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