2 * Copyright (C) 2005,2006,2007,2008 IBM Corporation
5 * Mimi Zohar <zohar@us.ibm.com>
6 * Kylene Hall <kjhall@us.ibm.com>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation, version 2 of the License.
13 * Calculates md5/sha1 file hash, template hash, boot-aggreate hash
16 #include <linux/kernel.h>
17 #include <linux/file.h>
18 #include <linux/crypto.h>
19 #include <linux/scatterlist.h>
20 #include <linux/err.h>
23 static int init_desc(struct hash_desc *desc)
27 desc->tfm = crypto_alloc_hash(ima_hash, 0, CRYPTO_ALG_ASYNC);
28 if (IS_ERR(desc->tfm)) {
29 pr_info("failed to load %s transform: %ld\n",
30 ima_hash, PTR_ERR(desc->tfm));
31 rc = PTR_ERR(desc->tfm);
35 rc = crypto_hash_init(desc);
37 crypto_free_hash(desc->tfm);
42 * Calculate the MD5/SHA1 file digest
44 int ima_calc_hash(struct file *file, char *digest)
46 struct hash_desc desc;
47 struct scatterlist sg[1];
48 loff_t i_size, offset = 0;
52 rc = init_desc(&desc);
56 rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL);
61 i_size = i_size_read(file->f_dentry->d_inode);
62 while (offset < i_size) {
65 rbuf_len = kernel_read(file, offset, rbuf, PAGE_SIZE);
73 sg_init_one(sg, rbuf, rbuf_len);
75 rc = crypto_hash_update(&desc, sg, rbuf_len);
81 rc = crypto_hash_final(&desc, digest);
83 crypto_free_hash(desc.tfm);
88 * Calculate the hash of a given template
90 int ima_calc_template_hash(int template_len, void *template, char *digest)
92 struct hash_desc desc;
93 struct scatterlist sg[1];
96 rc = init_desc(&desc);
100 sg_init_one(sg, template, template_len);
101 rc = crypto_hash_update(&desc, sg, template_len);
103 rc = crypto_hash_final(&desc, digest);
104 crypto_free_hash(desc.tfm);
108 static void __init ima_pcrread(int idx, u8 *pcr)
113 if (tpm_pcr_read(TPM_ANY_NUM, idx, pcr) != 0)
114 pr_err("Error Communicating to TPM chip\n");
118 * Calculate the boot aggregate hash
120 int __init ima_calc_boot_aggregate(char *digest)
122 struct hash_desc desc;
123 struct scatterlist sg;
124 u8 pcr_i[IMA_DIGEST_SIZE];
127 rc = init_desc(&desc);
131 /* cumulative sha1 over tpm registers 0-7 */
132 for (i = TPM_PCR0; i < TPM_PCR8; i++) {
133 ima_pcrread(i, pcr_i);
134 /* now accumulate with current aggregate */
135 sg_init_one(&sg, pcr_i, IMA_DIGEST_SIZE);
136 rc = crypto_hash_update(&desc, &sg, IMA_DIGEST_SIZE);
139 crypto_hash_final(&desc, digest);
140 crypto_free_hash(desc.tfm);