[PATCH 0/2] MR6294: mlang: Fix bug when multibyte string truncation in ConvertINetMultiByteToUnicode

[Yeshun Ye (＠yeyeshun)]

mlang/tests: Add test for multibyte string truncation
mlang: Fix bug when multibyte string truncation in ConvertINetMultiByteToUnicode

Signed-off-by: YeshunYe

[PATCH 1/2] mlang/tests: Add test for multibyte string truncation

[YeshunYe]

From: YeshunYe

Signed-off-by: YeshunYe 
---
 dlls/mlang/tests/mlang.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/dlls/mlang/tests/mlang.c b/dlls/mlang/tests/mlang.c
index d104d4d5184..c3d8274bb68 100644
--- a/dlls/mlang/tests/mlang.c
+++ b/dlls/mlang/tests/mlang.c
@@ -567,7 +567,9 @@ static void test_multibyte_to_unicode_translations(IMultiLanguage2 *iML2)
 {
     /* these APIs are broken regarding constness of the input buffer */
     char stringA[] = "Just a test string\0"; /* double 0 for CP_UNICODE tests */
+    char stringA936[] = "test\xb2\xe2\xca\xd4";
     WCHAR stringW[] = {'J','u','s','t',' ','a',' ','t','e','s','t',' ','s','t','r','i','n','g',0};
+    WCHAR stringW936[] = {'t','e','s','t',0x6d4b,0};
     char bufA[256];
     WCHAR bufW[256];
     UINT lenA, lenW, expected_len;
@@ -644,6 +646,17 @@ static void test_multibyte_to_unicode_translations(IMultiLanguage2 *iML2)
     expected_len = MultiByteToWideChar(1252, 0, stringA, lenA, NULL, 0);
     ok(lenW == expected_len, "expected lenW %u, got %u\n", expected_len, lenW);

+    memset(bufW, 'x', sizeof(bufW));
+    lenA = lstrlenA(stringA936);
+    lenA -= 1; /* chinese character truncation */
+    lenW = ARRAY_SIZE(bufW);
+    ret = pConvertINetMultiByteToUnicode(NULL, 936, stringA936, (INT *)&lenA, bufW, (INT *)&lenW);
+    ok(ret == S_OK, "ConvertINetMultiByteToUnicode failed: %08lx\n", ret);
+    todo_wine ok(lenA == lstrlenA(stringA936) - 2, "expected lenA %u, got %u\n", lstrlenA(stringA936) - 2, lenA);
+    expected_len = MultiByteToWideChar(936, 0, stringA936, lenA, NULL, 0);
+    ok(lenW == expected_len, "expected lenW %u, got %u\n", expected_len, lenW);
+    todo_wine ok(!memcmp(bufW, stringW936, lenW * sizeof(WCHAR)), "bufW/stringW mismatch\n");
+
     /* IMultiLanguage2_ConvertStringFromUnicode tests */

memset(bufA, 'x', sizeof(bufA));

[PATCH 2/2] mlang: Fix bug when multibyte string truncation in ConvertINetMultiByteToUnicode

[YeshunYe]

From: YeshunYe

Signed-off-by: YeshunYe 
---
 dlls/mlang/mlang.c       | 5 ++++-
 dlls/mlang/tests/mlang.c | 4 ++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/dlls/mlang/mlang.c b/dlls/mlang/mlang.c
index e340a5f57c7..2a7b047a614 100644
--- a/dlls/mlang/mlang.c
+++ b/dlls/mlang/mlang.c
@@ -983,7 +983,10 @@ HRESULT WINAPI ConvertINetMultiByteToUnicode(
     default:
         if (*pcSrcSize == -1)
             *pcSrcSize = lstrlenA(pSrcStr);
-
+        while (MultiByteToWideChar(dwEncoding, MB_ERR_INVALID_CHARS, pSrcStr, *pcSrcSize, 0, 0) == 0)
+        {
+            (*pcSrcSize)--;
+        }
         if (pDstStr)
             *pcDstSize = MultiByteToWideChar(dwEncoding, 0, pSrcStr, *pcSrcSize, pDstStr, *pcDstSize);
         else
diff --git a/dlls/mlang/tests/mlang.c b/dlls/mlang/tests/mlang.c
index c3d8274bb68..936b5a301e2 100644
--- a/dlls/mlang/tests/mlang.c
+++ b/dlls/mlang/tests/mlang.c
@@ -652,10 +652,10 @@ static void test_multibyte_to_unicode_translations(IMultiLanguage2 *iML2)
     lenW = ARRAY_SIZE(bufW);
     ret = pConvertINetMultiByteToUnicode(NULL, 936, stringA936, (INT *)&lenA, bufW, (INT *)&lenW);
     ok(ret == S_OK, "ConvertINetMultiByteToUnicode failed: %08lx\n", ret);
-    todo_wine ok(lenA == lstrlenA(stringA936) - 2, "expected lenA %u, got %u\n", lstrlenA(stringA936) - 2, lenA);
+    ok(lenA == lstrlenA(stringA936) - 2, "expected lenA %u, got %u\n", lstrlenA(stringA936) - 2, lenA);
     expected_len = MultiByteToWideChar(936, 0, stringA936, lenA, NULL, 0);
     ok(lenW == expected_len, "expected lenW %u, got %u\n", expected_len, lenW);
-    todo_wine ok(!memcmp(bufW, stringW936, lenW * sizeof(WCHAR)), "bufW/stringW mismatch\n");
+    ok(!memcmp(bufW, stringW936, lenW * sizeof(WCHAR)), "bufW/stringW mismatch\n");

/* IMultiLanguage2_ConvertStringFromUnicode tests */