ima: restore the original behavior for sending data with ima template
[deliverable/linux.git] / security / integrity / ima / ima_template_lib.c
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1/*
2 * Copyright (C) 2013 Politecnico di Torino, Italy
3 * TORSEC group -- http://security.polito.it
4 *
5 * Author: Roberto Sassu <roberto.sassu@polito.it>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License as
9 * published by the Free Software Foundation, version 2 of the
10 * License.
11 *
12 * File: ima_template_lib.c
13 * Library of supported template fields.
14 */
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15#include <crypto/hash_info.h>
16
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17#include "ima_template_lib.h"
18
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19static bool ima_template_hash_algo_allowed(u8 algo)
20{
21 if (algo == HASH_ALGO_SHA1 || algo == HASH_ALGO_MD5)
22 return true;
23
24 return false;
25}
26
27enum data_formats {
28 DATA_FMT_DIGEST = 0,
29 DATA_FMT_DIGEST_WITH_ALGO,
30 DATA_FMT_EVENT_NAME,
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31 DATA_FMT_STRING,
32 DATA_FMT_HEX
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33};
34
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35static int ima_write_template_field_data(const void *data, const u32 datalen,
36 enum data_formats datafmt,
37 struct ima_field_data *field_data)
38{
39 u8 *buf, *buf_ptr;
40 u32 buflen;
41
42 switch (datafmt) {
43 case DATA_FMT_EVENT_NAME:
44 buflen = IMA_EVENT_NAME_LEN_MAX + 1;
45 break;
46 case DATA_FMT_STRING:
47 buflen = datalen + 1;
48 break;
49 default:
50 buflen = datalen;
51 }
52
53 buf = kzalloc(buflen, GFP_KERNEL);
54 if (!buf)
55 return -ENOMEM;
56
57 memcpy(buf, data, datalen);
58
59 /*
60 * Replace all space characters with underscore for event names and
61 * strings. This avoid that, during the parsing of a measurements list,
62 * filenames with spaces or that end with the suffix ' (deleted)' are
63 * split into multiple template fields (the space is the delimitator
64 * character for measurements lists in ASCII format).
65 */
66 if (datafmt == DATA_FMT_EVENT_NAME || datafmt == DATA_FMT_STRING) {
67 for (buf_ptr = buf; buf_ptr - buf < datalen; buf_ptr++)
68 if (*buf_ptr == ' ')
69 *buf_ptr = '_';
70 }
71
72 field_data->data = buf;
73 field_data->len = buflen;
74 return 0;
75}
76
77static void ima_show_template_data_ascii(struct seq_file *m,
78 enum ima_show_type show,
79 enum data_formats datafmt,
80 struct ima_field_data *field_data)
81{
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82 u8 *buf_ptr = field_data->data, buflen = field_data->len;
83
3ce1217d 84 switch (datafmt) {
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85 case DATA_FMT_DIGEST_WITH_ALGO:
86 buf_ptr = strnchr(field_data->data, buflen, ':');
87 if (buf_ptr != field_data->data)
88 seq_printf(m, "%s", field_data->data);
89
90 /* skip ':' and '\0' */
91 buf_ptr += 2;
92 buflen -= buf_ptr - field_data->data;
3ce1217d 93 case DATA_FMT_DIGEST:
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94 case DATA_FMT_HEX:
95 if (!buflen)
96 break;
4d7aeee7 97 ima_print_digest(m, buf_ptr, buflen);
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98 break;
99 case DATA_FMT_STRING:
4d7aeee7 100 seq_printf(m, "%s", buf_ptr);
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101 break;
102 default:
103 break;
104 }
105}
106
107static void ima_show_template_data_binary(struct seq_file *m,
108 enum ima_show_type show,
109 enum data_formats datafmt,
110 struct ima_field_data *field_data)
111{
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112 u32 len = (show == IMA_SHOW_BINARY_OLD_STRING_FMT) ?
113 strlen(field_data->data) : field_data->len;
114
3e8e5503 115 if (show != IMA_SHOW_BINARY_NO_FIELD_LEN)
c019e307 116 ima_putc(m, &len, sizeof(len));
3e8e5503 117
c019e307 118 if (!len)
3ce1217d 119 return;
3e8e5503 120
c019e307 121 ima_putc(m, field_data->data, len);
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122}
123
124static void ima_show_template_field_data(struct seq_file *m,
125 enum ima_show_type show,
126 enum data_formats datafmt,
127 struct ima_field_data *field_data)
128{
129 switch (show) {
130 case IMA_SHOW_ASCII:
131 ima_show_template_data_ascii(m, show, datafmt, field_data);
132 break;
133 case IMA_SHOW_BINARY:
3e8e5503 134 case IMA_SHOW_BINARY_NO_FIELD_LEN:
c019e307 135 case IMA_SHOW_BINARY_OLD_STRING_FMT:
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136 ima_show_template_data_binary(m, show, datafmt, field_data);
137 break;
138 default:
139 break;
140 }
141}
142
143void ima_show_template_digest(struct seq_file *m, enum ima_show_type show,
144 struct ima_field_data *field_data)
145{
146 ima_show_template_field_data(m, show, DATA_FMT_DIGEST, field_data);
147}
148
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149void ima_show_template_digest_ng(struct seq_file *m, enum ima_show_type show,
150 struct ima_field_data *field_data)
151{
152 ima_show_template_field_data(m, show, DATA_FMT_DIGEST_WITH_ALGO,
153 field_data);
154}
155
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156void ima_show_template_string(struct seq_file *m, enum ima_show_type show,
157 struct ima_field_data *field_data)
158{
159 ima_show_template_field_data(m, show, DATA_FMT_STRING, field_data);
160}
161
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162void ima_show_template_sig(struct seq_file *m, enum ima_show_type show,
163 struct ima_field_data *field_data)
164{
165 ima_show_template_field_data(m, show, DATA_FMT_HEX, field_data);
166}
167
4d7aeee7 168static int ima_eventdigest_init_common(u8 *digest, u32 digestsize, u8 hash_algo,
dcf4e392 169 struct ima_field_data *field_data)
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170{
171 /*
172 * digest formats:
173 * - DATA_FMT_DIGEST: digest
174 * - DATA_FMT_DIGEST_WITH_ALGO: [<hash algo>] + ':' + '\0' + digest,
175 * where <hash algo> is provided if the hash algoritm is not
176 * SHA1 or MD5
177 */
178 u8 buffer[CRYPTO_MAX_ALG_NAME + 2 + IMA_MAX_DIGEST_SIZE] = { 0 };
179 enum data_formats fmt = DATA_FMT_DIGEST;
180 u32 offset = 0;
181
dcf4e392 182 if (hash_algo < HASH_ALGO__LAST) {
4d7aeee7 183 fmt = DATA_FMT_DIGEST_WITH_ALGO;
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184 offset += snprintf(buffer, CRYPTO_MAX_ALG_NAME + 1, "%s",
185 hash_algo_name[hash_algo]);
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186 buffer[offset] = ':';
187 offset += 2;
188 }
189
190 if (digest)
191 memcpy(buffer + offset, digest, digestsize);
192 else
193 /*
194 * If digest is NULL, the event being recorded is a violation.
195 * Make room for the digest by increasing the offset of
196 * IMA_DIGEST_SIZE.
197 */
198 offset += IMA_DIGEST_SIZE;
199
200 return ima_write_template_field_data(buffer, offset + digestsize,
201 fmt, field_data);
202}
203
3ce1217d 204/*
4d7aeee7 205 * This function writes the digest of an event (with size limit).
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206 */
207int ima_eventdigest_init(struct integrity_iint_cache *iint, struct file *file,
208 const unsigned char *filename,
bcbc9b0c 209 struct evm_ima_xattr_data *xattr_value, int xattr_len,
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210 struct ima_field_data *field_data)
211{
212 struct {
213 struct ima_digest_data hdr;
214 char digest[IMA_MAX_DIGEST_SIZE];
215 } hash;
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216 u8 *cur_digest = NULL;
217 u32 cur_digestsize = 0;
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218 struct inode *inode;
219 int result;
220
221 memset(&hash, 0, sizeof(hash));
222
223 if (!iint) /* recording a violation. */
224 goto out;
225
4d7aeee7 226 if (ima_template_hash_algo_allowed(iint->ima_hash->algo)) {
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227 cur_digest = iint->ima_hash->digest;
228 cur_digestsize = iint->ima_hash->length;
229 goto out;
230 }
231
232 if (!file) /* missing info to re-calculate the digest */
233 return -EINVAL;
234
235 inode = file_inode(file);
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236 hash.hdr.algo = ima_template_hash_algo_allowed(ima_hash_algo) ?
237 ima_hash_algo : HASH_ALGO_SHA1;
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238 result = ima_calc_file_hash(file, &hash.hdr);
239 if (result) {
240 integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode,
241 filename, "collect_data",
242 "failed", result, 0);
243 return result;
244 }
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245 cur_digest = hash.hdr.digest;
246 cur_digestsize = hash.hdr.length;
3ce1217d 247out:
712a49bd 248 return ima_eventdigest_init_common(cur_digest, cur_digestsize,
dcf4e392 249 HASH_ALGO__LAST, field_data);
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250}
251
252/*
4d7aeee7 253 * This function writes the digest of an event (without size limit).
3ce1217d 254 */
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255int ima_eventdigest_ng_init(struct integrity_iint_cache *iint,
256 struct file *file, const unsigned char *filename,
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257 struct evm_ima_xattr_data *xattr_value,
258 int xattr_len, struct ima_field_data *field_data)
4d7aeee7 259{
c502c78b 260 u8 *cur_digest = NULL, hash_algo = HASH_ALGO_SHA1;
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261 u32 cur_digestsize = 0;
262
263 /* If iint is NULL, we are recording a violation. */
264 if (!iint)
265 goto out;
266
267 cur_digest = iint->ima_hash->digest;
268 cur_digestsize = iint->ima_hash->length;
269
270 hash_algo = iint->ima_hash->algo;
271out:
272 return ima_eventdigest_init_common(cur_digest, cur_digestsize,
dcf4e392 273 hash_algo, field_data);
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274}
275
276static int ima_eventname_init_common(struct integrity_iint_cache *iint,
277 struct file *file,
278 const unsigned char *filename,
279 struct ima_field_data *field_data,
280 bool size_limit)
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281{
282 const char *cur_filename = NULL;
283 u32 cur_filename_len = 0;
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284 enum data_formats fmt = size_limit ?
285 DATA_FMT_EVENT_NAME : DATA_FMT_STRING;
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286
287 BUG_ON(filename == NULL && file == NULL);
288
289 if (filename) {
290 cur_filename = filename;
291 cur_filename_len = strlen(filename);
292
4d7aeee7 293 if (!size_limit || cur_filename_len <= IMA_EVENT_NAME_LEN_MAX)
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294 goto out;
295 }
296
297 if (file) {
298 cur_filename = file->f_dentry->d_name.name;
299 cur_filename_len = strlen(cur_filename);
300 } else
301 /*
302 * Truncate filename if the latter is too long and
303 * the file descriptor is not available.
304 */
305 cur_filename_len = IMA_EVENT_NAME_LEN_MAX;
306out:
307 return ima_write_template_field_data(cur_filename, cur_filename_len,
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308 fmt, field_data);
309}
310
311/*
312 * This function writes the name of an event (with size limit).
313 */
314int ima_eventname_init(struct integrity_iint_cache *iint, struct file *file,
315 const unsigned char *filename,
bcbc9b0c 316 struct evm_ima_xattr_data *xattr_value, int xattr_len,
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317 struct ima_field_data *field_data)
318{
319 return ima_eventname_init_common(iint, file, filename,
320 field_data, true);
321}
322
323/*
324 * This function writes the name of an event (without size limit).
325 */
326int ima_eventname_ng_init(struct integrity_iint_cache *iint, struct file *file,
327 const unsigned char *filename,
bcbc9b0c 328 struct evm_ima_xattr_data *xattr_value, int xattr_len,
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329 struct ima_field_data *field_data)
330{
331 return ima_eventname_init_common(iint, file, filename,
332 field_data, false);
3ce1217d 333}
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334
335/*
336 * ima_eventsig_init - include the file signature as part of the template data
337 */
338int ima_eventsig_init(struct integrity_iint_cache *iint, struct file *file,
339 const unsigned char *filename,
340 struct evm_ima_xattr_data *xattr_value, int xattr_len,
341 struct ima_field_data *field_data)
342{
343 enum data_formats fmt = DATA_FMT_HEX;
344 int rc = 0;
345
346 if ((!xattr_value) || (xattr_value->type != EVM_IMA_XATTR_DIGSIG))
347 goto out;
348
349 rc = ima_write_template_field_data(xattr_value, xattr_len, fmt,
350 field_data);
351out:
352 return rc;
353}
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