From a44f33e5cafc02477c182119ee422ea54eb1f3db Mon Sep 17 00:00:00 2001
From: Eduardo Otubo <otubo@redhat.com>
Date: Fri, 28 Sep 2018 07:56:35 +0100
Subject: [PATCH 1/6] seccomp: allow sched_setscheduler() with SCHED_IDLE
policy
MIME-Version: 1.0
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RH-Author: Eduardo Otubo <otubo@redhat.com>
Message-id: <20180928075639.16746-2-otubo@redhat.com>
Patchwork-id: 82317
O-Subject: [RHEL-8 qemu-kvm PATCH 1/5] seccomp: allow sched_setscheduler() with SCHED_IDLE policy
Bugzilla: 1618356
RH-Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
RH-Acked-by: Marc-André Lureau <marcandre.lureau@redhat.com>
RH-Acked-by: Thomas Huth <thuth@redhat.com>
From: Marc-André Lureau <marcandre.lureau@redhat.com>
commit 056de1e894155fbb99e7b43c1c4382d4920cf437
Author: Marc-André Lureau <marcandre.lureau@redhat.com>
Date: Tue Jul 10 16:55:57 2018 +0200
seccomp: allow sched_setscheduler() with SCHED_IDLE policy
Current and upcoming mesa releases rely on a shader disk cash. It uses
a thread job queue with low priority, set with
sched_setscheduler(SCHED_IDLE). However, that syscall is rejected by
the "resourcecontrol" seccomp qemu filter.
Since it should be safe to allow lowering thread priority, let's allow
scheduling thread to idle policy.
Related to:
https://bugzilla.redhat.com/show_bug.cgi?id=1594456
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Eduardo Otubo <otubo@redhat.com>
Signed-by-off: Eduardo Otubo <otubo@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
qemu-seccomp.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/qemu-seccomp.c b/qemu-seccomp.c
index b770a77..845a333 100644
--- a/qemu-seccomp.c
+++ b/qemu-seccomp.c
@@ -29,6 +29,12 @@
struct QemuSeccompSyscall {
int32_t num;
uint8_t set;
+ uint8_t narg;
+ const struct scmp_arg_cmp *arg_cmp;
+};
+
+const struct scmp_arg_cmp sched_setscheduler_arg[] = {
+ SCMP_A1(SCMP_CMP_NE, SCHED_IDLE)
};
static const struct QemuSeccompSyscall blacklist[] = {
@@ -87,7 +93,8 @@ static const struct QemuSeccompSyscall blacklist[] = {
{ SCMP_SYS(setpriority), QEMU_SECCOMP_SET_RESOURCECTL },
{ SCMP_SYS(sched_setparam), QEMU_SECCOMP_SET_RESOURCECTL },
{ SCMP_SYS(sched_getparam), QEMU_SECCOMP_SET_RESOURCECTL },
- { SCMP_SYS(sched_setscheduler), QEMU_SECCOMP_SET_RESOURCECTL },
+ { SCMP_SYS(sched_setscheduler), QEMU_SECCOMP_SET_RESOURCECTL,
+ ARRAY_SIZE(sched_setscheduler_arg), sched_setscheduler_arg },
{ SCMP_SYS(sched_getscheduler), QEMU_SECCOMP_SET_RESOURCECTL },
{ SCMP_SYS(sched_setaffinity), QEMU_SECCOMP_SET_RESOURCECTL },
{ SCMP_SYS(sched_getaffinity), QEMU_SECCOMP_SET_RESOURCECTL },
@@ -113,7 +120,8 @@ int seccomp_start(uint32_t seccomp_opts)
continue;
}
- rc = seccomp_rule_add(ctx, SCMP_ACT_KILL, blacklist[i].num, 0);
+ rc = seccomp_rule_add_array(ctx, SCMP_ACT_KILL, blacklist[i].num,
+ blacklist[i].narg, blacklist[i].arg_cmp);
if (rc < 0) {
goto seccomp_return;
}
--
1.8.3.1