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16#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17
18#include <linux/kernel.h>
19#include <linux/file.h>
20#include <linux/crypto.h>
21#include <linux/scatterlist.h>
22#include <linux/err.h>
23#include <linux/slab.h>
24#include <crypto/hash.h>
25#include <crypto/hash_info.h>
26#include "ima.h"
27
28static struct crypto_shash *ima_shash_tfm;
29
30
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36
37
38static int ima_kernel_read(struct file *file, loff_t offset,
39 char *addr, unsigned long count)
40{
41 mm_segment_t old_fs;
42 char __user *buf = addr;
43 ssize_t ret;
44
45 if (!(file->f_mode & FMODE_READ))
46 return -EBADF;
47 if (!file->f_op->read && !file->f_op->aio_read)
48 return -EINVAL;
49
50 old_fs = get_fs();
51 set_fs(get_ds());
52 if (file->f_op->read)
53 ret = file->f_op->read(file, buf, count, &offset);
54 else
55 ret = do_sync_read(file, buf, count, &offset);
56 set_fs(old_fs);
57 return ret;
58}
59
60int ima_init_crypto(void)
61{
62 long rc;
63
64 ima_shash_tfm = crypto_alloc_shash(hash_algo_name[ima_hash_algo], 0, 0);
65 if (IS_ERR(ima_shash_tfm)) {
66 rc = PTR_ERR(ima_shash_tfm);
67 pr_err("Can not allocate %s (reason: %ld)\n",
68 hash_algo_name[ima_hash_algo], rc);
69 return rc;
70 }
71 return 0;
72}
73
74static struct crypto_shash *ima_alloc_tfm(enum hash_algo algo)
75{
76 struct crypto_shash *tfm = ima_shash_tfm;
77 int rc;
78
79 if (algo != ima_hash_algo && algo < HASH_ALGO__LAST) {
80 tfm = crypto_alloc_shash(hash_algo_name[algo], 0, 0);
81 if (IS_ERR(tfm)) {
82 rc = PTR_ERR(tfm);
83 pr_err("Can not allocate %s (reason: %d)\n",
84 hash_algo_name[algo], rc);
85 }
86 }
87 return tfm;
88}
89
90static void ima_free_tfm(struct crypto_shash *tfm)
91{
92 if (tfm != ima_shash_tfm)
93 crypto_free_shash(tfm);
94}
95
96
97
98
99static int ima_calc_file_hash_tfm(struct file *file,
100 struct ima_digest_data *hash,
101 struct crypto_shash *tfm)
102{
103 loff_t i_size, offset = 0;
104 char *rbuf;
105 int rc, read = 0;
106 struct {
107 struct shash_desc shash;
108 char ctx[crypto_shash_descsize(tfm)];
109 } desc;
110
111 desc.shash.tfm = tfm;
112 desc.shash.flags = 0;
113
114 hash->length = crypto_shash_digestsize(tfm);
115
116 rc = crypto_shash_init(&desc.shash);
117 if (rc != 0)
118 return rc;
119
120 i_size = i_size_read(file_inode(file));
121
122 if (i_size == 0)
123 goto out;
124
125 rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL);
126 if (!rbuf)
127 return -ENOMEM;
128
129 if (!(file->f_mode & FMODE_READ)) {
130 file->f_mode |= FMODE_READ;
131 read = 1;
132 }
133
134 while (offset < i_size) {
135 int rbuf_len;
136
137 rbuf_len = ima_kernel_read(file, offset, rbuf, PAGE_SIZE);
138 if (rbuf_len < 0) {
139 rc = rbuf_len;
140 break;
141 }
142 if (rbuf_len == 0)
143 break;
144 offset += rbuf_len;
145
146 rc = crypto_shash_update(&desc.shash, rbuf, rbuf_len);
147 if (rc)
148 break;
149 }
150 if (read)
151 file->f_mode &= ~FMODE_READ;
152 kfree(rbuf);
153out:
154 if (!rc)
155 rc = crypto_shash_final(&desc.shash, hash->digest);
156 return rc;
157}
158
159int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash)
160{
161 struct crypto_shash *tfm;
162 int rc;
163
164 tfm = ima_alloc_tfm(hash->algo);
165 if (IS_ERR(tfm))
166 return PTR_ERR(tfm);
167
168 rc = ima_calc_file_hash_tfm(file, hash, tfm);
169
170 ima_free_tfm(tfm);
171
172 return rc;
173}
174
175
176
177
178static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
179 struct ima_template_desc *td,
180 int num_fields,
181 struct ima_digest_data *hash,
182 struct crypto_shash *tfm)
183{
184 struct {
185 struct shash_desc shash;
186 char ctx[crypto_shash_descsize(tfm)];
187 } desc;
188 int rc, i;
189
190 desc.shash.tfm = tfm;
191 desc.shash.flags = 0;
192
193 hash->length = crypto_shash_digestsize(tfm);
194
195 rc = crypto_shash_init(&desc.shash);
196 if (rc != 0)
197 return rc;
198
199 for (i = 0; i < num_fields; i++) {
200 u8 buffer[IMA_EVENT_NAME_LEN_MAX + 1] = { 0 };
201 u8 *data_to_hash = field_data[i].data;
202 u32 datalen = field_data[i].len;
203
204 if (strcmp(td->name, IMA_TEMPLATE_IMA_NAME) != 0) {
205 rc = crypto_shash_update(&desc.shash,
206 (const u8 *) &field_data[i].len,
207 sizeof(field_data[i].len));
208 if (rc)
209 break;
210 } else if (strcmp(td->fields[i]->field_id, "n") == 0) {
211 memcpy(buffer, data_to_hash, datalen);
212 data_to_hash = buffer;
213 datalen = IMA_EVENT_NAME_LEN_MAX + 1;
214 }
215 rc = crypto_shash_update(&desc.shash, data_to_hash, datalen);
216 if (rc)
217 break;
218 }
219
220 if (!rc)
221 rc = crypto_shash_final(&desc.shash, hash->digest);
222
223 return rc;
224}
225
226int ima_calc_field_array_hash(struct ima_field_data *field_data,
227 struct ima_template_desc *desc, int num_fields,
228 struct ima_digest_data *hash)
229{
230 struct crypto_shash *tfm;
231 int rc;
232
233 tfm = ima_alloc_tfm(hash->algo);
234 if (IS_ERR(tfm))
235 return PTR_ERR(tfm);
236
237 rc = ima_calc_field_array_hash_tfm(field_data, desc, num_fields,
238 hash, tfm);
239
240 ima_free_tfm(tfm);
241
242 return rc;
243}
244
245static void __init ima_pcrread(int idx, u8 *pcr)
246{
247 if (!ima_used_chip)
248 return;
249
250 if (tpm_pcr_read(TPM_ANY_NUM, idx, pcr) != 0)
251 pr_err("Error Communicating to TPM chip\n");
252}
253
254
255
256
257static int __init ima_calc_boot_aggregate_tfm(char *digest,
258 struct crypto_shash *tfm)
259{
260 u8 pcr_i[TPM_DIGEST_SIZE];
261 int rc, i;
262 struct {
263 struct shash_desc shash;
264 char ctx[crypto_shash_descsize(tfm)];
265 } desc;
266
267 desc.shash.tfm = tfm;
268 desc.shash.flags = 0;
269
270 rc = crypto_shash_init(&desc.shash);
271 if (rc != 0)
272 return rc;
273
274
275 for (i = TPM_PCR0; i < TPM_PCR8; i++) {
276 ima_pcrread(i, pcr_i);
277
278 rc = crypto_shash_update(&desc.shash, pcr_i, TPM_DIGEST_SIZE);
279 }
280 if (!rc)
281 crypto_shash_final(&desc.shash, digest);
282 return rc;
283}
284
285int __init ima_calc_boot_aggregate(struct ima_digest_data *hash)
286{
287 struct crypto_shash *tfm;
288 int rc;
289
290 tfm = ima_alloc_tfm(hash->algo);
291 if (IS_ERR(tfm))
292 return PTR_ERR(tfm);
293
294 hash->length = crypto_shash_digestsize(tfm);
295 rc = ima_calc_boot_aggregate_tfm(hash->digest, tfm);
296
297 ima_free_tfm(tfm);
298
299 return rc;
300}
301
