nx-aes-gcm.c

Go to the documentation of this file.

#include <crypto/internal/aead.h>
#include <crypto/aes.h>
#include <crypto/algapi.h>
#include <crypto/scatterwalk.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/crypto.h>
#include <asm/vio.h>

#include "nx_csbcpb.h"
#include "nx.h"


static int gcm_aes_nx_set_key(struct crypto_aead *tfm,
                  const u8           *in_key,
                  unsigned int        key_len)
{
    struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(&tfm->base);
    struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
    struct nx_csbcpb *csbcpb_aead = nx_ctx->csbcpb_aead;

    nx_ctx_init(nx_ctx, HCOP_FC_AES);

    switch (key_len) {
    case AES_KEYSIZE_128:
        NX_CPB_SET_KEY_SIZE(csbcpb, NX_KS_AES_128);
        NX_CPB_SET_KEY_SIZE(csbcpb_aead, NX_KS_AES_128);
        nx_ctx->ap = &nx_ctx->props[NX_PROPS_AES_128];
        break;
    case AES_KEYSIZE_192:
        NX_CPB_SET_KEY_SIZE(csbcpb, NX_KS_AES_192);
        NX_CPB_SET_KEY_SIZE(csbcpb_aead, NX_KS_AES_192);
        nx_ctx->ap = &nx_ctx->props[NX_PROPS_AES_192];
        break;
    case AES_KEYSIZE_256:
        NX_CPB_SET_KEY_SIZE(csbcpb, NX_KS_AES_256);
        NX_CPB_SET_KEY_SIZE(csbcpb_aead, NX_KS_AES_256);
        nx_ctx->ap = &nx_ctx->props[NX_PROPS_AES_256];
        break;
    default:
        return -EINVAL;
    }

    csbcpb->cpb.hdr.mode = NX_MODE_AES_GCM;
    memcpy(csbcpb->cpb.aes_gcm.key, in_key, key_len);

    csbcpb_aead->cpb.hdr.mode = NX_MODE_AES_GCA;
    memcpy(csbcpb_aead->cpb.aes_gca.key, in_key, key_len);

    return 0;
}

static int gcm4106_aes_nx_set_key(struct crypto_aead *tfm,
                  const u8           *in_key,
                  unsigned int        key_len)
{
    struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(&tfm->base);
    char *nonce = nx_ctx->priv.gcm.nonce;
    int rc;

    if (key_len < 4)
        return -EINVAL;

    key_len -= 4;

    rc = gcm_aes_nx_set_key(tfm, in_key, key_len);
    if (rc)
        goto out;

    memcpy(nonce, in_key + key_len, 4);
out:
    return rc;
}

static int gcm_aes_nx_setauthsize(struct crypto_aead *tfm,
                  unsigned int authsize)
{
    if (authsize > crypto_aead_alg(tfm)->maxauthsize)
        return -EINVAL;

    crypto_aead_crt(tfm)->authsize = authsize;

    return 0;
}

static int gcm4106_aes_nx_setauthsize(struct crypto_aead *tfm,
                      unsigned int authsize)
{
    switch (authsize) {
    case 8:
    case 12:
    case 16:
        break;
    default:
        return -EINVAL;
    }

    crypto_aead_crt(tfm)->authsize = authsize;

    return 0;
}

static int nx_gca(struct nx_crypto_ctx  *nx_ctx,
          struct aead_request   *req,
          u8                    *out)
{
    struct nx_csbcpb *csbcpb_aead = nx_ctx->csbcpb_aead;
    int rc = -EINVAL;
    struct scatter_walk walk;
    struct nx_sg *nx_sg = nx_ctx->in_sg;

    if (req->assoclen > nx_ctx->ap->databytelen)
        goto out;

    if (req->assoclen <= AES_BLOCK_SIZE) {
        scatterwalk_start(&walk, req->assoc);
        scatterwalk_copychunks(out, &walk, req->assoclen,
                       SCATTERWALK_FROM_SG);
        scatterwalk_done(&walk, SCATTERWALK_FROM_SG, 0);

        rc = 0;
        goto out;
    }

    nx_sg = nx_walk_and_build(nx_sg, nx_ctx->ap->sglen, req->assoc, 0,
                  req->assoclen);
    nx_ctx->op_aead.inlen = (nx_ctx->in_sg - nx_sg) * sizeof(struct nx_sg);

    rc = nx_hcall_sync(nx_ctx, &nx_ctx->op_aead,
               req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP);
    if (rc)
        goto out;

    atomic_inc(&(nx_ctx->stats->aes_ops));
    atomic64_add(req->assoclen, &(nx_ctx->stats->aes_bytes));

    memcpy(out, csbcpb_aead->cpb.aes_gca.out_pat, AES_BLOCK_SIZE);
out:
    return rc;
}

static int gcm_aes_nx_crypt(struct aead_request *req, int enc)
{
    struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
    struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
    struct blkcipher_desc desc;
    unsigned int nbytes = req->cryptlen;
    int rc = -EINVAL;

    if (nbytes > nx_ctx->ap->databytelen)
        goto out;

    desc.info = nx_ctx->priv.gcm.iv;
    /* initialize the counter */
    *(u32 *)(desc.info + NX_GCM_CTR_OFFSET) = 1;

    /* For scenarios where the input message is zero length, AES CTR mode
     * may be used. Set the source data to be a single block (16B) of all
     * zeros, and set the input IV value to be the same as the GMAC IV
     * value. - nx_wb 4.8.1.3 */
    if (nbytes == 0) {
        char src[AES_BLOCK_SIZE] = {};
        struct scatterlist sg;

        desc.tfm = crypto_alloc_blkcipher("ctr(aes)", 0, 0);
        if (IS_ERR(desc.tfm)) {
            rc = -ENOMEM;
            goto out;
        }

        crypto_blkcipher_setkey(desc.tfm, csbcpb->cpb.aes_gcm.key,
            NX_CPB_KEY_SIZE(csbcpb) == NX_KS_AES_128 ? 16 :
            NX_CPB_KEY_SIZE(csbcpb) == NX_KS_AES_192 ? 24 : 32);

        sg_init_one(&sg, src, AES_BLOCK_SIZE);
        if (enc)
            crypto_blkcipher_encrypt_iv(&desc, req->dst, &sg,
                            AES_BLOCK_SIZE);
        else
            crypto_blkcipher_decrypt_iv(&desc, req->dst, &sg,
                            AES_BLOCK_SIZE);
        crypto_free_blkcipher(desc.tfm);

        rc = 0;
        goto out;
    }

    desc.tfm = (struct crypto_blkcipher *)req->base.tfm;

    csbcpb->cpb.aes_gcm.bit_length_aad = req->assoclen * 8;

    if (req->assoclen) {
        rc = nx_gca(nx_ctx, req, csbcpb->cpb.aes_gcm.in_pat_or_aad);
        if (rc)
            goto out;
    }

    if (enc)
        NX_CPB_FDM(csbcpb) |= NX_FDM_ENDE_ENCRYPT;
    else
        nbytes -= AES_BLOCK_SIZE;

    csbcpb->cpb.aes_gcm.bit_length_data = nbytes * 8;

    rc = nx_build_sg_lists(nx_ctx, &desc, req->dst, req->src, nbytes,
                   csbcpb->cpb.aes_gcm.iv_or_cnt);
    if (rc)
        goto out;

    rc = nx_hcall_sync(nx_ctx, &nx_ctx->op,
               req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP);
    if (rc)
        goto out;

    atomic_inc(&(nx_ctx->stats->aes_ops));
    atomic64_add(csbcpb->csb.processed_byte_count,
             &(nx_ctx->stats->aes_bytes));

    if (enc) {
        /* copy out the auth tag */
        scatterwalk_map_and_copy(csbcpb->cpb.aes_gcm.out_pat_or_mac,
                 req->dst, nbytes,
                 crypto_aead_authsize(crypto_aead_reqtfm(req)),
                 SCATTERWALK_TO_SG);
    } else if (req->assoclen) {
        u8 *itag = nx_ctx->priv.gcm.iauth_tag;
        u8 *otag = csbcpb->cpb.aes_gcm.out_pat_or_mac;

        scatterwalk_map_and_copy(itag, req->dst, nbytes,
                 crypto_aead_authsize(crypto_aead_reqtfm(req)),
                 SCATTERWALK_FROM_SG);
        rc = memcmp(itag, otag,
                crypto_aead_authsize(crypto_aead_reqtfm(req))) ?
             -EBADMSG : 0;
    }
out:
    return rc;
}

static int gcm_aes_nx_encrypt(struct aead_request *req)
{
    struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
    char *iv = nx_ctx->priv.gcm.iv;

    memcpy(iv, req->iv, 12);

    return gcm_aes_nx_crypt(req, 1);
}

static int gcm_aes_nx_decrypt(struct aead_request *req)
{
    struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
    char *iv = nx_ctx->priv.gcm.iv;

    memcpy(iv, req->iv, 12);

    return gcm_aes_nx_crypt(req, 0);
}

static int gcm4106_aes_nx_encrypt(struct aead_request *req)
{
    struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
    char *iv = nx_ctx->priv.gcm.iv;
    char *nonce = nx_ctx->priv.gcm.nonce;

    memcpy(iv, nonce, NX_GCM4106_NONCE_LEN);
    memcpy(iv + NX_GCM4106_NONCE_LEN, req->iv, 8);

    return gcm_aes_nx_crypt(req, 1);
}

static int gcm4106_aes_nx_decrypt(struct aead_request *req)
{
    struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
    char *iv = nx_ctx->priv.gcm.iv;
    char *nonce = nx_ctx->priv.gcm.nonce;

    memcpy(iv, nonce, NX_GCM4106_NONCE_LEN);
    memcpy(iv + NX_GCM4106_NONCE_LEN, req->iv, 8);

    return gcm_aes_nx_crypt(req, 0);
}

/* tell the block cipher walk routines that this is a stream cipher by
 * setting cra_blocksize to 1. Even using blkcipher_walk_virt_block
 * during encrypt/decrypt doesn't solve this problem, because it calls
 * blkcipher_walk_done under the covers, which doesn't use walk->blocksize,
 * but instead uses this tfm->blocksize. */
struct crypto_alg nx_gcm_aes_alg = {
    .cra_name        = "gcm(aes)",
    .cra_driver_name = "gcm-aes-nx",
    .cra_priority    = 300,
    .cra_flags       = CRYPTO_ALG_TYPE_AEAD,
    .cra_blocksize   = 1,
    .cra_ctxsize     = sizeof(struct nx_crypto_ctx),
    .cra_type        = &crypto_aead_type,
    .cra_module      = THIS_MODULE,
    .cra_init        = nx_crypto_ctx_aes_gcm_init,
    .cra_exit        = nx_crypto_ctx_exit,
    .cra_aead = {
        .ivsize      = AES_BLOCK_SIZE,
        .maxauthsize = AES_BLOCK_SIZE,
        .setkey      = gcm_aes_nx_set_key,
        .setauthsize = gcm_aes_nx_setauthsize,
        .encrypt     = gcm_aes_nx_encrypt,
        .decrypt     = gcm_aes_nx_decrypt,
    }
};

struct crypto_alg nx_gcm4106_aes_alg = {
    .cra_name        = "rfc4106(gcm(aes))",
    .cra_driver_name = "rfc4106-gcm-aes-nx",
    .cra_priority    = 300,
    .cra_flags       = CRYPTO_ALG_TYPE_AEAD,
    .cra_blocksize   = 1,
    .cra_ctxsize     = sizeof(struct nx_crypto_ctx),
    .cra_type        = &crypto_nivaead_type,
    .cra_module      = THIS_MODULE,
    .cra_init        = nx_crypto_ctx_aes_gcm_init,
    .cra_exit        = nx_crypto_ctx_exit,
    .cra_aead = {
        .ivsize      = 8,
        .maxauthsize = AES_BLOCK_SIZE,
        .geniv       = "seqiv",
        .setkey      = gcm4106_aes_nx_set_key,
        .setauthsize = gcm4106_aes_nx_setauthsize,
        .encrypt     = gcm4106_aes_nx_encrypt,
        .decrypt     = gcm4106_aes_nx_decrypt,
    }
};