File boo1187704-0001-cgroupv2-ebpf-ignore-inaccessib... of Package runc

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File boo1187704-0001-cgroupv2-ebpf-ignore-inaccessible-existing-programs.patch of Package runc (Revision 908aa3486026bb6f547cdc7a2319d74a)

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From 46a2505edda4b5e146d51d796d7071364e457f81 Mon Sep 17 00:00:00 2001
From: Aleksa Sarai <cyphar@cyphar.com>
Date: Thu, 1 Jul 2021 12:55:08 +1000
Subject: [PATCH] cgroupv2: ebpf: ignore inaccessible existing programs

This is necessary in order for runc to be able to configure device
cgroups with --systemd-cgroup on distributions that have very strict
SELinux policies such as openSUSE MicroOS[1].

The core issue here is that systemd is adding its own BPF policy that
has an SELinux label such that runc cannot interact with it. In order to
work around this, we can just ignore the policy -- in theory this
behaviour is not correct but given that the most obvious case
(--systemd-cgroup) will still handle updates correctly, this logic is
reasonable.

[1]: https://bugzilla.suse.com/show_bug.cgi?id=1182428

Fixes: d0f2c25f521e ("cgroup2: devices: replace all existing filters when attaching")
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
---
 go.mod                                    |  2 ++
 go.sum                                    |  4 ++++
 libcontainer/cgroups/ebpf/ebpf_linux.go   | 19 ++++++++++++++++---
 vendor/github.com/cilium/ebpf/syscalls.go |  5 ++---
 vendor/modules.txt                        |  2 +-
 5 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/go.mod b/go.mod
index df98934d3d50..b155440e1e32 100644
--- a/go.mod
+++ b/go.mod
@@ -25,3 +25,5 @@ require (
 	golang.org/x/sys v0.0.0-20210426230700-d19ff857e887
 	google.golang.org/protobuf v1.27.1
 )
+
+replace github.com/cilium/ebpf => github.com/cyphar/ebpf v0.6.1-0.20210701060515-e654431ae87f
diff --git a/go.sum b/go.sum
index 15d3ac3fa791..413f1361ece6 100644
--- a/go.sum
+++ b/go.sum
@@ -11,6 +11,10 @@ github.com/coreos/go-systemd/v22 v22.3.2 h1:D9/bQk5vlXQFZ6Kwuu6zaiXJ9oTPe68++AzA
 github.com/coreos/go-systemd/v22 v22.3.2/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
 github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d h1:U+s90UTSYgptZMwQh2aRr3LuazLJIa+Pg3Kc1ylSYVY=
 github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
+github.com/cyphar/ebpf v0.6.1-0.20210701040454-26565c82f4f1 h1:Y+9BQzEwXR1yEhvf843TRwrMgwH7ZbO3arwgZfXPhFU=
+github.com/cyphar/ebpf v0.6.1-0.20210701040454-26565c82f4f1/go.mod h1:4tRaxcgiL706VnOzHOdBlY8IEAIdxINsQBcU4xJJXRs=
+github.com/cyphar/ebpf v0.6.1-0.20210701060515-e654431ae87f h1:MqvjlbU/U6s12v7ru6MbLKIkLlzGMDiMKYi4yGHGz2Q=
+github.com/cyphar/ebpf v0.6.1-0.20210701060515-e654431ae87f/go.mod h1:4tRaxcgiL706VnOzHOdBlY8IEAIdxINsQBcU4xJJXRs=
 github.com/cyphar/filepath-securejoin v0.2.2 h1:jCwT2GTP+PY5nBz3c/YL5PAIbusElVrPujOBSCj8xRg=
 github.com/cyphar/filepath-securejoin v0.2.2/go.mod h1:FpkQEhXnPnOthhzymB7CGsFk2G9VLXONKD9G7QGMM+4=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
diff --git a/libcontainer/cgroups/ebpf/ebpf_linux.go b/libcontainer/cgroups/ebpf/ebpf_linux.go
index fa1b04e25991..b4141aaf6699 100644
--- a/libcontainer/cgroups/ebpf/ebpf_linux.go
+++ b/libcontainer/cgroups/ebpf/ebpf_linux.go
@@ -59,13 +59,26 @@ func findAttachedCgroupDeviceFilters(dirFd int) ([]*ebpf.Program, error) {
 
 		// Convert the ids to program handles.
 		progIds = progIds[:size]
-		programs := make([]*ebpf.Program, len(progIds))
-		for idx, progId := range progIds {
+		programs := make([]*ebpf.Program, 0, len(progIds))
+		for _, progId := range progIds {
 			program, err := ebpf.NewProgramFromID(ebpf.ProgramID(progId))
 			if err != nil {
+				// We skip over programs that give us -EACCES. This is
+				// necessary because there may be BPF programs that have been
+				// attached (such as with --systemd-cgroup) which have an LSM
+				// label that blocks us from interacting with the program.
+				//
+				// Because additional BPF_CGROUP_DEVICE programs only can add
+				// restrictions, there's no real issue with just ignoring these
+				// programs (and stops runc from breaking on distributions with
+				// very strict SELinux policies).
+				if errors.Is(err, unix.EACCES) {
+					logrus.Debugf("ignoring existing CGROUP_DEVICE program (prog_id=%v) which cannot be accessed by runc -- likely due to LSM policy", progId)
+					continue
+				}
 				return nil, fmt.Errorf("cannot fetch program from id: %w", err)
 			}
-			programs[idx] = program
+			programs = append(programs, program)
 		}
 		runtime.KeepAlive(progIds)
 		return programs, nil
diff --git a/vendor/github.com/cilium/ebpf/syscalls.go b/vendor/github.com/cilium/ebpf/syscalls.go
index c530aadd9a5b..82678eb4043d 100644
--- a/vendor/github.com/cilium/ebpf/syscalls.go
+++ b/vendor/github.com/cilium/ebpf/syscalls.go
@@ -360,10 +360,9 @@ func wrapObjError(err error) error {
 		return nil
 	}
 	if errors.Is(err, unix.ENOENT) {
-		return fmt.Errorf("%w", ErrNotExist)
+		return ErrNotExist
 	}
-
-	return errors.New(err.Error())
+	return err
 }
 
 func wrapMapError(err error) error {
diff --git a/vendor/modules.txt b/vendor/modules.txt
index 8c99aca8c125..7797d5acecb5 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -3,7 +3,7 @@ github.com/bits-and-blooms/bitset
 # github.com/checkpoint-restore/go-criu/v5 v5.0.0
 github.com/checkpoint-restore/go-criu/v5
 github.com/checkpoint-restore/go-criu/v5/rpc
-# github.com/cilium/ebpf v0.6.1
+# github.com/cilium/ebpf v0.6.1 => github.com/cyphar/ebpf v0.6.1-0.20210701060515-e654431ae87f
 github.com/cilium/ebpf
 github.com/cilium/ebpf/asm
 github.com/cilium/ebpf/internal
-- 
2.32.0

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File boo1187704-0001-cgroupv2-ebpf-ignore-inaccessible-existing-programs.patch of Package runc (Revision 908aa3486026bb6f547cdc7a2319d74a)

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