init(void) |
| 352 | { |
| 353 | return crypto_register_template(&seqiv_tmpl); |
| 354 | } |
| 355 | |
| 356 | static void __exit seqiv_module_exit(void) |
| 357 | { |
| 358 | crypto_unregister_template(&seqiv_tmpl); |
| 359 | } |
| 360 | |
| 361 | module_init(seqiv_module_init); |
| 362 | module_exit(seqiv_module_exit); |
| 363 | |
| 364 | MODULE_LICENSE("GPL"); |
| 365 | MODULE_DESCRIPTION("Sequence Number IV Generator"); |