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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * iovec manipulation routines. | |
3 | * | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or | |
6 | * modify it under the terms of the GNU General Public License | |
7 | * as published by the Free Software Foundation; either version | |
8 | * 2 of the License, or (at your option) any later version. | |
9 | * | |
10 | * Fixes: | |
11 | * Andrew Lunn : Errors in iovec copying. | |
12 | * Pedro Roque : Added memcpy_fromiovecend and | |
13 | * csum_..._fromiovecend. | |
14 | * Andi Kleen : fixed error handling for 2.1 | |
15 | * Alexey Kuznetsov: 2.1 optimisations | |
16 | * Andi Kleen : Fix csum*fromiovecend for IPv6. | |
17 | */ | |
18 | ||
19 | #include <linux/errno.h> | |
20 | #include <linux/module.h> | |
1da177e4 LT |
21 | #include <linux/kernel.h> |
22 | #include <linux/mm.h> | |
1da177e4 LT |
23 | #include <linux/net.h> |
24 | #include <linux/in6.h> | |
25 | #include <asm/uaccess.h> | |
26 | #include <asm/byteorder.h> | |
27 | #include <net/checksum.h> | |
28 | #include <net/sock.h> | |
29 | ||
30 | /* | |
31 | * Verify iovec. The caller must ensure that the iovec is big enough | |
32 | * to hold the message iovec. | |
33 | * | |
e49332bd | 34 | * Save time not doing access_ok. copy_*_user will make this work |
1da177e4 LT |
35 | * in any case. |
36 | */ | |
37 | ||
01db403c | 38 | long verify_iovec(struct msghdr *m, struct iovec *iov, struct sockaddr *address, int mode) |
1da177e4 | 39 | { |
01db403c DM |
40 | int size, ct; |
41 | long err; | |
4ec93edb | 42 | |
1da177e4 LT |
43 | if (m->msg_namelen) { |
44 | if (mode == VERIFY_READ) { | |
a700d8be NK |
45 | void __user *namep; |
46 | namep = (void __user __force *) m->msg_name; | |
47 | err = move_addr_to_kernel(namep, m->msg_namelen, | |
1da177e4 LT |
48 | address); |
49 | if (err < 0) | |
50 | return err; | |
51 | } | |
52 | m->msg_name = address; | |
53 | } else { | |
54 | m->msg_name = NULL; | |
55 | } | |
56 | ||
57 | size = m->msg_iovlen * sizeof(struct iovec); | |
a700d8be | 58 | if (copy_from_user(iov, (void __user __force *) m->msg_iov, size)) |
1da177e4 LT |
59 | return -EFAULT; |
60 | ||
61 | m->msg_iov = iov; | |
62 | err = 0; | |
63 | ||
64 | for (ct = 0; ct < m->msg_iovlen; ct++) { | |
65 | err += iov[ct].iov_len; | |
66 | /* | |
67 | * Goal is not to verify user data, but to prevent returning | |
68 | * negative value, which is interpreted as errno. | |
69 | * Overflow is still possible, but it is harmless. | |
70 | */ | |
71 | if (err < 0) | |
72 | return -EMSGSIZE; | |
73 | } | |
74 | ||
75 | return err; | |
76 | } | |
77 | ||
78 | /* | |
79 | * Copy kernel to iovec. Returns -EFAULT on error. | |
80 | * | |
81 | * Note: this modifies the original iovec. | |
82 | */ | |
4ec93edb | 83 | |
1da177e4 LT |
84 | int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len) |
85 | { | |
86 | while (len > 0) { | |
87 | if (iov->iov_len) { | |
88 | int copy = min_t(unsigned int, iov->iov_len, len); | |
89 | if (copy_to_user(iov->iov_base, kdata, copy)) | |
90 | return -EFAULT; | |
91 | kdata += copy; | |
92 | len -= copy; | |
93 | iov->iov_len -= copy; | |
94 | iov->iov_base += copy; | |
95 | } | |
96 | iov++; | |
97 | } | |
98 | ||
99 | return 0; | |
100 | } | |
9e34a5b5 | 101 | EXPORT_SYMBOL(memcpy_toiovec); |
1da177e4 | 102 | |
0a1ec07a MT |
103 | /* |
104 | * Copy kernel to iovec. Returns -EFAULT on error. | |
105 | */ | |
106 | ||
107 | int memcpy_toiovecend(const struct iovec *iov, unsigned char *kdata, | |
108 | int offset, int len) | |
109 | { | |
110 | int copy; | |
111 | for (; len > 0; ++iov) { | |
112 | /* Skip over the finished iovecs */ | |
113 | if (unlikely(offset >= iov->iov_len)) { | |
114 | offset -= iov->iov_len; | |
115 | continue; | |
116 | } | |
117 | copy = min_t(unsigned int, iov->iov_len - offset, len); | |
2faef52b | 118 | if (copy_to_user(iov->iov_base + offset, kdata, copy)) |
0a1ec07a | 119 | return -EFAULT; |
2faef52b | 120 | offset = 0; |
0a1ec07a MT |
121 | kdata += copy; |
122 | len -= copy; | |
123 | } | |
124 | ||
125 | return 0; | |
126 | } | |
9e34a5b5 | 127 | EXPORT_SYMBOL(memcpy_toiovecend); |
0a1ec07a | 128 | |
1da177e4 LT |
129 | /* |
130 | * Copy iovec to kernel. Returns -EFAULT on error. | |
131 | * | |
132 | * Note: this modifies the original iovec. | |
133 | */ | |
4ec93edb | 134 | |
1da177e4 LT |
135 | int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len) |
136 | { | |
137 | while (len > 0) { | |
138 | if (iov->iov_len) { | |
139 | int copy = min_t(unsigned int, len, iov->iov_len); | |
140 | if (copy_from_user(kdata, iov->iov_base, copy)) | |
141 | return -EFAULT; | |
142 | len -= copy; | |
143 | kdata += copy; | |
144 | iov->iov_base += copy; | |
145 | iov->iov_len -= copy; | |
146 | } | |
147 | iov++; | |
148 | } | |
149 | ||
150 | return 0; | |
151 | } | |
9e34a5b5 | 152 | EXPORT_SYMBOL(memcpy_fromiovec); |
1da177e4 LT |
153 | |
154 | /* | |
6f26c9a7 | 155 | * Copy iovec from kernel. Returns -EFAULT on error. |
1da177e4 | 156 | */ |
6f26c9a7 MT |
157 | |
158 | int memcpy_fromiovecend(unsigned char *kdata, const struct iovec *iov, | |
159 | int offset, int len) | |
1da177e4 LT |
160 | { |
161 | /* Skip over the finished iovecs */ | |
162 | while (offset >= iov->iov_len) { | |
163 | offset -= iov->iov_len; | |
164 | iov++; | |
165 | } | |
166 | ||
167 | while (len > 0) { | |
168 | u8 __user *base = iov->iov_base + offset; | |
169 | int copy = min_t(unsigned int, len, iov->iov_len - offset); | |
170 | ||
171 | offset = 0; | |
172 | if (copy_from_user(kdata, base, copy)) | |
173 | return -EFAULT; | |
174 | len -= copy; | |
175 | kdata += copy; | |
176 | iov++; | |
177 | } | |
178 | ||
179 | return 0; | |
180 | } | |
9e34a5b5 | 181 | EXPORT_SYMBOL(memcpy_fromiovecend); |
1da177e4 LT |
182 | |
183 | /* | |
184 | * And now for the all-in-one: copy and checksum from a user iovec | |
185 | * directly to a datagram | |
186 | * Calls to csum_partial but the last must be in 32 bit chunks | |
187 | * | |
188 | * ip_build_xmit must ensure that when fragmenting only the last | |
189 | * call to this function will be unaligned also. | |
190 | */ | |
191 | int csum_partial_copy_fromiovecend(unsigned char *kdata, struct iovec *iov, | |
44bb9363 | 192 | int offset, unsigned int len, __wsum *csump) |
1da177e4 | 193 | { |
44bb9363 | 194 | __wsum csum = *csump; |
1da177e4 LT |
195 | int partial_cnt = 0, err = 0; |
196 | ||
197 | /* Skip over the finished iovecs */ | |
198 | while (offset >= iov->iov_len) { | |
199 | offset -= iov->iov_len; | |
200 | iov++; | |
201 | } | |
202 | ||
203 | while (len > 0) { | |
204 | u8 __user *base = iov->iov_base + offset; | |
205 | int copy = min_t(unsigned int, len, iov->iov_len - offset); | |
206 | ||
207 | offset = 0; | |
208 | ||
209 | /* There is a remnant from previous iov. */ | |
210 | if (partial_cnt) { | |
211 | int par_len = 4 - partial_cnt; | |
212 | ||
213 | /* iov component is too short ... */ | |
214 | if (par_len > copy) { | |
215 | if (copy_from_user(kdata, base, copy)) | |
216 | goto out_fault; | |
217 | kdata += copy; | |
218 | base += copy; | |
219 | partial_cnt += copy; | |
220 | len -= copy; | |
221 | iov++; | |
222 | if (len) | |
223 | continue; | |
224 | *csump = csum_partial(kdata - partial_cnt, | |
225 | partial_cnt, csum); | |
226 | goto out; | |
227 | } | |
228 | if (copy_from_user(kdata, base, par_len)) | |
229 | goto out_fault; | |
230 | csum = csum_partial(kdata - partial_cnt, 4, csum); | |
231 | kdata += par_len; | |
232 | base += par_len; | |
233 | copy -= par_len; | |
234 | len -= par_len; | |
235 | partial_cnt = 0; | |
236 | } | |
237 | ||
238 | if (len > copy) { | |
239 | partial_cnt = copy % 4; | |
240 | if (partial_cnt) { | |
241 | copy -= partial_cnt; | |
242 | if (copy_from_user(kdata + copy, base + copy, | |
4ec93edb | 243 | partial_cnt)) |
1da177e4 LT |
244 | goto out_fault; |
245 | } | |
246 | } | |
247 | ||
248 | if (copy) { | |
249 | csum = csum_and_copy_from_user(base, kdata, copy, | |
250 | csum, &err); | |
251 | if (err) | |
252 | goto out; | |
253 | } | |
254 | len -= copy + partial_cnt; | |
255 | kdata += copy + partial_cnt; | |
256 | iov++; | |
257 | } | |
4ec93edb | 258 | *csump = csum; |
1da177e4 LT |
259 | out: |
260 | return err; | |
261 | ||
262 | out_fault: | |
263 | err = -EFAULT; | |
264 | goto out; | |
265 | } | |
1da177e4 | 266 | EXPORT_SYMBOL(csum_partial_copy_fromiovecend); |