Commit ff118479 authored Nov 06, 2015 by Jeff Mahoney Committed by John Johansen Jul 12, 2016

apparmor: allow SYS_CAP_RESOURCE to be sufficient to prlimit another task



While using AppArmor, SYS_CAP_RESOURCE is insufficient to call prlimit
on another task. The only other example of a AppArmor mediating access to
another, already running, task (ignoring fork+exec) is ptrace.

The AppArmor model for ptrace is that one of the following must be true:
1) The tracer is unconfined
2) The tracer is in complain mode
3) The tracer and tracee are confined by the same profile
4) The tracer is confined but has SYS_CAP_PTRACE

1), 2, and 3) are already true for setrlimit.

We can match the ptrace model just by allowing CAP_SYS_RESOURCE.

We still test the values of the rlimit since it can always be overridden
using a value that means unlimited for a particular resource.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>

parent 38dbd7d8

security/apparmor/resource.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -101,9 +101,11 @@ int aa_task_setrlimit(struct aa_profile profile, struct task_struct task,
		/* TODO: extend resource control to handle other (non current)
		* profiles. AppArmor rules currently have the implicit assumption
		* that the task is setting the resource of a task confined with
		* the same profile.
		* the same profile or that the task setting the resource of another
		* task has CAP_SYS_RESOURCE.
		*/
		if (profile != task_profile \|\|
		if ((profile != task_profile &&
		aa_capable(profile, CAP_SYS_RESOURCE, 1)) \|\|
		(profile->rlimits.mask & (1 << resource) &&
		new_rlim->rlim_max > profile->rlimits.limits[resource].rlim_max))
		error = -EACCES;

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