From: Andrew Cooper <andrew.cooper3@citrix.com>
To: "Marek Marczykowski-Górecki" <marmarek@invisiblethingslab.com>
Cc: Xen-devel <xen-devel@lists.xenproject.org>,
Demi Marie Obenour <demi@invisiblethingslab.com>,
Anthony PERARD <anthony@xenproject.org>,
Juergen Gross <jgross@suse.com>
Subject: Re: [PATCH] tools/xl: Open xldevd.log with O_CLOEXEC
Date: Tue, 7 May 2024 15:26:47 +0100 [thread overview]
Message-ID: <27a67c41-6dd3-416a-8be1-cd0daa600449@citrix.com> (raw)
In-Reply-To: <Zjo5dbC6iaFWUA8R@mail-itl>
On 07/05/2024 3:23 pm, Marek Marczykowski-Górecki wrote:
> On Tue, May 07, 2024 at 03:15:48PM +0100, Andrew Cooper wrote:
>> On 07/05/2024 12:32 pm, Marek Marczykowski-Górecki wrote:
>>> On Tue, May 07, 2024 at 12:08:06PM +0100, Andrew Cooper wrote:
>>>> `xl devd` has been observed leaking /var/log/xldevd.log into children.
>>>>
>>>> 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>
>>>> ---
>>>> 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>
>>>>
>>>> Also entirely speculative based on the QubesOS ticket.
>>>> ---
>>>> 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));
>>> This one might be not enough, as the FD gets dup2()-ed to stdout/stderr
>>> just outside of the context here, and then inherited by various hotplug
>>> script. Just adding O_CLOEXEC here means the hotplug scripts will run
>>> with stdout/stderr closed.
>> Lovely :( Yes - this won't work. I guess what we want instead is:
>>
>> diff --git a/tools/xl/xl_utils.c b/tools/xl/xl_utils.c
>> index 060186db3a59..a0ce7dd7fa21 100644
>> --- a/tools/xl/xl_utils.c
>> +++ b/tools/xl/xl_utils.c
>> @@ -282,6 +282,7 @@ int do_daemonize(const char *name, const char *pidfile)
>> dup2(logfile, 2);
>>
>> close(nullfd);
>> + close(logfile);
>>
>> CHK_SYSCALL(daemon(0, 1));
>>
>> which at least means there's not a random extra fd attached to the logfile.
> But logfile is a global variable, and it looks to be used in dolog()...
Urgh, fine. Lets go back to your suggestion of setting CLOEXEC after
dup()ing.
~Andrew
next prev parent reply other threads:[~2024-05-07 14:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-07 11:08 [PATCH] tools/xl: Open xldevd.log with O_CLOEXEC Andrew Cooper
2024-05-07 11:32 ` Marek Marczykowski-Górecki
2024-05-07 14:15 ` Andrew Cooper
2024-05-07 14:23 ` Marek Marczykowski-Górecki
2024-05-07 14:26 ` Andrew Cooper [this message]
2024-05-07 14:26 ` Marek Marczykowski-Górecki
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