Libguestfs - Jan 2014 - [PATCH] hivex: Make empty strings in REG_MULTI_SZ values available.

---
 lib/value.c | 26 +++++++++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/lib/value.c b/lib/value.c
index db6396f..c4e21ec 100644
--- a/lib/value.c
+++ b/lib/value.c
@@ -462,7 +462,27 @@ hivex_value_string (hive_h *h, hive_value_h value)
   return ret;
 }
 
-/* http://blogs.msdn.com/oldnewthing/archive/2009/10/08/9904646.aspx */
+/* Even though
+ * http://msdn.microsoft.com/en-us/library/windows/desktop/ms724884.aspx
+ * and
+ * http://blogs.msdn.com/oldnewthing/archive/2009/10/08/9904646.aspx
+ * claim that it is not possible to store empty strings in MULTI_SZ
+ * string lists, such lists are used by Windows itself:
+ *
+ * The MoveFileEx function can schedule files to be renamed (or
+ * removed) at restart time by storing pairs of filenames in the
+ *
HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\PendingFileRenameOperations
+ * value.
+ *
+ * The documentation for MoveFileEx
+ * (http://msdn.microsoft.com/en-us/library/windows/desktop/aa365240)
+ * states that "[i]f dwFlags specifies MOVEFILE_DELAY_UNTIL_REBOOT,
+ * and lpNewFileName is NULL, MoveFileEx registers the
+ * lpExistingFileName file to be deleted when the system restarts."
+ *
+ * For scheduled removals, the second file name of any pair stored in
+ * PendingFileRenameOperations is an empty string.
+ */
 char **
 hivex_value_multiple_strings (hive_h *h, hive_value_h value)
 {
@@ -490,8 +510,8 @@ hivex_value_multiple_strings (hive_h *h, hive_value_h value)
   char *p = data;
   size_t plen;
 
-  while (p < data + len &&
-         (plen = _hivex_utf16_string_len_in_bytes_max (p, data + len - p)) >
0) {
+  while (p < data + len) {
+    plen = _hivex_utf16_string_len_in_bytes_max (p, data + len - p);
     nr_strings++;
     char **ret2 = realloc (ret, (1 + nr_strings) * sizeof (char *));
     if (ret2 == NULL) {
-- 
1.8.5.2

On Tue, Jan 14, 2014 at 04:41:34PM +0100, Hilko Bengen
wrote:
> ---
>  lib/value.c | 26 +++++++++++++++++++++++---
>  1 file changed, 23 insertions(+), 3 deletions(-)
> 
> diff --git a/lib/value.c b/lib/value.c
> index db6396f..c4e21ec 100644
> --- a/lib/value.c
> +++ b/lib/value.c
> @@ -462,7 +462,27 @@ hivex_value_string (hive_h *h, hive_value_h value)
>    return ret;
>  }
>  
> -/* http://blogs.msdn.com/oldnewthing/archive/2009/10/08/9904646.aspx */
> +/* Even though
> + * http://msdn.microsoft.com/en-us/library/windows/desktop/ms724884.aspx
> + * and
> + * http://blogs.msdn.com/oldnewthing/archive/2009/10/08/9904646.aspx
> + * claim that it is not possible to store empty strings in MULTI_SZ
> + * string lists, such lists are used by Windows itself:
> + *
> + * The MoveFileEx function can schedule files to be renamed (or
> + * removed) at restart time by storing pairs of filenames in the
> + *
HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\PendingFileRenameOperations
> + * value.
> + *
> + * The documentation for MoveFileEx
> + * (http://msdn.microsoft.com/en-us/library/windows/desktop/aa365240)
> + * states that "[i]f dwFlags specifies MOVEFILE_DELAY_UNTIL_REBOOT,
> + * and lpNewFileName is NULL, MoveFileEx registers the
> + * lpExistingFileName file to be deleted when the system restarts."
> + *
> + * For scheduled removals, the second file name of any pair stored in
> + * PendingFileRenameOperations is an empty string.
> + */
>  char **
>  hivex_value_multiple_strings (hive_h *h, hive_value_h value)
>  {
> @@ -490,8 +510,8 @@ hivex_value_multiple_strings (hive_h *h, hive_value_h
value)
>    char *p = data;
>    size_t plen;
>  
> -  while (p < data + len &&
> -         (plen = _hivex_utf16_string_len_in_bytes_max (p, data + len - p))
> 0) {
> +  while (p < data + len) {
> +    plen = _hivex_utf16_string_len_in_bytes_max (p, data + len - p);
>      nr_strings++;
>      char **ret2 = realloc (ret, (1 + nr_strings) * sizeof (char *));
>      if (ret2 == NULL) {
> -- 
> 1.8.5.2
ACK.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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