From: Mimi Zohar <zohar@linux.ibm.com>
To: Arnd Bergmann <arnd@arndb.de>,
Dmitry Kasatkin <dmitry.kasatkin@gmail.com>,
James Morris <jmorris@namei.org>,
"Serge E. Hallyn" <serge@hallyn.com>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
Stefan Berger <stefanb@linux.vnet.ibm.com>,
linux-integrity@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ima: dynamically allocate shash_desc
Date: Mon, 17 Jun 2019 11:55:51 -0400 [thread overview]
Message-ID: <1560786951.4072.103.camel@linux.ibm.com> (raw)
In-Reply-To: <20190617115838.2397872-1-arnd@arndb.de>
On Mon, 2019-06-17 at 13:20 +0200, Arnd Bergmann wrote:
> On 32-bit ARM, we get a warning about excessive stack usage when
> building with clang.
>
> security/integrity/ima/ima_crypto.c:504:5: error: stack frame size
> of 1152 bytes in function 'ima_calc_field_array_hash' [-Werror,-
> Wframe-larger-than=]
I'm definitely not seeing this. Is this problem a result of non
upstreamed patches? For sha1, currently the only possible hash
algorithm, I'm seeing 664.
Mimi
>
> Using kmalloc to get the descriptor reduces this to 320 bytes.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> security/integrity/ima/ima_crypto.c | 12 +++++++++---
> 1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
> index d4c7b8e1b083..8a66bab4c435 100644
> --- a/security/integrity/ima/ima_crypto.c
> +++ b/security/integrity/ima/ima_crypto.c
> @@ -461,16 +461,21 @@ static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
> struct ima_digest_data *hash,
> struct crypto_shash *tfm)
> {
> - SHASH_DESC_ON_STACK(shash, tfm);
> + struct shash_desc *shash;
> int rc, i;
>
> + shash = kmalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm),
> + GFP_KERNEL);
> + if (!shash)
> + return -ENOMEM;
> +
> shash->tfm = tfm;
>
> hash->length = crypto_shash_digestsize(tfm);
>
> rc = crypto_shash_init(shash);
> if (rc != 0)
> - return rc;
> + goto out;
>
> for (i = 0; i < num_fields; i++) {
> u8 buffer[IMA_EVENT_NAME_LEN_MAX + 1] = { 0 };
> @@ -497,7 +502,8 @@ static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
>
> if (!rc)
> rc = crypto_shash_final(shash, hash->digest);
> -
> +out:
> + kfree(shash);
> return rc;
> }
>
next prev parent reply other threads:[~2019-06-17 15:56 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-17 11:20 [PATCH] ima: dynamically allocate shash_desc Arnd Bergmann
2019-06-17 15:55 ` Mimi Zohar [this message]
2019-06-17 18:07 ` Mimi Zohar
2019-06-17 20:08 ` Arnd Bergmann
2019-06-18 12:44 ` Mimi Zohar
2019-06-18 18:06 ` Arnd Bergmann
2019-06-18 18:53 ` Mimi Zohar
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