| // 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; |
| |
| 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(struct fdt_property) - FDT_TAGSIZE); |
| if (!can_assume(VALID_DTB) && !lenp) |
| return FDT_END; /* premature end */ |
| |
| /* skip name offset, length */ |
| offset += sizeof(struct fdt_property) - FDT_TAGSIZE; |
| |
| if (!can_assume(VALID_DTB) |
| && !fdt_offset_ptr(fdt, offset, fdt32_to_cpu(*lenp))) |
| return FDT_END; /* premature end */ |
| |
| /* skip value */ |
| offset += 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 (!can_assume(VALID_DTB) && (offset <= startoffset |
| || !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)) |
| return offset; |
| if ((offset < 0) || (offset % FDT_TAGSIZE) |
| || (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 ((offset < 0) || (offset % FDT_TAGSIZE) |
| || (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) |
| { |
| FDT_RO_PROBE(fdt); |
| |
| if (fdt_totalsize(fdt) > bufsize) |
| return -FDT_ERR_NOSPACE; |
| |
| memmove(buf, fdt, fdt_totalsize(fdt)); |
| return 0; |
| } |