1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef __TRACE_PROBE_KERNEL_H_ |
3 | #define __TRACE_PROBE_KERNEL_H_ |
4 | |
5 | /* |
6 | * This depends on trace_probe.h, but can not include it due to |
7 | * the way trace_probe_tmpl.h is used by trace_kprobe.c and trace_eprobe.c. |
8 | * Which means that any other user must include trace_probe.h before including |
9 | * this file. |
10 | */ |
11 | /* Return the length of string -- including null terminal byte */ |
12 | static nokprobe_inline int |
13 | fetch_store_strlen_user(unsigned long addr) |
14 | { |
15 | const void __user *uaddr = (__force const void __user *)addr; |
16 | |
17 | return strnlen_user_nofault(unsafe_addr: uaddr, MAX_STRING_SIZE); |
18 | } |
19 | |
20 | /* Return the length of string -- including null terminal byte */ |
21 | static nokprobe_inline int |
22 | fetch_store_strlen(unsigned long addr) |
23 | { |
24 | int ret, len = 0; |
25 | u8 c; |
26 | |
27 | #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE |
28 | if (addr < TASK_SIZE) |
29 | return fetch_store_strlen_user(addr); |
30 | #endif |
31 | |
32 | do { |
33 | ret = copy_from_kernel_nofault(dst: &c, src: (u8 *)addr + len, size: 1); |
34 | len++; |
35 | } while (c && ret == 0 && len < MAX_STRING_SIZE); |
36 | |
37 | return (ret < 0) ? ret : len; |
38 | } |
39 | |
40 | static nokprobe_inline void set_data_loc(int ret, void *dest, void *__dest, void *base) |
41 | { |
42 | if (ret < 0) |
43 | ret = 0; |
44 | *(u32 *)dest = make_data_loc(ret, __dest - base); |
45 | } |
46 | |
47 | /* |
48 | * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf |
49 | * with max length and relative data location. |
50 | */ |
51 | static nokprobe_inline int |
52 | fetch_store_string_user(unsigned long addr, void *dest, void *base) |
53 | { |
54 | const void __user *uaddr = (__force const void __user *)addr; |
55 | int maxlen = get_loc_len(*(u32 *)dest); |
56 | void *__dest; |
57 | long ret; |
58 | |
59 | if (unlikely(!maxlen)) |
60 | return -ENOMEM; |
61 | |
62 | __dest = get_loc_data(dl: dest, ent: base); |
63 | |
64 | ret = strncpy_from_user_nofault(dst: __dest, unsafe_addr: uaddr, count: maxlen); |
65 | set_data_loc(ret, dest, __dest, base); |
66 | |
67 | return ret; |
68 | } |
69 | |
70 | /* |
71 | * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max |
72 | * length and relative data location. |
73 | */ |
74 | static nokprobe_inline int |
75 | fetch_store_string(unsigned long addr, void *dest, void *base) |
76 | { |
77 | int maxlen = get_loc_len(*(u32 *)dest); |
78 | void *__dest; |
79 | long ret; |
80 | |
81 | #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE |
82 | if ((unsigned long)addr < TASK_SIZE) |
83 | return fetch_store_string_user(addr, dest, base); |
84 | #endif |
85 | |
86 | if (unlikely(!maxlen)) |
87 | return -ENOMEM; |
88 | |
89 | __dest = get_loc_data(dl: dest, ent: base); |
90 | |
91 | /* |
92 | * Try to get string again, since the string can be changed while |
93 | * probing. |
94 | */ |
95 | ret = strncpy_from_kernel_nofault(dst: __dest, unsafe_addr: (void *)addr, count: maxlen); |
96 | set_data_loc(ret, dest, __dest, base); |
97 | |
98 | return ret; |
99 | } |
100 | |
101 | static nokprobe_inline int |
102 | probe_mem_read_user(void *dest, void *src, size_t size) |
103 | { |
104 | const void __user *uaddr = (__force const void __user *)src; |
105 | |
106 | return copy_from_user_nofault(dst: dest, src: uaddr, size); |
107 | } |
108 | |
109 | static nokprobe_inline int |
110 | probe_mem_read(void *dest, void *src, size_t size) |
111 | { |
112 | #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE |
113 | if ((unsigned long)src < TASK_SIZE) |
114 | return probe_mem_read_user(dest, src, size); |
115 | #endif |
116 | return copy_from_kernel_nofault(dst: dest, src, size); |
117 | } |
118 | |
119 | #endif /* __TRACE_PROBE_KERNEL_H_ */ |
120 | |