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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 */
5
6#include <linux/err.h>
7#include <linux/highmem.h>
8#include <linux/mm.h>
9#include <linux/module.h>
10#include <linux/sched.h>
11#include <asm/current.h>
12#include <asm/page.h>
13#include <kern_util.h>
14#include <os.h>
15
16pte_t *virt_to_pte(struct mm_struct *mm, unsigned long addr)
17{
18 pgd_t *pgd;
19 p4d_t *p4d;
20 pud_t *pud;
21 pmd_t *pmd;
22
23 if (mm == NULL)
24 return NULL;
25
26 pgd = pgd_offset(mm, addr);
27 if (!pgd_present(*pgd))
28 return NULL;
29
30 p4d = p4d_offset(pgd, addr);
31 if (!p4d_present(*p4d))
32 return NULL;
33
34 pud = pud_offset(p4d, addr);
35 if (!pud_present(*pud))
36 return NULL;
37
38 pmd = pmd_offset(pud, addr);
39 if (!pmd_present(*pmd))
40 return NULL;
41
42 return pte_offset_kernel(pmd, addr);
43}
44
45static pte_t *maybe_map(unsigned long virt, int is_write)
46{
47 pte_t *pte = virt_to_pte(current->mm, virt);
48 int err, dummy_code;
49
50 if ((pte == NULL) || !pte_present(*pte) ||
51 (is_write && !pte_write(*pte))) {
52 err = handle_page_fault(virt, 0, is_write, 1, &dummy_code);
53 if (err)
54 return NULL;
55 pte = virt_to_pte(current->mm, virt);
56 }
57 if (!pte_present(*pte))
58 pte = NULL;
59
60 return pte;
61}
62
63static int do_op_one_page(unsigned long addr, int len, int is_write,
64 int (*op)(unsigned long addr, int len, void *arg), void *arg)
65{
66 struct page *page;
67 pte_t *pte;
68 int n;
69
70 pte = maybe_map(addr, is_write);
71 if (pte == NULL)
72 return -1;
73
74 page = pte_page(*pte);
75#ifdef CONFIG_64BIT
76 pagefault_disable();
77 addr = (unsigned long) page_address(page) +
78 (addr & ~PAGE_MASK);
79#else
80 addr = (unsigned long) kmap_atomic(page) +
81 (addr & ~PAGE_MASK);
82#endif
83 n = (*op)(addr, len, arg);
84
85#ifdef CONFIG_64BIT
86 pagefault_enable();
87#else
88 kunmap_atomic((void *)addr);
89#endif
90
91 return n;
92}
93
94static long buffer_op(unsigned long addr, int len, int is_write,
95 int (*op)(unsigned long, int, void *), void *arg)
96{
97 long size, remain, n;
98
99 size = min(PAGE_ALIGN(addr) - addr, (unsigned long) len);
100 remain = len;
101
102 n = do_op_one_page(addr, size, is_write, op, arg);
103 if (n != 0) {
104 remain = (n < 0 ? remain : 0);
105 goto out;
106 }
107
108 addr += size;
109 remain -= size;
110 if (remain == 0)
111 goto out;
112
113 while (addr < ((addr + remain) & PAGE_MASK)) {
114 n = do_op_one_page(addr, PAGE_SIZE, is_write, op, arg);
115 if (n != 0) {
116 remain = (n < 0 ? remain : 0);
117 goto out;
118 }
119
120 addr += PAGE_SIZE;
121 remain -= PAGE_SIZE;
122 }
123 if (remain == 0)
124 goto out;
125
126 n = do_op_one_page(addr, remain, is_write, op, arg);
127 if (n != 0) {
128 remain = (n < 0 ? remain : 0);
129 goto out;
130 }
131
132 return 0;
133 out:
134 return remain;
135}
136
137static int copy_chunk_from_user(unsigned long from, int len, void *arg)
138{
139 unsigned long *to_ptr = arg, to = *to_ptr;
140
141 memcpy((void *) to, (void *) from, len);
142 *to_ptr += len;
143 return 0;
144}
145
146unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n)
147{
148 if (uaccess_kernel()) {
149 memcpy(to, (__force void*)from, n);
150 return 0;
151 }
152
153 return buffer_op((unsigned long) from, n, 0, copy_chunk_from_user, &to);
154}
155EXPORT_SYMBOL(raw_copy_from_user);
156
157static int copy_chunk_to_user(unsigned long to, int len, void *arg)
158{
159 unsigned long *from_ptr = arg, from = *from_ptr;
160
161 memcpy((void *) to, (void *) from, len);
162 *from_ptr += len;
163 return 0;
164}
165
166unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n)
167{
168 if (uaccess_kernel()) {
169 memcpy((__force void *) to, from, n);
170 return 0;
171 }
172
173 return buffer_op((unsigned long) to, n, 1, copy_chunk_to_user, &from);
174}
175EXPORT_SYMBOL(raw_copy_to_user);
176
177static int strncpy_chunk_from_user(unsigned long from, int len, void *arg)
178{
179 char **to_ptr = arg, *to = *to_ptr;
180 int n;
181
182 strncpy(to, (void *) from, len);
183 n = strnlen(to, len);
184 *to_ptr += n;
185
186 if (n < len)
187 return 1;
188 return 0;
189}
190
191long __strncpy_from_user(char *dst, const char __user *src, long count)
192{
193 long n;
194 char *ptr = dst;
195
196 if (uaccess_kernel()) {
197 strncpy(dst, (__force void *) src, count);
198 return strnlen(dst, count);
199 }
200
201 n = buffer_op((unsigned long) src, count, 0, strncpy_chunk_from_user,
202 &ptr);
203 if (n != 0)
204 return -EFAULT;
205 return strnlen(dst, count);
206}
207EXPORT_SYMBOL(__strncpy_from_user);
208
209static int clear_chunk(unsigned long addr, int len, void *unused)
210{
211 memset((void *) addr, 0, len);
212 return 0;
213}
214
215unsigned long __clear_user(void __user *mem, unsigned long len)
216{
217 if (uaccess_kernel()) {
218 memset((__force void*)mem, 0, len);
219 return 0;
220 }
221
222 return buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL);
223}
224EXPORT_SYMBOL(__clear_user);
225
226static int strnlen_chunk(unsigned long str, int len, void *arg)
227{
228 int *len_ptr = arg, n;
229
230 n = strnlen((void *) str, len);
231 *len_ptr += n;
232
233 if (n < len)
234 return 1;
235 return 0;
236}
237
238long __strnlen_user(const void __user *str, long len)
239{
240 int count = 0, n;
241
242 if (uaccess_kernel())
243 return strnlen((__force char*)str, len) + 1;
244
245 n = buffer_op((unsigned long) str, len, 0, strnlen_chunk, &count);
246 if (n == 0)
247 return count + 1;
248 return 0;
249}
250EXPORT_SYMBOL(__strnlen_user);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 */
5
6#include <linux/err.h>
7#include <linux/highmem.h>
8#include <linux/mm.h>
9#include <linux/module.h>
10#include <linux/sched.h>
11#include <asm/current.h>
12#include <asm/page.h>
13#include <asm/pgtable.h>
14#include <kern_util.h>
15#include <os.h>
16
17pte_t *virt_to_pte(struct mm_struct *mm, unsigned long addr)
18{
19 pgd_t *pgd;
20 pud_t *pud;
21 pmd_t *pmd;
22
23 if (mm == NULL)
24 return NULL;
25
26 pgd = pgd_offset(mm, addr);
27 if (!pgd_present(*pgd))
28 return NULL;
29
30 pud = pud_offset(pgd, addr);
31 if (!pud_present(*pud))
32 return NULL;
33
34 pmd = pmd_offset(pud, addr);
35 if (!pmd_present(*pmd))
36 return NULL;
37
38 return pte_offset_kernel(pmd, addr);
39}
40
41static pte_t *maybe_map(unsigned long virt, int is_write)
42{
43 pte_t *pte = virt_to_pte(current->mm, virt);
44 int err, dummy_code;
45
46 if ((pte == NULL) || !pte_present(*pte) ||
47 (is_write && !pte_write(*pte))) {
48 err = handle_page_fault(virt, 0, is_write, 1, &dummy_code);
49 if (err)
50 return NULL;
51 pte = virt_to_pte(current->mm, virt);
52 }
53 if (!pte_present(*pte))
54 pte = NULL;
55
56 return pte;
57}
58
59static int do_op_one_page(unsigned long addr, int len, int is_write,
60 int (*op)(unsigned long addr, int len, void *arg), void *arg)
61{
62 struct page *page;
63 pte_t *pte;
64 int n;
65
66 pte = maybe_map(addr, is_write);
67 if (pte == NULL)
68 return -1;
69
70 page = pte_page(*pte);
71#ifdef CONFIG_64BIT
72 pagefault_disable();
73 addr = (unsigned long) page_address(page) +
74 (addr & ~PAGE_MASK);
75#else
76 addr = (unsigned long) kmap_atomic(page) +
77 (addr & ~PAGE_MASK);
78#endif
79 n = (*op)(addr, len, arg);
80
81#ifdef CONFIG_64BIT
82 pagefault_enable();
83#else
84 kunmap_atomic((void *)addr);
85#endif
86
87 return n;
88}
89
90static long buffer_op(unsigned long addr, int len, int is_write,
91 int (*op)(unsigned long, int, void *), void *arg)
92{
93 long size, remain, n;
94
95 size = min(PAGE_ALIGN(addr) - addr, (unsigned long) len);
96 remain = len;
97
98 n = do_op_one_page(addr, size, is_write, op, arg);
99 if (n != 0) {
100 remain = (n < 0 ? remain : 0);
101 goto out;
102 }
103
104 addr += size;
105 remain -= size;
106 if (remain == 0)
107 goto out;
108
109 while (addr < ((addr + remain) & PAGE_MASK)) {
110 n = do_op_one_page(addr, PAGE_SIZE, is_write, op, arg);
111 if (n != 0) {
112 remain = (n < 0 ? remain : 0);
113 goto out;
114 }
115
116 addr += PAGE_SIZE;
117 remain -= PAGE_SIZE;
118 }
119 if (remain == 0)
120 goto out;
121
122 n = do_op_one_page(addr, remain, is_write, op, arg);
123 if (n != 0) {
124 remain = (n < 0 ? remain : 0);
125 goto out;
126 }
127
128 return 0;
129 out:
130 return remain;
131}
132
133static int copy_chunk_from_user(unsigned long from, int len, void *arg)
134{
135 unsigned long *to_ptr = arg, to = *to_ptr;
136
137 memcpy((void *) to, (void *) from, len);
138 *to_ptr += len;
139 return 0;
140}
141
142unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n)
143{
144 if (uaccess_kernel()) {
145 memcpy(to, (__force void*)from, n);
146 return 0;
147 }
148
149 return buffer_op((unsigned long) from, n, 0, copy_chunk_from_user, &to);
150}
151EXPORT_SYMBOL(raw_copy_from_user);
152
153static int copy_chunk_to_user(unsigned long to, int len, void *arg)
154{
155 unsigned long *from_ptr = arg, from = *from_ptr;
156
157 memcpy((void *) to, (void *) from, len);
158 *from_ptr += len;
159 return 0;
160}
161
162unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n)
163{
164 if (uaccess_kernel()) {
165 memcpy((__force void *) to, from, n);
166 return 0;
167 }
168
169 return buffer_op((unsigned long) to, n, 1, copy_chunk_to_user, &from);
170}
171EXPORT_SYMBOL(raw_copy_to_user);
172
173static int strncpy_chunk_from_user(unsigned long from, int len, void *arg)
174{
175 char **to_ptr = arg, *to = *to_ptr;
176 int n;
177
178 strncpy(to, (void *) from, len);
179 n = strnlen(to, len);
180 *to_ptr += n;
181
182 if (n < len)
183 return 1;
184 return 0;
185}
186
187long __strncpy_from_user(char *dst, const char __user *src, long count)
188{
189 long n;
190 char *ptr = dst;
191
192 if (uaccess_kernel()) {
193 strncpy(dst, (__force void *) src, count);
194 return strnlen(dst, count);
195 }
196
197 n = buffer_op((unsigned long) src, count, 0, strncpy_chunk_from_user,
198 &ptr);
199 if (n != 0)
200 return -EFAULT;
201 return strnlen(dst, count);
202}
203EXPORT_SYMBOL(__strncpy_from_user);
204
205static int clear_chunk(unsigned long addr, int len, void *unused)
206{
207 memset((void *) addr, 0, len);
208 return 0;
209}
210
211unsigned long __clear_user(void __user *mem, unsigned long len)
212{
213 if (uaccess_kernel()) {
214 memset((__force void*)mem, 0, len);
215 return 0;
216 }
217
218 return buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL);
219}
220EXPORT_SYMBOL(__clear_user);
221
222static int strnlen_chunk(unsigned long str, int len, void *arg)
223{
224 int *len_ptr = arg, n;
225
226 n = strnlen((void *) str, len);
227 *len_ptr += n;
228
229 if (n < len)
230 return 1;
231 return 0;
232}
233
234long __strnlen_user(const void __user *str, long len)
235{
236 int count = 0, n;
237
238 if (uaccess_kernel())
239 return strnlen((__force char*)str, len) + 1;
240
241 n = buffer_op((unsigned long) str, len, 0, strnlen_chunk, &count);
242 if (n == 0)
243 return count + 1;
244 return 0;
245}
246EXPORT_SYMBOL(__strnlen_user);