crypto/geniv.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * geniv: Shared IV generator code
   4  *
   5  * This file provides common code to IV generators such as seqiv.
   6  *
   7  * Copyright (c) 2007-2019 Herbert Xu <herbert@gondor.apana.org.au>
   8  */
   9
  10 #include <crypto/internal/geniv.h>
  11 #include <crypto/internal/rng.h>
  12 #include <crypto/null.h>
  13 #include <linux/err.h>
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/rtnetlink.h>
  17 #include <linux/slab.h>
  18
  19 static int aead_geniv_setkey(struct crypto_aead *tfm,
  20                              const u8 *key, unsigned int keylen)
  21 {
  22         struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
  23
  24         return crypto_aead_setkey(ctx->child, key, keylen);
  25 }
  26
  27 static int aead_geniv_setauthsize(struct crypto_aead *tfm,
  28                                   unsigned int authsize)
  29 {
  30         struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
  31
  32         return crypto_aead_setauthsize(ctx->child, authsize);
  33 }
  34
  35 struct aead_instance *aead_geniv_alloc(struct crypto_template *tmpl,
  36                                        struct rtattr **tb, u32 type, u32 mask)
  37 {
  38         const char *name;
  39         struct crypto_aead_spawn *spawn;
  40         struct crypto_attr_type *algt;
  41         struct aead_instance *inst;
  42         struct aead_alg *alg;
  43         unsigned int ivsize;
  44         unsigned int maxauthsize;
  45         int err;
  46
  47         algt = crypto_get_attr_type(tb);
  48         if (IS_ERR(algt))
  49                 return ERR_CAST(algt);
  50
  51         if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
  52                 return ERR_PTR(-EINVAL);
  53
  54         name = crypto_attr_alg_name(tb[1]);
  55         if (IS_ERR(name))
  56                 return ERR_CAST(name);
  57
  58         inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
  59         if (!inst)
  60                 return ERR_PTR(-ENOMEM);
  61
  62         spawn = aead_instance_ctx(inst);
  63
  64         /* Ignore async algorithms if necessary. */
  65         mask |= crypto_requires_sync(algt->type, algt->mask);
  66
  67         crypto_set_aead_spawn(spawn, aead_crypto_instance(inst));
  68         err = crypto_grab_aead(spawn, name, type, mask);
  69         if (err)
  70                 goto err_free_inst;
  71
  72         alg = crypto_spawn_aead_alg(spawn);
  73
  74         ivsize = crypto_aead_alg_ivsize(alg);
  75         maxauthsize = crypto_aead_alg_maxauthsize(alg);
  76
  77         err = -EINVAL;
  78         if (ivsize < sizeof(u64))
  79                 goto err_drop_alg;
  80
  81         err = -ENAMETOOLONG;
  82         if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
  83                      "%s(%s)", tmpl->name, alg->base.cra_name) >=
  84             CRYPTO_MAX_ALG_NAME)
  85                 goto err_drop_alg;
  86         if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
  87                      "%s(%s)", tmpl->name, alg->base.cra_driver_name) >=
  88             CRYPTO_MAX_ALG_NAME)
  89                 goto err_drop_alg;
  90
  91         inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
  92         inst->alg.base.cra_priority = alg->base.cra_priority;
  93         inst->alg.base.cra_blocksize = alg->base.cra_blocksize;
  94         inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
  95         inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx);
  96
  97         inst->alg.setkey = aead_geniv_setkey;
  98         inst->alg.setauthsize = aead_geniv_setauthsize;
  99
 100         inst->alg.ivsize = ivsize;
 101         inst->alg.maxauthsize = maxauthsize;
 102
 103 out:
 104         return inst;
 105
 106 err_drop_alg:
 107         crypto_drop_aead(spawn);
 108 err_free_inst:
 109         kfree(inst);
 110         inst = ERR_PTR(err);
 111         goto out;
 112 }
 113 EXPORT_SYMBOL_GPL(aead_geniv_alloc);
 114
 115 void aead_geniv_free(struct aead_instance *inst)
 116 {
 117         crypto_drop_aead(aead_instance_ctx(inst));
 118         kfree(inst);
 119 }
 120 EXPORT_SYMBOL_GPL(aead_geniv_free);
 121
 122 int aead_init_geniv(struct crypto_aead *aead)
 123 {
 124         struct aead_geniv_ctx *ctx = crypto_aead_ctx(aead);
 125         struct aead_instance *inst = aead_alg_instance(aead);
 126         struct crypto_aead *child;
 127         int err;
 128
 129         spin_lock_init(&ctx->lock);
 130
 131         err = crypto_get_default_rng();
 132         if (err)
 133                 goto out;
 134
 135         err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
 136                                    crypto_aead_ivsize(aead));
 137         crypto_put_default_rng();
 138         if (err)
 139                 goto out;
 140
 141         ctx->sknull = crypto_get_default_null_skcipher();
 142         err = PTR_ERR(ctx->sknull);
 143         if (IS_ERR(ctx->sknull))
 144                 goto out;
 145
 146         child = crypto_spawn_aead(aead_instance_ctx(inst));
 147         err = PTR_ERR(child);
 148         if (IS_ERR(child))
 149                 goto drop_null;
 150
 151         ctx->child = child;
 152         crypto_aead_set_reqsize(aead, crypto_aead_reqsize(child) +
 153                                       sizeof(struct aead_request));
 154
 155         err = 0;
 156
 157 out:
 158         return err;
 159
 160 drop_null:
 161         crypto_put_default_null_skcipher();
 162         goto out;
 163 }
 164 EXPORT_SYMBOL_GPL(aead_init_geniv);
 165
 166 void aead_exit_geniv(struct crypto_aead *tfm)
 167 {
 168         struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
 169
 170         crypto_free_aead(ctx->child);
 171         crypto_put_default_null_skcipher();
 172 }
 173 EXPORT_SYMBOL_GPL(aead_exit_geniv);
 174
 175 MODULE_LICENSE("GPL");
 176 MODULE_DESCRIPTION("Shared IV generator code");