[PATCH v1] kernel32: make GetEnvironmentStringsW returns a copy of the environment

[Jon Doron]

There are certain applications which try to traverse the environement
being returned, but this is problematic since they cannot acquire the
PEB Lock (i.e cl.exe on Visual Studio 14.15) .

To resolve the issue provide a copy of the current environment same as
in GetEnvironmentStringsA .

Signed-off-by: Jon Doron <arilou(a)gmail.com>
---
 dlls/kernel32/environ.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/dlls/kernel32/environ.c b/dlls/kernel32/environ.c
index 99bf706e95..c8f32aa0fb 100644
--- a/dlls/kernel32/environ.c
+++ b/dlls/kernel32/environ.c
@@ -139,7 +139,22 @@ LPSTR WINAPI GetEnvironmentStringsA(void)
  */
 LPWSTR WINAPI GetEnvironmentStringsW(void)
 {
-    return NtCurrentTeb()->Peb->ProcessParameters->Environment;
+    LPWSTR ret, ptrW;
+    unsigned len;
+
+    RtlAcquirePebLock();
+
+    ptrW = NtCurrentTeb()->Peb->ProcessParameters->Environment;
+    while (*ptrW)
+        ptrW += strlenW(ptrW) + 1;
+
+    len = (ULONG_PTR)ptrW - (ULONG_PTR)NtCurrentTeb()->Peb->ProcessParameters->Environment;
+    ret = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, len + (sizeof(WCHAR) * 2));
+    if (ret)
+        memcpy(ret, NtCurrentTeb()->Peb->ProcessParameters->Environment, len);
+
+    RtlReleasePebLock();
+    return ret;
 }
 
 
@@ -157,7 +172,7 @@ BOOL WINAPI FreeEnvironmentStringsA( LPSTR ptr )
  */
 BOOL WINAPI FreeEnvironmentStringsW( LPWSTR ptr )
 {
-    return TRUE;
+    return HeapFree( GetProcessHeap(), 0, ptr );
 }
 
 
-- 
2.19.2

[Nikolay Sivov]

On 3/16/19 9:57 PM, Jon Doron wrote:
> There are certain applications which try to traverse the environement 
> being returned, but this is problematic since they cannot acquire the 
> PEB Lock (i.e cl.exe on Visual Studio 14.15) . To resolve the issue 
> provide a copy of the current environment same as in 
> GetEnvironmentStringsA .
> Please add a test to confirm this change.