[CRT] Fix buffer-overrun in I10_OUTPUT on MSVC builds

This function is totally broken on MSVC builds and the tests are hacked and also broken, so skip them on MSVC builds.
tkreuzer · Nov 2, 2023 · b63719c · b63719c
1 parent 6bc9281
commit b63719c
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Showing 2 changed files with 6 additions and 1 deletion.
diff --git a/modules/rostests/winetests/msvcrt/misc.c b/modules/rostests/winetests/msvcrt/misc.c
@@ -167,6 +167,11 @@ static void test_I10_OUTPUT(void)
         win_skip("I10_OUTPUT not available\n");
         return;
     }
+    if (sizeof(long double) == 8)
+    {
+        skip("I10_OUTPUT test is broken on MSVC builds!\n");
+        return;
+    }
     if (j != 12)
         trace("sizeof(long double) = %d on this machine\n", j);
 

diff --git a/sdk/lib/crt/misc/i10output.c b/sdk/lib/crt/misc/i10output.c
@@ -38,7 +38,7 @@ int CDECL MSVCRT_I10_OUTPUT(_LDOUBLE ld80, int prec, int flag, struct _I10_OUTPU
     char buf[I10_OUTPUT_MAX_PREC+9]; /* 9 = strlen("0.e+0000") + '\0' */
     char *p;
 
-    memcpy(&ld, &ld80, 10);
+    memcpy(&ld, &ld80, min(sizeof(ld80), sizeof(ld))); // This is broken on MSVC builds!
     d = ld;
     TRACE("(%lf %d %x %p)\n", d, prec, flag, data);