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From: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
To: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: linux-security-module <linux-security-module@vger.kernel.org>,
	"Luis R. Rodriguez" <mcgrof@suse.com>,
	kexec@lists.infradead.org, linux-modules@vger.kernel.org,
	fsdevel@vger.kernel.org, David Howells <dhowells@redhat.com>,
	David Woodhouse <dwmw2@infradead.org>,
	Kees Cook <keescook@chromium.org>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	Eric Biederman <ebiederm@xmission.com>,
	Rusty Russell <rusty@rustcorp.com.au>
Subject: Re: [PATCH v3 10/22] ima: calculate the hash of a buffer using aynchronous hash(ahash)
Date: Wed, 10 Feb 2016 21:58:27 +0200
Message-ID: <CACE9dm9uTYHP1+9K2mo-F=8Z9KQzTBAZGm3-mwG2_YeyfV4xVA@mail.gmail.com> (raw)
In-Reply-To: <1454526390-19792-11-git-send-email-zohar@linux.vnet.ibm.com>

On Wed, Feb 3, 2016 at 9:06 PM, Mimi Zohar <zohar@linux.vnet.ibm.com> wrote:
> Setting up ahash has some overhead.  Only use ahash to calculate the
> hash of a buffer, if the buffer is larger than ima_ahash_minsize.
>
> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>

Acked-by: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>

> ---
>  security/integrity/ima/ima_crypto.c | 75 ++++++++++++++++++++++++++++++++++++-
>  1 file changed, 73 insertions(+), 2 deletions(-)
>
> diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
> index fccb6ce..38f2ed8 100644
> --- a/security/integrity/ima/ima_crypto.c
> +++ b/security/integrity/ima/ima_crypto.c
> @@ -519,6 +519,63 @@ int ima_calc_field_array_hash(struct ima_field_data *field_data,
>         return rc;
>  }
>
> +static int calc_buffer_ahash_atfm(const void *buf, loff_t len,
> +                                 struct ima_digest_data *hash,
> +                                 struct crypto_ahash *tfm)
> +{
> +       struct ahash_request *req;
> +       struct scatterlist sg;
> +       struct ahash_completion res;
> +       int rc, ahash_rc = 0;
> +
> +       hash->length = crypto_ahash_digestsize(tfm);
> +
> +       req = ahash_request_alloc(tfm, GFP_KERNEL);
> +       if (!req)
> +               return -ENOMEM;
> +
> +       init_completion(&res.completion);
> +       ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
> +                                  CRYPTO_TFM_REQ_MAY_SLEEP,
> +                                  ahash_complete, &res);
> +
> +       rc = ahash_wait(crypto_ahash_init(req), &res);
> +       if (rc)
> +               goto out;
> +
> +       sg_init_one(&sg, buf, len);
> +       ahash_request_set_crypt(req, &sg, NULL, len);
> +
> +       ahash_rc = crypto_ahash_update(req);
> +
> +       /* wait for the update request to complete */
> +       rc = ahash_wait(ahash_rc, &res);
> +       if (!rc) {
> +               ahash_request_set_crypt(req, NULL, hash->digest, 0);
> +               rc = ahash_wait(crypto_ahash_final(req), &res);
> +       }
> +out:
> +       ahash_request_free(req);
> +       return rc;
> +}
> +
> +static int calc_buffer_ahash(const void *buf, loff_t len,
> +                            struct ima_digest_data *hash)
> +{
> +       struct crypto_ahash *tfm;
> +       int rc;
> +
> +       tfm = ima_alloc_atfm(hash->algo);
> +       if (IS_ERR(tfm))
> +               return PTR_ERR(tfm);
> +
> +       rc = calc_buffer_ahash_atfm(buf, len, hash, tfm);
> +
> +       ima_free_atfm(tfm);
> +
> +       return rc;
> +}
> +
>  static int calc_buffer_shash_tfm(const void *buf, loff_t size,
>                                 struct ima_digest_data *hash,
>                                 struct crypto_shash *tfm)
> @@ -550,8 +607,8 @@ static int calc_buffer_shash_tfm(const void *buf, loff_t size,
>         return rc;
>  }
>
> -int ima_calc_buffer_hash(const void *buf, loff_t len,
> -                        struct ima_digest_data *hash)
> +static int calc_buffer_shash(const void *buf, loff_t len,
> +                            struct ima_digest_data *hash)
>  {
>         struct crypto_shash *tfm;
>         int rc;
> @@ -566,6 +623,20 @@ int ima_calc_buffer_hash(const void *buf, loff_t len,
>         return rc;
>  }
>
> +int ima_calc_buffer_hash(const void *buf, loff_t len,
> +                        struct ima_digest_data *hash)
> +{
> +       int rc;
> +
> +       if (ima_ahash_minsize && len >= ima_ahash_minsize) {
> +               rc = calc_buffer_ahash(buf, len, hash);
> +               if (!rc)
> +                       return 0;
> +       }
> +
> +       return calc_buffer_shash(buf, len, hash);
> +}
> +
>  static void __init ima_pcrread(int idx, u8 *pcr)
>  {
>         if (!ima_used_chip)
> --
> 2.1.0
>



-- 
Thanks,
Dmitry

  reply index

Thread overview: 77+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-03 19:06 [PATCH v3 00/22] vfs: support for a common kernel file loader Mimi Zohar
2016-02-03 19:06 ` [PATCH v3 01/22] ima: separate 'security.ima' reading functionality from collect Mimi Zohar
2016-02-03 19:06 ` [PATCH v3 02/22] ima: refactor ima_policy_show() to display "ima_hooks" rules Mimi Zohar
2016-02-07 19:45   ` Petko Manolov
2016-02-10 19:33   ` Dmitry Kasatkin
2016-02-03 19:06 ` [PATCH v3 03/22] ima: use "ima_hooks" enum as function argument Mimi Zohar
2016-02-07 19:46   ` Petko Manolov
2016-02-10 19:35   ` Dmitry Kasatkin
2016-02-03 19:06 ` [PATCH v3 04/22] firmware: simplify dev_*() print messages for generic helpers Mimi Zohar
2016-02-04 17:26   ` Kees Cook
2016-02-03 19:06 ` [PATCH v3 05/22] firmware: move completing fw into a helper Mimi Zohar
2016-02-04 17:27   ` Kees Cook
2016-02-03 19:06 ` [PATCH v3 06/22] firmware: fold successful fw read early Mimi Zohar
2016-02-04 17:36   ` Kees Cook
2016-02-04 20:26     ` Luis R. Rodriguez
2016-02-03 19:06 ` [PATCH v3 07/22] vfs: define a generic function to read a file from the kernel Mimi Zohar
2016-02-04 17:41   ` Kees Cook
2016-02-03 19:06 ` [PATCH v3 08/22] vfs: define kernel_read_file_id enumeration Mimi Zohar
2016-02-04 17:41   ` Kees Cook
2016-02-04 19:45   ` Luis R. Rodriguez
2016-02-03 19:06 ` [PATCH v3 09/22] ima: provide buffer hash calculation function Mimi Zohar
2016-02-03 19:06 ` [PATCH v3 10/22] ima: calculate the hash of a buffer using aynchronous hash(ahash) Mimi Zohar
2016-02-10 19:58   ` Dmitry Kasatkin [this message]
2016-02-03 19:06 ` [PATCH v3 11/22] ima: define a new hook to measure and appraise a file already in memory Mimi Zohar
2016-02-10 20:27   ` Dmitry Kasatkin
2016-02-03 19:06 ` [PATCH v3 12/22] vfs: define kernel_read_file_from_path Mimi Zohar
2016-02-04 17:46   ` Kees Cook
2016-02-04 19:47   ` Luis R. Rodriguez
2016-02-03 19:06 ` [PATCH v3 13/22] firmware: replace call to fw_read_file_contents() with kernel version Mimi Zohar
2016-02-04 17:56   ` Kees Cook
2016-02-04 19:51   ` Luis R. Rodriguez
2016-02-03 19:06 ` [PATCH v3 14/22] security: define kernel_read_file hook Mimi Zohar
2016-02-04 17:57   ` Kees Cook
2016-02-04 19:54   ` Luis R. Rodriguez
2016-02-11 16:54   ` Casey Schaufler
2016-02-11 19:35     ` Mimi Zohar
2016-02-03 19:06 ` [PATCH v3 15/22] vfs: define kernel_copy_file_from_fd() Mimi Zohar
2016-02-04 17:58   ` Kees Cook
2016-02-04 19:55   ` Luis R. Rodriguez
2016-02-03 19:06 ` [PATCH v3 16/22] module: replace copy_module_from_fd with kernel version Mimi Zohar
2016-02-04 18:04   ` Kees Cook
2016-02-04 19:56   ` Luis R. Rodriguez
2016-02-05  0:19     ` Mimi Zohar
2016-02-03 19:06 ` [PATCH v3 17/22] ima: remove firmware and module specific cached status info Mimi Zohar
2016-02-07 19:56   ` Petko Manolov
2016-02-10 20:18   ` Dmitry Kasatkin
2016-02-10 23:14     ` Mimi Zohar
2016-02-03 19:06 ` [PATCH v3 18/22] kexec: replace call to copy_file_from_fd() with kernel version Mimi Zohar
2016-02-04 18:05   ` Kees Cook
2016-02-04 19:57   ` Luis R. Rodriguez
2016-02-12 12:50   ` Dave Young
2016-02-03 19:06 ` [PATCH v3 19/22] ima: support for kexec image and initramfs Mimi Zohar
2016-02-07 20:10   ` Petko Manolov
2016-02-08 23:34     ` Mimi Zohar
2016-02-10 21:09   ` Dmitry Kasatkin
2016-02-10 23:21     ` Mimi Zohar
     [not found]       ` <CACE9dm8OJ1cgbKszUG-pCiEMVarUFLLWi_jewVV-JEMGAJsA-g@mail.gmail.com>
2016-02-11  2:08         ` Mimi Zohar
2016-02-11  8:47           ` Dmitry Kasatkin
2016-02-11 12:16             ` Mimi Zohar
2016-02-12 12:53   ` Dave Young
2016-02-12 13:09     ` Mimi Zohar
2016-02-03 19:06 ` [PATCH v3 20/22] ima: load policy using path Mimi Zohar
2016-02-07 19:59   ` Petko Manolov
2016-02-08  9:58     ` Dmitry Kasatkin
2016-02-08 10:35       ` Petko Manolov
2016-02-08 10:45         ` Dmitry Kasatkin
2016-02-08 21:12           ` Mimi Zohar
2016-02-09  7:47             ` Petko Manolov
2016-02-03 19:06 ` [PATCH v3 21/22] ima: measure and appraise the IMA policy itself Mimi Zohar
2016-02-07 20:01   ` Petko Manolov
2016-02-10 20:22   ` Dmitry Kasatkin
2016-02-10 23:15     ` Mimi Zohar
2016-02-03 19:06 ` [PATCH v3 22/22] ima: require signed IMA policy Mimi Zohar
2016-02-07 20:02   ` Petko Manolov
2016-02-10 20:24   ` Dmitry Kasatkin
2016-02-04 18:15 ` [PATCH v3 00/22] vfs: support for a common kernel file loader Kees Cook
2016-02-04 23:54   ` Mimi Zohar

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