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// SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
/*
* libfdt - Flat Device Tree manipulation
* Copyright (C) 2006 David Gibson, IBM Corporation.
*/
#include "libfdt_env.h"
#include <fdt.h>
#include <libfdt.h>
#include "libfdt_internal.h"
/*
* Minimal sanity check for a read-only tree. fdt_ro_probe_() checks
* that the given buffer contains what appears to be a flattened
* device tree with sane information in its header.
*/
int32_t fdt_ro_probe_(const void *fdt)
{
uint32_t totalsize = fdt_totalsize(fdt);
if (can_assume(VALID_DTB))
return totalsize;
/* The device tree must be at an 8-byte aligned address */
if ((uintptr_t)fdt & 7)
return -FDT_ERR_ALIGNMENT;
if (fdt_magic(fdt) == FDT_MAGIC) {
/* Complete tree */
if (!can_assume(LATEST)) {
if (fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
return -FDT_ERR_BADVERSION;
if (fdt_last_comp_version(fdt) >
FDT_LAST_SUPPORTED_VERSION)
return -FDT_ERR_BADVERSION;
}
} else if (fdt_magic(fdt) == FDT_SW_MAGIC) {
/* Unfinished sequential-write blob */
if (!can_assume(VALID_INPUT) && fdt_size_dt_struct(fdt) == 0)
return -FDT_ERR_BADSTATE;
} else {
return -FDT_ERR_BADMAGIC;
}
if (totalsize < INT32_MAX)
return totalsize;
else
return -FDT_ERR_TRUNCATED;
}
static int check_off_(uint32_t hdrsize, uint32_t totalsize, uint32_t off)
{
return (off >= hdrsize) && (off <= totalsize);
}
static int check_block_(uint32_t hdrsize, uint32_t totalsize,
uint32_t base, uint32_t size)
{
if (!check_off_(hdrsize, totalsize, base))
return 0; /* block start out of bounds */
if ((base + size) < base)
return 0; /* overflow */
if (!check_off_(hdrsize, totalsize, base + size))
return 0; /* block end out of bounds */
return 1;
}
size_t fdt_header_size_(uint32_t version)
{
if (version <= 1)
return FDT_V1_SIZE;
else if (version <= 2)
return FDT_V2_SIZE;
else if (version <= 3)
return FDT_V3_SIZE;
else if (version <= 16)
return FDT_V16_SIZE;
else
return FDT_V17_SIZE;
}
size_t fdt_header_size(const void *fdt)
{
return can_assume(LATEST) ? FDT_V17_SIZE :
fdt_header_size_(fdt_version(fdt));
}
int fdt_check_header(const void *fdt)
{
size_t hdrsize;
if (fdt_magic(fdt) != FDT_MAGIC)
return -FDT_ERR_BADMAGIC;
if (!can_assume(LATEST)) {
if ((fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
|| (fdt_last_comp_version(fdt) >
FDT_LAST_SUPPORTED_VERSION))
return -FDT_ERR_BADVERSION;
if (fdt_version(fdt) < fdt_last_comp_version(fdt))
return -FDT_ERR_BADVERSION;
}
hdrsize = fdt_header_size(fdt);
if (!can_assume(VALID_DTB)) {
if ((fdt_totalsize(fdt) < hdrsize)
|| (fdt_totalsize(fdt) > INT_MAX))
return -FDT_ERR_TRUNCATED;
/* Bounds check memrsv block */
if (!check_off_(hdrsize, fdt_totalsize(fdt),
fdt_off_mem_rsvmap(fdt)))
return -FDT_ERR_TRUNCATED;
}
if (!can_assume(VALID_DTB)) {
/* Bounds check structure block */
if (!can_assume(LATEST) && fdt_version(fdt) < 17) {
if (!check_off_(hdrsize, fdt_totalsize(fdt),
fdt_off_dt_struct(fdt)))
return -FDT_ERR_TRUNCATED;
} else {
if (!check_block_(hdrsize, fdt_totalsize(fdt),
fdt_off_dt_struct(fdt),
fdt_size_dt_struct(fdt)))
return -FDT_ERR_TRUNCATED;
}
/* Bounds check strings block */
if (!check_block_(hdrsize, fdt_totalsize(fdt),
fdt_off_dt_strings(fdt),
fdt_size_dt_strings(fdt)))
return -FDT_ERR_TRUNCATED;
}
return 0;
}
const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int len)
{
unsigned int uoffset = offset;
unsigned int absoffset = offset + fdt_off_dt_struct(fdt);
if (offset < 0)
return NULL;
if (!can_assume(VALID_INPUT))
if ((absoffset < uoffset)
|| ((absoffset + len) < absoffset)
|| (absoffset + len) > fdt_totalsize(fdt))
return NULL;
if (can_assume(LATEST) || fdt_version(fdt) >= 0x11)
if (((uoffset + len) < uoffset)
|| ((offset + len) > fdt_size_dt_struct(fdt)))
return NULL;
return fdt_offset_ptr_(fdt, offset);
}
uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
{
const fdt32_t *tagp, *lenp;
uint32_t tag;
int offset = startoffset;
const char *p;
*nextoffset = -FDT_ERR_TRUNCATED;
tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE);
if (!can_assume(VALID_DTB) && !tagp)
return FDT_END; /* premature end */
tag = fdt32_to_cpu(*tagp);
offset += FDT_TAGSIZE;
*nextoffset = -FDT_ERR_BADSTRUCTURE;
switch (tag) {
case FDT_BEGIN_NODE:
/* skip name */
do {
p = fdt_offset_ptr(fdt, offset++, 1);
} while (p && (*p != '\0'));
if (!can_assume(VALID_DTB) && !p)
return FDT_END; /* premature end */
break;
case FDT_PROP:
lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp));
if (!can_assume(VALID_DTB) && !lenp)
return FDT_END; /* premature end */
/* skip-name offset, length and value */
offset += sizeof(struct fdt_property) - FDT_TAGSIZE
+ fdt32_to_cpu(*lenp);
if (!can_assume(LATEST) &&
fdt_version(fdt) < 0x10 && fdt32_to_cpu(*lenp) >= 8 &&
((offset - fdt32_to_cpu(*lenp)) % 8) != 0)
offset += 4;
break;
case FDT_END:
case FDT_END_NODE:
case FDT_NOP:
break;
default:
return FDT_END;
}
if (!fdt_offset_ptr(fdt, startoffset, offset - startoffset))
return FDT_END; /* premature end */
*nextoffset = FDT_TAGALIGN(offset);
return tag;
}
int fdt_check_node_offset_(const void *fdt, int offset)
{
if (!can_assume(VALID_INPUT)
&& ((offset < 0) || (offset % FDT_TAGSIZE)))
return -FDT_ERR_BADOFFSET;
if (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE)
return -FDT_ERR_BADOFFSET;
return offset;
}
int fdt_check_prop_offset_(const void *fdt, int offset)
{
if (!can_assume(VALID_INPUT)
&& ((offset < 0) || (offset % FDT_TAGSIZE)))
return -FDT_ERR_BADOFFSET;
if (fdt_next_tag(fdt, offset, &offset) != FDT_PROP)
return -FDT_ERR_BADOFFSET;
return offset;
}
int fdt_next_node(const void *fdt, int offset, int *depth)
{
int nextoffset = 0;
uint32_t tag;
if (offset >= 0)
if ((nextoffset = fdt_check_node_offset_(fdt, offset)) < 0)
return nextoffset;
do {
offset = nextoffset;
tag = fdt_next_tag(fdt, offset, &nextoffset);
switch (tag) {
case FDT_PROP:
case FDT_NOP:
break;
case FDT_BEGIN_NODE:
if (depth)
(*depth)++;
break;
case FDT_END_NODE:
if (depth && ((--(*depth)) < 0))
return nextoffset;
break;
case FDT_END:
if ((nextoffset >= 0)
|| ((nextoffset == -FDT_ERR_TRUNCATED) && !depth))
return -FDT_ERR_NOTFOUND;
else
return nextoffset;
}
} while (tag != FDT_BEGIN_NODE);
return offset;
}
int fdt_first_subnode(const void *fdt, int offset)
{
int depth = 0;
offset = fdt_next_node(fdt, offset, &depth);
if (offset < 0 || depth != 1)
return -FDT_ERR_NOTFOUND;
return offset;
}
int fdt_next_subnode(const void *fdt, int offset)
{
int depth = 1;
/*
* With respect to the parent, the depth of the next subnode will be
* the same as the last.
*/
do {
offset = fdt_next_node(fdt, offset, &depth);
if (offset < 0 || depth < 1)
return -FDT_ERR_NOTFOUND;
} while (depth > 1);
return offset;
}
const char *fdt_find_string_(const char *strtab, int tabsize, const char *s)
{
int len = strlen(s) + 1;
const char *last = strtab + tabsize - len;
const char *p;
for (p = strtab; p <= last; p++)
if (memcmp(p, s, len) == 0)
return p;
return NULL;
}
int fdt_move(const void *fdt, void *buf, int bufsize)
{
if (!can_assume(VALID_INPUT) && bufsize < 0)
return -FDT_ERR_NOSPACE;
FDT_RO_PROBE(fdt);
if (fdt_totalsize(fdt) > (unsigned int)bufsize)
return -FDT_ERR_NOSPACE;
memmove(buf, fdt, fdt_totalsize(fdt));
return 0;
}
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