[PATCH 0/2] MR10035: kernelbase: Don't write *result on async NtWriteFile returns.

[Stefan Dösinger (＠stefan)]

If the caller passes the same pointer to WriteFile as it passes to
GetOverlappedResult in another thread, the writes to the memory
location in the two files will race each other.

---

Is there ever a case where piosb->Information != 0 when status != 0 (or
NT_ERROR(status))? If an error status always suggests a 0 length, we can
remove the check for overlapped != NULL here.

DeviceIoControl is potentially affected too, but it doesn't set
*returned=0 in any situation. I think ws2_32:AcceptEx might be affected
by the same problem too. The other ws32_32 functions look ok.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/10035

[PATCH 1/2] kernelbase: Don't write *result on async NtWriteFile returns.

[Stefan Dösinger]

From: Stefan Dösinger <[e-mail]>

If the caller passes the same pointer to WriteFile as it passes to
GetOverlappedResult in another thread, the writes to the memory
location in the two files will race each other.

---

Is there ever a case where piosb->Information != 0 when status != 0 (or
NT_ERROR(status))? If an error status always suggests a 0 length, we can
remove the check for overlapped != NULL here.

DeviceIoControl is potentially affected too, but it doesn't set
*returned=0 in any situation. I think ws2_32:AcceptEx might be affected
by the same problem too. The other ws32_32 functions look ok.
---
 dlls/kernelbase/file.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/dlls/kernelbase/file.c b/dlls/kernelbase/file.c
index e271b03de1f..d99d63f185e 100644
--- a/dlls/kernelbase/file.c
+++ b/dlls/kernelbase/file.c
@@ -4013,6 +4013,8 @@ BOOL WINAPI DECLSPEC_HOTPATCH WriteFile( HANDLE file, LPCVOID buffer, DWORD coun
     else piosb->Information = 0;
     piosb->Status = STATUS_PENDING;
 
+    if (result) *result = 0;
+
     status = NtWriteFile( file, event, NULL, cvalue, piosb, buffer, count, poffset, NULL );
 
     if (status == STATUS_PENDING && !overlapped)
@@ -4021,7 +4023,7 @@ BOOL WINAPI DECLSPEC_HOTPATCH WriteFile( HANDLE file, LPCVOID buffer, DWORD coun
         status = piosb->Status;
     }
 
-    if (result) *result = overlapped && status ? 0 : piosb->Information;
+    if (result && (!overlapped || !status)) *result = piosb->Information;
 
     if (status && status != STATUS_TIMEOUT)
     {
-- 
GitLab


https://gitlab.winehq.org/wine/wine/-/merge_requests/10035

[PATCH 2/2] kernelbase: Don't write *result on async NtReadFile returns.

[Stefan Dösinger]

From: Stefan Dösinger <[e-mail]>

---

The assignment of *result = 0 is already in place in this function.
---
 dlls/kernelbase/file.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/dlls/kernelbase/file.c b/dlls/kernelbase/file.c
index d99d63f185e..7c079260af9 100644
--- a/dlls/kernelbase/file.c
+++ b/dlls/kernelbase/file.c
@@ -3620,7 +3620,7 @@ BOOL WINAPI DECLSPEC_HOTPATCH ReadFile( HANDLE file, LPVOID buffer, DWORD count,
         status = io_status->Status;
     }
 
-    if (result) *result = overlapped && status ? 0 : io_status->Information;
+    if (result && (!overlapped || !status)) *result = io_status->Information;
 
     if (status == STATUS_END_OF_FILE)
     {
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/10035