[PATCH 0/1] MR870: ntdll: Calculate the necessary length after calling snprintf() in SystemWineVersionInformation.

[Zebediah Figura (＠zfigura)]

This is a gcc bug:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96367

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/870

[PATCH 1/1] ntdll: Calculate the necessary length after calling snprintf() in SystemWineVersionInformation.

[Zebediah Figura]

From: Zebediah Figura <zfigura(a)codeweavers.com>

This works around a spurious gcc warning:

../wine/dlls/ntdll/unix/system.c: In function ‘NtQuerySystemInformation’:
../wine/dlls/ntdll/unix/system.c:3176:36: error: ‘%s’ directive output between 0 and 2147483644 bytes may cause result to exceed ‘INT_MAX’ [-Werror=format-truncation=]
 3176 |         snprintf( info, size, "%s%c%s%c%s%c%s", version, 0, wine_build, 0, buf.sysname, 0, buf.release );
      |                                    ^~                       ~~~~~~~~~~
../wine/dlls/ntdll/unix/system.c:3176:9: note: ‘snprintf’ output between 8 and 2147483780 bytes into a destination of size 4294967295
 3176 |         snprintf( info, size, "%s%c%s%c%s%c%s", version, 0, wine_build, 0, buf.sysname, 0, buf.release );
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
---
 dlls/ntdll/unix/system.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/dlls/ntdll/unix/system.c b/dlls/ntdll/unix/system.c
index 83e0521a3c9..136fc80adf1 100644
--- a/dlls/ntdll/unix/system.c
+++ b/dlls/ntdll/unix/system.c
@@ -3172,8 +3172,8 @@ NTSTATUS WINAPI NtQuerySystemInformation( SYSTEM_INFORMATION_CLASS class,
         struct utsname buf;
 
         uname( &buf );
-        len = strlen(version) + strlen(wine_build) + strlen(buf.sysname) + strlen(buf.release) + 4;
         snprintf( info, size, "%s%c%s%c%s%c%s", version, 0, wine_build, 0, buf.sysname, 0, buf.release );
+        len = strlen(version) + strlen(wine_build) + strlen(buf.sysname) + strlen(buf.release) + 4;
         if (size < len) ret = STATUS_INFO_LENGTH_MISMATCH;
         break;
     }
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/870