hivex: page 'offset_next' field is really 'page_size'.

The documentation, as usual, is contradictory.  However this
field is definitely the page size in all observed registries.
Furthermore the following field marked 'unknown' is always
zero, although this contradicts what the sentinelchicken.com
paper says.

diff --git a/hivex/hivex.c b/hivex/hivex.c
index c0e456f..fd65f8c 100644 (file)
--- a/hivex/hivex.c
+++ b/hivex/hivex.c
@@ -161,7 +161,7 @@ struct ntreg_header {
 struct ntreg_hbin_page {
   char magic[4];                /* "hbin" */
   uint32_t offset_first;        /* offset from 1st block */
-  uint32_t offset_next;         /* offset of next (relative to this) */
+  uint32_t page_size;           /* size of this page (multiple of 4KB) */
   char unknown[20];
   /* Linked list of blocks follows here. */
 } __attribute__((__packed__));
@@ -386,7 +386,7 @@ hivex_open (const char *filename, int flags)
    */
   size_t off;
   struct ntreg_hbin_page *page;
-  for (off = 0x1000; off < h->size; off += le32toh (page->offset_next)) {
+  for (off = 0x1000; off < h->size; off += le32toh (page->page_size)) {
     if (off >= h->endpages)
       break;
 
@@ -401,17 +401,17 @@ hivex_open (const char *filename, int flags)
       goto error;
     }
 
-    size_t page_size = le32toh (page->offset_next);
+    size_t page_size = le32toh (page->page_size);
     if (h->msglvl >= 2)
       fprintf (stderr, "hivex_open: page at 0x%zx, size %zu\n", off, page_size);
     pages++;
     if (page_size < smallest_page) smallest_page = page_size;
     if (page_size > largest_page) largest_page = page_size;
 
-    if (le32toh (page->offset_next) <= sizeof (struct ntreg_hbin_page) ||
-        (le32toh (page->offset_next) & 3) != 0) {
-      fprintf (stderr, "hivex: %s: pagesize %d at %zu, bad registry\n",
-               filename, le32toh (page->offset_next), off);
+    if (page_size <= sizeof (struct ntreg_hbin_page) ||
+        (page_size & 0x0fff) != 0) {
+      fprintf (stderr, "hivex: %s: page size %zu at 0x%zx, bad registry\n",
+               filename, page_size, off);
       errno = ENOTSUP;
       goto error;
     }
@@ -421,7 +421,7 @@ hivex_open (const char *filename, int flags)
     struct ntreg_hbin_block *block;
     size_t seg_len;
     for (blkoff = off + 0x20;
-         blkoff < off + le32toh (page->offset_next);
+         blkoff < off + page_size;
          blkoff += seg_len) {
       blocks++;