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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 | ||
230b1839 | 38 | int verify_iovec(struct msghdr *m, struct iovec *iov, struct sockaddr *address, int mode) |
1da177e4 LT |
39 | { |
40 | int size, err, ct; | |
4ec93edb | 41 | |
1da177e4 LT |
42 | if (m->msg_namelen) { |
43 | if (mode == VERIFY_READ) { | |
a700d8be NK |
44 | void __user *namep; |
45 | namep = (void __user __force *) m->msg_name; | |
46 | err = move_addr_to_kernel(namep, m->msg_namelen, | |
1da177e4 LT |
47 | address); |
48 | if (err < 0) | |
49 | return err; | |
50 | } | |
51 | m->msg_name = address; | |
52 | } else { | |
53 | m->msg_name = NULL; | |
54 | } | |
55 | ||
56 | size = m->msg_iovlen * sizeof(struct iovec); | |
a700d8be | 57 | if (copy_from_user(iov, (void __user __force *) m->msg_iov, size)) |
1da177e4 LT |
58 | return -EFAULT; |
59 | ||
60 | m->msg_iov = iov; | |
61 | err = 0; | |
62 | ||
63 | for (ct = 0; ct < m->msg_iovlen; ct++) { | |
64 | err += iov[ct].iov_len; | |
65 | /* | |
66 | * Goal is not to verify user data, but to prevent returning | |
67 | * negative value, which is interpreted as errno. | |
68 | * Overflow is still possible, but it is harmless. | |
69 | */ | |
70 | if (err < 0) | |
71 | return -EMSGSIZE; | |
72 | } | |
73 | ||
74 | return err; | |
75 | } | |
76 | ||
77 | /* | |
78 | * Copy kernel to iovec. Returns -EFAULT on error. | |
79 | * | |
80 | * Note: this modifies the original iovec. | |
81 | */ | |
4ec93edb | 82 | |
1da177e4 LT |
83 | int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len) |
84 | { | |
85 | while (len > 0) { | |
86 | if (iov->iov_len) { | |
87 | int copy = min_t(unsigned int, iov->iov_len, len); | |
88 | if (copy_to_user(iov->iov_base, kdata, copy)) | |
89 | return -EFAULT; | |
90 | kdata += copy; | |
91 | len -= copy; | |
92 | iov->iov_len -= copy; | |
93 | iov->iov_base += copy; | |
94 | } | |
95 | iov++; | |
96 | } | |
97 | ||
98 | return 0; | |
99 | } | |
9e34a5b5 | 100 | EXPORT_SYMBOL(memcpy_toiovec); |
1da177e4 | 101 | |
0a1ec07a MT |
102 | /* |
103 | * Copy kernel to iovec. Returns -EFAULT on error. | |
104 | */ | |
105 | ||
106 | int memcpy_toiovecend(const struct iovec *iov, unsigned char *kdata, | |
107 | int offset, int len) | |
108 | { | |
109 | int copy; | |
110 | for (; len > 0; ++iov) { | |
111 | /* Skip over the finished iovecs */ | |
112 | if (unlikely(offset >= iov->iov_len)) { | |
113 | offset -= iov->iov_len; | |
114 | continue; | |
115 | } | |
116 | copy = min_t(unsigned int, iov->iov_len - offset, len); | |
2faef52b | 117 | if (copy_to_user(iov->iov_base + offset, kdata, copy)) |
0a1ec07a | 118 | return -EFAULT; |
2faef52b | 119 | offset = 0; |
0a1ec07a MT |
120 | kdata += copy; |
121 | len -= copy; | |
122 | } | |
123 | ||
124 | return 0; | |
125 | } | |
9e34a5b5 | 126 | EXPORT_SYMBOL(memcpy_toiovecend); |
0a1ec07a | 127 | |
1da177e4 LT |
128 | /* |
129 | * Copy iovec to kernel. Returns -EFAULT on error. | |
130 | * | |
131 | * Note: this modifies the original iovec. | |
132 | */ | |
4ec93edb | 133 | |
1da177e4 LT |
134 | int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len) |
135 | { | |
136 | while (len > 0) { | |
137 | if (iov->iov_len) { | |
138 | int copy = min_t(unsigned int, len, iov->iov_len); | |
139 | if (copy_from_user(kdata, iov->iov_base, copy)) | |
140 | return -EFAULT; | |
141 | len -= copy; | |
142 | kdata += copy; | |
143 | iov->iov_base += copy; | |
144 | iov->iov_len -= copy; | |
145 | } | |
146 | iov++; | |
147 | } | |
148 | ||
149 | return 0; | |
150 | } | |
9e34a5b5 | 151 | EXPORT_SYMBOL(memcpy_fromiovec); |
1da177e4 LT |
152 | |
153 | /* | |
6f26c9a7 | 154 | * Copy iovec from kernel. Returns -EFAULT on error. |
1da177e4 | 155 | */ |
6f26c9a7 MT |
156 | |
157 | int memcpy_fromiovecend(unsigned char *kdata, const struct iovec *iov, | |
158 | int offset, int len) | |
1da177e4 LT |
159 | { |
160 | /* Skip over the finished iovecs */ | |
161 | while (offset >= iov->iov_len) { | |
162 | offset -= iov->iov_len; | |
163 | iov++; | |
164 | } | |
165 | ||
166 | while (len > 0) { | |
167 | u8 __user *base = iov->iov_base + offset; | |
168 | int copy = min_t(unsigned int, len, iov->iov_len - offset); | |
169 | ||
170 | offset = 0; | |
171 | if (copy_from_user(kdata, base, copy)) | |
172 | return -EFAULT; | |
173 | len -= copy; | |
174 | kdata += copy; | |
175 | iov++; | |
176 | } | |
177 | ||
178 | return 0; | |
179 | } | |
9e34a5b5 | 180 | EXPORT_SYMBOL(memcpy_fromiovecend); |
1da177e4 LT |
181 | |
182 | /* | |
183 | * And now for the all-in-one: copy and checksum from a user iovec | |
184 | * directly to a datagram | |
185 | * Calls to csum_partial but the last must be in 32 bit chunks | |
186 | * | |
187 | * ip_build_xmit must ensure that when fragmenting only the last | |
188 | * call to this function will be unaligned also. | |
189 | */ | |
190 | int csum_partial_copy_fromiovecend(unsigned char *kdata, struct iovec *iov, | |
44bb9363 | 191 | int offset, unsigned int len, __wsum *csump) |
1da177e4 | 192 | { |
44bb9363 | 193 | __wsum csum = *csump; |
1da177e4 LT |
194 | int partial_cnt = 0, err = 0; |
195 | ||
196 | /* Skip over the finished iovecs */ | |
197 | while (offset >= iov->iov_len) { | |
198 | offset -= iov->iov_len; | |
199 | iov++; | |
200 | } | |
201 | ||
202 | while (len > 0) { | |
203 | u8 __user *base = iov->iov_base + offset; | |
204 | int copy = min_t(unsigned int, len, iov->iov_len - offset); | |
205 | ||
206 | offset = 0; | |
207 | ||
208 | /* There is a remnant from previous iov. */ | |
209 | if (partial_cnt) { | |
210 | int par_len = 4 - partial_cnt; | |
211 | ||
212 | /* iov component is too short ... */ | |
213 | if (par_len > copy) { | |
214 | if (copy_from_user(kdata, base, copy)) | |
215 | goto out_fault; | |
216 | kdata += copy; | |
217 | base += copy; | |
218 | partial_cnt += copy; | |
219 | len -= copy; | |
220 | iov++; | |
221 | if (len) | |
222 | continue; | |
223 | *csump = csum_partial(kdata - partial_cnt, | |
224 | partial_cnt, csum); | |
225 | goto out; | |
226 | } | |
227 | if (copy_from_user(kdata, base, par_len)) | |
228 | goto out_fault; | |
229 | csum = csum_partial(kdata - partial_cnt, 4, csum); | |
230 | kdata += par_len; | |
231 | base += par_len; | |
232 | copy -= par_len; | |
233 | len -= par_len; | |
234 | partial_cnt = 0; | |
235 | } | |
236 | ||
237 | if (len > copy) { | |
238 | partial_cnt = copy % 4; | |
239 | if (partial_cnt) { | |
240 | copy -= partial_cnt; | |
241 | if (copy_from_user(kdata + copy, base + copy, | |
4ec93edb | 242 | partial_cnt)) |
1da177e4 LT |
243 | goto out_fault; |
244 | } | |
245 | } | |
246 | ||
247 | if (copy) { | |
248 | csum = csum_and_copy_from_user(base, kdata, copy, | |
249 | csum, &err); | |
250 | if (err) | |
251 | goto out; | |
252 | } | |
253 | len -= copy + partial_cnt; | |
254 | kdata += copy + partial_cnt; | |
255 | iov++; | |
256 | } | |
4ec93edb | 257 | *csump = csum; |
1da177e4 LT |
258 | out: |
259 | return err; | |
260 | ||
261 | out_fault: | |
262 | err = -EFAULT; | |
263 | goto out; | |
264 | } | |
1da177e4 | 265 | EXPORT_SYMBOL(csum_partial_copy_fromiovecend); |