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 timespec
198 */
ceph_decode_timespec(struct timespec * ts,const struct ceph_timespec * tv)199 static inline void ceph_decode_timespec(struct timespec *ts,
200 const struct ceph_timespec *tv)
201 {
202 ts->tv_sec = (__kernel_time_t)le32_to_cpu(tv->tv_sec);
203 ts->tv_nsec = (long)le32_to_cpu(tv->tv_nsec);
204 }
ceph_encode_timespec(struct ceph_timespec * tv,const struct timespec * ts)205 static inline void ceph_encode_timespec(struct ceph_timespec *tv,
206 const struct timespec *ts)
207 {
208 tv->tv_sec = cpu_to_le32((u32)ts->tv_sec);
209 tv->tv_nsec = cpu_to_le32((u32)ts->tv_nsec);
210 }
211
212 /*
213 * sockaddr_storage <-> ceph_sockaddr
214 */
ceph_encode_addr(struct ceph_entity_addr * a)215 static inline void ceph_encode_addr(struct ceph_entity_addr *a)
216 {
217 __be16 ss_family = htons(a->in_addr.ss_family);
218 a->in_addr.ss_family = *(__u16 *)&ss_family;
219 }
ceph_decode_addr(struct ceph_entity_addr * a)220 static inline void ceph_decode_addr(struct ceph_entity_addr *a)
221 {
222 __be16 ss_family = *(__be16 *)&a->in_addr.ss_family;
223 a->in_addr.ss_family = ntohs(ss_family);
224 WARN_ON(a->in_addr.ss_family == 512);
225 }
226
227 /*
228 * encoders
229 */
ceph_encode_64(void ** p,u64 v)230 static inline void ceph_encode_64(void **p, u64 v)
231 {
232 put_unaligned_le64(v, (__le64 *)*p);
233 *p += sizeof(u64);
234 }
ceph_encode_32(void ** p,u32 v)235 static inline void ceph_encode_32(void **p, u32 v)
236 {
237 put_unaligned_le32(v, (__le32 *)*p);
238 *p += sizeof(u32);
239 }
ceph_encode_16(void ** p,u16 v)240 static inline void ceph_encode_16(void **p, u16 v)
241 {
242 put_unaligned_le16(v, (__le16 *)*p);
243 *p += sizeof(u16);
244 }
ceph_encode_8(void ** p,u8 v)245 static inline void ceph_encode_8(void **p, u8 v)
246 {
247 *(u8 *)*p = v;
248 (*p)++;
249 }
ceph_encode_copy(void ** p,const void * s,int len)250 static inline void ceph_encode_copy(void **p, const void *s, int len)
251 {
252 memcpy(*p, s, len);
253 *p += len;
254 }
255
256 /*
257 * filepath, string encoders
258 */
ceph_encode_filepath(void ** p,void * end,u64 ino,const char * path)259 static inline void ceph_encode_filepath(void **p, void *end,
260 u64 ino, const char *path)
261 {
262 u32 len = path ? strlen(path) : 0;
263 BUG_ON(*p + 1 + sizeof(ino) + sizeof(len) + len > end);
264 ceph_encode_8(p, 1);
265 ceph_encode_64(p, ino);
266 ceph_encode_32(p, len);
267 if (len)
268 memcpy(*p, path, len);
269 *p += len;
270 }
271
ceph_encode_string(void ** p,void * end,const char * s,u32 len)272 static inline void ceph_encode_string(void **p, void *end,
273 const char *s, u32 len)
274 {
275 BUG_ON(*p + sizeof(len) + len > end);
276 ceph_encode_32(p, len);
277 if (len)
278 memcpy(*p, s, len);
279 *p += len;
280 }
281
282 /*
283 * version and length starting block encoders/decoders
284 */
285
286 /* current code version (u8) + compat code version (u8) + len of struct (u32) */
287 #define CEPH_ENCODING_START_BLK_LEN 6
288
289 /**
290 * ceph_start_encoding - start encoding block
291 * @struct_v: current (code) version of the encoding
292 * @struct_compat: oldest code version that can decode it
293 * @struct_len: length of struct encoding
294 */
ceph_start_encoding(void ** p,u8 struct_v,u8 struct_compat,u32 struct_len)295 static inline void ceph_start_encoding(void **p, u8 struct_v, u8 struct_compat,
296 u32 struct_len)
297 {
298 ceph_encode_8(p, struct_v);
299 ceph_encode_8(p, struct_compat);
300 ceph_encode_32(p, struct_len);
301 }
302
303 /**
304 * ceph_start_decoding - start decoding block
305 * @v: current version of the encoding that the code supports
306 * @name: name of the struct (free-form)
307 * @struct_v: out param for the encoding version
308 * @struct_len: out param for the length of struct encoding
309 *
310 * Validates the length of struct encoding, so unsafe ceph_decode_*
311 * variants can be used for decoding.
312 */
ceph_start_decoding(void ** p,void * end,u8 v,const char * name,u8 * struct_v,u32 * struct_len)313 static inline int ceph_start_decoding(void **p, void *end, u8 v,
314 const char *name, u8 *struct_v,
315 u32 *struct_len)
316 {
317 u8 struct_compat;
318
319 ceph_decode_need(p, end, CEPH_ENCODING_START_BLK_LEN, bad);
320 *struct_v = ceph_decode_8(p);
321 struct_compat = ceph_decode_8(p);
322 if (v < struct_compat) {
323 pr_warn("got struct_v %d struct_compat %d > %d of %s\n",
324 *struct_v, struct_compat, v, name);
325 return -EINVAL;
326 }
327
328 *struct_len = ceph_decode_32(p);
329 ceph_decode_need(p, end, *struct_len, bad);
330 return 0;
331
332 bad:
333 return -ERANGE;
334 }
335
336 #define ceph_encode_need(p, end, n, bad) \
337 do { \
338 if (!likely(ceph_has_room(p, end, n))) \
339 goto bad; \
340 } while (0)
341
342 #define ceph_encode_64_safe(p, end, v, bad) \
343 do { \
344 ceph_encode_need(p, end, sizeof(u64), bad); \
345 ceph_encode_64(p, v); \
346 } while (0)
347 #define ceph_encode_32_safe(p, end, v, bad) \
348 do { \
349 ceph_encode_need(p, end, sizeof(u32), bad); \
350 ceph_encode_32(p, v); \
351 } while (0)
352 #define ceph_encode_16_safe(p, end, v, bad) \
353 do { \
354 ceph_encode_need(p, end, sizeof(u16), bad); \
355 ceph_encode_16(p, v); \
356 } while (0)
357 #define ceph_encode_8_safe(p, end, v, bad) \
358 do { \
359 ceph_encode_need(p, end, sizeof(u8), bad); \
360 ceph_encode_8(p, v); \
361 } while (0)
362
363 #define ceph_encode_copy_safe(p, end, pv, n, bad) \
364 do { \
365 ceph_encode_need(p, end, n, bad); \
366 ceph_encode_copy(p, pv, n); \
367 } while (0)
368 #define ceph_encode_string_safe(p, end, s, n, bad) \
369 do { \
370 ceph_encode_need(p, end, n, bad); \
371 ceph_encode_string(p, end, s, n); \
372 } while (0)
373
374
375 #endif
376