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         const char *name;
  45         struct crypto_aead_spawn *spawn;
  46         struct crypto_attr_type *algt;
  47         struct aead_instance *inst;
  48         struct aead_alg *alg;
  49         unsigned int ivsize;
  50         unsigned int maxauthsize;
  51         int err;
  52
  53         algt = crypto_get_attr_type(tb);
  54         if (IS_ERR(algt))
  55                 return ERR_CAST(algt);
  56
  57         if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
  58                 return ERR_PTR(-EINVAL);
  59
  60         name = crypto_attr_alg_name(tb[1]);
  61         if (IS_ERR(name))
  62                 return ERR_CAST(name);
  63
  64         inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
  65         if (!inst)
  66                 return ERR_PTR(-ENOMEM);
  67
  68         spawn = aead_instance_ctx(inst);
  69
  70         /* Ignore async algorithms if necessary. */
  71         mask |= crypto_requires_sync(algt->type, algt->mask);
  72
  73         err = crypto_grab_aead(spawn, aead_crypto_instance(inst),
  74                                name, type, mask);
  75         if (err)
  76                 goto err_free_inst;
  77
  78         alg = crypto_spawn_aead_alg(spawn);
  79
  80         ivsize = crypto_aead_alg_ivsize(alg);
  81         maxauthsize = crypto_aead_alg_maxauthsize(alg);
  82
  83         err = -EINVAL;
  84         if (ivsize < sizeof(u64))
  85                 goto err_drop_alg;
  86
  87         err = -ENAMETOOLONG;
  88         if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
  89                      "%s(%s)", tmpl->name, alg->base.cra_name) >=
  90             CRYPTO_MAX_ALG_NAME)
  91                 goto err_drop_alg;
  92         if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
  93                      "%s(%s)", tmpl->name, alg->base.cra_driver_name) >=
  94             CRYPTO_MAX_ALG_NAME)
  95                 goto err_drop_alg;
  96
  97         inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
  98         inst->alg.base.cra_priority = alg->base.cra_priority;
  99         inst->alg.base.cra_blocksize = alg->base.cra_blocksize;
 100         inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
 101         inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx);
 102
 103         inst->alg.setkey = aead_geniv_setkey;
 104         inst->alg.setauthsize = aead_geniv_setauthsize;
 105
 106         inst->alg.ivsize = ivsize;
 107         inst->alg.maxauthsize = maxauthsize;
 108
 109         inst->free = aead_geniv_free;
 110
 111 out:
 112         return inst;
 113
 114 err_drop_alg:
 115         crypto_drop_aead(spawn);
 116 err_free_inst:
 117         kfree(inst);
 118         inst = ERR_PTR(err);
 119         goto out;
 120 }
 121 EXPORT_SYMBOL_GPL(aead_geniv_alloc);
 122
 123 int aead_init_geniv(struct crypto_aead *aead)
 124 {
 125         struct aead_geniv_ctx *ctx = crypto_aead_ctx(aead);
 126         struct aead_instance *inst = aead_alg_instance(aead);
 127         struct crypto_aead *child;
 128         int err;
 129
 130         spin_lock_init(&ctx->lock);
 131
 132         err = crypto_get_default_rng();
 133         if (err)
 134                 goto out;
 135
 136         err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
 137                                    crypto_aead_ivsize(aead));
 138         crypto_put_default_rng();
 139         if (err)
 140                 goto out;
 141
 142         ctx->sknull = crypto_get_default_null_skcipher();
 143         err = PTR_ERR(ctx->sknull);
 144         if (IS_ERR(ctx->sknull))
 145                 goto out;
 146
 147         child = crypto_spawn_aead(aead_instance_ctx(inst));
 148         err = PTR_ERR(child);
 149         if (IS_ERR(child))
 150                 goto drop_null;
 151
 152         ctx->child = child;
 153         crypto_aead_set_reqsize(aead, crypto_aead_reqsize(child) +
 154                                       sizeof(struct aead_request));
 155
 156         err = 0;
 157
 158 out:
 159         return err;
 160
 161 drop_null:
 162         crypto_put_default_null_skcipher();
 163         goto out;
 164 }
 165 EXPORT_SYMBOL_GPL(aead_init_geniv);
 166
 167 void aead_exit_geniv(struct crypto_aead *tfm)
 168 {
 169         struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
 170
 171         crypto_free_aead(ctx->child);
 172         crypto_put_default_null_skcipher();
 173 }
 174 EXPORT_SYMBOL_GPL(aead_exit_geniv);
 175
 176 MODULE_LICENSE("GPL");
 177 MODULE_DESCRIPTION("Shared IV generator code");