diff options
Diffstat (limited to 'security/integrity/ima/ima_crypto.c')
| -rw-r--r-- | security/integrity/ima/ima_crypto.c | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c new file mode 100644 index 00000000000..50d572b74ca --- /dev/null +++ b/security/integrity/ima/ima_crypto.c @@ -0,0 +1,140 @@ +/* + * Copyright (C) 2005,2006,2007,2008 IBM Corporation + * + * Authors: + * Mimi Zohar <zohar@us.ibm.com> + * Kylene Hall <kjhall@us.ibm.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, version 2 of the License. + * + * File: ima_crypto.c + * Calculates md5/sha1 file hash, template hash, boot-aggreate hash + */ + +#include <linux/kernel.h> +#include <linux/file.h> +#include <linux/crypto.h> +#include <linux/scatterlist.h> +#include <linux/err.h> +#include "ima.h" + +static int init_desc(struct hash_desc *desc) +{ + int rc; + + desc->tfm = crypto_alloc_hash(ima_hash, 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(desc->tfm)) { + pr_info("failed to load %s transform: %ld\n", + ima_hash, PTR_ERR(desc->tfm)); + rc = PTR_ERR(desc->tfm); + return rc; + } + desc->flags = 0; + rc = crypto_hash_init(desc); + if (rc) + crypto_free_hash(desc->tfm); + return rc; +} + +/* + * Calculate the MD5/SHA1 file digest + */ +int ima_calc_hash(struct file *file, char *digest) +{ + struct hash_desc desc; + struct scatterlist sg[1]; + loff_t i_size; + char *rbuf; + int rc, offset = 0; + + rc = init_desc(&desc); + if (rc != 0) + return rc; + + rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL); + if (!rbuf) { + rc = -ENOMEM; + goto out; + } + i_size = i_size_read(file->f_dentry->d_inode); + while (offset < i_size) { + int rbuf_len; + + rbuf_len = kernel_read(file, offset, rbuf, PAGE_SIZE); + if (rbuf_len < 0) { + rc = rbuf_len; + break; + } + offset += rbuf_len; + sg_init_one(sg, rbuf, rbuf_len); + + rc = crypto_hash_update(&desc, sg, rbuf_len); + if (rc) + break; + } + kfree(rbuf); + if (!rc) + rc = crypto_hash_final(&desc, digest); +out: + crypto_free_hash(desc.tfm); + return rc; +} + +/* + * Calculate the hash of a given template + */ +int ima_calc_template_hash(int template_len, void *template, char *digest) +{ + struct hash_desc desc; + struct scatterlist sg[1]; + int rc; + + rc = init_desc(&desc); + if (rc != 0) + return rc; + + sg_init_one(sg, template, template_len); + rc = crypto_hash_update(&desc, sg, template_len); + if (!rc) + rc = crypto_hash_final(&desc, digest); + crypto_free_hash(desc.tfm); + return rc; +} + +static void ima_pcrread(int idx, u8 *pcr) +{ + if (!ima_used_chip) + return; + + if (tpm_pcr_read(TPM_ANY_NUM, idx, pcr) != 0) + pr_err("Error Communicating to TPM chip\n"); +} + +/* + * Calculate the boot aggregate hash + */ +int ima_calc_boot_aggregate(char *digest) +{ + struct hash_desc desc; + struct scatterlist sg; + u8 pcr_i[IMA_DIGEST_SIZE]; + int rc, i; + + rc = init_desc(&desc); + if (rc != 0) + return rc; + + /* cumulative sha1 over tpm registers 0-7 */ + for (i = TPM_PCR0; i < TPM_PCR8; i++) { + ima_pcrread(i, pcr_i); + /* now accumulate with current aggregate */ + sg_init_one(&sg, pcr_i, IMA_DIGEST_SIZE); + rc = crypto_hash_update(&desc, &sg, IMA_DIGEST_SIZE); + } + if (!rc) + crypto_hash_final(&desc, digest); + crypto_free_hash(desc.tfm); + return rc; +} |