aead.c

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/*
 * AEAD: Authenticated Encryption with Associated Data
 *
 * This file provides API support for AEAD algorithms.
 *
 * Copyright (c) 2007 Herbert Xu <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 */

#include <crypto/internal/aead.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/rtnetlink.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/cryptouser.h>
#include <net/netlink.h>

#include "internal.h"

static int setkey_unaligned(struct crypto_aead *tfm, const u8 *key,
                unsigned int keylen)
{
    struct aead_alg *aead = crypto_aead_alg(tfm);
    unsigned long alignmask = crypto_aead_alignmask(tfm);
    int ret;
    u8 *buffer, *alignbuffer;
    unsigned long absize;

    absize = keylen + alignmask;
    buffer = kmalloc(absize, GFP_ATOMIC);
    if (!buffer)
        return -ENOMEM;

    alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
    memcpy(alignbuffer, key, keylen);
    ret = aead->setkey(tfm, alignbuffer, keylen);
    memset(alignbuffer, 0, keylen);
    kfree(buffer);
    return ret;
}

static int setkey(struct crypto_aead *tfm, const u8 *key, unsigned int keylen)
{
    struct aead_alg *aead = crypto_aead_alg(tfm);
    unsigned long alignmask = crypto_aead_alignmask(tfm);

    if ((unsigned long)key & alignmask)
        return setkey_unaligned(tfm, key, keylen);

    return aead->setkey(tfm, key, keylen);
}

int crypto_aead_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
{
    struct aead_tfm *crt = crypto_aead_crt(tfm);
    int err;

    if (authsize > crypto_aead_alg(tfm)->maxauthsize)
        return -EINVAL;

    if (crypto_aead_alg(tfm)->setauthsize) {
        err = crypto_aead_alg(tfm)->setauthsize(crt->base, authsize);
        if (err)
            return err;
    }

    crypto_aead_crt(crt->base)->authsize = authsize;
    crt->authsize = authsize;
    return 0;
}
EXPORT_SYMBOL_GPL(crypto_aead_setauthsize);

static unsigned int crypto_aead_ctxsize(struct crypto_alg *alg, u32 type,
                    u32 mask)
{
    return alg->cra_ctxsize;
}

static int no_givcrypt(struct aead_givcrypt_request *req)
{
    return -ENOSYS;
}

static int crypto_init_aead_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
{
    struct aead_alg *alg = &tfm->__crt_alg->cra_aead;
    struct aead_tfm *crt = &tfm->crt_aead;

    if (max(alg->maxauthsize, alg->ivsize) > PAGE_SIZE / 8)
        return -EINVAL;

    crt->setkey = tfm->__crt_alg->cra_flags & CRYPTO_ALG_GENIV ?
              alg->setkey : setkey;
    crt->encrypt = alg->encrypt;
    crt->decrypt = alg->decrypt;
    crt->givencrypt = alg->givencrypt ?: no_givcrypt;
    crt->givdecrypt = alg->givdecrypt ?: no_givcrypt;
    crt->base = __crypto_aead_cast(tfm);
    crt->ivsize = alg->ivsize;
    crt->authsize = alg->maxauthsize;

    return 0;
}

#ifdef CONFIG_NET
static int crypto_aead_report(struct sk_buff *skb, struct crypto_alg *alg)
{
    struct crypto_report_aead raead;
    struct aead_alg *aead = &alg->cra_aead;

    snprintf(raead.type, CRYPTO_MAX_ALG_NAME, "%s", "aead");
    snprintf(raead.geniv, CRYPTO_MAX_ALG_NAME, "%s",
         aead->geniv ?: "<built-in>");

    raead.blocksize = alg->cra_blocksize;
    raead.maxauthsize = aead->maxauthsize;
    raead.ivsize = aead->ivsize;

    if (nla_put(skb, CRYPTOCFGA_REPORT_AEAD,
            sizeof(struct crypto_report_aead), &raead))
        goto nla_put_failure;
    return 0;

nla_put_failure:
    return -EMSGSIZE;
}
#else
static int crypto_aead_report(struct sk_buff *skb, struct crypto_alg *alg)
{
    return -ENOSYS;
}
#endif

static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
    __attribute__ ((unused));
static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
{
    struct aead_alg *aead = &alg->cra_aead;

    seq_printf(m, "type         : aead\n");
    seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
                         "yes" : "no");
    seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
    seq_printf(m, "ivsize       : %u\n", aead->ivsize);
    seq_printf(m, "maxauthsize  : %u\n", aead->maxauthsize);
    seq_printf(m, "geniv        : %s\n", aead->geniv ?: "<built-in>");
}

const struct crypto_type crypto_aead_type = {
    .ctxsize = crypto_aead_ctxsize,
    .init = crypto_init_aead_ops,
#ifdef CONFIG_PROC_FS
    .show = crypto_aead_show,
#endif
    .report = crypto_aead_report,
};
EXPORT_SYMBOL_GPL(crypto_aead_type);

static int aead_null_givencrypt(struct aead_givcrypt_request *req)
{
    return crypto_aead_encrypt(&req->areq);
}

static int aead_null_givdecrypt(struct aead_givcrypt_request *req)
{
    return crypto_aead_decrypt(&req->areq);
}

static int crypto_init_nivaead_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
{
    struct aead_alg *alg = &tfm->__crt_alg->cra_aead;
    struct aead_tfm *crt = &tfm->crt_aead;

    if (max(alg->maxauthsize, alg->ivsize) > PAGE_SIZE / 8)
        return -EINVAL;

    crt->setkey = setkey;
    crt->encrypt = alg->encrypt;
    crt->decrypt = alg->decrypt;
    if (!alg->ivsize) {
        crt->givencrypt = aead_null_givencrypt;
        crt->givdecrypt = aead_null_givdecrypt;
    }
    crt->base = __crypto_aead_cast(tfm);
    crt->ivsize = alg->ivsize;
    crt->authsize = alg->maxauthsize;

    return 0;
}

#ifdef CONFIG_NET
static int crypto_nivaead_report(struct sk_buff *skb, struct crypto_alg *alg)
{
    struct crypto_report_aead raead;
    struct aead_alg *aead = &alg->cra_aead;

    snprintf(raead.type, CRYPTO_MAX_ALG_NAME, "%s", "nivaead");
    snprintf(raead.geniv, CRYPTO_MAX_ALG_NAME, "%s", aead->geniv);

    raead.blocksize = alg->cra_blocksize;
    raead.maxauthsize = aead->maxauthsize;
    raead.ivsize = aead->ivsize;

    if (nla_put(skb, CRYPTOCFGA_REPORT_AEAD,
            sizeof(struct crypto_report_aead), &raead))
        goto nla_put_failure;
    return 0;

nla_put_failure:
    return -EMSGSIZE;
}
#else
static int crypto_nivaead_report(struct sk_buff *skb, struct crypto_alg *alg)
{
    return -ENOSYS;
}
#endif


static void crypto_nivaead_show(struct seq_file *m, struct crypto_alg *alg)
    __attribute__ ((unused));
static void crypto_nivaead_show(struct seq_file *m, struct crypto_alg *alg)
{
    struct aead_alg *aead = &alg->cra_aead;

    seq_printf(m, "type         : nivaead\n");
    seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
                         "yes" : "no");
    seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
    seq_printf(m, "ivsize       : %u\n", aead->ivsize);
    seq_printf(m, "maxauthsize  : %u\n", aead->maxauthsize);
    seq_printf(m, "geniv        : %s\n", aead->geniv);
}

const struct crypto_type crypto_nivaead_type = {
    .ctxsize = crypto_aead_ctxsize,
    .init = crypto_init_nivaead_ops,
#ifdef CONFIG_PROC_FS
    .show = crypto_nivaead_show,
#endif
    .report = crypto_nivaead_report,
};
EXPORT_SYMBOL_GPL(crypto_nivaead_type);

static int crypto_grab_nivaead(struct crypto_aead_spawn *spawn,
                   const char *name, u32 type, u32 mask)
{
    struct crypto_alg *alg;
    int err;

    type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
    type |= CRYPTO_ALG_TYPE_AEAD;
    mask |= CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV;

    alg = crypto_alg_mod_lookup(name, type, mask);
    if (IS_ERR(alg))
        return PTR_ERR(alg);

    err = crypto_init_spawn(&spawn->base, alg, spawn->base.inst, mask);
    crypto_mod_put(alg);
    return err;
}

struct crypto_instance *aead_geniv_alloc(struct crypto_template *tmpl,
                     struct rtattr **tb, u32 type,
                     u32 mask)
{
    const char *name;
    struct crypto_aead_spawn *spawn;
    struct crypto_attr_type *algt;
    struct crypto_instance *inst;
    struct crypto_alg *alg;
    int err;

    algt = crypto_get_attr_type(tb);
    err = PTR_ERR(algt);
    if (IS_ERR(algt))
        return ERR_PTR(err);

    if ((algt->type ^ (CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_GENIV)) &
        algt->mask)
        return ERR_PTR(-EINVAL);

    name = crypto_attr_alg_name(tb[1]);
    err = PTR_ERR(name);
    if (IS_ERR(name))
        return ERR_PTR(err);

    inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
    if (!inst)
        return ERR_PTR(-ENOMEM);

    spawn = crypto_instance_ctx(inst);

    /* Ignore async algorithms if necessary. */
    mask |= crypto_requires_sync(algt->type, algt->mask);

    crypto_set_aead_spawn(spawn, inst);
    err = crypto_grab_nivaead(spawn, name, type, mask);
    if (err)
        goto err_free_inst;

    alg = crypto_aead_spawn_alg(spawn);

    err = -EINVAL;
    if (!alg->cra_aead.ivsize)
        goto err_drop_alg;

    /*
     * This is only true if we're constructing an algorithm with its
     * default IV generator.  For the default generator we elide the
     * template name and double-check the IV generator.
     */
    if (algt->mask & CRYPTO_ALG_GENIV) {
        if (strcmp(tmpl->name, alg->cra_aead.geniv))
            goto err_drop_alg;

        memcpy(inst->alg.cra_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
        memcpy(inst->alg.cra_driver_name, alg->cra_driver_name,
               CRYPTO_MAX_ALG_NAME);
    } else {
        err = -ENAMETOOLONG;
        if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
                 "%s(%s)", tmpl->name, alg->cra_name) >=
            CRYPTO_MAX_ALG_NAME)
            goto err_drop_alg;
        if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
                 "%s(%s)", tmpl->name, alg->cra_driver_name) >=
            CRYPTO_MAX_ALG_NAME)
            goto err_drop_alg;
    }

    inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_GENIV;
    inst->alg.cra_flags |= alg->cra_flags & CRYPTO_ALG_ASYNC;
    inst->alg.cra_priority = alg->cra_priority;
    inst->alg.cra_blocksize = alg->cra_blocksize;
    inst->alg.cra_alignmask = alg->cra_alignmask;
    inst->alg.cra_type = &crypto_aead_type;

    inst->alg.cra_aead.ivsize = alg->cra_aead.ivsize;
    inst->alg.cra_aead.maxauthsize = alg->cra_aead.maxauthsize;
    inst->alg.cra_aead.geniv = alg->cra_aead.geniv;

    inst->alg.cra_aead.setkey = alg->cra_aead.setkey;
    inst->alg.cra_aead.setauthsize = alg->cra_aead.setauthsize;
    inst->alg.cra_aead.encrypt = alg->cra_aead.encrypt;
    inst->alg.cra_aead.decrypt = alg->cra_aead.decrypt;

out:
    return inst;

err_drop_alg:
    crypto_drop_aead(spawn);
err_free_inst:
    kfree(inst);
    inst = ERR_PTR(err);
    goto out;
}
EXPORT_SYMBOL_GPL(aead_geniv_alloc);

void aead_geniv_free(struct crypto_instance *inst)
{
    crypto_drop_aead(crypto_instance_ctx(inst));
    kfree(inst);
}
EXPORT_SYMBOL_GPL(aead_geniv_free);

int aead_geniv_init(struct crypto_tfm *tfm)
{
    struct crypto_instance *inst = (void *)tfm->__crt_alg;
    struct crypto_aead *aead;

    aead = crypto_spawn_aead(crypto_instance_ctx(inst));
    if (IS_ERR(aead))
        return PTR_ERR(aead);

    tfm->crt_aead.base = aead;
    tfm->crt_aead.reqsize += crypto_aead_reqsize(aead);

    return 0;
}
EXPORT_SYMBOL_GPL(aead_geniv_init);

void aead_geniv_exit(struct crypto_tfm *tfm)
{
    crypto_free_aead(tfm->crt_aead.base);
}
EXPORT_SYMBOL_GPL(aead_geniv_exit);

static int crypto_nivaead_default(struct crypto_alg *alg, u32 type, u32 mask)
{
    struct rtattr *tb[3];
    struct {
        struct rtattr attr;
        struct crypto_attr_type data;
    } ptype;
    struct {
        struct rtattr attr;
        struct crypto_attr_alg data;
    } palg;
    struct crypto_template *tmpl;
    struct crypto_instance *inst;
    struct crypto_alg *larval;
    const char *geniv;
    int err;

    larval = crypto_larval_lookup(alg->cra_driver_name,
                      CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_GENIV,
                      CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
    err = PTR_ERR(larval);
    if (IS_ERR(larval))
        goto out;

    err = -EAGAIN;
    if (!crypto_is_larval(larval))
        goto drop_larval;

    ptype.attr.rta_len = sizeof(ptype);
    ptype.attr.rta_type = CRYPTOA_TYPE;
    ptype.data.type = type | CRYPTO_ALG_GENIV;
    /* GENIV tells the template that we're making a default geniv. */
    ptype.data.mask = mask | CRYPTO_ALG_GENIV;
    tb[0] = &ptype.attr;

    palg.attr.rta_len = sizeof(palg);
    palg.attr.rta_type = CRYPTOA_ALG;
    /* Must use the exact name to locate ourselves. */
    memcpy(palg.data.name, alg->cra_driver_name, CRYPTO_MAX_ALG_NAME);
    tb[1] = &palg.attr;

    tb[2] = NULL;

    geniv = alg->cra_aead.geniv;

    tmpl = crypto_lookup_template(geniv);
    err = -ENOENT;
    if (!tmpl)
        goto kill_larval;

    inst = tmpl->alloc(tb);
    err = PTR_ERR(inst);
    if (IS_ERR(inst))
        goto put_tmpl;

    if ((err = crypto_register_instance(tmpl, inst))) {
        tmpl->free(inst);
        goto put_tmpl;
    }

    /* Redo the lookup to use the instance we just registered. */
    err = -EAGAIN;

put_tmpl:
    crypto_tmpl_put(tmpl);
kill_larval:
    crypto_larval_kill(larval);
drop_larval:
    crypto_mod_put(larval);
out:
    crypto_mod_put(alg);
    return err;
}

struct crypto_alg *crypto_lookup_aead(const char *name, u32 type, u32 mask)
{
    struct crypto_alg *alg;

    alg = crypto_alg_mod_lookup(name, type, mask);
    if (IS_ERR(alg))
        return alg;

    if (alg->cra_type == &crypto_aead_type)
        return alg;

    if (!alg->cra_aead.ivsize)
        return alg;

    crypto_mod_put(alg);
    alg = crypto_alg_mod_lookup(name, type | CRYPTO_ALG_TESTED,
                    mask & ~CRYPTO_ALG_TESTED);
    if (IS_ERR(alg))
        return alg;

    if (alg->cra_type == &crypto_aead_type) {
        if ((alg->cra_flags ^ type ^ ~mask) & CRYPTO_ALG_TESTED) {
            crypto_mod_put(alg);
            alg = ERR_PTR(-ENOENT);
        }
        return alg;
    }

    BUG_ON(!alg->cra_aead.ivsize);

    return ERR_PTR(crypto_nivaead_default(alg, type, mask));
}
EXPORT_SYMBOL_GPL(crypto_lookup_aead);

int crypto_grab_aead(struct crypto_aead_spawn *spawn, const char *name,
             u32 type, u32 mask)
{
    struct crypto_alg *alg;
    int err;

    type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
    type |= CRYPTO_ALG_TYPE_AEAD;
    mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
    mask |= CRYPTO_ALG_TYPE_MASK;

    alg = crypto_lookup_aead(name, type, mask);
    if (IS_ERR(alg))
        return PTR_ERR(alg);

    err = crypto_init_spawn(&spawn->base, alg, spawn->base.inst, mask);
    crypto_mod_put(alg);
    return err;
}
EXPORT_SYMBOL_GPL(crypto_grab_aead);

struct crypto_aead *crypto_alloc_aead(const char *alg_name, u32 type, u32 mask)
{
    struct crypto_tfm *tfm;
    int err;

    type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
    type |= CRYPTO_ALG_TYPE_AEAD;
    mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
    mask |= CRYPTO_ALG_TYPE_MASK;

    for (;;) {
        struct crypto_alg *alg;

        alg = crypto_lookup_aead(alg_name, type, mask);
        if (IS_ERR(alg)) {
            err = PTR_ERR(alg);
            goto err;
        }

        tfm = __crypto_alloc_tfm(alg, type, mask);
        if (!IS_ERR(tfm))
            return __crypto_aead_cast(tfm);

        crypto_mod_put(alg);
        err = PTR_ERR(tfm);

err:
        if (err != -EAGAIN)
            break;
        if (signal_pending(current)) {
            err = -EINTR;
            break;
        }
    }

    return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(crypto_alloc_aead);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Authenticated Encryption with Associated Data (AEAD)");