From 11d7646df8e800f434ff710ad6100acbea59068e Mon Sep 17 00:00:00 2001 From: Dmitry Kasatkin Date: Thu, 17 Apr 2014 12:01:40 +0300 Subject: [PATCH] ima: provide buffer hash calculation function 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 Signed-off-by: Mimi Zohar --- security/integrity/ima/ima.h | 2 ++ security/integrity/ima/ima_crypto.c | 47 +++++++++++++++++++++++++++++ 2 files changed, 49 insertions(+) diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index b7e793501bdb..2c5262f2823f 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -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); diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c index fb30ce406af4..fccb6ceb388b 100644 --- a/security/integrity/ima/ima_crypto.c +++ b/security/integrity/ima/ima_crypto.c @@ -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)