1 /*
2 * SPDX-License-Identifier: MIT
3 *
4 * Copyright © 2018 Intel Corporation
5 */
6
7 #include <linux/nospec.h>
8 #include <linux/sched/signal.h>
9 #include <linux/uaccess.h>
10
11 #include <uapi/drm/i915_drm.h>
12
13 #include "i915_user_extensions.h"
14 #include "i915_utils.h"
15
i915_user_extensions(struct i915_user_extension __user * ext,const i915_user_extension_fn * tbl,unsigned int count,void * data)16 int i915_user_extensions(struct i915_user_extension __user *ext,
17 const i915_user_extension_fn *tbl,
18 unsigned int count,
19 void *data)
20 {
21 unsigned int stackdepth = 512;
22
23 while (ext) {
24 int i, err;
25 u32 name;
26 u64 next;
27
28 if (!stackdepth--) /* recursion vs useful flexibility */
29 return -E2BIG;
30
31 err = check_user_mbz(&ext->flags);
32 if (err)
33 return err;
34
35 for (i = 0; i < ARRAY_SIZE(ext->rsvd); i++) {
36 err = check_user_mbz(&ext->rsvd[i]);
37 if (err)
38 return err;
39 }
40
41 if (get_user(name, &ext->name))
42 return -EFAULT;
43
44 err = -EINVAL;
45 if (name < count) {
46 name = array_index_nospec(name, count);
47 if (tbl[name])
48 err = tbl[name](ext, data);
49 }
50 if (err)
51 return err;
52
53 if (get_user(next, &ext->next_extension) ||
54 overflows_type(next, uintptr_t))
55 return -EFAULT;
56
57 ext = u64_to_user_ptr(next);
58 }
59
60 return 0;
61 }
62