+ 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 fdt_chk_version() ? fdt_header_size_(fdt_version(fdt)) :
+ FDT_V17_SIZE;
+}
+
+int fdt_check_header(const void *fdt)
+{
+ size_t hdrsize;
+
+ if (fdt_magic(fdt) != FDT_MAGIC)
+ return -FDT_ERR_BADMAGIC;
+ if (fdt_chk_version()) {
+ 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 (fdt_chk_basic()) {
+
+ 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 (fdt_chk_extra()) {
+ /* Bounds check structure block */
+ if (fdt_chk_version() && 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;
+ }
+