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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> | |
23 | #include <linux/slab.h> | |
24 | #include <linux/net.h> | |
25 | #include <linux/in6.h> | |
26 | #include <asm/uaccess.h> | |
27 | #include <asm/byteorder.h> | |
28 | #include <net/checksum.h> | |
29 | #include <net/sock.h> | |
30 | ||
31 | /* | |
32 | * Verify iovec. The caller must ensure that the iovec is big enough | |
33 | * to hold the message iovec. | |
34 | * | |
e49332bd | 35 | * Save time not doing access_ok. copy_*_user will make this work |
1da177e4 LT |
36 | * in any case. |
37 | */ | |
38 | ||
230b1839 | 39 | int verify_iovec(struct msghdr *m, struct iovec *iov, struct sockaddr *address, int mode) |
1da177e4 LT |
40 | { |
41 | int size, err, ct; | |
4ec93edb | 42 | |
1da177e4 LT |
43 | if (m->msg_namelen) { |
44 | if (mode == VERIFY_READ) { | |
45 | err = move_addr_to_kernel(m->msg_name, m->msg_namelen, | |
46 | address); | |
47 | if (err < 0) | |
48 | return err; | |
49 | } | |
50 | m->msg_name = address; | |
51 | } else { | |
52 | m->msg_name = NULL; | |
53 | } | |
54 | ||
55 | size = m->msg_iovlen * sizeof(struct iovec); | |
56 | if (copy_from_user(iov, m->msg_iov, size)) | |
57 | return -EFAULT; | |
58 | ||
59 | m->msg_iov = iov; | |
60 | err = 0; | |
61 | ||
62 | for (ct = 0; ct < m->msg_iovlen; ct++) { | |
63 | err += iov[ct].iov_len; | |
64 | /* | |
65 | * Goal is not to verify user data, but to prevent returning | |
66 | * negative value, which is interpreted as errno. | |
67 | * Overflow is still possible, but it is harmless. | |
68 | */ | |
69 | if (err < 0) | |
70 | return -EMSGSIZE; | |
71 | } | |
72 | ||
73 | return err; | |
74 | } | |
75 | ||
76 | /* | |
77 | * Copy kernel to iovec. Returns -EFAULT on error. | |
78 | * | |
79 | * Note: this modifies the original iovec. | |
80 | */ | |
4ec93edb | 81 | |
1da177e4 LT |
82 | int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len) |
83 | { | |
84 | while (len > 0) { | |
85 | if (iov->iov_len) { | |
86 | int copy = min_t(unsigned int, iov->iov_len, len); | |
87 | if (copy_to_user(iov->iov_base, kdata, copy)) | |
88 | return -EFAULT; | |
89 | kdata += copy; | |
90 | len -= copy; | |
91 | iov->iov_len -= copy; | |
92 | iov->iov_base += copy; | |
93 | } | |
94 | iov++; | |
95 | } | |
96 | ||
97 | return 0; | |
98 | } | |
99 | ||
0a1ec07a MT |
100 | /* |
101 | * Copy kernel to iovec. Returns -EFAULT on error. | |
102 | */ | |
103 | ||
104 | int memcpy_toiovecend(const struct iovec *iov, unsigned char *kdata, | |
105 | int offset, int len) | |
106 | { | |
107 | int copy; | |
108 | for (; len > 0; ++iov) { | |
109 | /* Skip over the finished iovecs */ | |
110 | if (unlikely(offset >= iov->iov_len)) { | |
111 | offset -= iov->iov_len; | |
112 | continue; | |
113 | } | |
114 | copy = min_t(unsigned int, iov->iov_len - offset, len); | |
115 | offset = 0; | |
116 | if (copy_to_user(iov->iov_base, kdata, copy)) | |
117 | return -EFAULT; | |
118 | kdata += copy; | |
119 | len -= copy; | |
120 | } | |
121 | ||
122 | return 0; | |
123 | } | |
124 | ||
1da177e4 LT |
125 | /* |
126 | * Copy iovec to kernel. Returns -EFAULT on error. | |
127 | * | |
128 | * Note: this modifies the original iovec. | |
129 | */ | |
4ec93edb | 130 | |
1da177e4 LT |
131 | int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len) |
132 | { | |
133 | while (len > 0) { | |
134 | if (iov->iov_len) { | |
135 | int copy = min_t(unsigned int, len, iov->iov_len); | |
136 | if (copy_from_user(kdata, iov->iov_base, copy)) | |
137 | return -EFAULT; | |
138 | len -= copy; | |
139 | kdata += copy; | |
140 | iov->iov_base += copy; | |
141 | iov->iov_len -= copy; | |
142 | } | |
143 | iov++; | |
144 | } | |
145 | ||
146 | return 0; | |
147 | } | |
148 | ||
149 | /* | |
150 | * For use with ip_build_xmit | |
151 | */ | |
152 | int memcpy_fromiovecend(unsigned char *kdata, struct iovec *iov, int offset, | |
153 | int len) | |
154 | { | |
155 | /* Skip over the finished iovecs */ | |
156 | while (offset >= iov->iov_len) { | |
157 | offset -= iov->iov_len; | |
158 | iov++; | |
159 | } | |
160 | ||
161 | while (len > 0) { | |
162 | u8 __user *base = iov->iov_base + offset; | |
163 | int copy = min_t(unsigned int, len, iov->iov_len - offset); | |
164 | ||
165 | offset = 0; | |
166 | if (copy_from_user(kdata, base, copy)) | |
167 | return -EFAULT; | |
168 | len -= copy; | |
169 | kdata += copy; | |
170 | iov++; | |
171 | } | |
172 | ||
173 | return 0; | |
174 | } | |
175 | ||
176 | /* | |
177 | * And now for the all-in-one: copy and checksum from a user iovec | |
178 | * directly to a datagram | |
179 | * Calls to csum_partial but the last must be in 32 bit chunks | |
180 | * | |
181 | * ip_build_xmit must ensure that when fragmenting only the last | |
182 | * call to this function will be unaligned also. | |
183 | */ | |
184 | int csum_partial_copy_fromiovecend(unsigned char *kdata, struct iovec *iov, | |
44bb9363 | 185 | int offset, unsigned int len, __wsum *csump) |
1da177e4 | 186 | { |
44bb9363 | 187 | __wsum csum = *csump; |
1da177e4 LT |
188 | int partial_cnt = 0, err = 0; |
189 | ||
190 | /* Skip over the finished iovecs */ | |
191 | while (offset >= iov->iov_len) { | |
192 | offset -= iov->iov_len; | |
193 | iov++; | |
194 | } | |
195 | ||
196 | while (len > 0) { | |
197 | u8 __user *base = iov->iov_base + offset; | |
198 | int copy = min_t(unsigned int, len, iov->iov_len - offset); | |
199 | ||
200 | offset = 0; | |
201 | ||
202 | /* There is a remnant from previous iov. */ | |
203 | if (partial_cnt) { | |
204 | int par_len = 4 - partial_cnt; | |
205 | ||
206 | /* iov component is too short ... */ | |
207 | if (par_len > copy) { | |
208 | if (copy_from_user(kdata, base, copy)) | |
209 | goto out_fault; | |
210 | kdata += copy; | |
211 | base += copy; | |
212 | partial_cnt += copy; | |
213 | len -= copy; | |
214 | iov++; | |
215 | if (len) | |
216 | continue; | |
217 | *csump = csum_partial(kdata - partial_cnt, | |
218 | partial_cnt, csum); | |
219 | goto out; | |
220 | } | |
221 | if (copy_from_user(kdata, base, par_len)) | |
222 | goto out_fault; | |
223 | csum = csum_partial(kdata - partial_cnt, 4, csum); | |
224 | kdata += par_len; | |
225 | base += par_len; | |
226 | copy -= par_len; | |
227 | len -= par_len; | |
228 | partial_cnt = 0; | |
229 | } | |
230 | ||
231 | if (len > copy) { | |
232 | partial_cnt = copy % 4; | |
233 | if (partial_cnt) { | |
234 | copy -= partial_cnt; | |
235 | if (copy_from_user(kdata + copy, base + copy, | |
4ec93edb | 236 | partial_cnt)) |
1da177e4 LT |
237 | goto out_fault; |
238 | } | |
239 | } | |
240 | ||
241 | if (copy) { | |
242 | csum = csum_and_copy_from_user(base, kdata, copy, | |
243 | csum, &err); | |
244 | if (err) | |
245 | goto out; | |
246 | } | |
247 | len -= copy + partial_cnt; | |
248 | kdata += copy + partial_cnt; | |
249 | iov++; | |
250 | } | |
4ec93edb | 251 | *csump = csum; |
1da177e4 LT |
252 | out: |
253 | return err; | |
254 | ||
255 | out_fault: | |
256 | err = -EFAULT; | |
257 | goto out; | |
258 | } | |
259 | ||
260 | EXPORT_SYMBOL(csum_partial_copy_fromiovecend); | |
261 | EXPORT_SYMBOL(memcpy_fromiovec); | |
262 | EXPORT_SYMBOL(memcpy_fromiovecend); | |
263 | EXPORT_SYMBOL(memcpy_toiovec); | |
0a1ec07a | 264 | EXPORT_SYMBOL(memcpy_toiovecend); |