include/linux/ceph/decode.h

   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 timespec
 198  */
 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 }
 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  */
 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 }
 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  */
 230 static inline void ceph_encode_64(void **p, u64 v)
 231 {
 232         put_unaligned_le64(v, (__le64 *)*p);
 233         *p += sizeof(u64);
 234 }
 235 static inline void ceph_encode_32(void **p, u32 v)
 236 {
 237         put_unaligned_le32(v, (__le32 *)*p);
 238         *p += sizeof(u32);
 239 }
 240 static inline void ceph_encode_16(void **p, u16 v)
 241 {
 242         put_unaligned_le16(v, (__le16 *)*p);
 243         *p += sizeof(u16);
 244 }
 245 static inline void ceph_encode_8(void **p, u8 v)
 246 {
 247         *(u8 *)*p = v;
 248         (*p)++;
 249 }
 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  */
 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
 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  */
 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  */
 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