[Libguestfs] [PATCH 3/3, take 2] lib: Add support for creating nodes (keys) and values with UTF-16LE-encoded names

[Hilko Bengen]

---
 lib/write.c | 50 +++++++++++++++++++++++++++++++++++---------------
 1 file changed, 35 insertions(+), 15 deletions(-)

diff --git a/lib/write.c b/lib/write.c
index dbb8292..8c4dd8e 100644
--- a/lib/write.c
+++ b/lib/write.c
@@ -608,9 +608,17 @@ hivex_node_add_child (hive_h *h, hive_node_h parent, const char *name)
     return 0;
   }
 
+  size_t recoded_name_len;
+  int use_utf16 = 0;
+  char* recoded_name = _hivex_encode_string (name, &recoded_name_len, &use_utf16);
+  if (recoded_name == NULL) {
+    SET_ERRNO (EINVAL, "malformed name");
+    return 0;
+  }
+
   /* Create the new nk-record. */
   static const char nk_id[2] = { 'n', 'k' };
-  size_t seg_len = sizeof (struct ntreg_nk_record) + strlen (name);
+  size_t seg_len = sizeof (struct ntreg_nk_record) + recoded_name_len;
   hive_node_h nkoffset = allocate_block (h, seg_len, nk_id);
   if (nkoffset == 0)
     return 0;
@@ -619,14 +627,18 @@ hivex_node_add_child (hive_h *h, hive_node_h parent, const char *name)
 
   struct ntreg_nk_record *nk =
     (struct ntreg_nk_record *) ((char *) h->addr + nkoffset);
-  nk->flags = htole16 (0x0020); /* key is ASCII. */
+  if (use_utf16)
+    nk->flags = htole16 (0x0000);
+  else
+    nk->flags = htole16 (0x0020);
   nk->parent = htole32 (parent - 0x1000);
   nk->subkey_lf = htole32 (0xffffffff);
   nk->subkey_lf_volatile = htole32 (0xffffffff);
   nk->vallist = htole32 (0xffffffff);
   nk->classname = htole32 (0xffffffff);
-  nk->name_len = htole16 (strlen (name));
-  strcpy (nk->name, name);
+  nk->name_len = htole16 (recoded_name_len);
+  memcpy (nk->name, recoded_name, recoded_name_len);
+  free (recoded_name);
 
   /* Inherit parent sk. */
   struct ntreg_nk_record *parent_nk =
@@ -719,9 +731,9 @@ hivex_node_add_child (hive_h *h, hive_node_h parent, const char *name)
   parent_nk->nr_subkeys = htole32 (nr_subkeys_in_parent_nk);
 
   /* Update max_subkey_name_len in parent nk. */
-  uint16_t max = le16toh (parent_nk->max_subkey_name_len);
-  if (max < strlen (name) * 2)  /* *2 because "recoded" in UTF16-LE. */
-    parent_nk->max_subkey_name_len = htole16 (strlen (name) * 2);
+  size_t utf16_len = use_utf16 ? recoded_name_len : recoded_name_len * 2;
+  if (le16toh (parent_nk->max_subkey_name_len) < utf16_len)
+    parent_nk->max_subkey_name_len = htole16 (utf16_len);
 
   return nkoffset;
 }
@@ -942,7 +954,12 @@ hivex_node_set_values (hive_h *h, hive_node_h node,
   for (i = 0; i < nr_values; ++i) {
     /* Allocate vk record to store this (key, value) pair. */
     static const char vk_id[2] = { 'v', 'k' };
-    seg_len = sizeof (struct ntreg_vk_record) + strlen (values[i].key);
+    size_t name_len = strlen (values[i].key);
+    size_t recoded_name_len;
+    int use_utf16;
+    char* recoded_name = _hivex_encode_string (values[i].key, &recoded_name_len,
+                                               &use_utf16);
+    seg_len = sizeof (struct ntreg_vk_record) + recoded_name_len;
     size_t vk_offs = allocate_block (h, seg_len, vk_id);
     if (vk_offs == 0)
       return -1;
@@ -957,15 +974,18 @@ hivex_node_set_values (hive_h *h, hive_node_h node,
 
     struct ntreg_vk_record *vk =
       (struct ntreg_vk_record *) ((char *) h->addr + vk_offs);
-    size_t name_len = strlen (values[i].key);
-    vk->name_len = htole16 (name_len);
-    strcpy (vk->name, values[i].key);
+    vk->name_len = htole16 (recoded_name_len);
+    memcpy (vk->name, recoded_name, recoded_name_len);
+    free (recoded_name);
     vk->data_type = htole32 (values[i].t);
     uint32_t len = values[i].len;
     if (len <= 4)               /* store it inline => set MSB flag */
       len |= 0x80000000;
     vk->data_len = htole32 (len);
-    vk->flags = name_len == 0 ? 0 : 1;
+    if (recoded_name_len == 0)
+      vk->flags = 0;
+    else
+      vk->flags = htole16 (!use_utf16);
 
     if (values[i].len <= 4)     /* store it inline */
       memcpy (&vk->data_offset, values[i].value, values[i].len);
@@ -985,9 +1005,9 @@ hivex_node_set_values (hive_h *h, hive_node_h node,
       vk->data_offset = htole32 (offs - 0x1000);
     }
 
-    if (name_len * 2 > le32toh (nk->max_vk_name_len))
-      /* * 2 for UTF16-LE "reencoding" */
-      nk->max_vk_name_len = htole32 (name_len * 2);
+    size_t utf16_len = use_utf16 ? recoded_name_len : recoded_name_len * 2;
+    if (utf16_len > le32toh (nk->max_vk_name_len))
+      nk->max_vk_name_len = htole32 (utf16_len);
     if (values[i].len > le32toh (nk->max_vk_data_len))
       nk->max_vk_data_len = htole32 (values[i].len);
   }
-- 
1.8.4.4