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 static void aead_geniv_free(struct aead_instance *inst)
  36 {
  37         crypto_drop_aead(aead_instance_ctx(inst));
  38         kfree(inst);
  39 }
  40
  41 struct aead_instance *aead_geniv_alloc(struct crypto_template *tmpl,
  42                                        struct rtattr **tb, u32 type, u32 mask)
  43 {
  44         struct crypto_aead_spawn *spawn;
  45         struct crypto_attr_type *algt;
  46         struct aead_instance *inst;
  47         struct aead_alg *alg;
  48         unsigned int ivsize;
  49         unsigned int maxauthsize;
  50         int err;
  51
  52         algt = crypto_get_attr_type(tb);
  53         if (IS_ERR(algt))
  54                 return ERR_CAST(algt);
  55
  56         if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
  57                 return ERR_PTR(-EINVAL);
  58
  59         inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
  60         if (!inst)
  61                 return ERR_PTR(-ENOMEM);
  62
  63         spawn = aead_instance_ctx(inst);
  64
  65         /* Ignore async algorithms if necessary. */
  66         mask |= crypto_requires_sync(algt->type, algt->mask);
  67
  68         err = crypto_grab_aead(spawn, aead_crypto_instance(inst),
  69                                crypto_attr_alg_name(tb[1]), type, mask);
  70         if (err)
  71                 goto err_free_inst;
  72
  73         alg = crypto_spawn_aead_alg(spawn);
  74
  75         ivsize = crypto_aead_alg_ivsize(alg);
  76         maxauthsize = crypto_aead_alg_maxauthsize(alg);
  77
  78         err = -EINVAL;
  79         if (ivsize < sizeof(u64))
  80                 goto err_free_inst;
  81
  82         err = -ENAMETOOLONG;
  83         if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
  84                      "%s(%s)", tmpl->name, alg->base.cra_name) >=
  85             CRYPTO_MAX_ALG_NAME)
  86                 goto err_free_inst;
  87         if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
  88                      "%s(%s)", tmpl->name, alg->base.cra_driver_name) >=
  89             CRYPTO_MAX_ALG_NAME)
  90                 goto err_free_inst;
  91
  92         inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
  93         inst->alg.base.cra_priority = alg->base.cra_priority;
  94         inst->alg.base.cra_blocksize = alg->base.cra_blocksize;
  95         inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
  96         inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx);
  97
  98         inst->alg.setkey = aead_geniv_setkey;
  99         inst->alg.setauthsize = aead_geniv_setauthsize;
 100
 101         inst->alg.ivsize = ivsize;
 102         inst->alg.maxauthsize = maxauthsize;
 103
 104         inst->free = aead_geniv_free;
 105
 106 out:
 107         return inst;
 108
 109 err_free_inst:
 110         aead_geniv_free(inst);
 111         inst = ERR_PTR(err);
 112         goto out;
 113 }
 114 EXPORT_SYMBOL_GPL(aead_geniv_alloc);
 115
 116 int aead_init_geniv(struct crypto_aead *aead)
 117 {
 118         struct aead_geniv_ctx *ctx = crypto_aead_ctx(aead);
 119         struct aead_instance *inst = aead_alg_instance(aead);
 120         struct crypto_aead *child;
 121         int err;
 122
 123         spin_lock_init(&ctx->lock);
 124
 125         err = crypto_get_default_rng();
 126         if (err)
 127                 goto out;
 128
 129         err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
 130                                    crypto_aead_ivsize(aead));
 131         crypto_put_default_rng();
 132         if (err)
 133                 goto out;
 134
 135         ctx->sknull = crypto_get_default_null_skcipher();
 136         err = PTR_ERR(ctx->sknull);
 137         if (IS_ERR(ctx->sknull))
 138                 goto out;
 139
 140         child = crypto_spawn_aead(aead_instance_ctx(inst));
 141         err = PTR_ERR(child);
 142         if (IS_ERR(child))
 143                 goto drop_null;
 144
 145         ctx->child = child;
 146         crypto_aead_set_reqsize(aead, crypto_aead_reqsize(child) +
 147                                       sizeof(struct aead_request));
 148
 149         err = 0;
 150
 151 out:
 152         return err;
 153
 154 drop_null:
 155         crypto_put_default_null_skcipher();
 156         goto out;
 157 }
 158 EXPORT_SYMBOL_GPL(aead_init_geniv);
 159
 160 void aead_exit_geniv(struct crypto_aead *tfm)
 161 {
 162         struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
 163
 164         crypto_free_aead(ctx->child);
 165         crypto_put_default_null_skcipher();
 166 }
 167 EXPORT_SYMBOL_GPL(aead_exit_geniv);
 168
 169 MODULE_LICENSE("GPL");
 170 MODULE_DESCRIPTION("Shared IV generator code");