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
ceph_decode_64(void ** p)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 }
ceph_decode_32(void ** p)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 }
ceph_decode_16(void ** p)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 }
ceph_decode_8(void ** p)37 static inline u8 ceph_decode_8(void **p)
38 {
39 u8 v = *(u8 *)*p;
40 (*p)++;
41 return v;
42 }
ceph_decode_copy(void ** p,void * pv,size_t n)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 */
ceph_has_room(void ** p,void * end,size_t n)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 */
ceph_extract_encoded_string(void ** p,void * end,size_t * lenp,gfp_t gfp)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 */
ceph_decode_timespec64(struct timespec64 * ts,const struct ceph_timespec * tv)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 }
ceph_encode_timespec64(struct ceph_timespec * tv,const struct timespec64 * ts)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 */
ceph_encode_addr(struct ceph_entity_addr * a)221 static inline void ceph_encode_addr(struct ceph_entity_addr *a)
222 {
223 __be16 ss_family = htons(a->in_addr.ss_family);
224 a->in_addr.ss_family = *(__u16 *)&ss_family;
225 }
ceph_decode_addr(struct ceph_entity_addr * a)226 static inline void ceph_decode_addr(struct ceph_entity_addr *a)
227 {
228 __be16 ss_family = *(__be16 *)&a->in_addr.ss_family;
229 a->in_addr.ss_family = ntohs(ss_family);
230 WARN_ON(a->in_addr.ss_family == 512);
231 }
232
233 /*
234 * encoders
235 */
ceph_encode_64(void ** p,u64 v)236 static inline void ceph_encode_64(void **p, u64 v)
237 {
238 put_unaligned_le64(v, (__le64 *)*p);
239 *p += sizeof(u64);
240 }
ceph_encode_32(void ** p,u32 v)241 static inline void ceph_encode_32(void **p, u32 v)
242 {
243 put_unaligned_le32(v, (__le32 *)*p);
244 *p += sizeof(u32);
245 }
ceph_encode_16(void ** p,u16 v)246 static inline void ceph_encode_16(void **p, u16 v)
247 {
248 put_unaligned_le16(v, (__le16 *)*p);
249 *p += sizeof(u16);
250 }
ceph_encode_8(void ** p,u8 v)251 static inline void ceph_encode_8(void **p, u8 v)
252 {
253 *(u8 *)*p = v;
254 (*p)++;
255 }
ceph_encode_copy(void ** p,const void * s,int len)256 static inline void ceph_encode_copy(void **p, const void *s, int len)
257 {
258 memcpy(*p, s, len);
259 *p += len;
260 }
261
262 /*
263 * filepath, string encoders
264 */
ceph_encode_filepath(void ** p,void * end,u64 ino,const char * path)265 static inline void ceph_encode_filepath(void **p, void *end,
266 u64 ino, const char *path)
267 {
268 u32 len = path ? strlen(path) : 0;
269 BUG_ON(*p + 1 + sizeof(ino) + sizeof(len) + len > end);
270 ceph_encode_8(p, 1);
271 ceph_encode_64(p, ino);
272 ceph_encode_32(p, len);
273 if (len)
274 memcpy(*p, path, len);
275 *p += len;
276 }
277
ceph_encode_string(void ** p,void * end,const char * s,u32 len)278 static inline void ceph_encode_string(void **p, void *end,
279 const char *s, u32 len)
280 {
281 BUG_ON(*p + sizeof(len) + len > end);
282 ceph_encode_32(p, len);
283 if (len)
284 memcpy(*p, s, len);
285 *p += len;
286 }
287
288 /*
289 * version and length starting block encoders/decoders
290 */
291
292 /* current code version (u8) + compat code version (u8) + len of struct (u32) */
293 #define CEPH_ENCODING_START_BLK_LEN 6
294
295 /**
296 * ceph_start_encoding - start encoding block
297 * @struct_v: current (code) version of the encoding
298 * @struct_compat: oldest code version that can decode it
299 * @struct_len: length of struct encoding
300 */
ceph_start_encoding(void ** p,u8 struct_v,u8 struct_compat,u32 struct_len)301 static inline void ceph_start_encoding(void **p, u8 struct_v, u8 struct_compat,
302 u32 struct_len)
303 {
304 ceph_encode_8(p, struct_v);
305 ceph_encode_8(p, struct_compat);
306 ceph_encode_32(p, struct_len);
307 }
308
309 /**
310 * ceph_start_decoding - start decoding block
311 * @v: current version of the encoding that the code supports
312 * @name: name of the struct (free-form)
313 * @struct_v: out param for the encoding version
314 * @struct_len: out param for the length of struct encoding
315 *
316 * Validates the length of struct encoding, so unsafe ceph_decode_*
317 * variants can be used for decoding.
318 */
ceph_start_decoding(void ** p,void * end,u8 v,const char * name,u8 * struct_v,u32 * struct_len)319 static inline int ceph_start_decoding(void **p, void *end, u8 v,
320 const char *name, u8 *struct_v,
321 u32 *struct_len)
322 {
323 u8 struct_compat;
324
325 ceph_decode_need(p, end, CEPH_ENCODING_START_BLK_LEN, bad);
326 *struct_v = ceph_decode_8(p);
327 struct_compat = ceph_decode_8(p);
328 if (v < struct_compat) {
329 pr_warn("got struct_v %d struct_compat %d > %d of %s\n",
330 *struct_v, struct_compat, v, name);
331 return -EINVAL;
332 }
333
334 *struct_len = ceph_decode_32(p);
335 ceph_decode_need(p, end, *struct_len, bad);
336 return 0;
337
338 bad:
339 return -ERANGE;
340 }
341
342 #define ceph_encode_need(p, end, n, bad) \
343 do { \
344 if (!likely(ceph_has_room(p, end, n))) \
345 goto bad; \
346 } while (0)
347
348 #define ceph_encode_64_safe(p, end, v, bad) \
349 do { \
350 ceph_encode_need(p, end, sizeof(u64), bad); \
351 ceph_encode_64(p, v); \
352 } while (0)
353 #define ceph_encode_32_safe(p, end, v, bad) \
354 do { \
355 ceph_encode_need(p, end, sizeof(u32), bad); \
356 ceph_encode_32(p, v); \
357 } while (0)
358 #define ceph_encode_16_safe(p, end, v, bad) \
359 do { \
360 ceph_encode_need(p, end, sizeof(u16), bad); \
361 ceph_encode_16(p, v); \
362 } while (0)
363 #define ceph_encode_8_safe(p, end, v, bad) \
364 do { \
365 ceph_encode_need(p, end, sizeof(u8), bad); \
366 ceph_encode_8(p, v); \
367 } while (0)
368
369 #define ceph_encode_copy_safe(p, end, pv, n, bad) \
370 do { \
371 ceph_encode_need(p, end, n, bad); \
372 ceph_encode_copy(p, pv, n); \
373 } while (0)
374 #define ceph_encode_string_safe(p, end, s, n, bad) \
375 do { \
376 ceph_encode_need(p, end, n, bad); \
377 ceph_encode_string(p, end, s, n); \
378 } while (0)
379
380
381 #endif
382