Re: [PATCH for-4.19 v2] tools/xl: Open xldevd.log with O_CLOEXEC

[Oleksii <oleksii.kurochko@gmail.com>]

On Fri, 2024-06-21 at 17:16 +0100, Andrew Cooper wrote:
> `xl devd` has been observed leaking /var/log/xldevd.log into
> children.
> 
> Note this is specifically safe; dup2() leaves O_CLOEXEC disabled on
> newfd, so
> after setting up stdout/stderr, it's only the logfile fd which will
> close on
> exec().
> 
> Link: https://github.com/QubesOS/qubes-issues/issues/8292
> Reported-by: Demi Marie Obenour <demi@invisiblethingslab.com>
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-Acked-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>

~ Oleksii

> ---
> CC: Anthony PERARD <anthony@xenproject.org>
> CC: Juergen Gross <jgross@suse.com>
> CC: Demi Marie Obenour <demi@invisiblethingslab.com>
> CC: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
> CC: Oleksii Kurochko <oleksii.kurochko@gmail.com>
> 
> Also entirely speculative based on the QubesOS ticket.
> 
> v2:
>  * Extend the commit message to explain why stdout/stderr aren't
> closed by
>    this change
> 
> For 4.19.  This bugfix was posted earlier, but fell between the
> cracks.
> ---
>  tools/xl/xl_utils.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/xl/xl_utils.c b/tools/xl/xl_utils.c
> index 17489d182954..060186db3a59 100644
> --- a/tools/xl/xl_utils.c
> +++ b/tools/xl/xl_utils.c
> @@ -270,7 +270,7 @@ int do_daemonize(const char *name, const char
> *pidfile)
>          exit(-1);
>      }
>  
> -    CHK_SYSCALL(logfile = open(fullname, O_WRONLY|O_CREAT|O_APPEND,
> 0644));
> +    CHK_SYSCALL(logfile = open(fullname, O_WRONLY | O_CREAT |
> O_APPEND | O_CLOEXEC, 0644));
>      free(fullname);
>      assert(logfile >= 3);
>