Commit | Line | Data |
---|---|---|
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> | |
21 | #include <linux/sched.h> | |
22 | #include <linux/kernel.h> | |
23 | #include <linux/mm.h> | |
24 | #include <linux/slab.h> | |
25 | #include <linux/net.h> | |
26 | #include <linux/in6.h> | |
27 | #include <asm/uaccess.h> | |
28 | #include <asm/byteorder.h> | |
29 | #include <net/checksum.h> | |
30 | #include <net/sock.h> | |
31 | ||
32 | /* | |
33 | * Verify iovec. The caller must ensure that the iovec is big enough | |
34 | * to hold the message iovec. | |
35 | * | |
e49332bd | 36 | * Save time not doing access_ok. copy_*_user will make this work |
1da177e4 LT |
37 | * in any case. |
38 | */ | |
39 | ||
40 | int verify_iovec(struct msghdr *m, struct iovec *iov, char *address, int mode) | |
41 | { | |
42 | int size, err, ct; | |
43 | ||
44 | if (m->msg_namelen) { | |
45 | if (mode == VERIFY_READ) { | |
46 | err = move_addr_to_kernel(m->msg_name, m->msg_namelen, | |
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); | |
57 | if (copy_from_user(iov, m->msg_iov, size)) | |
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 | */ | |
82 | ||
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 | } | |
100 | ||
101 | /* | |
102 | * Copy iovec to kernel. Returns -EFAULT on error. | |
103 | * | |
104 | * Note: this modifies the original iovec. | |
105 | */ | |
106 | ||
107 | int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len) | |
108 | { | |
109 | while (len > 0) { | |
110 | if (iov->iov_len) { | |
111 | int copy = min_t(unsigned int, len, iov->iov_len); | |
112 | if (copy_from_user(kdata, iov->iov_base, copy)) | |
113 | return -EFAULT; | |
114 | len -= copy; | |
115 | kdata += copy; | |
116 | iov->iov_base += copy; | |
117 | iov->iov_len -= copy; | |
118 | } | |
119 | iov++; | |
120 | } | |
121 | ||
122 | return 0; | |
123 | } | |
124 | ||
125 | /* | |
126 | * For use with ip_build_xmit | |
127 | */ | |
128 | int memcpy_fromiovecend(unsigned char *kdata, struct iovec *iov, int offset, | |
129 | int len) | |
130 | { | |
131 | /* Skip over the finished iovecs */ | |
132 | while (offset >= iov->iov_len) { | |
133 | offset -= iov->iov_len; | |
134 | iov++; | |
135 | } | |
136 | ||
137 | while (len > 0) { | |
138 | u8 __user *base = iov->iov_base + offset; | |
139 | int copy = min_t(unsigned int, len, iov->iov_len - offset); | |
140 | ||
141 | offset = 0; | |
142 | if (copy_from_user(kdata, base, copy)) | |
143 | return -EFAULT; | |
144 | len -= copy; | |
145 | kdata += copy; | |
146 | iov++; | |
147 | } | |
148 | ||
149 | return 0; | |
150 | } | |
151 | ||
152 | /* | |
153 | * And now for the all-in-one: copy and checksum from a user iovec | |
154 | * directly to a datagram | |
155 | * Calls to csum_partial but the last must be in 32 bit chunks | |
156 | * | |
157 | * ip_build_xmit must ensure that when fragmenting only the last | |
158 | * call to this function will be unaligned also. | |
159 | */ | |
160 | int csum_partial_copy_fromiovecend(unsigned char *kdata, struct iovec *iov, | |
44bb9363 | 161 | int offset, unsigned int len, __wsum *csump) |
1da177e4 | 162 | { |
44bb9363 | 163 | __wsum csum = *csump; |
1da177e4 LT |
164 | int partial_cnt = 0, err = 0; |
165 | ||
166 | /* Skip over the finished iovecs */ | |
167 | while (offset >= iov->iov_len) { | |
168 | offset -= iov->iov_len; | |
169 | iov++; | |
170 | } | |
171 | ||
172 | while (len > 0) { | |
173 | u8 __user *base = iov->iov_base + offset; | |
174 | int copy = min_t(unsigned int, len, iov->iov_len - offset); | |
175 | ||
176 | offset = 0; | |
177 | ||
178 | /* There is a remnant from previous iov. */ | |
179 | if (partial_cnt) { | |
180 | int par_len = 4 - partial_cnt; | |
181 | ||
182 | /* iov component is too short ... */ | |
183 | if (par_len > copy) { | |
184 | if (copy_from_user(kdata, base, copy)) | |
185 | goto out_fault; | |
186 | kdata += copy; | |
187 | base += copy; | |
188 | partial_cnt += copy; | |
189 | len -= copy; | |
190 | iov++; | |
191 | if (len) | |
192 | continue; | |
193 | *csump = csum_partial(kdata - partial_cnt, | |
194 | partial_cnt, csum); | |
195 | goto out; | |
196 | } | |
197 | if (copy_from_user(kdata, base, par_len)) | |
198 | goto out_fault; | |
199 | csum = csum_partial(kdata - partial_cnt, 4, csum); | |
200 | kdata += par_len; | |
201 | base += par_len; | |
202 | copy -= par_len; | |
203 | len -= par_len; | |
204 | partial_cnt = 0; | |
205 | } | |
206 | ||
207 | if (len > copy) { | |
208 | partial_cnt = copy % 4; | |
209 | if (partial_cnt) { | |
210 | copy -= partial_cnt; | |
211 | if (copy_from_user(kdata + copy, base + copy, | |
212 | partial_cnt)) | |
213 | goto out_fault; | |
214 | } | |
215 | } | |
216 | ||
217 | if (copy) { | |
218 | csum = csum_and_copy_from_user(base, kdata, copy, | |
219 | csum, &err); | |
220 | if (err) | |
221 | goto out; | |
222 | } | |
223 | len -= copy + partial_cnt; | |
224 | kdata += copy + partial_cnt; | |
225 | iov++; | |
226 | } | |
227 | *csump = csum; | |
228 | out: | |
229 | return err; | |
230 | ||
231 | out_fault: | |
232 | err = -EFAULT; | |
233 | goto out; | |
234 | } | |
235 | ||
236 | EXPORT_SYMBOL(csum_partial_copy_fromiovecend); | |
237 | EXPORT_SYMBOL(memcpy_fromiovec); | |
238 | EXPORT_SYMBOL(memcpy_fromiovecend); | |
239 | EXPORT_SYMBOL(memcpy_toiovec); |