ada/4482: Ada: /tmp race condition fixed only partially

[fw@deneb.enyo.de]

>Number:         4482
>Category:       ada
>Synopsis:       /tmp race condition fixed only partially
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Oct 05 11:06:01 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator:     Florian Weimer
>Release:        3.1 20011005 (experimental)
>Organization:
>Environment:
*BSD, and probably others.

>Description:

The implementation of __gnat_tmp_name() in ada/adainit.c creates temporary
files safely only on GNU/Linux.  (/tmp race conditions are a security
problem.)

>How-To-Repeat:

Compile the following program:

with Ada.Text_IO;
use Ada.Text_IO;
procedure Test_Temp_File is
   File : File_Type;
begin
   Create (File);
end Test_Temp_File;

and run it under  strace or a similar tool to check if the open() system
call for the tempory file uses the O_EXCL flag.  If it doesn't,
it's very unlikely that the temporary file is created in a safe manner.

>Fix:
Use mkstemp() on more platforms, or copy the mkstemp() implementation from
GNU libc (which should work on most UNIX-like platforms).
>Release-Note:
>Audit-Trail:
>Unformatted: