1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __CEPH_DECODE_H
3 #define __CEPH_DECODE_H
4
5 #include <linux/err.h>
6 #include <linux/bug.h>
7 #include <linux/slab.h>
8 #include <linux/time.h>
9 #include <asm/unaligned.h>
10
11 #include <linux/ceph/types.h>
12
13 /*
14 * in all cases,
15 * void **p pointer to position pointer
16 * void *end pointer to end of buffer (last byte + 1)
17 */
18
19 static inline u64 ceph_decode_64(void **p)
20 {
21 u64 v = get_unaligned_le64(*p);
22 *p += sizeof(u64);
23 return v;
24 }
25 static inline u32 ceph_decode_32(void **p)
26 {
27 u32 v = get_unaligned_le32(*p);
28 *p += sizeof(u32);
29 return v;
30 }
31 static inline u16 ceph_decode_16(void **p)
32 {
33 u16 v = get_unaligned_le16(*p);
34 *p += sizeof(u16);
35 return v;
36 }
37 static inline u8 ceph_decode_8(void **p)
38 {
39 u8 v = *(u8 *)*p;
40 (*p)++;
41 return v;
42 }
43 static inline void ceph_decode_copy(void **p, void *pv, size_t n)
44 {
45 memcpy(pv, *p, n);
46 *p += n;
47 }
48
49 /*
50 * bounds check input.
51 */
52 static inline bool ceph_has_room(void **p, void *end, size_t n)
53 {
54 return end >= *p && n <= end - *p;
55 }
56
57 #define ceph_decode_need(p, end, n, bad) \
58 do { \
59 if (!likely(ceph_has_room(p, end, n))) \
60 goto bad; \
61 } while (0)
62
63 #define ceph_decode_64_safe(p, end, v, bad) \
64 do { \
65 ceph_decode_need(p, end, sizeof(u64), bad); \
66 v = ceph_decode_64(p); \
67 } while (0)
68 #define ceph_decode_32_safe(p, end, v, bad) \
69 do { \
70 ceph_decode_need(p, end, sizeof(u32), bad); \
71 v = ceph_decode_32(p); \
72 } while (0)
73 #define ceph_decode_16_safe(p, end, v, bad) \
74 do { \
75 ceph_decode_need(p, end, sizeof(u16), bad); \
76 v = ceph_decode_16(p); \
77 } while (0)
78 #define ceph_decode_8_safe(p, end, v, bad) \
79 do { \
80 ceph_decode_need(p, end, sizeof(u8), bad); \
81 v = ceph_decode_8(p); \
82 } while (0)
83
84 #define ceph_decode_copy_safe(p, end, pv, n, bad) \
85 do { \
86 ceph_decode_need(p, end, n, bad); \
87 ceph_decode_copy(p, pv, n); \
88 } while (0)
89
90 /*
91 * Allocate a buffer big enough to hold the wire-encoded string, and
92 * decode the string into it. The resulting string will always be
93 * terminated with '\0'. If successful, *p will be advanced
94 * past the decoded data. Also, if lenp is not a null pointer, the
95 * length (not including the terminating '\0') will be recorded in
96 * *lenp. Note that a zero-length string is a valid return value.
97 *
98 * Returns a pointer to the newly-allocated string buffer, or a
99 * pointer-coded errno if an error occurs. Neither *p nor *lenp
100 * will have been updated if an error is returned.
101 *
102 * There are two possible failures:
103 * - converting the string would require accessing memory at or
104 * beyond the "end" pointer provided (-ERANGE)
105 * - memory could not be allocated for the result (-ENOMEM)
106 */
107 static inline char *ceph_extract_encoded_string(void **p, void *end,
108 size_t *lenp, gfp_t gfp)
109 {
110 u32 len;
111 void *sp = *p;
112 char *buf;
113
114 ceph_decode_32_safe(&sp, end, len, bad);
115 if (!ceph_has_room(&sp, end, len))
116 goto bad;
117
118 buf = kmalloc(len + 1, gfp);
119 if (!buf)
120 return ERR_PTR(-ENOMEM);
121
122 if (len)
123 memcpy(buf, sp, len);
124 buf[len] = '\0';
125
126 *p = (char *) *p + sizeof (u32) + len;
127 if (lenp)
128 *lenp = (size_t) len;
129
130 return buf;
131
132 bad:
133 return ERR_PTR(-ERANGE);
134 }
135
136 /*
137 * skip helpers
138 */
139 #define ceph_decode_skip_n(p, end, n, bad) \
140 do { \
141 ceph_decode_need(p, end, n, bad); \
142 *p += n; \
143 } while (0)
144
145 #define ceph_decode_skip_64(p, end, bad) \
146 ceph_decode_skip_n(p, end, sizeof(u64), bad)
147
148 #define ceph_decode_skip_32(p, end, bad) \
149 ceph_decode_skip_n(p, end, sizeof(u32), bad)
150
151 #define ceph_decode_skip_16(p, end, bad) \
152 ceph_decode_skip_n(p, end, sizeof(u16), bad)
153
154 #define ceph_decode_skip_8(p, end, bad) \
155 ceph_decode_skip_n(p, end, sizeof(u8), bad)
156
157 #define ceph_decode_skip_string(p, end, bad) \
158 do { \
159 u32 len; \
160 \
161 ceph_decode_32_safe(p, end, len, bad); \
162 ceph_decode_skip_n(p, end, len, bad); \
163 } while (0)
164
165 #define ceph_decode_skip_set(p, end, type, bad) \
166 do { \
167 u32 len; \
168 \
169 ceph_decode_32_safe(p, end, len, bad); \
170 while (len--) \
171 ceph_decode_skip_##type(p, end, bad); \
172 } while (0)
173
174 #define ceph_decode_skip_map(p, end, ktype, vtype, bad) \
175 do { \
176 u32 len; \
177 \
178 ceph_decode_32_safe(p, end, len, bad); \
179 while (len--) { \
180 ceph_decode_skip_##ktype(p, end, bad); \
181 ceph_decode_skip_##vtype(p, end, bad); \
182 } \
183 } while (0)
184
185 #define ceph_decode_skip_map_of_map(p, end, ktype1, ktype2, vtype2, bad) \
186 do { \
187 u32 len; \
188 \
189 ceph_decode_32_safe(p, end, len, bad); \
190 while (len--) { \
191 ceph_decode_skip_##ktype1(p, end, bad); \
192 ceph_decode_skip_map(p, end, ktype2, vtype2, bad); \
193 } \
194 } while (0)
195
196 /*
197 * struct ceph_timespec <-> struct timespec64
198 */
199 static inline void ceph_decode_timespec64(struct timespec64 *ts,
200 const struct ceph_timespec *tv)
201 {
202 /*
203 * This will still overflow in year 2106. We could extend
204 * the protocol to steal two more bits from tv_nsec to
205 * add three more 136 year epochs after that the way ext4
206 * does if necessary.
207 */
208 ts->tv_sec = (time64_t)le32_to_cpu(tv->tv_sec);
209 ts->tv_nsec = (long)le32_to_cpu(tv->tv_nsec);
210 }
211 static inline void ceph_encode_timespec64(struct ceph_timespec *tv,
212 const struct timespec64 *ts)
213 {
214 tv->tv_sec = cpu_to_le32((u32)ts->tv_sec);
215 tv->tv_nsec = cpu_to_le32((u32)ts->tv_nsec);
216 }
217
218 /*
219 * sockaddr_storage <-> ceph_sockaddr
220 */
221 #define CEPH_ENTITY_ADDR_TYPE_NONE 0
222 #define CEPH_ENTITY_ADDR_TYPE_LEGACY __cpu_to_le32(1)
223 #define CEPH_ENTITY_ADDR_TYPE_MSGR2 __cpu_to_le32(2)
224 #define CEPH_ENTITY_ADDR_TYPE_ANY __cpu_to_le32(3)
225
226 static inline void ceph_encode_banner_addr(struct ceph_entity_addr *a)
227 {
228 __be16 ss_family = htons(a->in_addr.ss_family);
229 a->in_addr.ss_family = *(__u16 *)&ss_family;
230
231 /* Banner addresses require TYPE_NONE */
232 a->type = CEPH_ENTITY_ADDR_TYPE_NONE;
233 }
234 static inline void ceph_decode_banner_addr(struct ceph_entity_addr *a)
235 {
236 __be16 ss_family = *(__be16 *)&a->in_addr.ss_family;
237 a->in_addr.ss_family = ntohs(ss_family);
238 WARN_ON(a->in_addr.ss_family == 512);
239 a->type = CEPH_ENTITY_ADDR_TYPE_LEGACY;
240 }
241
242 extern int ceph_decode_entity_addr(void **p, void *end,
243 struct ceph_entity_addr *addr);
244 int ceph_decode_entity_addrvec(void **p, void *end, bool msgr2,
245 struct ceph_entity_addr *addr);
246
247 int ceph_entity_addr_encoding_len(const struct ceph_entity_addr *addr);
248 void ceph_encode_entity_addr(void **p, const struct ceph_entity_addr *addr);
249
250 /*
251 * encoders
252 */
253 static inline void ceph_encode_64(void **p, u64 v)
254 {
255 put_unaligned_le64(v, (__le64 *)*p);
256 *p += sizeof(u64);
257 }
258 static inline void ceph_encode_32(void **p, u32 v)
259 {
260 put_unaligned_le32(v, (__le32 *)*p);
261 *p += sizeof(u32);
262 }
263 static inline void ceph_encode_16(void **p, u16 v)
264 {
265 put_unaligned_le16(v, (__le16 *)*p);
266 *p += sizeof(u16);
267 }
268 static inline void ceph_encode_8(void **p, u8 v)
269 {
270 *(u8 *)*p = v;
271 (*p)++;
272 }
273 static inline void ceph_encode_copy(void **p, const void *s, int len)
274 {
275 memcpy(*p, s, len);
276 *p += len;
277 }
278
279 /*
280 * filepath, string encoders
281 */
282 static inline void ceph_encode_filepath(void **p, void *end,
283 u64 ino, const char *path)
284 {
285 u32 len = path ? strlen(path) : 0;
286 BUG_ON(*p + 1 + sizeof(ino) + sizeof(len) + len > end);
287 ceph_encode_8(p, 1);
288 ceph_encode_64(p, ino);
289 ceph_encode_32(p, len);
290 if (len)
291 memcpy(*p, path, len);
292 *p += len;
293 }
294
295 static inline void ceph_encode_string(void **p, void *end,
296 const char *s, u32 len)
297 {
298 BUG_ON(*p + sizeof(len) + len > end);
299 ceph_encode_32(p, len);
300 if (len)
301 memcpy(*p, s, len);
302 *p += len;
303 }
304
305 /*
306 * version and length starting block encoders/decoders
307 */
308
309 /* current code version (u8) + compat code version (u8) + len of struct (u32) */
310 #define CEPH_ENCODING_START_BLK_LEN 6
311
312 /**
313 * ceph_start_encoding - start encoding block
314 * @struct_v: current (code) version of the encoding
315 * @struct_compat: oldest code version that can decode it
316 * @struct_len: length of struct encoding
317 */
318 static inline void ceph_start_encoding(void **p, u8 struct_v, u8 struct_compat,
319 u32 struct_len)
320 {
321 ceph_encode_8(p, struct_v);
322 ceph_encode_8(p, struct_compat);
323 ceph_encode_32(p, struct_len);
324 }
325
326 /**
327 * ceph_start_decoding - start decoding block
328 * @v: current version of the encoding that the code supports
329 * @name: name of the struct (free-form)
330 * @struct_v: out param for the encoding version
331 * @struct_len: out param for the length of struct encoding
332 *
333 * Validates the length of struct encoding, so unsafe ceph_decode_*
334 * variants can be used for decoding.
335 */
336 static inline int ceph_start_decoding(void **p, void *end, u8 v,
337 const char *name, u8 *struct_v,
338 u32 *struct_len)
339 {
340 u8 struct_compat;
341
342 ceph_decode_need(p, end, CEPH_ENCODING_START_BLK_LEN, bad);
343 *struct_v = ceph_decode_8(p);
344 struct_compat = ceph_decode_8(p);
345 if (v < struct_compat) {
346 pr_warn("got struct_v %d struct_compat %d > %d of %s\n",
347 *struct_v, struct_compat, v, name);
348 return -EINVAL;
349 }
350
351 *struct_len = ceph_decode_32(p);
352 ceph_decode_need(p, end, *struct_len, bad);
353 return 0;
354
355 bad:
356 return -ERANGE;
357 }
358
359 #define ceph_encode_need(p, end, n, bad) \
360 do { \
361 if (!likely(ceph_has_room(p, end, n))) \
362 goto bad; \
363 } while (0)
364
365 #define ceph_encode_64_safe(p, end, v, bad) \
366 do { \
367 ceph_encode_need(p, end, sizeof(u64), bad); \
368 ceph_encode_64(p, v); \
369 } while (0)
370 #define ceph_encode_32_safe(p, end, v, bad) \
371 do { \
372 ceph_encode_need(p, end, sizeof(u32), bad); \
373 ceph_encode_32(p, v); \
374 } while (0)
375 #define ceph_encode_16_safe(p, end, v, bad) \
376 do { \
377 ceph_encode_need(p, end, sizeof(u16), bad); \
378 ceph_encode_16(p, v); \
379 } while (0)
380 #define ceph_encode_8_safe(p, end, v, bad) \
381 do { \
382 ceph_encode_need(p, end, sizeof(u8), bad); \
383 ceph_encode_8(p, v); \
384 } while (0)
385
386 #define ceph_encode_copy_safe(p, end, pv, n, bad) \
387 do { \
388 ceph_encode_need(p, end, n, bad); \
389 ceph_encode_copy(p, pv, n); \
390 } while (0)
391 #define ceph_encode_string_safe(p, end, s, n, bad) \
392 do { \
393 ceph_encode_need(p, end, n, bad); \
394 ceph_encode_string(p, end, s, n); \
395 } while (0)
396
397
398 #endif
399
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