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2024-10-09 244b2c5ca8b14627e4a17755e5922221e121c771 
 kernel/drivers/char/tpm/tpm-dev-common.c
....@@ -1,3 +1,4 @@
1
+// SPDX-License-Identifier: GPL-2.0-only
12 /*
23  * Copyright (C) 2004 IBM Corporation
34  * Authors:
....@@ -10,17 +11,79 @@
1011  * Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
1112  *
1213  * Device file system interface to the TPM
13
- *
14
- * This program is free software; you can redistribute it and/or
15
- * modify it under the terms of the GNU General Public License as
16
- * published by the Free Software Foundation, version 2 of the
17
- * License.
18
- *
1914  */
15
+#include <linux/poll.h>
2016 #include <linux/slab.h>
2117 #include <linux/uaccess.h>
18
+#include <linux/workqueue.h>
2219 #include "tpm.h"
2320 #include "tpm-dev.h"
21
+
22
+static struct workqueue_struct *tpm_dev_wq;
23
+static DEFINE_MUTEX(tpm_dev_wq_lock);
24
+
25
+static 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
+
52
+out_rc:
53
+	return ret ? ret : len;
54
+}
55
+
56
+static 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_try_get_ops(priv->chip);
65
+	if (ret) {
66
+		priv->response_length = ret;
67
+		goto out;
68
+	}
69
+
70
+	ret = tpm_dev_transmit(priv->chip, priv->space, priv->data_buffer,
71
+			       sizeof(priv->data_buffer));
72
+	tpm_put_ops(priv->chip);
73
+
74
+	/*
75
+	 * If ret is > 0 then tpm_dev_transmit returned the size of the
76
+	 * response. If ret is < 0 then tpm_dev_transmit failed and
77
+	 * returned an error code.
78
+	 */
79
+	if (ret != 0) {
80
+		priv->response_length = ret;
81
+		mod_timer(&priv->user_read_timer, jiffies + (120 * HZ));
82
+	}
83
+out:
84
+	mutex_unlock(&priv->buffer_mutex);
85
+	wake_up_interruptible(&priv->async_wait);
86
+}
2487 
2588 static void user_reader_timeout(struct timer_list *t)
2689 {
....@@ -29,27 +92,34 @@
2992 	pr_warn("TPM user space timeout is deprecated (pid=%d)\n",
3093 		task_tgid_nr(current));
3194 
32
-	schedule_work(&priv->work);
95
+	schedule_work(&priv->timeout_work);
3396 }
3497 
35
-static void timeout_work(struct work_struct *work)
98
+static void tpm_timeout_work(struct work_struct *work)
3699 {
37
-	struct file_priv *priv = container_of(work, struct file_priv, work);
100
+	struct file_priv *priv = container_of(work, struct file_priv,
101
+					      timeout_work);
38102 
39103 	mutex_lock(&priv->buffer_mutex);
40
-	priv->data_pending = 0;
104
+	priv->response_read = true;
105
+	priv->response_length = 0;
41106 	memset(priv->data_buffer, 0, sizeof(priv->data_buffer));
42107 	mutex_unlock(&priv->buffer_mutex);
108
+	wake_up_interruptible(&priv->async_wait);
43109 }
44110 
45111 void tpm_common_open(struct file *file, struct tpm_chip *chip,
46
-		     struct file_priv *priv)
112
+		     struct file_priv *priv, struct tpm_space *space)
47113 {
48114 	priv->chip = chip;
115
+	priv->space = space;
116
+	priv->response_read = true;
117
+
49118 	mutex_init(&priv->buffer_mutex);
50119 	timer_setup(&priv->user_read_timer, user_reader_timeout, 0);
51
-	INIT_WORK(&priv->work, timeout_work);
52
-
120
+	INIT_WORK(&priv->timeout_work, tpm_timeout_work);
121
+	INIT_WORK(&priv->async_work, tpm_dev_async_work);
122
+	init_waitqueue_head(&priv->async_wait);
53123 	file->private_data = priv;
54124 }
55125 
....@@ -60,32 +130,46 @@
60130 	ssize_t ret_size = 0;
61131 	int rc;
62132 
63
-	del_singleshot_timer_sync(&priv->user_read_timer);
64
-	flush_work(&priv->work);
65133 	mutex_lock(&priv->buffer_mutex);
66134 
67
-	if (priv->data_pending) {
68
-		ret_size = min_t(ssize_t, size, priv->data_pending);
69
-		rc = copy_to_user(buf, priv->data_buffer, ret_size);
70
-		memset(priv->data_buffer, 0, priv->data_pending);
71
-		if (rc)
72
-			ret_size = -EFAULT;
135
+	if (priv->response_length) {
136
+		priv->response_read = true;
73137 
74
-		priv->data_pending = 0;
138
+		ret_size = min_t(ssize_t, size, priv->response_length);
139
+		if (ret_size <= 0) {
140
+			priv->response_length = 0;
141
+			goto out;
142
+		}
143
+
144
+		rc = copy_to_user(buf, priv->data_buffer + *off, ret_size);
145
+		if (rc) {
146
+			memset(priv->data_buffer, 0, TPM_BUFSIZE);
147
+			priv->response_length = 0;
148
+			ret_size = -EFAULT;
149
+		} else {
150
+			memset(priv->data_buffer + *off, 0, ret_size);
151
+			priv->response_length -= ret_size;
152
+			*off += ret_size;
153
+		}
75154 	}
76155 
156
+out:
157
+	if (!priv->response_length) {
158
+		*off = 0;
159
+		del_singleshot_timer_sync(&priv->user_read_timer);
160
+		flush_work(&priv->timeout_work);
161
+	}
77162 	mutex_unlock(&priv->buffer_mutex);
78163 	return ret_size;
79164 }
80165 
81166 ssize_t tpm_common_write(struct file *file, const char __user *buf,
82
-			 size_t size, loff_t *off, struct tpm_space *space)
167
+			 size_t size, loff_t *off)
83168 {
84169 	struct file_priv *priv = file->private_data;
85
-	size_t in_size = size;
86
-	ssize_t out_size;
170
+	int ret = 0;
87171 
88
-	if (in_size > TPM_BUFSIZE)
172
+	if (size > TPM_BUFSIZE)
89173 		return -E2BIG;
90174 
91175 	mutex_lock(&priv->buffer_mutex);
....@@ -94,21 +178,38 @@
94178 	 * tpm_read or a user_read_timer timeout. This also prevents split
95179 	 * buffered writes from blocking here.
96180 	 */
97
-	if (priv->data_pending != 0) {
98
-		mutex_unlock(&priv->buffer_mutex);
99
-		return -EBUSY;
181
+	if ((!priv->response_read && priv->response_length) ||
182
+	    priv->command_enqueued) {
183
+		ret = -EBUSY;
184
+		goto out;
100185 	}
101186 
102
-	if (copy_from_user
103
-	    (priv->data_buffer, (void __user *) buf, in_size)) {
104
-		mutex_unlock(&priv->buffer_mutex);
105
-		return -EFAULT;
187
+	if (copy_from_user(priv->data_buffer, buf, size)) {
188
+		ret = -EFAULT;
189
+		goto out;
106190 	}
107191 
108
-	if (in_size < 6 ||
109
-	    in_size < be32_to_cpu(*((__be32 *) (priv->data_buffer + 2)))) {
192
+	if (size < 6 ||
193
+	    size < be32_to_cpu(*((__be32 *)(priv->data_buffer + 2)))) {
194
+		ret = -EINVAL;
195
+		goto out;
196
+	}
197
+
198
+	priv->response_length = 0;
199
+	priv->response_read = false;
200
+	*off = 0;
201
+
202
+	/*
203
+	 * If in nonblocking mode schedule an async job to send
204
+	 * the command return the size.
205
+	 * In case of error the err code will be returned in
206
+	 * the subsequent read call.
207
+	 */
208
+	if (file->f_flags & O_NONBLOCK) {
209
+		priv->command_enqueued = true;
210
+		queue_work(tpm_dev_wq, &priv->async_work);
110211 		mutex_unlock(&priv->buffer_mutex);
111
-		return -EINVAL;
212
+		return size;
112213 	}
113214 
114215 	/* atomic tpm command send and result receive. We only hold the ops
....@@ -116,25 +217,44 @@
116217 	 * the char dev is held open.
117218 	 */
118219 	if (tpm_try_get_ops(priv->chip)) {
119
-		mutex_unlock(&priv->buffer_mutex);
120
-		return -EPIPE;
220
+		ret = -EPIPE;
221
+		goto out;
121222 	}
122
-	out_size = tpm_transmit(priv->chip, space, priv->data_buffer,
123
-				sizeof(priv->data_buffer), 0);
124223 
224
+	ret = tpm_dev_transmit(priv->chip, priv->space, priv->data_buffer,
225
+			       sizeof(priv->data_buffer));
125226 	tpm_put_ops(priv->chip);
126
-	if (out_size < 0) {
127
-		mutex_unlock(&priv->buffer_mutex);
128
-		return out_size;
227
+
228
+	if (ret > 0) {
229
+		priv->response_length = ret;
230
+		mod_timer(&priv->user_read_timer, jiffies + (120 * HZ));
231
+		ret = size;
129232 	}
130
-
131
-	priv->data_pending = out_size;
233
+out:
132234 	mutex_unlock(&priv->buffer_mutex);
235
+	return ret;
236
+}
133237 
134
-	/* Set a timeout by which the reader must come claim the result */
135
-	mod_timer(&priv->user_read_timer, jiffies + (120 * HZ));
238
+__poll_t tpm_common_poll(struct file *file, poll_table *wait)
239
+{
240
+	struct file_priv *priv = file->private_data;
241
+	__poll_t mask = 0;
136242 
137
-	return in_size;
243
+	poll_wait(file, &priv->async_wait, wait);
244
+	mutex_lock(&priv->buffer_mutex);
245
+
246
+	/*
247
+	 * The response_length indicates if there is still response
248
+	 * (or part of it) to be consumed. Partial reads decrease it
249
+	 * by the number of bytes read, and write resets it the zero.
250
+	 */
251
+	if (priv->response_length)
252
+		mask = EPOLLIN | EPOLLRDNORM;
253
+	else
254
+		mask = EPOLLOUT | EPOLLWRNORM;
255
+
256
+	mutex_unlock(&priv->buffer_mutex);
257
+	return mask;
138258 }
139259 
140260 /*
....@@ -142,8 +262,24 @@
142262  */
143263 void tpm_common_release(struct file *file, struct file_priv *priv)
144264 {
265
+	flush_work(&priv->async_work);
145266 	del_singleshot_timer_sync(&priv->user_read_timer);
146
-	flush_work(&priv->work);
267
+	flush_work(&priv->timeout_work);
147268 	file->private_data = NULL;
148
-	priv->data_pending = 0;
269
+	priv->response_length = 0;
270
+}
271
+
272
+int __init tpm_dev_common_init(void)
273
+{
274
+	tpm_dev_wq = alloc_workqueue("tpm_dev_wq", WQ_MEM_RECLAIM, 0);
275
+
276
+	return !tpm_dev_wq ? -ENOMEM : 0;
277
+}
278
+
279
+void __exit tpm_dev_common_exit(void)
280
+{
281
+	if (tpm_dev_wq) {
282
+		destroy_workqueue(tpm_dev_wq);
283
+		tpm_dev_wq = NULL;
284
+	}
149285 }