Loading...
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2004 IBM Corporation
4 * Authors:
5 * Leendert van Doorn <leendert@watson.ibm.com>
6 * Dave Safford <safford@watson.ibm.com>
7 * Reiner Sailer <sailer@watson.ibm.com>
8 * Kylene Hall <kjhall@us.ibm.com>
9 *
10 * Copyright (C) 2013 Obsidian Research Corp
11 * Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
12 *
13 * Device file system interface to the TPM
14 */
15#include <linux/poll.h>
16#include <linux/slab.h>
17#include <linux/uaccess.h>
18#include <linux/workqueue.h>
19#include "tpm.h"
20#include "tpm-dev.h"
21
22static struct workqueue_struct *tpm_dev_wq;
23
24static ssize_t tpm_dev_transmit(struct tpm_chip *chip, struct tpm_space *space,
25 u8 *buf, size_t bufsiz)
26{
27 struct tpm_header *header = (void *)buf;
28 ssize_t ret, len;
29
30 ret = tpm2_prepare_space(chip, space, buf, bufsiz);
31 /* If the command is not implemented by the TPM, synthesize a
32 * response with a TPM2_RC_COMMAND_CODE return for user-space.
33 */
34 if (ret == -EOPNOTSUPP) {
35 header->length = cpu_to_be32(sizeof(*header));
36 header->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
37 header->return_code = cpu_to_be32(TPM2_RC_COMMAND_CODE |
38 TSS2_RESMGR_TPM_RC_LAYER);
39 ret = sizeof(*header);
40 }
41 if (ret)
42 goto out_rc;
43
44 len = tpm_transmit(chip, buf, bufsiz);
45 if (len < 0)
46 ret = len;
47
48 if (!ret)
49 ret = tpm2_commit_space(chip, space, buf, &len);
50
51out_rc:
52 return ret ? ret : len;
53}
54
55static void tpm_dev_async_work(struct work_struct *work)
56{
57 struct file_priv *priv =
58 container_of(work, struct file_priv, async_work);
59 ssize_t ret;
60
61 mutex_lock(&priv->buffer_mutex);
62 priv->command_enqueued = false;
63 ret = tpm_try_get_ops(priv->chip);
64 if (ret) {
65 priv->response_length = ret;
66 goto out;
67 }
68
69 ret = tpm_dev_transmit(priv->chip, priv->space, priv->data_buffer,
70 sizeof(priv->data_buffer));
71 tpm_put_ops(priv->chip);
72
73 /*
74 * If ret is > 0 then tpm_dev_transmit returned the size of the
75 * response. If ret is < 0 then tpm_dev_transmit failed and
76 * returned an error code.
77 */
78 if (ret != 0) {
79 priv->response_length = ret;
80 mod_timer(&priv->user_read_timer, jiffies + (120 * HZ));
81 }
82out:
83 mutex_unlock(&priv->buffer_mutex);
84 wake_up_interruptible(&priv->async_wait);
85}
86
87static void user_reader_timeout(struct timer_list *t)
88{
89 struct file_priv *priv = from_timer(priv, t, user_read_timer);
90
91 pr_warn("TPM user space timeout is deprecated (pid=%d)\n",
92 task_tgid_nr(current));
93
94 schedule_work(&priv->timeout_work);
95}
96
97static void tpm_timeout_work(struct work_struct *work)
98{
99 struct file_priv *priv = container_of(work, struct file_priv,
100 timeout_work);
101
102 mutex_lock(&priv->buffer_mutex);
103 priv->response_read = true;
104 priv->response_length = 0;
105 memset(priv->data_buffer, 0, sizeof(priv->data_buffer));
106 mutex_unlock(&priv->buffer_mutex);
107 wake_up_interruptible(&priv->async_wait);
108}
109
110void tpm_common_open(struct file *file, struct tpm_chip *chip,
111 struct file_priv *priv, struct tpm_space *space)
112{
113 priv->chip = chip;
114 priv->space = space;
115 priv->response_read = true;
116
117 mutex_init(&priv->buffer_mutex);
118 timer_setup(&priv->user_read_timer, user_reader_timeout, 0);
119 INIT_WORK(&priv->timeout_work, tpm_timeout_work);
120 INIT_WORK(&priv->async_work, tpm_dev_async_work);
121 init_waitqueue_head(&priv->async_wait);
122 file->private_data = priv;
123}
124
125ssize_t tpm_common_read(struct file *file, char __user *buf,
126 size_t size, loff_t *off)
127{
128 struct file_priv *priv = file->private_data;
129 ssize_t ret_size = 0;
130 int rc;
131
132 mutex_lock(&priv->buffer_mutex);
133
134 if (priv->response_length) {
135 priv->response_read = true;
136
137 ret_size = min_t(ssize_t, size, priv->response_length);
138 if (ret_size <= 0) {
139 priv->response_length = 0;
140 goto out;
141 }
142
143 rc = copy_to_user(buf, priv->data_buffer + *off, ret_size);
144 if (rc) {
145 memset(priv->data_buffer, 0, TPM_BUFSIZE);
146 priv->response_length = 0;
147 ret_size = -EFAULT;
148 } else {
149 memset(priv->data_buffer + *off, 0, ret_size);
150 priv->response_length -= ret_size;
151 *off += ret_size;
152 }
153 }
154
155out:
156 if (!priv->response_length) {
157 *off = 0;
158 del_timer_sync(&priv->user_read_timer);
159 flush_work(&priv->timeout_work);
160 }
161 mutex_unlock(&priv->buffer_mutex);
162 return ret_size;
163}
164
165ssize_t tpm_common_write(struct file *file, const char __user *buf,
166 size_t size, loff_t *off)
167{
168 struct file_priv *priv = file->private_data;
169 int ret = 0;
170
171 if (size > TPM_BUFSIZE)
172 return -E2BIG;
173
174 mutex_lock(&priv->buffer_mutex);
175
176 /* Cannot perform a write until the read has cleared either via
177 * tpm_read or a user_read_timer timeout. This also prevents split
178 * buffered writes from blocking here.
179 */
180 if ((!priv->response_read && priv->response_length) ||
181 priv->command_enqueued) {
182 ret = -EBUSY;
183 goto out;
184 }
185
186 if (copy_from_user(priv->data_buffer, buf, size)) {
187 ret = -EFAULT;
188 goto out;
189 }
190
191 if (size < 6 ||
192 size < be32_to_cpu(*((__be32 *)(priv->data_buffer + 2)))) {
193 ret = -EINVAL;
194 goto out;
195 }
196
197 priv->response_length = 0;
198 priv->response_read = false;
199 *off = 0;
200
201 /*
202 * If in nonblocking mode schedule an async job to send
203 * the command return the size.
204 * In case of error the err code will be returned in
205 * the subsequent read call.
206 */
207 if (file->f_flags & O_NONBLOCK) {
208 priv->command_enqueued = true;
209 queue_work(tpm_dev_wq, &priv->async_work);
210 mutex_unlock(&priv->buffer_mutex);
211 return size;
212 }
213
214 /* atomic tpm command send and result receive. We only hold the ops
215 * lock during this period so that the tpm can be unregistered even if
216 * the char dev is held open.
217 */
218 if (tpm_try_get_ops(priv->chip)) {
219 ret = -EPIPE;
220 goto out;
221 }
222
223 ret = tpm_dev_transmit(priv->chip, priv->space, priv->data_buffer,
224 sizeof(priv->data_buffer));
225 tpm_put_ops(priv->chip);
226
227 if (ret > 0) {
228 priv->response_length = ret;
229 mod_timer(&priv->user_read_timer, jiffies + (120 * HZ));
230 ret = size;
231 }
232out:
233 mutex_unlock(&priv->buffer_mutex);
234 return ret;
235}
236
237__poll_t tpm_common_poll(struct file *file, poll_table *wait)
238{
239 struct file_priv *priv = file->private_data;
240 __poll_t mask = 0;
241
242 poll_wait(file, &priv->async_wait, wait);
243 mutex_lock(&priv->buffer_mutex);
244
245 /*
246 * The response_length indicates if there is still response
247 * (or part of it) to be consumed. Partial reads decrease it
248 * by the number of bytes read, and write resets it the zero.
249 */
250 if (priv->response_length)
251 mask = EPOLLIN | EPOLLRDNORM;
252 else
253 mask = EPOLLOUT | EPOLLWRNORM;
254
255 mutex_unlock(&priv->buffer_mutex);
256 return mask;
257}
258
259/*
260 * Called on file close
261 */
262void tpm_common_release(struct file *file, struct file_priv *priv)
263{
264 flush_work(&priv->async_work);
265 del_timer_sync(&priv->user_read_timer);
266 flush_work(&priv->timeout_work);
267 file->private_data = NULL;
268 priv->response_length = 0;
269}
270
271int __init tpm_dev_common_init(void)
272{
273 tpm_dev_wq = alloc_workqueue("tpm_dev_wq", WQ_MEM_RECLAIM, 0);
274
275 return !tpm_dev_wq ? -ENOMEM : 0;
276}
277
278void __exit tpm_dev_common_exit(void)
279{
280 if (tpm_dev_wq) {
281 destroy_workqueue(tpm_dev_wq);
282 tpm_dev_wq = NULL;
283 }
284}
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2004 IBM Corporation
4 * Authors:
5 * Leendert van Doorn <leendert@watson.ibm.com>
6 * Dave Safford <safford@watson.ibm.com>
7 * Reiner Sailer <sailer@watson.ibm.com>
8 * Kylene Hall <kjhall@us.ibm.com>
9 *
10 * Copyright (C) 2013 Obsidian Research Corp
11 * Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
12 *
13 * Device file system interface to the TPM
14 */
15#include <linux/poll.h>
16#include <linux/slab.h>
17#include <linux/uaccess.h>
18#include <linux/workqueue.h>
19#include "tpm.h"
20#include "tpm-dev.h"
21
22static struct workqueue_struct *tpm_dev_wq;
23static DEFINE_MUTEX(tpm_dev_wq_lock);
24
25static ssize_t tpm_dev_transmit(struct tpm_chip *chip, struct tpm_space *space,
26 u8 *buf, size_t bufsiz)
27{
28 struct tpm_header *header = (void *)buf;
29 ssize_t ret, len;
30
31 ret = tpm2_prepare_space(chip, space, buf, bufsiz);
32 /* If the command is not implemented by the TPM, synthesize a
33 * response with a TPM2_RC_COMMAND_CODE return for user-space.
34 */
35 if (ret == -EOPNOTSUPP) {
36 header->length = cpu_to_be32(sizeof(*header));
37 header->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
38 header->return_code = cpu_to_be32(TPM2_RC_COMMAND_CODE |
39 TSS2_RESMGR_TPM_RC_LAYER);
40 ret = sizeof(*header);
41 }
42 if (ret)
43 goto out_rc;
44
45 len = tpm_transmit(chip, buf, bufsiz);
46 if (len < 0)
47 ret = len;
48
49 if (!ret)
50 ret = tpm2_commit_space(chip, space, buf, &len);
51
52out_rc:
53 return ret ? ret : len;
54}
55
56static void tpm_dev_async_work(struct work_struct *work)
57{
58 struct file_priv *priv =
59 container_of(work, struct file_priv, async_work);
60 ssize_t ret;
61
62 mutex_lock(&priv->buffer_mutex);
63 priv->command_enqueued = false;
64 ret = tpm_dev_transmit(priv->chip, priv->space, priv->data_buffer,
65 sizeof(priv->data_buffer));
66 tpm_put_ops(priv->chip);
67 if (ret > 0) {
68 priv->response_length = ret;
69 mod_timer(&priv->user_read_timer, jiffies + (120 * HZ));
70 }
71 mutex_unlock(&priv->buffer_mutex);
72 wake_up_interruptible(&priv->async_wait);
73}
74
75static void user_reader_timeout(struct timer_list *t)
76{
77 struct file_priv *priv = from_timer(priv, t, user_read_timer);
78
79 pr_warn("TPM user space timeout is deprecated (pid=%d)\n",
80 task_tgid_nr(current));
81
82 schedule_work(&priv->timeout_work);
83}
84
85static void tpm_timeout_work(struct work_struct *work)
86{
87 struct file_priv *priv = container_of(work, struct file_priv,
88 timeout_work);
89
90 mutex_lock(&priv->buffer_mutex);
91 priv->response_read = true;
92 priv->response_length = 0;
93 memset(priv->data_buffer, 0, sizeof(priv->data_buffer));
94 mutex_unlock(&priv->buffer_mutex);
95 wake_up_interruptible(&priv->async_wait);
96}
97
98void tpm_common_open(struct file *file, struct tpm_chip *chip,
99 struct file_priv *priv, struct tpm_space *space)
100{
101 priv->chip = chip;
102 priv->space = space;
103 priv->response_read = true;
104
105 mutex_init(&priv->buffer_mutex);
106 timer_setup(&priv->user_read_timer, user_reader_timeout, 0);
107 INIT_WORK(&priv->timeout_work, tpm_timeout_work);
108 INIT_WORK(&priv->async_work, tpm_dev_async_work);
109 init_waitqueue_head(&priv->async_wait);
110 file->private_data = priv;
111}
112
113ssize_t tpm_common_read(struct file *file, char __user *buf,
114 size_t size, loff_t *off)
115{
116 struct file_priv *priv = file->private_data;
117 ssize_t ret_size = 0;
118 int rc;
119
120 mutex_lock(&priv->buffer_mutex);
121
122 if (priv->response_length) {
123 priv->response_read = true;
124
125 ret_size = min_t(ssize_t, size, priv->response_length);
126 if (!ret_size) {
127 priv->response_length = 0;
128 goto out;
129 }
130
131 rc = copy_to_user(buf, priv->data_buffer + *off, ret_size);
132 if (rc) {
133 memset(priv->data_buffer, 0, TPM_BUFSIZE);
134 priv->response_length = 0;
135 ret_size = -EFAULT;
136 } else {
137 memset(priv->data_buffer + *off, 0, ret_size);
138 priv->response_length -= ret_size;
139 *off += ret_size;
140 }
141 }
142
143out:
144 if (!priv->response_length) {
145 *off = 0;
146 del_singleshot_timer_sync(&priv->user_read_timer);
147 flush_work(&priv->timeout_work);
148 }
149 mutex_unlock(&priv->buffer_mutex);
150 return ret_size;
151}
152
153ssize_t tpm_common_write(struct file *file, const char __user *buf,
154 size_t size, loff_t *off)
155{
156 struct file_priv *priv = file->private_data;
157 int ret = 0;
158
159 if (size > TPM_BUFSIZE)
160 return -E2BIG;
161
162 mutex_lock(&priv->buffer_mutex);
163
164 /* Cannot perform a write until the read has cleared either via
165 * tpm_read or a user_read_timer timeout. This also prevents split
166 * buffered writes from blocking here.
167 */
168 if ((!priv->response_read && priv->response_length) ||
169 priv->command_enqueued) {
170 ret = -EBUSY;
171 goto out;
172 }
173
174 if (copy_from_user(priv->data_buffer, buf, size)) {
175 ret = -EFAULT;
176 goto out;
177 }
178
179 if (size < 6 ||
180 size < be32_to_cpu(*((__be32 *)(priv->data_buffer + 2)))) {
181 ret = -EINVAL;
182 goto out;
183 }
184
185 /* atomic tpm command send and result receive. We only hold the ops
186 * lock during this period so that the tpm can be unregistered even if
187 * the char dev is held open.
188 */
189 if (tpm_try_get_ops(priv->chip)) {
190 ret = -EPIPE;
191 goto out;
192 }
193
194 priv->response_length = 0;
195 priv->response_read = false;
196 *off = 0;
197
198 /*
199 * If in nonblocking mode schedule an async job to send
200 * the command return the size.
201 * In case of error the err code will be returned in
202 * the subsequent read call.
203 */
204 if (file->f_flags & O_NONBLOCK) {
205 priv->command_enqueued = true;
206 queue_work(tpm_dev_wq, &priv->async_work);
207 mutex_unlock(&priv->buffer_mutex);
208 return size;
209 }
210
211 ret = tpm_dev_transmit(priv->chip, priv->space, priv->data_buffer,
212 sizeof(priv->data_buffer));
213 tpm_put_ops(priv->chip);
214
215 if (ret > 0) {
216 priv->response_length = ret;
217 mod_timer(&priv->user_read_timer, jiffies + (120 * HZ));
218 ret = size;
219 }
220out:
221 mutex_unlock(&priv->buffer_mutex);
222 return ret;
223}
224
225__poll_t tpm_common_poll(struct file *file, poll_table *wait)
226{
227 struct file_priv *priv = file->private_data;
228 __poll_t mask = 0;
229
230 poll_wait(file, &priv->async_wait, wait);
231 mutex_lock(&priv->buffer_mutex);
232
233 /*
234 * The response_length indicates if there is still response
235 * (or part of it) to be consumed. Partial reads decrease it
236 * by the number of bytes read, and write resets it the zero.
237 */
238 if (priv->response_length)
239 mask = EPOLLIN | EPOLLRDNORM;
240 else
241 mask = EPOLLOUT | EPOLLWRNORM;
242
243 mutex_unlock(&priv->buffer_mutex);
244 return mask;
245}
246
247/*
248 * Called on file close
249 */
250void tpm_common_release(struct file *file, struct file_priv *priv)
251{
252 flush_work(&priv->async_work);
253 del_singleshot_timer_sync(&priv->user_read_timer);
254 flush_work(&priv->timeout_work);
255 file->private_data = NULL;
256 priv->response_length = 0;
257}
258
259int __init tpm_dev_common_init(void)
260{
261 tpm_dev_wq = alloc_workqueue("tpm_dev_wq", WQ_MEM_RECLAIM, 0);
262
263 return !tpm_dev_wq ? -ENOMEM : 0;
264}
265
266void __exit tpm_dev_common_exit(void)
267{
268 if (tpm_dev_wq) {
269 destroy_workqueue(tpm_dev_wq);
270 tpm_dev_wq = NULL;
271 }
272}