1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Copyright (c) 2015-2017, 2019-2021 Linaro Limited |
4 | */ |
5 | #include <linux/anon_inodes.h> |
6 | #include <linux/device.h> |
7 | #include <linux/idr.h> |
8 | #include <linux/mm.h> |
9 | #include <linux/sched.h> |
10 | #include <linux/slab.h> |
11 | #include <linux/tee_drv.h> |
12 | #include <linux/uaccess.h> |
13 | #include <linux/uio.h> |
14 | #include <linux/highmem.h> |
15 | #include "tee_private.h" |
16 | |
17 | static void shm_put_kernel_pages(struct page **pages, size_t page_count) |
18 | { |
19 | size_t n; |
20 | |
21 | for (n = 0; n < page_count; n++) |
22 | put_page(page: pages[n]); |
23 | } |
24 | |
25 | static void shm_get_kernel_pages(struct page **pages, size_t page_count) |
26 | { |
27 | size_t n; |
28 | |
29 | for (n = 0; n < page_count; n++) |
30 | get_page(page: pages[n]); |
31 | } |
32 | |
33 | static void release_registered_pages(struct tee_shm *shm) |
34 | { |
35 | if (shm->pages) { |
36 | if (shm->flags & TEE_SHM_USER_MAPPED) |
37 | unpin_user_pages(pages: shm->pages, npages: shm->num_pages); |
38 | else |
39 | shm_put_kernel_pages(pages: shm->pages, page_count: shm->num_pages); |
40 | |
41 | kfree(objp: shm->pages); |
42 | } |
43 | } |
44 | |
45 | static void tee_shm_release(struct tee_device *teedev, struct tee_shm *shm) |
46 | { |
47 | if (shm->flags & TEE_SHM_POOL) { |
48 | teedev->pool->ops->free(teedev->pool, shm); |
49 | } else if (shm->flags & TEE_SHM_DYNAMIC) { |
50 | int rc = teedev->desc->ops->shm_unregister(shm->ctx, shm); |
51 | |
52 | if (rc) |
53 | dev_err(teedev->dev.parent, |
54 | "unregister shm %p failed: %d" , shm, rc); |
55 | |
56 | release_registered_pages(shm); |
57 | } |
58 | |
59 | teedev_ctx_put(ctx: shm->ctx); |
60 | |
61 | kfree(objp: shm); |
62 | |
63 | tee_device_put(teedev); |
64 | } |
65 | |
66 | static struct tee_shm *shm_alloc_helper(struct tee_context *ctx, size_t size, |
67 | size_t align, u32 flags, int id) |
68 | { |
69 | struct tee_device *teedev = ctx->teedev; |
70 | struct tee_shm *shm; |
71 | void *ret; |
72 | int rc; |
73 | |
74 | if (!tee_device_get(teedev)) |
75 | return ERR_PTR(error: -EINVAL); |
76 | |
77 | if (!teedev->pool) { |
78 | /* teedev has been detached from driver */ |
79 | ret = ERR_PTR(error: -EINVAL); |
80 | goto err_dev_put; |
81 | } |
82 | |
83 | shm = kzalloc(size: sizeof(*shm), GFP_KERNEL); |
84 | if (!shm) { |
85 | ret = ERR_PTR(error: -ENOMEM); |
86 | goto err_dev_put; |
87 | } |
88 | |
89 | refcount_set(r: &shm->refcount, n: 1); |
90 | shm->flags = flags; |
91 | shm->id = id; |
92 | |
93 | /* |
94 | * We're assigning this as it is needed if the shm is to be |
95 | * registered. If this function returns OK then the caller expected |
96 | * to call teedev_ctx_get() or clear shm->ctx in case it's not |
97 | * needed any longer. |
98 | */ |
99 | shm->ctx = ctx; |
100 | |
101 | rc = teedev->pool->ops->alloc(teedev->pool, shm, size, align); |
102 | if (rc) { |
103 | ret = ERR_PTR(error: rc); |
104 | goto err_kfree; |
105 | } |
106 | |
107 | teedev_ctx_get(ctx); |
108 | return shm; |
109 | err_kfree: |
110 | kfree(objp: shm); |
111 | err_dev_put: |
112 | tee_device_put(teedev); |
113 | return ret; |
114 | } |
115 | |
116 | /** |
117 | * tee_shm_alloc_user_buf() - Allocate shared memory for user space |
118 | * @ctx: Context that allocates the shared memory |
119 | * @size: Requested size of shared memory |
120 | * |
121 | * Memory allocated as user space shared memory is automatically freed when |
122 | * the TEE file pointer is closed. The primary usage of this function is |
123 | * when the TEE driver doesn't support registering ordinary user space |
124 | * memory. |
125 | * |
126 | * @returns a pointer to 'struct tee_shm' |
127 | */ |
128 | struct tee_shm *tee_shm_alloc_user_buf(struct tee_context *ctx, size_t size) |
129 | { |
130 | u32 flags = TEE_SHM_DYNAMIC | TEE_SHM_POOL; |
131 | struct tee_device *teedev = ctx->teedev; |
132 | struct tee_shm *shm; |
133 | void *ret; |
134 | int id; |
135 | |
136 | mutex_lock(&teedev->mutex); |
137 | id = idr_alloc(&teedev->idr, NULL, start: 1, end: 0, GFP_KERNEL); |
138 | mutex_unlock(lock: &teedev->mutex); |
139 | if (id < 0) |
140 | return ERR_PTR(error: id); |
141 | |
142 | shm = shm_alloc_helper(ctx, size, PAGE_SIZE, flags, id); |
143 | if (IS_ERR(ptr: shm)) { |
144 | mutex_lock(&teedev->mutex); |
145 | idr_remove(&teedev->idr, id); |
146 | mutex_unlock(lock: &teedev->mutex); |
147 | return shm; |
148 | } |
149 | |
150 | mutex_lock(&teedev->mutex); |
151 | ret = idr_replace(&teedev->idr, shm, id); |
152 | mutex_unlock(lock: &teedev->mutex); |
153 | if (IS_ERR(ptr: ret)) { |
154 | tee_shm_free(shm); |
155 | return ret; |
156 | } |
157 | |
158 | return shm; |
159 | } |
160 | |
161 | /** |
162 | * tee_shm_alloc_kernel_buf() - Allocate shared memory for kernel buffer |
163 | * @ctx: Context that allocates the shared memory |
164 | * @size: Requested size of shared memory |
165 | * |
166 | * The returned memory registered in secure world and is suitable to be |
167 | * passed as a memory buffer in parameter argument to |
168 | * tee_client_invoke_func(). The memory allocated is later freed with a |
169 | * call to tee_shm_free(). |
170 | * |
171 | * @returns a pointer to 'struct tee_shm' |
172 | */ |
173 | struct tee_shm *tee_shm_alloc_kernel_buf(struct tee_context *ctx, size_t size) |
174 | { |
175 | u32 flags = TEE_SHM_DYNAMIC | TEE_SHM_POOL; |
176 | |
177 | return shm_alloc_helper(ctx, size, PAGE_SIZE, flags, id: -1); |
178 | } |
179 | EXPORT_SYMBOL_GPL(tee_shm_alloc_kernel_buf); |
180 | |
181 | /** |
182 | * tee_shm_alloc_priv_buf() - Allocate shared memory for a privately shared |
183 | * kernel buffer |
184 | * @ctx: Context that allocates the shared memory |
185 | * @size: Requested size of shared memory |
186 | * |
187 | * This function returns similar shared memory as |
188 | * tee_shm_alloc_kernel_buf(), but with the difference that the memory |
189 | * might not be registered in secure world in case the driver supports |
190 | * passing memory not registered in advance. |
191 | * |
192 | * This function should normally only be used internally in the TEE |
193 | * drivers. |
194 | * |
195 | * @returns a pointer to 'struct tee_shm' |
196 | */ |
197 | struct tee_shm *tee_shm_alloc_priv_buf(struct tee_context *ctx, size_t size) |
198 | { |
199 | u32 flags = TEE_SHM_PRIV | TEE_SHM_POOL; |
200 | |
201 | return shm_alloc_helper(ctx, size, align: sizeof(long) * 2, flags, id: -1); |
202 | } |
203 | EXPORT_SYMBOL_GPL(tee_shm_alloc_priv_buf); |
204 | |
205 | static struct tee_shm * |
206 | register_shm_helper(struct tee_context *ctx, struct iov_iter *iter, u32 flags, |
207 | int id) |
208 | { |
209 | struct tee_device *teedev = ctx->teedev; |
210 | struct tee_shm *shm; |
211 | unsigned long start, addr; |
212 | size_t num_pages, off; |
213 | ssize_t len; |
214 | void *ret; |
215 | int rc; |
216 | |
217 | if (!tee_device_get(teedev)) |
218 | return ERR_PTR(error: -EINVAL); |
219 | |
220 | if (!teedev->desc->ops->shm_register || |
221 | !teedev->desc->ops->shm_unregister) { |
222 | ret = ERR_PTR(error: -ENOTSUPP); |
223 | goto err_dev_put; |
224 | } |
225 | |
226 | teedev_ctx_get(ctx); |
227 | |
228 | shm = kzalloc(size: sizeof(*shm), GFP_KERNEL); |
229 | if (!shm) { |
230 | ret = ERR_PTR(error: -ENOMEM); |
231 | goto err_ctx_put; |
232 | } |
233 | |
234 | refcount_set(r: &shm->refcount, n: 1); |
235 | shm->flags = flags; |
236 | shm->ctx = ctx; |
237 | shm->id = id; |
238 | addr = untagged_addr((unsigned long)iter_iov_addr(iter)); |
239 | start = rounddown(addr, PAGE_SIZE); |
240 | num_pages = iov_iter_npages(i: iter, INT_MAX); |
241 | if (!num_pages) { |
242 | ret = ERR_PTR(error: -ENOMEM); |
243 | goto err_ctx_put; |
244 | } |
245 | |
246 | shm->pages = kcalloc(n: num_pages, size: sizeof(*shm->pages), GFP_KERNEL); |
247 | if (!shm->pages) { |
248 | ret = ERR_PTR(error: -ENOMEM); |
249 | goto err_free_shm; |
250 | } |
251 | |
252 | len = iov_iter_extract_pages(i: iter, pages: &shm->pages, LONG_MAX, maxpages: num_pages, extraction_flags: 0, |
253 | offset0: &off); |
254 | if (unlikely(len <= 0)) { |
255 | ret = len ? ERR_PTR(error: len) : ERR_PTR(error: -ENOMEM); |
256 | goto err_free_shm_pages; |
257 | } |
258 | |
259 | /* |
260 | * iov_iter_extract_kvec_pages does not get reference on the pages, |
261 | * get a reference on them. |
262 | */ |
263 | if (iov_iter_is_kvec(i: iter)) |
264 | shm_get_kernel_pages(pages: shm->pages, page_count: num_pages); |
265 | |
266 | shm->offset = off; |
267 | shm->size = len; |
268 | shm->num_pages = num_pages; |
269 | |
270 | rc = teedev->desc->ops->shm_register(ctx, shm, shm->pages, |
271 | shm->num_pages, start); |
272 | if (rc) { |
273 | ret = ERR_PTR(error: rc); |
274 | goto err_put_shm_pages; |
275 | } |
276 | |
277 | return shm; |
278 | err_put_shm_pages: |
279 | if (!iov_iter_is_kvec(i: iter)) |
280 | unpin_user_pages(pages: shm->pages, npages: shm->num_pages); |
281 | else |
282 | shm_put_kernel_pages(pages: shm->pages, page_count: shm->num_pages); |
283 | err_free_shm_pages: |
284 | kfree(objp: shm->pages); |
285 | err_free_shm: |
286 | kfree(objp: shm); |
287 | err_ctx_put: |
288 | teedev_ctx_put(ctx); |
289 | err_dev_put: |
290 | tee_device_put(teedev); |
291 | return ret; |
292 | } |
293 | |
294 | /** |
295 | * tee_shm_register_user_buf() - Register a userspace shared memory buffer |
296 | * @ctx: Context that registers the shared memory |
297 | * @addr: The userspace address of the shared buffer |
298 | * @length: Length of the shared buffer |
299 | * |
300 | * @returns a pointer to 'struct tee_shm' |
301 | */ |
302 | struct tee_shm *tee_shm_register_user_buf(struct tee_context *ctx, |
303 | unsigned long addr, size_t length) |
304 | { |
305 | u32 flags = TEE_SHM_USER_MAPPED | TEE_SHM_DYNAMIC; |
306 | struct tee_device *teedev = ctx->teedev; |
307 | struct tee_shm *shm; |
308 | struct iov_iter iter; |
309 | void *ret; |
310 | int id; |
311 | |
312 | if (!access_ok((void __user *)addr, length)) |
313 | return ERR_PTR(error: -EFAULT); |
314 | |
315 | mutex_lock(&teedev->mutex); |
316 | id = idr_alloc(&teedev->idr, NULL, start: 1, end: 0, GFP_KERNEL); |
317 | mutex_unlock(lock: &teedev->mutex); |
318 | if (id < 0) |
319 | return ERR_PTR(error: id); |
320 | |
321 | iov_iter_ubuf(i: &iter, ITER_DEST, buf: (void __user *)addr, count: length); |
322 | shm = register_shm_helper(ctx, iter: &iter, flags, id); |
323 | if (IS_ERR(ptr: shm)) { |
324 | mutex_lock(&teedev->mutex); |
325 | idr_remove(&teedev->idr, id); |
326 | mutex_unlock(lock: &teedev->mutex); |
327 | return shm; |
328 | } |
329 | |
330 | mutex_lock(&teedev->mutex); |
331 | ret = idr_replace(&teedev->idr, shm, id); |
332 | mutex_unlock(lock: &teedev->mutex); |
333 | if (IS_ERR(ptr: ret)) { |
334 | tee_shm_free(shm); |
335 | return ret; |
336 | } |
337 | |
338 | return shm; |
339 | } |
340 | |
341 | /** |
342 | * tee_shm_register_kernel_buf() - Register kernel memory to be shared with |
343 | * secure world |
344 | * @ctx: Context that registers the shared memory |
345 | * @addr: The buffer |
346 | * @length: Length of the buffer |
347 | * |
348 | * @returns a pointer to 'struct tee_shm' |
349 | */ |
350 | |
351 | struct tee_shm *tee_shm_register_kernel_buf(struct tee_context *ctx, |
352 | void *addr, size_t length) |
353 | { |
354 | u32 flags = TEE_SHM_DYNAMIC; |
355 | struct kvec kvec; |
356 | struct iov_iter iter; |
357 | |
358 | kvec.iov_base = addr; |
359 | kvec.iov_len = length; |
360 | iov_iter_kvec(i: &iter, ITER_DEST, kvec: &kvec, nr_segs: 1, count: length); |
361 | |
362 | return register_shm_helper(ctx, iter: &iter, flags, id: -1); |
363 | } |
364 | EXPORT_SYMBOL_GPL(tee_shm_register_kernel_buf); |
365 | |
366 | static int tee_shm_fop_release(struct inode *inode, struct file *filp) |
367 | { |
368 | tee_shm_put(shm: filp->private_data); |
369 | return 0; |
370 | } |
371 | |
372 | static int tee_shm_fop_mmap(struct file *filp, struct vm_area_struct *vma) |
373 | { |
374 | struct tee_shm *shm = filp->private_data; |
375 | size_t size = vma->vm_end - vma->vm_start; |
376 | |
377 | /* Refuse sharing shared memory provided by application */ |
378 | if (shm->flags & TEE_SHM_USER_MAPPED) |
379 | return -EINVAL; |
380 | |
381 | /* check for overflowing the buffer's size */ |
382 | if (vma->vm_pgoff + vma_pages(vma) > shm->size >> PAGE_SHIFT) |
383 | return -EINVAL; |
384 | |
385 | return remap_pfn_range(vma, addr: vma->vm_start, pfn: shm->paddr >> PAGE_SHIFT, |
386 | size, vma->vm_page_prot); |
387 | } |
388 | |
389 | static const struct file_operations tee_shm_fops = { |
390 | .owner = THIS_MODULE, |
391 | .release = tee_shm_fop_release, |
392 | .mmap = tee_shm_fop_mmap, |
393 | }; |
394 | |
395 | /** |
396 | * tee_shm_get_fd() - Increase reference count and return file descriptor |
397 | * @shm: Shared memory handle |
398 | * @returns user space file descriptor to shared memory |
399 | */ |
400 | int tee_shm_get_fd(struct tee_shm *shm) |
401 | { |
402 | int fd; |
403 | |
404 | if (shm->id < 0) |
405 | return -EINVAL; |
406 | |
407 | /* matched by tee_shm_put() in tee_shm_op_release() */ |
408 | refcount_inc(r: &shm->refcount); |
409 | fd = anon_inode_getfd(name: "tee_shm" , fops: &tee_shm_fops, priv: shm, O_RDWR); |
410 | if (fd < 0) |
411 | tee_shm_put(shm); |
412 | return fd; |
413 | } |
414 | |
415 | /** |
416 | * tee_shm_free() - Free shared memory |
417 | * @shm: Handle to shared memory to free |
418 | */ |
419 | void tee_shm_free(struct tee_shm *shm) |
420 | { |
421 | tee_shm_put(shm); |
422 | } |
423 | EXPORT_SYMBOL_GPL(tee_shm_free); |
424 | |
425 | /** |
426 | * tee_shm_get_va() - Get virtual address of a shared memory plus an offset |
427 | * @shm: Shared memory handle |
428 | * @offs: Offset from start of this shared memory |
429 | * @returns virtual address of the shared memory + offs if offs is within |
430 | * the bounds of this shared memory, else an ERR_PTR |
431 | */ |
432 | void *tee_shm_get_va(struct tee_shm *shm, size_t offs) |
433 | { |
434 | if (!shm->kaddr) |
435 | return ERR_PTR(error: -EINVAL); |
436 | if (offs >= shm->size) |
437 | return ERR_PTR(error: -EINVAL); |
438 | return (char *)shm->kaddr + offs; |
439 | } |
440 | EXPORT_SYMBOL_GPL(tee_shm_get_va); |
441 | |
442 | /** |
443 | * tee_shm_get_pa() - Get physical address of a shared memory plus an offset |
444 | * @shm: Shared memory handle |
445 | * @offs: Offset from start of this shared memory |
446 | * @pa: Physical address to return |
447 | * @returns 0 if offs is within the bounds of this shared memory, else an |
448 | * error code. |
449 | */ |
450 | int tee_shm_get_pa(struct tee_shm *shm, size_t offs, phys_addr_t *pa) |
451 | { |
452 | if (offs >= shm->size) |
453 | return -EINVAL; |
454 | if (pa) |
455 | *pa = shm->paddr + offs; |
456 | return 0; |
457 | } |
458 | EXPORT_SYMBOL_GPL(tee_shm_get_pa); |
459 | |
460 | /** |
461 | * tee_shm_get_from_id() - Find shared memory object and increase reference |
462 | * count |
463 | * @ctx: Context owning the shared memory |
464 | * @id: Id of shared memory object |
465 | * @returns a pointer to 'struct tee_shm' on success or an ERR_PTR on failure |
466 | */ |
467 | struct tee_shm *tee_shm_get_from_id(struct tee_context *ctx, int id) |
468 | { |
469 | struct tee_device *teedev; |
470 | struct tee_shm *shm; |
471 | |
472 | if (!ctx) |
473 | return ERR_PTR(error: -EINVAL); |
474 | |
475 | teedev = ctx->teedev; |
476 | mutex_lock(&teedev->mutex); |
477 | shm = idr_find(&teedev->idr, id); |
478 | /* |
479 | * If the tee_shm was found in the IDR it must have a refcount |
480 | * larger than 0 due to the guarantee in tee_shm_put() below. So |
481 | * it's safe to use refcount_inc(). |
482 | */ |
483 | if (!shm || shm->ctx != ctx) |
484 | shm = ERR_PTR(error: -EINVAL); |
485 | else |
486 | refcount_inc(r: &shm->refcount); |
487 | mutex_unlock(lock: &teedev->mutex); |
488 | return shm; |
489 | } |
490 | EXPORT_SYMBOL_GPL(tee_shm_get_from_id); |
491 | |
492 | /** |
493 | * tee_shm_put() - Decrease reference count on a shared memory handle |
494 | * @shm: Shared memory handle |
495 | */ |
496 | void tee_shm_put(struct tee_shm *shm) |
497 | { |
498 | struct tee_device *teedev = shm->ctx->teedev; |
499 | bool do_release = false; |
500 | |
501 | mutex_lock(&teedev->mutex); |
502 | if (refcount_dec_and_test(r: &shm->refcount)) { |
503 | /* |
504 | * refcount has reached 0, we must now remove it from the |
505 | * IDR before releasing the mutex. This will guarantee that |
506 | * the refcount_inc() in tee_shm_get_from_id() never starts |
507 | * from 0. |
508 | */ |
509 | if (shm->id >= 0) |
510 | idr_remove(&teedev->idr, id: shm->id); |
511 | do_release = true; |
512 | } |
513 | mutex_unlock(lock: &teedev->mutex); |
514 | |
515 | if (do_release) |
516 | tee_shm_release(teedev, shm); |
517 | } |
518 | EXPORT_SYMBOL_GPL(tee_shm_put); |
519 | |