nx-aes-ccm.c

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#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 ccm_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;
    default:
        return -EINVAL;
    }

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

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

    return 0;

}

static int ccm4309_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);

    if (key_len < 3)
        return -EINVAL;

    key_len -= 3;

    memcpy(nx_ctx->priv.ccm.nonce, in_key + key_len, 3);

    return ccm_aes_nx_set_key(tfm, in_key, key_len);
}

static int ccm_aes_nx_setauthsize(struct crypto_aead *tfm,
                  unsigned int authsize)
{
    switch (authsize) {
    case 4:
    case 6:
    case 8:
    case 10:
    case 12:
    case 14:
    case 16:
        break;
    default:
        return -EINVAL;
    }

    crypto_aead_crt(tfm)->authsize = authsize;

    return 0;
}

static int ccm4309_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;
}

/* taken from crypto/ccm.c */
static int set_msg_len(u8 *block, unsigned int msglen, int csize)
{
    __be32 data;

    memset(block, 0, csize);
    block += csize;

    if (csize >= 4)
        csize = 4;
    else if (msglen > (unsigned int)(1 << (8 * csize)))
        return -EOVERFLOW;

    data = cpu_to_be32(msglen);
    memcpy(block - csize, (u8 *)&data + 4 - csize, csize);

    return 0;
}

/* taken from crypto/ccm.c */
static inline int crypto_ccm_check_iv(const u8 *iv)
{
    /* 2 <= L <= 8, so 1 <= L' <= 7. */
    if (1 > iv[0] || iv[0] > 7)
        return -EINVAL;

    return 0;
}

/* based on code from crypto/ccm.c */
static int generate_b0(u8 *iv, unsigned int assoclen, unsigned int authsize,
               unsigned int cryptlen, u8 *b0)
{
    unsigned int l, lp, m = authsize;
    int rc;

    memcpy(b0, iv, 16);

    lp = b0[0];
    l = lp + 1;

    /* set m, bits 3-5 */
    *b0 |= (8 * ((m - 2) / 2));

    /* set adata, bit 6, if associated data is used */
    if (assoclen)
        *b0 |= 64;

    rc = set_msg_len(b0 + 16 - l, cryptlen, l);

    return rc;
}

static int generate_pat(u8                   *iv,
            struct aead_request  *req,
            struct nx_crypto_ctx *nx_ctx,
            unsigned int          authsize,
            unsigned int          nbytes,
            u8                   *out)
{
    struct nx_sg *nx_insg = nx_ctx->in_sg;
    struct nx_sg *nx_outsg = nx_ctx->out_sg;
    unsigned int iauth_len = 0;
    struct vio_pfo_op *op = NULL;
    u8 tmp[16], *b1 = NULL, *b0 = NULL, *result = NULL;
    int rc;

    /* zero the ctr value */
    memset(iv + 15 - iv[0], 0, iv[0] + 1);

    if (!req->assoclen) {
        b0 = nx_ctx->csbcpb->cpb.aes_ccm.in_pat_or_b0;
    } else if (req->assoclen <= 14) {
        /* if associated data is 14 bytes or less, we do 1 GCM
         * operation on 2 AES blocks, B0 (stored in the csbcpb) and B1,
         * which is fed in through the source buffers here */
        b0 = nx_ctx->csbcpb->cpb.aes_ccm.in_pat_or_b0;
        b1 = nx_ctx->priv.ccm.iauth_tag;
        iauth_len = req->assoclen;

        nx_insg = nx_build_sg_list(nx_insg, b1, 16, nx_ctx->ap->sglen);
        nx_outsg = nx_build_sg_list(nx_outsg, tmp, 16,
                        nx_ctx->ap->sglen);

        /* inlen should be negative, indicating to phyp that its a
         * pointer to an sg list */
        nx_ctx->op.inlen = (nx_ctx->in_sg - nx_insg) *
                    sizeof(struct nx_sg);
        nx_ctx->op.outlen = (nx_ctx->out_sg - nx_outsg) *
                    sizeof(struct nx_sg);

        NX_CPB_FDM(nx_ctx->csbcpb) |= NX_FDM_ENDE_ENCRYPT;
        NX_CPB_FDM(nx_ctx->csbcpb) |= NX_FDM_INTERMEDIATE;

        op = &nx_ctx->op;
        result = nx_ctx->csbcpb->cpb.aes_ccm.out_pat_or_mac;
    } else if (req->assoclen <= 65280) {
        /* if associated data is less than (2^16 - 2^8), we construct
         * B1 differently and feed in the associated data to a CCA
         * operation */
        b0 = nx_ctx->csbcpb_aead->cpb.aes_cca.b0;
        b1 = nx_ctx->csbcpb_aead->cpb.aes_cca.b1;
        iauth_len = 14;

        /* remaining assoc data must have scatterlist built for it */
        nx_insg = nx_walk_and_build(nx_insg, nx_ctx->ap->sglen,
                        req->assoc, iauth_len,
                        req->assoclen - iauth_len);
        nx_ctx->op_aead.inlen = (nx_ctx->in_sg - nx_insg) *
                        sizeof(struct nx_sg);

        op = &nx_ctx->op_aead;
        result = nx_ctx->csbcpb_aead->cpb.aes_cca.out_pat_or_b0;
    } else {
        /* if associated data is less than (2^32), we construct B1
         * differently yet again and feed in the associated data to a
         * CCA operation */
        pr_err("associated data len is %u bytes (returning -EINVAL)\n",
               req->assoclen);
        rc = -EINVAL;
    }

    rc = generate_b0(iv, req->assoclen, authsize, nbytes, b0);
    if (rc)
        goto done;

    if (b1) {
        memset(b1, 0, 16);
        *(u16 *)b1 = (u16)req->assoclen;

        scatterwalk_map_and_copy(b1 + 2, req->assoc, 0,
                     iauth_len, SCATTERWALK_FROM_SG);

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

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

        memcpy(out, result, AES_BLOCK_SIZE);
    }
done:
    return rc;
}

static int ccm_nx_decrypt(struct aead_request   *req,
              struct blkcipher_desc *desc)
{
    struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
    struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
    unsigned int nbytes = req->cryptlen;
    unsigned int authsize = crypto_aead_authsize(crypto_aead_reqtfm(req));
    struct nx_ccm_priv *priv = &nx_ctx->priv.ccm;
    int rc = -1;

    if (nbytes > nx_ctx->ap->databytelen)
        return -EINVAL;

    nbytes -= authsize;

    /* copy out the auth tag to compare with later */
    scatterwalk_map_and_copy(priv->oauth_tag,
                 req->src, nbytes, authsize,
                 SCATTERWALK_FROM_SG);

    rc = generate_pat(desc->info, req, nx_ctx, authsize, nbytes,
              csbcpb->cpb.aes_ccm.in_pat_or_b0);
    if (rc)
        goto out;

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

    NX_CPB_FDM(nx_ctx->csbcpb) &= ~NX_FDM_ENDE_ENCRYPT;
    NX_CPB_FDM(nx_ctx->csbcpb) &= ~NX_FDM_INTERMEDIATE;

    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));

    rc = memcmp(csbcpb->cpb.aes_ccm.out_pat_or_mac, priv->oauth_tag,
            authsize) ? -EBADMSG : 0;
out:
    return rc;
}

static int ccm_nx_encrypt(struct aead_request   *req,
              struct blkcipher_desc *desc)
{
    struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
    struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
    unsigned int nbytes = req->cryptlen;
    unsigned int authsize = crypto_aead_authsize(crypto_aead_reqtfm(req));
    int rc = -1;

    if (nbytes > nx_ctx->ap->databytelen)
        return -EINVAL;

    rc = generate_pat(desc->info, req, nx_ctx, authsize, nbytes,
              csbcpb->cpb.aes_ccm.in_pat_or_b0);
    if (rc)
        goto out;

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

    NX_CPB_FDM(csbcpb) |= NX_FDM_ENDE_ENCRYPT;
    NX_CPB_FDM(csbcpb) &= ~NX_FDM_INTERMEDIATE;

    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));

    /* copy out the auth tag */
    scatterwalk_map_and_copy(csbcpb->cpb.aes_ccm.out_pat_or_mac,
                 req->dst, nbytes, authsize,
                 SCATTERWALK_TO_SG);
out:
    return rc;
}

static int ccm4309_aes_nx_encrypt(struct aead_request *req)
{
    struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
    struct blkcipher_desc desc;
    u8 *iv = nx_ctx->priv.ccm.iv;

    iv[0] = 3;
    memcpy(iv + 1, nx_ctx->priv.ccm.nonce, 3);
    memcpy(iv + 4, req->iv, 8);

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

    return ccm_nx_encrypt(req, &desc);
}

static int ccm_aes_nx_encrypt(struct aead_request *req)
{
    struct blkcipher_desc desc;
    int rc;

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

    rc = crypto_ccm_check_iv(desc.info);
    if (rc)
        return rc;

    return ccm_nx_encrypt(req, &desc);
}

static int ccm4309_aes_nx_decrypt(struct aead_request *req)
{
    struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
    struct blkcipher_desc desc;
    u8 *iv = nx_ctx->priv.ccm.iv;

    iv[0] = 3;
    memcpy(iv + 1, nx_ctx->priv.ccm.nonce, 3);
    memcpy(iv + 4, req->iv, 8);

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

    return ccm_nx_decrypt(req, &desc);
}

static int ccm_aes_nx_decrypt(struct aead_request *req)
{
    struct blkcipher_desc desc;
    int rc;

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

    rc = crypto_ccm_check_iv(desc.info);
    if (rc)
        return rc;

    return ccm_nx_decrypt(req, &desc);
}

/* 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_ccm_aes_alg = {
    .cra_name        = "ccm(aes)",
    .cra_driver_name = "ccm-aes-nx",
    .cra_priority    = 300,
    .cra_flags       = CRYPTO_ALG_TYPE_AEAD |
               CRYPTO_ALG_NEED_FALLBACK,
    .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_ccm_init,
    .cra_exit        = nx_crypto_ctx_exit,
    .cra_aead = {
        .ivsize      = AES_BLOCK_SIZE,
        .maxauthsize = AES_BLOCK_SIZE,
        .setkey      = ccm_aes_nx_set_key,
        .setauthsize = ccm_aes_nx_setauthsize,
        .encrypt     = ccm_aes_nx_encrypt,
        .decrypt     = ccm_aes_nx_decrypt,
    }
};

struct crypto_alg nx_ccm4309_aes_alg = {
    .cra_name        = "rfc4309(ccm(aes))",
    .cra_driver_name = "rfc4309-ccm-aes-nx",
    .cra_priority    = 300,
    .cra_flags       = CRYPTO_ALG_TYPE_AEAD |
               CRYPTO_ALG_NEED_FALLBACK,
    .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_ccm_init,
    .cra_exit        = nx_crypto_ctx_exit,
    .cra_aead = {
        .ivsize      = 8,
        .maxauthsize = AES_BLOCK_SIZE,
        .setkey      = ccm4309_aes_nx_set_key,
        .setauthsize = ccm4309_aes_nx_setauthsize,
        .encrypt     = ccm4309_aes_nx_encrypt,
        .decrypt     = ccm4309_aes_nx_decrypt,
        .geniv       = "seqiv",
    }
};