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>
21 #include <linux/slab.h>
22 #include <crypto/hash.h>
23 #include <crypto/hash_info.h>
26 static struct crypto_shash *ima_shash_tfm;
29 * ima_kernel_read - read file content
31 * This is a function for reading file content instead of kernel_read().
32 * It does not perform locking checks to ensure it cannot be blocked.
33 * It does not perform security checks because it is irrelevant for IMA.
36 static int ima_kernel_read(struct file *file, loff_t offset,
37 char *addr, unsigned long count)
40 char __user *buf = addr;
43 if (!(file->f_mode & FMODE_READ))
45 if (!file->f_op->read && !file->f_op->aio_read)
51 ret = file->f_op->read(file, buf, count, &offset);
53 ret = do_sync_read(file, buf, count, &offset);
58 int ima_init_crypto(void)
62 ima_shash_tfm = crypto_alloc_shash(hash_algo_name[ima_hash_algo], 0, 0);
63 if (IS_ERR(ima_shash_tfm)) {
64 rc = PTR_ERR(ima_shash_tfm);
65 pr_err("Can not allocate %s (reason: %ld)\n",
66 hash_algo_name[ima_hash_algo], rc);
72 static struct crypto_shash *ima_alloc_tfm(enum hash_algo algo)
74 struct crypto_shash *tfm = ima_shash_tfm;
77 if (algo != ima_hash_algo && algo < HASH_ALGO__LAST) {
78 tfm = crypto_alloc_shash(hash_algo_name[algo], 0, 0);
81 pr_err("Can not allocate %s (reason: %d)\n",
82 hash_algo_name[algo], rc);
88 static void ima_free_tfm(struct crypto_shash *tfm)
90 if (tfm != ima_shash_tfm)
91 crypto_free_shash(tfm);
95 * Calculate the MD5/SHA1 file digest
97 static int ima_calc_file_hash_tfm(struct file *file,
98 struct ima_digest_data *hash,
99 struct crypto_shash *tfm)
101 loff_t i_size, offset = 0;
105 struct shash_desc shash;
106 char ctx[crypto_shash_descsize(tfm)];
109 desc.shash.tfm = tfm;
110 desc.shash.flags = 0;
112 hash->length = crypto_shash_digestsize(tfm);
114 rc = crypto_shash_init(&desc.shash);
118 rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL);
123 if (!(file->f_mode & FMODE_READ)) {
124 file->f_mode |= FMODE_READ;
127 i_size = i_size_read(file_inode(file));
128 while (offset < i_size) {
131 rbuf_len = ima_kernel_read(file, offset, rbuf, PAGE_SIZE);
140 rc = crypto_shash_update(&desc.shash, rbuf, rbuf_len);
146 rc = crypto_shash_final(&desc.shash, hash->digest);
148 file->f_mode &= ~FMODE_READ;
153 int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash)
155 struct crypto_shash *tfm;
158 tfm = ima_alloc_tfm(hash->algo);
162 rc = ima_calc_file_hash_tfm(file, hash, tfm);
170 * Calculate the hash of template data
172 static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
173 struct ima_template_desc *td,
175 struct ima_digest_data *hash,
176 struct crypto_shash *tfm)
179 struct shash_desc shash;
180 char ctx[crypto_shash_descsize(tfm)];
184 desc.shash.tfm = tfm;
185 desc.shash.flags = 0;
187 hash->length = crypto_shash_digestsize(tfm);
189 rc = crypto_shash_init(&desc.shash);
193 for (i = 0; i < num_fields; i++) {
194 if (strcmp(td->name, IMA_TEMPLATE_IMA_NAME) != 0) {
195 rc = crypto_shash_update(&desc.shash,
196 (const u8 *) &field_data[i].len,
197 sizeof(field_data[i].len));
201 rc = crypto_shash_update(&desc.shash, field_data[i].data,
208 rc = crypto_shash_final(&desc.shash, hash->digest);
213 int ima_calc_field_array_hash(struct ima_field_data *field_data,
214 struct ima_template_desc *desc, int num_fields,
215 struct ima_digest_data *hash)
217 struct crypto_shash *tfm;
220 tfm = ima_alloc_tfm(hash->algo);
224 rc = ima_calc_field_array_hash_tfm(field_data, desc, num_fields,
232 static void __init ima_pcrread(int idx, u8 *pcr)
237 if (tpm_pcr_read(TPM_ANY_NUM, idx, pcr) != 0)
238 pr_err("IMA: Error Communicating to TPM chip\n");
242 * Calculate the boot aggregate hash
244 static int __init ima_calc_boot_aggregate_tfm(char *digest,
245 struct crypto_shash *tfm)
247 u8 pcr_i[TPM_DIGEST_SIZE];
250 struct shash_desc shash;
251 char ctx[crypto_shash_descsize(tfm)];
254 desc.shash.tfm = tfm;
255 desc.shash.flags = 0;
257 rc = crypto_shash_init(&desc.shash);
261 /* cumulative sha1 over tpm registers 0-7 */
262 for (i = TPM_PCR0; i < TPM_PCR8; i++) {
263 ima_pcrread(i, pcr_i);
264 /* now accumulate with current aggregate */
265 rc = crypto_shash_update(&desc.shash, pcr_i, TPM_DIGEST_SIZE);
268 crypto_shash_final(&desc.shash, digest);
272 int __init ima_calc_boot_aggregate(struct ima_digest_data *hash)
274 struct crypto_shash *tfm;
277 tfm = ima_alloc_tfm(hash->algo);
281 hash->length = crypto_shash_digestsize(tfm);
282 rc = ima_calc_boot_aggregate_tfm(hash->digest, tfm);