On Mon, Jul 29, 2024 at 09:43:48AM +0530, Pavitrakumar M wrote:
> +static int spacc_aead_setkey(struct crypto_aead *tfm, const u8 *key,
> + unsigned int keylen)
> +{
> + struct spacc_crypto_ctx *ctx = crypto_aead_ctx(tfm);
> + const struct spacc_alg *salg = spacc_tfm_aead(&tfm->base);
> + struct spacc_priv *priv;
> + struct rtattr *rta = (void *)key;
> + struct crypto_authenc_key_param *param;
> + unsigned int authkeylen, enckeylen;
> + const unsigned char *authkey, *enckey;
> + unsigned char xcbc[64];
> +
> + int err = -EINVAL;
> + int singlekey = 0;
> +
> + /* are keylens valid? */
> + ctx->ctx_valid = false;
> +
> + switch (ctx->mode & 0xFF) {
> + case CRYPTO_MODE_SM4_GCM:
> + case CRYPTO_MODE_SM4_CCM:
> + case CRYPTO_MODE_NULL:
> + case CRYPTO_MODE_AES_GCM:
> + case CRYPTO_MODE_AES_CCM:
> + case CRYPTO_MODE_CHACHA20_POLY1305:
> + authkey = key;
> + authkeylen = 0;
> + enckey = key;
> + enckeylen = keylen;
> + ctx->keylen = keylen;
> + singlekey = 1;
> + goto skipover;
> + }
> +
> + if (!RTA_OK(rta, keylen) ||
^^^^^^^^^^^
This check validates that rta->rta_len is less than keylen.
> + rta->rta_type != CRYPTO_AUTHENC_KEYA_PARAM ||
> + RTA_PAYLOAD(rta) < sizeof(*param))
> + return -EINVAL;
> +
> + param = RTA_DATA(rta);
> + enckeylen = be32_to_cpu(param->enckeylen);
> + key += RTA_ALIGN(rta->rta_len);
> + keylen -= RTA_ALIGN(rta->rta_len);
However we're subtracting RTA_ALIGN() not rta->rta_len so there is a chance that
this subtraction can make keylen negative (but it's unsigned so a large positive
value). Both keylen and rta->rta_len would need have to not be multples of 4.
For example, if they were both set to 9.
(I'm not a domain expert so maybe here is checking for % 4 at a different level).
A high positive value of keylen would lead to memory corruption later in the
function.
regards,
dan carpenter
> +
> + if (keylen < enckeylen)
> + return -EINVAL;
> +
> + authkeylen = keylen - enckeylen;
> +
> + /* enckey is at &key[authkeylen] and
> + * authkey is at &key[0]
> + */
> + authkey = &key[0];
> + enckey = &key[authkeylen];
> +
> +skipover:
> + /* detect RFC3686/4106 and trim from enckeylen(and copy salt..) */
> + if (ctx->mode & SPACC_MANGLE_IV_FLAG) {
> + switch (ctx->mode & 0x7F00) {
> + case SPACC_MANGLE_IV_RFC3686:
> + case SPACC_MANGLE_IV_RFC4106:
> + case SPACC_MANGLE_IV_RFC4543:
> + memcpy(ctx->csalt, enckey + enckeylen - 4, 4);
> + enckeylen -= 4;
> + break;
> + case SPACC_MANGLE_IV_RFC4309:
> + memcpy(ctx->csalt, enckey + enckeylen - 3, 3);
> + enckeylen -= 3;
> + break;
> + }
> + }
> +
> + if (!singlekey) {
> + if (authkeylen > salg->mode->hashlen) {
> + dev_warn(ctx->dev, "Auth key size of %u is not valid\n",
> + authkeylen);
> + return -EINVAL;
> + }
> + }
> +
> + if (!spacc_check_keylen(salg, enckeylen)) {
> + dev_warn(ctx->dev, "Enc key size of %u is not valid\n",
> + enckeylen);
> + return -EINVAL;
> + }
> +
> + /* if we're already open close the handle since
> + * the size may have changed
> + */
> + if (ctx->handle != -1) {
> + priv = dev_get_drvdata(ctx->dev);
> + spacc_close(&priv->spacc, ctx->handle);
> + put_device(ctx->dev);
> + ctx->handle = -1;
> + }
> +
> + /* Open a handle and
> + * search all devices for an open handle
> + */
> + priv = NULL;
> + priv = dev_get_drvdata(salg->dev[0]);
> +
> + /* increase reference */
> + ctx->dev = get_device(salg->dev[0]);
> +
> + /* check if its a valid mode ... */
> + if (spacc_isenabled(&priv->spacc, salg->mode->aead.ciph & 0xFF,
> + enckeylen) &&
> + spacc_isenabled(&priv->spacc,
> + salg->mode->aead.hash & 0xFF, authkeylen)) {
> + /* try to open spacc handle */
> + ctx->handle = spacc_open(&priv->spacc,
> + salg->mode->aead.ciph & 0xFF,
> + salg->mode->aead.hash & 0xFF,
> + -1, 0, spacc_aead_cb, tfm);
> + }
> +
> + if (ctx->handle < 0) {
> + put_device(salg->dev[0]);
> + pr_debug("Failed to open SPAcc context\n");
> + return -EIO;
> + }
> +
> + /* setup XCBC key */
> + if (salg->mode->aead.hash == CRYPTO_MODE_MAC_XCBC) {
> + err = spacc_compute_xcbc_key(&priv->spacc,
> + salg->mode->aead.hash,
> + ctx->handle, authkey,
> + authkeylen, xcbc);
> + if (err < 0) {
> + dev_warn(ctx->dev, "Failed to compute XCBC key: %d\n",
> + err);
> + return -EIO;
> + }
> + authkey = xcbc;
> + authkeylen = 48;
> + }
> +
> + /* handle zero key/zero len DEC condition for SM4/AES GCM mode */
> + ctx->zero_key = 0;
> + if (!key[0]) {
> + int i, val = 0;
> +
> + for (i = 0; i < keylen ; i++)
> + val += key[i];
> +
> + if (val == 0)
> + ctx->zero_key = 1;
> + }
> +
> + err = spacc_write_context(&priv->spacc, ctx->handle,
> + SPACC_CRYPTO_OPERATION, enckey,
> + enckeylen, NULL, 0);
> +
> + if (err) {
> + dev_warn(ctx->dev,
> + "Could not write ciphering context: %d\n", err);
> + return -EIO;
> + }
> +
> + if (!singlekey) {
> + err = spacc_write_context(&priv->spacc, ctx->handle,
> + SPACC_HASH_OPERATION, authkey,
> + authkeylen, NULL, 0);
> + if (err) {
> + dev_warn(ctx->dev,
> + "Could not write hashing context: %d\n", err);
> + return -EIO;
> + }
> + }
> +
> + /* set expand key */
> + spacc_set_key_exp(&priv->spacc, ctx->handle);
> + ctx->ctx_valid = true;
> +
> + memset(xcbc, 0, sizeof(xcbc));
> +
> + /* copy key to ctx for fallback */
> + memcpy(ctx->key, key, keylen);
> +
> + return 0;
> +}
