[Bug 55928] New: NtQuerySystemInformation SystemProcessInformation result misaligned

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=55928

Bug ID: 55928
           Summary: NtQuerySystemInformation SystemProcessInformation
                    result misaligned
           Product: Wine
           Version: 8.19
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: ntdll
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

Created attachment 75493
  --> https://bugs.winehq.org/attachment.cgi?id=75493
Reproducer

NtQuerySystemInformation with SystemProcessInformation returns misaligned
entries.

Reproducer attached.

Windows output:

Process name: (null)
Process name: System
Process name: Secure System
Process name: Registry
... (trimmed)

Wine output:

Process name: Z
Misaligned at entry 1

[Bug 55928] NtQuerySystemInformation SystemProcessInformation result misaligned

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=55928

Fabian Maurer  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |[e-mail]

[Bug 55928] NtQuerySystemInformation SystemProcessInformation result misaligned

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=55928

--- Comment #1 from Fabian Maurer  ---
Not sure how big the impact is, but yes that's a deviation. Do you know a
program that relies on that alignment?

[Bug 55928] NtQuerySystemInformation SystemProcessInformation result misaligned

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=55928

--- Comment #2 from [e-mail] ---
Any program as long as you compile it with clang and ubsan. This is how I ran
into the issue.

[Bug 55928] NtQuerySystemInformation SystemProcessInformation result misaligned

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=55928

Bernhard Übelacker  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |[e-mail]

--- Comment #3 from Bernhard Übelacker  ---
I could reproduce it with compiling with this line:
clang++ -O0 -g -Wl,/debug -fsanitize=undefined -lntdll main.cpp -o main.exe

Following modification would fix the alignment.
Nearby there are similar lines to align the "pos" pointer.

dlls/ntdll/unix/system.c
@@ -2527,2 +2527,3 @@ static unsigned int get_system_process_info
                      + (name_len + 1) * sizeof(WCHAR);
+        proc_len = (proc_len + 7) & ~7;
         *len += proc_len;