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 (fdt_magic(fdt) == FDT_MAGIC) {
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;
33 return -FDT_ERR_BADMAGIC;
36 if (totalsize < INT32_MAX)
39 return -FDT_ERR_TRUNCATED;
42 static int check_off_(uint32_t hdrsize, uint32_t totalsize, uint32_t off)
44 return (off >= hdrsize) && (off <= totalsize);
47 static int check_block_(uint32_t hdrsize, uint32_t totalsize,
48 uint32_t base, uint32_t size)
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 */
59 size_t fdt_header_size_(uint32_t version)
63 else if (version <= 2)
65 else if (version <= 3)
67 else if (version <= 16)
73 int fdt_check_header(const void *fdt)
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;
86 if ((fdt_totalsize(fdt) < hdrsize)
87 || (fdt_totalsize(fdt) > INT_MAX))
88 return -FDT_ERR_TRUNCATED;
90 /* Bounds check memrsv block */
91 if (!check_off_(hdrsize, fdt_totalsize(fdt), fdt_off_mem_rsvmap(fdt)))
92 return -FDT_ERR_TRUNCATED;
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;
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;
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;
114 const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int len)
116 unsigned absoffset = offset + fdt_off_dt_struct(fdt);
118 if ((absoffset < offset)
119 || ((absoffset + len) < absoffset)
120 || (absoffset + len) > fdt_totalsize(fdt))
123 if (fdt_version(fdt) >= 0x11)
124 if (((offset + len) < offset)
125 || ((offset + len) > fdt_size_dt_struct(fdt)))
128 return fdt_offset_ptr_(fdt, offset);
131 uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
133 const fdt32_t *tagp, *lenp;
135 int offset = startoffset;
138 *nextoffset = -FDT_ERR_TRUNCATED;
139 tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE);
141 return FDT_END; /* premature end */
142 tag = fdt32_to_cpu(*tagp);
143 offset += FDT_TAGSIZE;
145 *nextoffset = -FDT_ERR_BADSTRUCTURE;
150 p = fdt_offset_ptr(fdt, offset++, 1);
151 } while (p && (*p != '\0'));
153 return FDT_END; /* premature end */
157 lenp = fdt_offset_ptr(fdt, offset, sizeof(*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)
177 if (!fdt_offset_ptr(fdt, startoffset, offset - startoffset))
178 return FDT_END; /* premature end */
180 *nextoffset = FDT_TAGALIGN(offset);
184 int fdt_check_node_offset_(const void *fdt, int offset)
186 if ((offset < 0) || (offset % FDT_TAGSIZE)
187 || (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE))
188 return -FDT_ERR_BADOFFSET;
193 int fdt_check_prop_offset_(const void *fdt, int offset)
195 if ((offset < 0) || (offset % FDT_TAGSIZE)
196 || (fdt_next_tag(fdt, offset, &offset) != FDT_PROP))
197 return -FDT_ERR_BADOFFSET;
202 int fdt_next_node(const void *fdt, int offset, int *depth)
208 if ((nextoffset = fdt_check_node_offset_(fdt, offset)) < 0)
213 tag = fdt_next_tag(fdt, offset, &nextoffset);
226 if (depth && ((--(*depth)) < 0))
231 if ((nextoffset >= 0)
232 || ((nextoffset == -FDT_ERR_TRUNCATED) && !depth))
233 return -FDT_ERR_NOTFOUND;
237 } while (tag != FDT_BEGIN_NODE);
242 int fdt_first_subnode(const void *fdt, int offset)
246 offset = fdt_next_node(fdt, offset, &depth);
247 if (offset < 0 || depth != 1)
248 return -FDT_ERR_NOTFOUND;
253 int fdt_next_subnode(const void *fdt, int offset)
258 * With respect to the parent, the depth of the next subnode will be
259 * the same as the last.
262 offset = fdt_next_node(fdt, offset, &depth);
263 if (offset < 0 || depth < 1)
264 return -FDT_ERR_NOTFOUND;
270 const char *fdt_find_string_(const char *strtab, int tabsize, const char *s)
272 int len = strlen(s) + 1;
273 const char *last = strtab + tabsize - len;
276 for (p = strtab; p <= last; p++)
277 if (memcmp(p, s, len) == 0)
282 int fdt_move(const void *fdt, void *buf, int bufsize)
286 if (fdt_totalsize(fdt) > bufsize)
287 return -FDT_ERR_NOSPACE;
289 memmove(buf, fdt, fdt_totalsize(fdt));