Hugh McMaster : reg: Prevent buffer over-read when querying REG_NONE values with no data.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 60c8dfdd0bbaff4a2369f884ec1a553a06735676
URL:    https://source.winehq.org/git/wine.git/?a=commit;h=60c8dfdd0bbaff4a2369f884ec1a553a06735676

Author: Hugh McMaster <hugh.mcmaster at outlook.com>
Date:   Thu May  6 22:47:55 2021 +1000

reg: Prevent buffer over-read when querying REG_NONE values with no data.

Signed-off-by: Hugh McMaster <hugh.mcmaster at outlook.com>
Signed-off-by: Alexandre Julliard <julliard at winehq.org>

---

 programs/reg/query.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/programs/reg/query.c b/programs/reg/query.c
index 7e42719faf9..4886fb84bc1 100644
--- a/programs/reg/query.c
+++ b/programs/reg/query.c
@@ -50,7 +50,15 @@ static WCHAR *reg_data_to_wchar(DWORD type, const BYTE *src, DWORD size_bytes)
             WCHAR *ptr;
 
             buffer = malloc((size_bytes * 2 + 1) * sizeof(WCHAR));
+
+            if (!size_bytes)
+            {
+                *buffer = 0;
+                break;
+            }
+
             ptr = buffer;
+
             for (i = 0; i < size_bytes; i++)
                 ptr += swprintf(ptr, 3, L"%02X", src[i]);
             break;