LXR uboot/scripts/dtc/libfdt/fdt.c

   1// SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
   2/*
   3 * libfdt - Flat Device Tree manipulation
   4 * Copyright (C) 2006 David Gibson, IBM Corporation.
   5 */
   6#include "libfdt_env.h"
   7
   8#include <fdt.h>
   9#include <libfdt.h>
  10
  11#include "libfdt_internal.h"
  12
  13/*
  14 * Minimal sanity check for a read-only tree. fdt_ro_probe_() checks
  15 * that the given buffer contains what appears to be a flattened
  16 * device tree with sane information in its header.
  17 */
  18int32_t fdt_ro_probe_(const void *fdt)
  19{
  20        uint32_t totalsize = fdt_totalsize(fdt);
  21
  22        if (fdt_magic(fdt) == FDT_MAGIC) {
  23                /* Complete tree */
  24                if (fdt_chk_version()) {
  25                        if (fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
  26                                return -FDT_ERR_BADVERSION;
  27                        if (fdt_last_comp_version(fdt) >
  28                                        FDT_LAST_SUPPORTED_VERSION)
  29                                return -FDT_ERR_BADVERSION;
  30                }
  31        } else if (fdt_magic(fdt) == FDT_SW_MAGIC) {
  32                /* Unfinished sequential-write blob */
  33                if (fdt_size_dt_struct(fdt) == 0)
  34                        return -FDT_ERR_BADSTATE;
  35        } else {
  36                return -FDT_ERR_BADMAGIC;
  37        }
  38
  39        if (totalsize < INT32_MAX)
  40                return totalsize;
  41        else
  42                return -FDT_ERR_TRUNCATED;
  43}
  44
  45static int check_off_(uint32_t hdrsize, uint32_t totalsize, uint32_t off)
  46{
  47        return (off >= hdrsize) && (off <= totalsize);
  48}
  49
  50static int check_block_(uint32_t hdrsize, uint32_t totalsize,
  51                        uint32_t base, uint32_t size)
  52{
  53        if (!check_off_(hdrsize, totalsize, base))
  54                return 0; /* block start out of bounds */
  55        if ((base + size) < base)
  56                return 0; /* overflow */
  57        if (!check_off_(hdrsize, totalsize, base + size))
  58                return 0; /* block end out of bounds */
  59        return 1;
  60}
  61
  62size_t fdt_header_size_(uint32_t version)
  63{
  64        if (version <= 1)
  65                return FDT_V1_SIZE;
  66        else if (version <= 2)
  67                return FDT_V2_SIZE;
  68        else if (version <= 3)
  69                return FDT_V3_SIZE;
  70        else if (version <= 16)
  71                return FDT_V16_SIZE;
  72        else
  73                return FDT_V17_SIZE;
  74}
  75
  76size_t fdt_header_size(const void *fdt)
  77{
  78        return fdt_chk_version() ? fdt_header_size_(fdt_version(fdt)) :
  79                FDT_V17_SIZE;
  80}
  81
  82int fdt_check_header(const void *fdt)
  83{
  84        size_t hdrsize;
  85
  86        if (fdt_magic(fdt) != FDT_MAGIC)
  87                return -FDT_ERR_BADMAGIC;
  88        if (fdt_chk_version()) {
  89                if ((fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
  90                    || (fdt_last_comp_version(fdt) >
  91                        FDT_LAST_SUPPORTED_VERSION))
  92                        return -FDT_ERR_BADVERSION;
  93                if (fdt_version(fdt) < fdt_last_comp_version(fdt))
  94                        return -FDT_ERR_BADVERSION;
  95        }
  96        hdrsize = fdt_header_size(fdt);
  97        if (fdt_chk_basic()) {
  98
  99                if ((fdt_totalsize(fdt) < hdrsize)
 100                    || (fdt_totalsize(fdt) > INT_MAX))
 101                        return -FDT_ERR_TRUNCATED;
 102
 103                /* Bounds check memrsv block */
 104                if (!check_off_(hdrsize, fdt_totalsize(fdt),
 105                                fdt_off_mem_rsvmap(fdt)))
 106                        return -FDT_ERR_TRUNCATED;
 107        }
 108
 109        if (fdt_chk_extra()) {
 110                /* Bounds check structure block */
 111                if (fdt_chk_version() && fdt_version(fdt) < 17) {
 112                        if (!check_off_(hdrsize, fdt_totalsize(fdt),
 113                                        fdt_off_dt_struct(fdt)))
 114                                return -FDT_ERR_TRUNCATED;
 115                } else {
 116                        if (!check_block_(hdrsize, fdt_totalsize(fdt),
 117                                          fdt_off_dt_struct(fdt),
 118                                          fdt_size_dt_struct(fdt)))
 119                                return -FDT_ERR_TRUNCATED;
 120                }
 121
 122                /* Bounds check strings block */
 123                if (!check_block_(hdrsize, fdt_totalsize(fdt),
 124                                  fdt_off_dt_strings(fdt),
 125                                  fdt_size_dt_strings(fdt)))
 126                        return -FDT_ERR_TRUNCATED;
 127        }
 128
 129        return 0;
 130}
 131
 132const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int len)
 133{
 134        unsigned int uoffset = offset;
 135        unsigned int absoffset = offset + fdt_off_dt_struct(fdt);
 136
 137        if (offset < 0)
 138                return NULL;
 139
 140        if (fdt_chk_basic())
 141                if ((absoffset < uoffset)
 142                    || ((absoffset + len) < absoffset)
 143                    || (absoffset + len) > fdt_totalsize(fdt))
 144                        return NULL;
 145
 146        if (!fdt_chk_version() || fdt_version(fdt) >= 0x11)
 147                if (((uoffset + len) < uoffset)
 148                    || ((offset + len) > fdt_size_dt_struct(fdt)))
 149                        return NULL;
 150
 151        return fdt_offset_ptr_(fdt, offset);
 152}
 153
 154uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
 155{
 156        const fdt32_t *tagp, *lenp;
 157        uint32_t tag;
 158        int offset = startoffset;
 159        const char *p;
 160
 161        *nextoffset = -FDT_ERR_TRUNCATED;
 162        tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE);
 163        if (fdt_chk_basic() && !tagp)
 164                return FDT_END; /* premature end */
 165        tag = fdt32_to_cpu(*tagp);
 166        offset += FDT_TAGSIZE;
 167
 168        *nextoffset = -FDT_ERR_BADSTRUCTURE;
 169        switch (tag) {
 170        case FDT_BEGIN_NODE:
 171                /* skip name */
 172                do {
 173                        p = fdt_offset_ptr(fdt, offset++, 1);
 174                } while (p && (*p != '\0'));
 175                if (fdt_chk_basic() && !p)
 176                        return FDT_END; /* premature end */
 177                break;
 178
 179        case FDT_PROP:
 180                lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp));
 181                if (fdt_chk_basic() && !lenp)
 182                        return FDT_END; /* premature end */
 183                /* skip-name offset, length and value */
 184                offset += sizeof(struct fdt_property) - FDT_TAGSIZE
 185                        + fdt32_to_cpu(*lenp);
 186                if (fdt_chk_version() &&
 187                    fdt_version(fdt) < 0x10 && fdt32_to_cpu(*lenp) >= 8 &&
 188                    ((offset - fdt32_to_cpu(*lenp)) % 8) != 0)
 189                        offset += 4;
 190                break;
 191
 192        case FDT_END:
 193        case FDT_END_NODE:
 194        case FDT_NOP:
 195                break;
 196
 197        default:
 198                return FDT_END;
 199        }
 200
 201        if (fdt_chk_basic() &&
 202            !fdt_offset_ptr(fdt, startoffset, offset - startoffset))
 203                return FDT_END; /* premature end */
 204
 205        *nextoffset = FDT_TAGALIGN(offset);
 206        return tag;
 207}
 208
 209int fdt_check_node_offset_(const void *fdt, int offset)
 210{
 211        if ((offset < 0) || (offset % FDT_TAGSIZE)
 212            || (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE))
 213                return -FDT_ERR_BADOFFSET;
 214
 215        return offset;
 216}
 217
 218int fdt_check_prop_offset_(const void *fdt, int offset)
 219{
 220        if ((offset < 0) || (offset % FDT_TAGSIZE)
 221            || (fdt_next_tag(fdt, offset, &offset) != FDT_PROP))
 222                return -FDT_ERR_BADOFFSET;
 223
 224        return offset;
 225}
 226
 227int fdt_next_node(const void *fdt, int offset, int *depth)
 228{
 229        int nextoffset = 0;
 230        uint32_t tag;
 231
 232        if (offset >= 0)
 233                if ((nextoffset = fdt_check_node_offset_(fdt, offset)) < 0)
 234                        return nextoffset;
 235
 236        do {
 237                offset = nextoffset;
 238                tag = fdt_next_tag(fdt, offset, &nextoffset);
 239
 240                switch (tag) {
 241                case FDT_PROP:
 242                case FDT_NOP:
 243                        break;
 244
 245                case FDT_BEGIN_NODE:
 246                        if (depth)
 247                                (*depth)++;
 248                        break;
 249
 250                case FDT_END_NODE:
 251                        if (depth && ((--(*depth)) < 0))
 252                                return nextoffset;
 253                        break;
 254
 255                case FDT_END:
 256                        if ((nextoffset >= 0)
 257                            || ((nextoffset == -FDT_ERR_TRUNCATED) && !depth))
 258                                return -FDT_ERR_NOTFOUND;
 259                        else
 260                                return nextoffset;
 261                }
 262        } while (tag != FDT_BEGIN_NODE);
 263
 264        return offset;
 265}
 266
 267int fdt_first_subnode(const void *fdt, int offset)
 268{
 269        int depth = 0;
 270
 271        offset = fdt_next_node(fdt, offset, &depth);
 272        if (offset < 0 || depth != 1)
 273                return -FDT_ERR_NOTFOUND;
 274
 275        return offset;
 276}
 277
 278int fdt_next_subnode(const void *fdt, int offset)
 279{
 280        int depth = 1;
 281
 282        /*
 283         * With respect to the parent, the depth of the next subnode will be
 284         * the same as the last.
 285         */
 286        do {
 287                offset = fdt_next_node(fdt, offset, &depth);
 288                if (offset < 0 || depth < 1)
 289                        return -FDT_ERR_NOTFOUND;
 290        } while (depth > 1);
 291
 292        return offset;
 293}
 294
 295const char *fdt_find_string_(const char *strtab, int tabsize, const char *s)
 296{
 297        int len = strlen(s) + 1;
 298        const char *last = strtab + tabsize - len;
 299        const char *p;
 300
 301        for (p = strtab; p <= last; p++)
 302                if (memcmp(p, s, len) == 0)
 303                        return p;
 304        return NULL;
 305}
 306
 307int fdt_move(const void *fdt, void *buf, int bufsize)
 308{
 309        if (fdt_chk_basic() && bufsize < 0)
 310                return -FDT_ERR_NOSPACE;
 311
 312        FDT_RO_PROBE(fdt);
 313
 314        if (fdt_totalsize(fdt) > (unsigned int)bufsize)
 315                return -FDT_ERR_NOSPACE;
 316
 317        memmove(buf, fdt, fdt_totalsize(fdt));
 318        return 0;
 319}
 320