Esme Povirk : dwrite: Avoid calling memcpy with NULL source.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 412b36e45a7d086747b6ef42b9b9b0e432ac4d77
URL:    https://source.winehq.org/git/wine.git/?a=commit;h=412b36e45a7d086747b6ef42b9b9b0e432ac4d77

Author: Esme Povirk <esme at codeweavers.com>
Date:   Sat Dec 11 14:04:26 2021 -0600

dwrite: Avoid calling memcpy with NULL source.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=52187
Signed-off-by: Esme Povirk <esme at codeweavers.com>
Signed-off-by: Nikolay Sivov <nsivov at codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard at winehq.org>

---

 dlls/dwrite/analyzer.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/dlls/dwrite/analyzer.c b/dlls/dwrite/analyzer.c
index 7112ca71932..8ecfad5f3a5 100644
--- a/dlls/dwrite/analyzer.c
+++ b/dlls/dwrite/analyzer.c
@@ -868,7 +868,8 @@ static HRESULT get_text_source_ptr(IDWriteTextAnalysisSource *source, UINT32 pos
         *buff = malloc(length * sizeof(WCHAR));
         if (!*buff)
             return E_OUTOFMEMORY;
-        memcpy(*buff, *text, len*sizeof(WCHAR));
+        if (*text)
+            memcpy(*buff, *text, len*sizeof(WCHAR));
         read = len;
 
         while (read < length && *text) {
@@ -880,6 +881,8 @@ static HRESULT get_text_source_ptr(IDWriteTextAnalysisSource *source, UINT32 pos
                 free(*buff);
                 return hr;
             }
+            if (!*text)
+                break;
             memcpy(*buff + read, *text, min(len, length-read)*sizeof(WCHAR));
             read += len;
         }
@@ -1009,7 +1012,8 @@ static HRESULT WINAPI dwritetextanalyzer_AnalyzeLineBreakpoints(IDWriteTextAnaly
 
         if (!(buff = calloc(length, sizeof(*buff))))
             return E_OUTOFMEMORY;
-        memcpy(buff, text, len*sizeof(WCHAR));
+        if (text)
+            memcpy(buff, text, len*sizeof(WCHAR));
         read = len;
 
         while (read < length && text) {
@@ -1018,6 +1022,8 @@ static HRESULT WINAPI dwritetextanalyzer_AnalyzeLineBreakpoints(IDWriteTextAnaly
             hr = IDWriteTextAnalysisSource_GetTextAtPosition(source, read, &text, &len);
             if (FAILED(hr))
                 goto done;
+            if (!text)
+                break;
             memcpy(&buff[read], text, min(len, length-read)*sizeof(WCHAR));
             read += len;
         }