[Libguestfs] [PATCH 3/3, take 2] lib: Add support for creating nodes (keys) and values with UTF-16LE-encoded names
Richard W.M. Jones
rjones at redhat.com
Mon Nov 25 22:00:59 UTC 2013
On Mon, Nov 25, 2013 at 10:56:07PM +0100, Hilko Bengen wrote:
> ---
> 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;
* 2 again?
> + 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);
> }
This version is definitely an improvement however.
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming blog: http://rwmj.wordpress.com
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