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 int fdt_ro_probe_(const void *fdt)
20 if (fdt_magic(fdt) == FDT_MAGIC) {
22 if (fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
23 return -FDT_ERR_BADVERSION;
24 if (fdt_last_comp_version(fdt) > FDT_LAST_SUPPORTED_VERSION)
25 return -FDT_ERR_BADVERSION;
26 } else if (fdt_magic(fdt) == FDT_SW_MAGIC) {
27 /* Unfinished sequential-write blob */
28 if (fdt_size_dt_struct(fdt) == 0)
29 return -FDT_ERR_BADSTATE;
31 return -FDT_ERR_BADMAGIC;
37 static int check_off_(uint32_t hdrsize, uint32_t totalsize, uint32_t off)
39 return (off >= hdrsize) && (off <= totalsize);
42 static int check_block_(uint32_t hdrsize, uint32_t totalsize,
43 uint32_t base, uint32_t size)
45 if (!check_off_(hdrsize, totalsize, base))
46 return 0; /* block start out of bounds */
47 if ((base + size) < base)
48 return 0; /* overflow */
49 if (!check_off_(hdrsize, totalsize, base + size))
50 return 0; /* block end out of bounds */
54 size_t fdt_header_size_(uint32_t version)
58 else if (version <= 2)
60 else if (version <= 3)
62 else if (version <= 16)
68 int fdt_check_header(const void *fdt)
72 if (fdt_magic(fdt) != FDT_MAGIC)
73 return -FDT_ERR_BADMAGIC;
74 hdrsize = fdt_header_size(fdt);
75 if ((fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
76 || (fdt_last_comp_version(fdt) > FDT_LAST_SUPPORTED_VERSION))
77 return -FDT_ERR_BADVERSION;
78 if (fdt_version(fdt) < fdt_last_comp_version(fdt))
79 return -FDT_ERR_BADVERSION;
81 if ((fdt_totalsize(fdt) < hdrsize)
82 || (fdt_totalsize(fdt) > INT_MAX))
83 return -FDT_ERR_TRUNCATED;
85 /* Bounds check memrsv block */
86 if (!check_off_(hdrsize, fdt_totalsize(fdt), fdt_off_mem_rsvmap(fdt)))
87 return -FDT_ERR_TRUNCATED;
89 /* Bounds check structure block */
90 if (fdt_version(fdt) < 17) {
91 if (!check_off_(hdrsize, fdt_totalsize(fdt),
92 fdt_off_dt_struct(fdt)))
93 return -FDT_ERR_TRUNCATED;
95 if (!check_block_(hdrsize, fdt_totalsize(fdt),
96 fdt_off_dt_struct(fdt),
97 fdt_size_dt_struct(fdt)))
98 return -FDT_ERR_TRUNCATED;
101 /* Bounds check strings block */
102 if (!check_block_(hdrsize, fdt_totalsize(fdt),
103 fdt_off_dt_strings(fdt), fdt_size_dt_strings(fdt)))
104 return -FDT_ERR_TRUNCATED;
109 const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int len)
111 unsigned absoffset = offset + fdt_off_dt_struct(fdt);
113 if ((absoffset < offset)
114 || ((absoffset + len) < absoffset)
115 || (absoffset + len) > fdt_totalsize(fdt))
118 if (fdt_version(fdt) >= 0x11)
119 if (((offset + len) < offset)
120 || ((offset + len) > fdt_size_dt_struct(fdt)))
123 return fdt_offset_ptr_(fdt, offset);
126 uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
128 const fdt32_t *tagp, *lenp;
130 int offset = startoffset;
133 *nextoffset = -FDT_ERR_TRUNCATED;
134 tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE);
136 return FDT_END; /* premature end */
137 tag = fdt32_to_cpu(*tagp);
138 offset += FDT_TAGSIZE;
140 *nextoffset = -FDT_ERR_BADSTRUCTURE;
145 p = fdt_offset_ptr(fdt, offset++, 1);
146 } while (p && (*p != '\0'));
148 return FDT_END; /* premature end */
152 lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp));
154 return FDT_END; /* premature end */
155 /* skip-name offset, length and value */
156 offset += sizeof(struct fdt_property) - FDT_TAGSIZE
157 + fdt32_to_cpu(*lenp);
158 if (fdt_version(fdt) < 0x10 && fdt32_to_cpu(*lenp) >= 8 &&
159 ((offset - fdt32_to_cpu(*lenp)) % 8) != 0)
172 if (!fdt_offset_ptr(fdt, startoffset, offset - startoffset))
173 return FDT_END; /* premature end */
175 *nextoffset = FDT_TAGALIGN(offset);
179 int fdt_check_node_offset_(const void *fdt, int offset)
181 if ((offset < 0) || (offset % FDT_TAGSIZE)
182 || (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE))
183 return -FDT_ERR_BADOFFSET;
188 int fdt_check_prop_offset_(const void *fdt, int offset)
190 if ((offset < 0) || (offset % FDT_TAGSIZE)
191 || (fdt_next_tag(fdt, offset, &offset) != FDT_PROP))
192 return -FDT_ERR_BADOFFSET;
197 int fdt_next_node(const void *fdt, int offset, int *depth)
203 if ((nextoffset = fdt_check_node_offset_(fdt, offset)) < 0)
208 tag = fdt_next_tag(fdt, offset, &nextoffset);
221 if (depth && ((--(*depth)) < 0))
226 if ((nextoffset >= 0)
227 || ((nextoffset == -FDT_ERR_TRUNCATED) && !depth))
228 return -FDT_ERR_NOTFOUND;
232 } while (tag != FDT_BEGIN_NODE);
237 int fdt_first_subnode(const void *fdt, int offset)
241 offset = fdt_next_node(fdt, offset, &depth);
242 if (offset < 0 || depth != 1)
243 return -FDT_ERR_NOTFOUND;
248 int fdt_next_subnode(const void *fdt, int offset)
253 * With respect to the parent, the depth of the next subnode will be
254 * the same as the last.
257 offset = fdt_next_node(fdt, offset, &depth);
258 if (offset < 0 || depth < 1)
259 return -FDT_ERR_NOTFOUND;
265 const char *fdt_find_string_(const char *strtab, int tabsize, const char *s)
267 int len = strlen(s) + 1;
268 const char *last = strtab + tabsize - len;
271 for (p = strtab; p <= last; p++)
272 if (memcmp(p, s, len) == 0)
277 int fdt_move(const void *fdt, void *buf, int bufsize)
281 if (fdt_totalsize(fdt) > bufsize)
282 return -FDT_ERR_NOSPACE;
284 memmove(buf, fdt, fdt_totalsize(fdt));