the-tree/crypto/geniv.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * geniv: Shared IV generator code
0004  *
0005  * This file provides common code to IV generators such as seqiv.
0006  *
0007  * Copyright (c) 2007-2019 Herbert Xu <herbert@gondor.apana.org.au>
0008  */
0009
0010 #include <crypto/internal/geniv.h>
0011 #include <crypto/internal/rng.h>
0012 #include <crypto/null.h>
0013 #include <linux/err.h>
0014 #include <linux/kernel.h>
0015 #include <linux/module.h>
0016 #include <linux/rtnetlink.h>
0017 #include <linux/slab.h>
0018
0019 static int aead_geniv_setkey(struct crypto_aead *tfm,
0020                  const u8 *key, unsigned int keylen)
0021 {
0022     struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
0023
0024     return crypto_aead_setkey(ctx->child, key, keylen);
0025 }
0026
0027 static int aead_geniv_setauthsize(struct crypto_aead *tfm,
0028                   unsigned int authsize)
0029 {
0030     struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
0031
0032     return crypto_aead_setauthsize(ctx->child, authsize);
0033 }
0034
0035 static void aead_geniv_free(struct aead_instance *inst)
0036 {
0037     crypto_drop_aead(aead_instance_ctx(inst));
0038     kfree(inst);
0039 }
0040
0041 struct aead_instance *aead_geniv_alloc(struct crypto_template *tmpl,
0042                        struct rtattr **tb)
0043 {
0044     struct crypto_aead_spawn *spawn;
0045     struct aead_instance *inst;
0046     struct aead_alg *alg;
0047     unsigned int ivsize;
0048     unsigned int maxauthsize;
0049     u32 mask;
0050     int err;
0051
0052     err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD, &mask);
0053     if (err)
0054         return ERR_PTR(err);
0055
0056     inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
0057     if (!inst)
0058         return ERR_PTR(-ENOMEM);
0059
0060     spawn = aead_instance_ctx(inst);
0061
0062     err = crypto_grab_aead(spawn, aead_crypto_instance(inst),
0063                    crypto_attr_alg_name(tb[1]), 0, mask);
0064     if (err)
0065         goto err_free_inst;
0066
0067     alg = crypto_spawn_aead_alg(spawn);
0068
0069     ivsize = crypto_aead_alg_ivsize(alg);
0070     maxauthsize = crypto_aead_alg_maxauthsize(alg);
0071
0072     err = -EINVAL;
0073     if (ivsize < sizeof(u64))
0074         goto err_free_inst;
0075
0076     err = -ENAMETOOLONG;
0077     if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
0078              "%s(%s)", tmpl->name, alg->base.cra_name) >=
0079         CRYPTO_MAX_ALG_NAME)
0080         goto err_free_inst;
0081     if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
0082              "%s(%s)", tmpl->name, alg->base.cra_driver_name) >=
0083         CRYPTO_MAX_ALG_NAME)
0084         goto err_free_inst;
0085
0086     inst->alg.base.cra_priority = alg->base.cra_priority;
0087     inst->alg.base.cra_blocksize = alg->base.cra_blocksize;
0088     inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
0089     inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx);
0090
0091     inst->alg.setkey = aead_geniv_setkey;
0092     inst->alg.setauthsize = aead_geniv_setauthsize;
0093
0094     inst->alg.ivsize = ivsize;
0095     inst->alg.maxauthsize = maxauthsize;
0096
0097     inst->free = aead_geniv_free;
0098
0099 out:
0100     return inst;
0101
0102 err_free_inst:
0103     aead_geniv_free(inst);
0104     inst = ERR_PTR(err);
0105     goto out;
0106 }
0107 EXPORT_SYMBOL_GPL(aead_geniv_alloc);
0108
0109 int aead_init_geniv(struct crypto_aead *aead)
0110 {
0111     struct aead_geniv_ctx *ctx = crypto_aead_ctx(aead);
0112     struct aead_instance *inst = aead_alg_instance(aead);
0113     struct crypto_aead *child;
0114     int err;
0115
0116     spin_lock_init(&ctx->lock);
0117
0118     err = crypto_get_default_rng();
0119     if (err)
0120         goto out;
0121
0122     err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
0123                    crypto_aead_ivsize(aead));
0124     crypto_put_default_rng();
0125     if (err)
0126         goto out;
0127
0128     ctx->sknull = crypto_get_default_null_skcipher();
0129     err = PTR_ERR(ctx->sknull);
0130     if (IS_ERR(ctx->sknull))
0131         goto out;
0132
0133     child = crypto_spawn_aead(aead_instance_ctx(inst));
0134     err = PTR_ERR(child);
0135     if (IS_ERR(child))
0136         goto drop_null;
0137
0138     ctx->child = child;
0139     crypto_aead_set_reqsize(aead, crypto_aead_reqsize(child) +
0140                       sizeof(struct aead_request));
0141
0142     err = 0;
0143
0144 out:
0145     return err;
0146
0147 drop_null:
0148     crypto_put_default_null_skcipher();
0149     goto out;
0150 }
0151 EXPORT_SYMBOL_GPL(aead_init_geniv);
0152
0153 void aead_exit_geniv(struct crypto_aead *tfm)
0154 {
0155     struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
0156
0157     crypto_free_aead(ctx->child);
0158     crypto_put_default_null_skcipher();
0159 }
0160 EXPORT_SYMBOL_GPL(aead_exit_geniv);
0161
0162 MODULE_LICENSE("GPL");
0163 MODULE_DESCRIPTION("Shared IV generator code");