Re: [PATCH v2 1/3] ima: use ahash API for file hash calculation

From: Mimi Zohar
Date: Wed Jul 02 2014 - 13:44:40 EST


On Tue, 2014-07-01 at 23:12 +0300, Dmitry Kasatkin wrote:

> -/*
> - * Calculate the MD5/SHA1 file digest
> - */
> +static struct crypto_ahash *ima_alloc_atfm(enum hash_algo algo)
> +{
> + struct crypto_ahash *tfm = ima_ahash_tfm;
> + int rc;
> +
> + if ((algo != ima_hash_algo && algo < HASH_ALGO__LAST) || !tfm) {
> + tfm = crypto_alloc_ahash(hash_algo_name[algo], 0, 0);

In the case where algo isn't the same as ima_hash_algo, won't this
replace the existing ima_ahash_tfm without freeing it?

Mimi

> + if (!IS_ERR(tfm)) {
> + if (algo == ima_hash_algo)
> + ima_ahash_tfm = tfm;
> + } else {
> + rc = PTR_ERR(tfm);
> + pr_err("Can not allocate %s (reason: %d)\n",
> + hash_algo_name[algo], rc);
> + }
> + }
> + return tfm;
> +}
> +
> +static void ima_free_atfm(struct crypto_ahash *tfm)
> +{
> + if (tfm != ima_ahash_tfm)
> + crypto_free_ahash(tfm);
> +}



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