[ros-dev] [ros-diffs] [hbelusca] 57504: [NTOSKRNL] Rearrange the NtQuerySystemEnvironmentValue code to have successive logical checks.

[Timo Kreuzer]

This changes the logic. I'm not sure how exact the previous version was, 
but these changes should be tested.


Am 06.10.2012 21:50, schrieb hbelusca at svn.reactos.org:
> Author: hbelusca
> Date: Sat Oct  6 19:50:17 2012
> New Revision: 57504
>
> URL: http://svn.reactos.org/svn/reactos?rev=57504&view=rev
> Log:
> [NTOSKRNL]
> Rearrange the NtQuerySystemEnvironmentValue code to have successive logical checks.
>
> Modified:
>      trunk/reactos/ntoskrnl/ex/sysinfo.c
>
> Modified: trunk/reactos/ntoskrnl/ex/sysinfo.c
> URL: http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/ex/sysinfo.c?rev=57504&r1=57503&r2=57504&view=diff
> ==============================================================================
> --- trunk/reactos/ntoskrnl/ex/sysinfo.c [iso-8859-1] (original)
> +++ trunk/reactos/ntoskrnl/ex/sysinfo.c [iso-8859-1] Sat Oct  6 19:50:17 2012
> @@ -235,44 +235,40 @@
>               _SEH2_YIELD(return _SEH2_GetExceptionCode());
>           }
>           _SEH2_END;
> -
> -    }
> -
> -    /* Allocate a buffer for the value */
> -    AnsiValueBuffer = ExAllocatePoolWithTag(NonPagedPool, ValueBufferLength, 'pmeT');
> -    if (AnsiValueBuffer == NULL)
> -    {
> -        return STATUS_INSUFFICIENT_RESOURCES;
> -    }
> -
> -    /*
> -     * Copy the name to kernel space if necessary and convert it to ANSI.
> -     */
> +    }
> +
> +    /* According to NTInternals the SeSystemEnvironmentName privilege is required! */
> +    if (!SeSinglePrivilegeCheck(SeSystemEnvironmentPrivilege, PreviousMode))
> +    {
> +        DPRINT1("NtQuerySystemEnvironmentValue: Caller requires the SeSystemEnvironmentPrivilege privilege!\n");
> +        return STATUS_PRIVILEGE_NOT_HELD;
> +    }
> +
> +    /* Copy the name to kernel space if necessary */
>       Status = ProbeAndCaptureUnicodeString(&WName, PreviousMode, VariableName);
>       if (!NT_SUCCESS(Status))
>       {
>           return Status;
>       }
>   
> -    /*
> -     * according to ntinternals the SeSystemEnvironmentName privilege is required!
> -     */
> -    if (!SeSinglePrivilegeCheck(SeSystemEnvironmentPrivilege, PreviousMode))
> -    {
> -        ReleaseCapturedUnicodeString(&WName, PreviousMode);
> -        DPRINT1("NtQuerySystemEnvironmentValue: Caller requires the SeSystemEnvironmentPrivilege privilege!\n");
> -        return STATUS_PRIVILEGE_NOT_HELD;
> -    }
> -
> -    /* Convert the value name to ansi and release the captured unicode string */
> +    /* Convert the name to ANSI and release the captured UNICODE string */
>       Status = RtlUnicodeStringToAnsiString(&AName, &WName, TRUE);
>       ReleaseCapturedUnicodeString(&WName, PreviousMode);
>       if (!NT_SUCCESS(Status)) return Status;
>   
> -    /* Get the environment variable */
> +    /* Allocate a buffer for the ANSI environment variable */
> +    AnsiValueBuffer = ExAllocatePoolWithTag(NonPagedPool, ValueBufferLength, 'pmeT');
> +    if (AnsiValueBuffer == NULL)
> +    {
> +        RtlFreeAnsiString(&AName);
> +        return STATUS_INSUFFICIENT_RESOURCES;
> +    }
> +
> +    /* Get the environment variable and free the ANSI name */
>       Result = HalGetEnvironmentVariable(AName.Buffer,
>                                          (USHORT)ValueBufferLength,
>                                          AnsiValueBuffer);
> +    RtlFreeAnsiString(&AName);
>   
>       /* Check if we had success */
>       if (Result == ESUCCESS)
> @@ -280,13 +276,13 @@
>           /* Copy the result back to the caller. */
>           _SEH2_TRY
>           {
> -            /* Initialize ansi string from the result */
> +            /* Initialize ANSI string from the result */
>               RtlInitAnsiString(&AValue, AnsiValueBuffer);
>   
> -            /* Initialize a unicode string from the callers buffer */
> +            /* Initialize a UNICODE string from the callers buffer */
>               RtlInitEmptyUnicodeString(&WValue, ValueBuffer, ValueBufferLength);
>   
> -            /* Convert the result to unicode */
> +            /* Convert the result to UNICODE */
>               Status = RtlAnsiStringToUnicodeString(&WValue, &AValue, FALSE);
>   
>               if (ReturnLength != NULL)
> @@ -305,8 +301,7 @@
>           Status = STATUS_UNSUCCESSFUL;
>       }
>   
> -    /* Cleanup allocated resources. */
> -    RtlFreeAnsiString(&AName);
> +    /* Free the allocated ANSI value buffer */
>       ExFreePoolWithTag(AnsiValueBuffer, 'pmeT');
>   
>       return Status;
>
>
>