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ima: provide buffer hash calculation function

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This patch provides convenient buffer hash calculation function.

Changelog v3:
- fix while hash calculation - Dmitry
v1:
- rewrite to support loff_t sized buffers - Mimi
  (based on Fenguang Wu's testing)

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
This commit is contained in:
Dmitry Kasatkin 2014-04-17 12:01:40 +03:00 committed by Mimi Zohar
parent bc8ca5b92d
commit 11d7646df8
2 changed files with 49 additions and 0 deletions
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2
security/integrity/ima/ima.h
View File

@ -107,6 +107,8 @@ int ima_add_template_entry(struct ima_template_entry *entry, int violation,
const char *op, struct inode *inode,
const unsigned char *filename);
int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash);
int ima_calc_buffer_hash(const void *buf, loff_t len,
struct ima_digest_data *hash);
int ima_calc_field_array_hash(struct ima_field_data *field_data,
struct ima_template_desc *desc, int num_fields,
struct ima_digest_data *hash);

47
security/integrity/ima/ima_crypto.c
View File

@ -519,6 +519,53 @@ int ima_calc_field_array_hash(struct ima_field_data *field_data,
return rc;
}
static int calc_buffer_shash_tfm(const void *buf, loff_t size,
struct ima_digest_data *hash,
struct crypto_shash *tfm)
{
SHASH_DESC_ON_STACK(shash, tfm);
unsigned int len;
int rc;
shash->tfm = tfm;
shash->flags = 0;
hash->length = crypto_shash_digestsize(tfm);
rc = crypto_shash_init(shash);
if (rc != 0)
return rc;
while (size) {
len = size < PAGE_SIZE ? size : PAGE_SIZE;
rc = crypto_shash_update(shash, buf, len);
if (rc)
break;
buf += len;
size -= len;
}
if (!rc)
rc = crypto_shash_final(shash, hash->digest);
return rc;
}
int ima_calc_buffer_hash(const void *buf, loff_t len,
struct ima_digest_data *hash)
{
struct crypto_shash *tfm;
int rc;
tfm = ima_alloc_tfm(hash->algo);
if (IS_ERR(tfm))
return PTR_ERR(tfm);
rc = calc_buffer_shash_tfm(buf, len, hash, tfm);
ima_free_tfm(tfm);
return rc;
}
static void __init ima_pcrread(int idx, u8 *pcr)
{
if (!ima_used_chip)