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