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743edf5727
This patch adds the underlying givcrypt operations for aead and associated support elements. The rationale is identical to that of the skcipher givcrypt operations, i.e., sometimes only the algorithm knows how the IV should be generated. A new request type aead_givcrypt_request is added which contains an embedded aead_request structure with two new elements to support this operation. The new elements are seq and giv. The seq field should contain a strictly increasing 64-bit integer which may be used by certain IV generators as an input value. The giv field will be used to store the generated IV. It does not need to obey the alignment requirements of the algorithm because it's not used during the operation. The existing iv field must still be available as it will be used to store intermediate IVs and the output IV if chaining is desired. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
127 lines
3.3 KiB
C
127 lines
3.3 KiB
C
/*
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* AEAD: Authenticated Encryption with Associated Data
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*
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* This file provides API support for AEAD algorithms.
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*
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* Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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*/
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#include <crypto/algapi.h>
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/seq_file.h>
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static int setkey_unaligned(struct crypto_aead *tfm, const u8 *key,
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unsigned int keylen)
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{
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struct aead_alg *aead = crypto_aead_alg(tfm);
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unsigned long alignmask = crypto_aead_alignmask(tfm);
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int ret;
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u8 *buffer, *alignbuffer;
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unsigned long absize;
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absize = keylen + alignmask;
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buffer = kmalloc(absize, GFP_ATOMIC);
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if (!buffer)
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return -ENOMEM;
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alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
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memcpy(alignbuffer, key, keylen);
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ret = aead->setkey(tfm, alignbuffer, keylen);
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memset(alignbuffer, 0, keylen);
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kfree(buffer);
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return ret;
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}
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static int setkey(struct crypto_aead *tfm, const u8 *key, unsigned int keylen)
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{
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struct aead_alg *aead = crypto_aead_alg(tfm);
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unsigned long alignmask = crypto_aead_alignmask(tfm);
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if ((unsigned long)key & alignmask)
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return setkey_unaligned(tfm, key, keylen);
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return aead->setkey(tfm, key, keylen);
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}
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int crypto_aead_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
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{
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int err;
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if (authsize > crypto_aead_alg(tfm)->maxauthsize)
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return -EINVAL;
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if (crypto_aead_alg(tfm)->setauthsize) {
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err = crypto_aead_alg(tfm)->setauthsize(tfm, authsize);
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if (err)
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return err;
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}
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crypto_aead_crt(tfm)->authsize = authsize;
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return 0;
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}
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EXPORT_SYMBOL_GPL(crypto_aead_setauthsize);
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static unsigned int crypto_aead_ctxsize(struct crypto_alg *alg, u32 type,
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u32 mask)
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{
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return alg->cra_ctxsize;
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}
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static int no_givdecrypt(struct aead_givcrypt_request *req)
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{
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return -ENOSYS;
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}
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static int crypto_init_aead_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
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{
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struct aead_alg *alg = &tfm->__crt_alg->cra_aead;
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struct aead_tfm *crt = &tfm->crt_aead;
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if (max(alg->maxauthsize, alg->ivsize) > PAGE_SIZE / 8)
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return -EINVAL;
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crt->setkey = setkey;
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crt->encrypt = alg->encrypt;
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crt->decrypt = alg->decrypt;
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crt->givencrypt = alg->givencrypt;
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crt->givdecrypt = alg->givdecrypt ?: no_givdecrypt;
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crt->ivsize = alg->ivsize;
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crt->authsize = alg->maxauthsize;
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return 0;
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}
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static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
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__attribute__ ((unused));
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static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
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{
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struct aead_alg *aead = &alg->cra_aead;
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seq_printf(m, "type : aead\n");
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seq_printf(m, "blocksize : %u\n", alg->cra_blocksize);
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seq_printf(m, "ivsize : %u\n", aead->ivsize);
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seq_printf(m, "maxauthsize : %u\n", aead->maxauthsize);
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}
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const struct crypto_type crypto_aead_type = {
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.ctxsize = crypto_aead_ctxsize,
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.init = crypto_init_aead_ops,
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#ifdef CONFIG_PROC_FS
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.show = crypto_aead_show,
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#endif
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};
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EXPORT_SYMBOL_GPL(crypto_aead_type);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Authenticated Encryption with Associated Data (AEAD)");
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