1 // SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
3 * libfdt - Flat Device Tree manipulation
4 * Copyright (C) 2006 David Gibson, IBM Corporation.
6 #include "libfdt_env.h"
11 #include "libfdt_internal.h"
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.
18 int32_t fdt_ro_probe_(const void *fdt)
20 uint32_t totalsize = fdt_totalsize(fdt);
22 if (can_assume(VALID_DTB))
25 /* The device tree must be at an 8-byte aligned address */
26 if ((uintptr_t)fdt & 7)
27 return -FDT_ERR_ALIGNMENT;
29 if (fdt_magic(fdt) == FDT_MAGIC) {
31 if (!can_assume(LATEST)) {
32 if (fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
33 return -FDT_ERR_BADVERSION;
34 if (fdt_last_comp_version(fdt) >
35 FDT_LAST_SUPPORTED_VERSION)
36 return -FDT_ERR_BADVERSION;
38 } else if (fdt_magic(fdt) == FDT_SW_MAGIC) {
39 /* Unfinished sequential-write blob */
40 if (!can_assume(VALID_INPUT) && fdt_size_dt_struct(fdt) == 0)
41 return -FDT_ERR_BADSTATE;
43 return -FDT_ERR_BADMAGIC;
46 if (totalsize < INT32_MAX)
49 return -FDT_ERR_TRUNCATED;
52 static int check_off_(uint32_t hdrsize, uint32_t totalsize, uint32_t off)
54 return (off >= hdrsize) && (off <= totalsize);
57 static int check_block_(uint32_t hdrsize, uint32_t totalsize,
58 uint32_t base, uint32_t size)
60 if (!check_off_(hdrsize, totalsize, base))
61 return 0; /* block start out of bounds */
62 if ((base + size) < base)
63 return 0; /* overflow */
64 if (!check_off_(hdrsize, totalsize, base + size))
65 return 0; /* block end out of bounds */
69 size_t fdt_header_size_(uint32_t version)
73 else if (version <= 2)
75 else if (version <= 3)
77 else if (version <= 16)
83 size_t fdt_header_size(const void *fdt)
85 return can_assume(LATEST) ? FDT_V17_SIZE :
86 fdt_header_size_(fdt_version(fdt));
89 int fdt_check_header(const void *fdt)
93 if (fdt_magic(fdt) != FDT_MAGIC)
94 return -FDT_ERR_BADMAGIC;
95 if (!can_assume(LATEST)) {
96 if ((fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
97 || (fdt_last_comp_version(fdt) >
98 FDT_LAST_SUPPORTED_VERSION))
99 return -FDT_ERR_BADVERSION;
100 if (fdt_version(fdt) < fdt_last_comp_version(fdt))
101 return -FDT_ERR_BADVERSION;
103 hdrsize = fdt_header_size(fdt);
104 if (!can_assume(VALID_DTB)) {
106 if ((fdt_totalsize(fdt) < hdrsize)
107 || (fdt_totalsize(fdt) > INT_MAX))
108 return -FDT_ERR_TRUNCATED;
110 /* Bounds check memrsv block */
111 if (!check_off_(hdrsize, fdt_totalsize(fdt),
112 fdt_off_mem_rsvmap(fdt)))
113 return -FDT_ERR_TRUNCATED;
116 if (!can_assume(VALID_DTB)) {
117 /* Bounds check structure block */
118 if (!can_assume(LATEST) && fdt_version(fdt) < 17) {
119 if (!check_off_(hdrsize, fdt_totalsize(fdt),
120 fdt_off_dt_struct(fdt)))
121 return -FDT_ERR_TRUNCATED;
123 if (!check_block_(hdrsize, fdt_totalsize(fdt),
124 fdt_off_dt_struct(fdt),
125 fdt_size_dt_struct(fdt)))
126 return -FDT_ERR_TRUNCATED;
129 /* Bounds check strings block */
130 if (!check_block_(hdrsize, fdt_totalsize(fdt),
131 fdt_off_dt_strings(fdt),
132 fdt_size_dt_strings(fdt)))
133 return -FDT_ERR_TRUNCATED;
139 const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int len)
141 unsigned int uoffset = offset;
142 unsigned int absoffset = offset + fdt_off_dt_struct(fdt);
147 if (!can_assume(VALID_INPUT))
148 if ((absoffset < uoffset)
149 || ((absoffset + len) < absoffset)
150 || (absoffset + len) > fdt_totalsize(fdt))
153 if (can_assume(LATEST) || fdt_version(fdt) >= 0x11)
154 if (((uoffset + len) < uoffset)
155 || ((offset + len) > fdt_size_dt_struct(fdt)))
158 return fdt_offset_ptr_(fdt, offset);
161 uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
163 const fdt32_t *tagp, *lenp;
165 int offset = startoffset;
168 *nextoffset = -FDT_ERR_TRUNCATED;
169 tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE);
170 if (!can_assume(VALID_DTB) && !tagp)
171 return FDT_END; /* premature end */
172 tag = fdt32_to_cpu(*tagp);
173 offset += FDT_TAGSIZE;
175 *nextoffset = -FDT_ERR_BADSTRUCTURE;
180 p = fdt_offset_ptr(fdt, offset++, 1);
181 } while (p && (*p != '\0'));
182 if (!can_assume(VALID_DTB) && !p)
183 return FDT_END; /* premature end */
187 lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp));
188 if (!can_assume(VALID_DTB) && !lenp)
189 return FDT_END; /* premature end */
190 /* skip-name offset, length and value */
191 offset += sizeof(struct fdt_property) - FDT_TAGSIZE
192 + fdt32_to_cpu(*lenp);
193 if (!can_assume(LATEST) &&
194 fdt_version(fdt) < 0x10 && fdt32_to_cpu(*lenp) >= 8 &&
195 ((offset - fdt32_to_cpu(*lenp)) % 8) != 0)
208 if (!fdt_offset_ptr(fdt, startoffset, offset - startoffset))
209 return FDT_END; /* premature end */
211 *nextoffset = FDT_TAGALIGN(offset);
215 int fdt_check_node_offset_(const void *fdt, int offset)
217 if (!can_assume(VALID_INPUT)
218 && ((offset < 0) || (offset % FDT_TAGSIZE)))
219 return -FDT_ERR_BADOFFSET;
221 if (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE)
222 return -FDT_ERR_BADOFFSET;
227 int fdt_check_prop_offset_(const void *fdt, int offset)
229 if (!can_assume(VALID_INPUT)
230 && ((offset < 0) || (offset % FDT_TAGSIZE)))
231 return -FDT_ERR_BADOFFSET;
233 if (fdt_next_tag(fdt, offset, &offset) != FDT_PROP)
234 return -FDT_ERR_BADOFFSET;
239 int fdt_next_node(const void *fdt, int offset, int *depth)
245 if ((nextoffset = fdt_check_node_offset_(fdt, offset)) < 0)
250 tag = fdt_next_tag(fdt, offset, &nextoffset);
263 if (depth && ((--(*depth)) < 0))
268 if ((nextoffset >= 0)
269 || ((nextoffset == -FDT_ERR_TRUNCATED) && !depth))
270 return -FDT_ERR_NOTFOUND;
274 } while (tag != FDT_BEGIN_NODE);
279 int fdt_first_subnode(const void *fdt, int offset)
283 offset = fdt_next_node(fdt, offset, &depth);
284 if (offset < 0 || depth != 1)
285 return -FDT_ERR_NOTFOUND;
290 int fdt_next_subnode(const void *fdt, int offset)
295 * With respect to the parent, the depth of the next subnode will be
296 * the same as the last.
299 offset = fdt_next_node(fdt, offset, &depth);
300 if (offset < 0 || depth < 1)
301 return -FDT_ERR_NOTFOUND;
307 const char *fdt_find_string_(const char *strtab, int tabsize, const char *s)
309 int len = strlen(s) + 1;
310 const char *last = strtab + tabsize - len;
313 for (p = strtab; p <= last; p++)
314 if (memcmp(p, s, len) == 0)
319 int fdt_move(const void *fdt, void *buf, int bufsize)
321 if (!can_assume(VALID_INPUT) && bufsize < 0)
322 return -FDT_ERR_NOSPACE;
326 if (fdt_totalsize(fdt) > (unsigned int)bufsize)
327 return -FDT_ERR_NOSPACE;
329 memmove(buf, fdt, fdt_totalsize(fdt));