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From: Florian Weimer <fweimer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: apparmor-nLRlyDuq1AZFpShjVBNYrg@public.gmane.org,
	linux-security-module-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	selinux-+05T5uksL2qpZYMLLGbcSA@public.gmane.org,
	linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>,
	"H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>
Subject: Security modules and sending signals within the same process
Date: Fri, 30 Nov 2018 16:14:27 +0100	[thread overview]
Message-ID: <87lg5asilo.fsf@oldenburg.str.redhat.com> (raw)

Is it guaranteed that tasks in the same thread group can always send
signals to each other, irrespective of their respective credentials
structs?

It's not clear to me whether this is always possible based on the
security_task_kill implementations I've examined.

I want to support per-thread setresuid/setresgid, but we also use
signals for inter-thread communication.  This is mainly for thread
cancellation; the setxgid stuff isn't needed for threads with private
credentials.  I wonder if I need to disable cancellation for threads
with such credentials.

Thanks,
Florian

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WARNING: multiple messages have this Message-ID (diff)
From: Florian Weimer <fweimer@redhat.com>
To: apparmor@lists.ubuntu.com, linux-security-module@vger.kernel.org,
	selinux@tycho.nsa.gov, linux-api@vger.kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>, Arnd Bergmann <arnd@arndb.de>
Subject: Security modules and sending signals within the same process
Date: Fri, 30 Nov 2018 16:14:27 +0100	[thread overview]
Message-ID: <87lg5asilo.fsf@oldenburg.str.redhat.com> (raw)

Is it guaranteed that tasks in the same thread group can always send
signals to each other, irrespective of their respective credentials
structs?

It's not clear to me whether this is always possible based on the
security_task_kill implementations I've examined.

I want to support per-thread setresuid/setresgid, but we also use
signals for inter-thread communication.  This is mainly for thread
cancellation; the setxgid stuff isn't needed for threads with private
credentials.  I wonder if I need to disable cancellation for threads
with such credentials.

Thanks,
Florian

             reply	other threads:[~2018-11-30 15:14 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-30 15:14 Florian Weimer [this message]
2018-11-30 15:14 ` Security modules and sending signals within the same process Florian Weimer
     [not found] ` <87lg5asilo.fsf-fjB847h8rq0pB0kWxzfTigCJwEvxM/w9@public.gmane.org>
2018-11-30 16:02   ` Stephen Smalley
2018-11-30 16:02     ` Stephen Smalley
     [not found]     ` <e754fa24-899b-f77e-f226-0f070ebad132-+05T5uksL2qpZYMLLGbcSA@public.gmane.org>
2018-12-11 10:42       ` Florian Weimer
2018-12-11 10:42         ` Florian Weimer
2018-11-30 17:54   ` Casey Schaufler
2018-11-30 17:54     ` Casey Schaufler
     [not found]     ` <2c3e813c-f56a-3354-1299-30b0646f40e1-iSGtlc1asvQWG2LlvL+J4A@public.gmane.org>
2018-11-30 18:00       ` Florian Weimer
2018-11-30 18:00         ` Florian Weimer
2018-11-30 23:38       ` John Johansen
2018-11-30 23:38         ` [apparmor] " John Johansen

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