run: add container gid to additional groups

When container is created with specific uid and gid also add container
gid to supplementary/additional group.

Signed-off-by: Aditya R <arajan@redhat.com>

run_common.go

@@ -262,6 +262,7 @@ func (b *Builder) configureUIDGID(g *generate.Generator, mountPoint string, opti
 	}
 	g.SetProcessUID(user.UID)
 	g.SetProcessGID(user.GID)
+	g.AddProcessAdditionalGid(user.GID)
 	for _, gid := range user.AdditionalGids {
 		g.AddProcessAdditionalGid(gid)
 	}

tests/bud.bats

@@ -366,6 +366,22 @@ _EOF
   expect_output --substring "invalid response status"
 }
 
+@test "build test has gid in supplemental groups" {
+  _prefetch alpine
+  run_buildah build $WITH_POLICY_JSON -t source -f $BUDFILES/supplemental-groups/Dockerfile
+  # gid 1000 must be in supplemental groups
+  expect_output --substring "Groups:	1000"
+}
+
+@test "build test if supplemental groups has gid with --isolation chroot" {
+  test -z "${BUILDAH_ISOLATION}" || skip "BUILDAH_ISOLATION=${BUILDAH_ISOLATION} overrides --isolation"
+
+  _prefetch alpine
+  run_buildah build --isolation chroot $WITH_POLICY_JSON -t source -f $BUDFILES/supplemental-groups/Dockerfile
+  # gid 1000 must be in supplemental groups
+  expect_output --substring "Groups:	1000"
+}
+
 # Test skipping images with FROM
 @test "build-test skipping unwanted stages with FROM" {
   mkdir -p ${TEST_SCRATCH_DIR}/bud/platform

tests/bud/supplemental-groups/Dockerfile

@@ -0,0 +1,3 @@
+FROM alpine
+USER 1000:1000
+RUN cat /proc/$$/status

tests/run.bats

@@ -349,6 +349,20 @@ function configure_and_check_user() {
   expect_output "888:888"
 }
 
+@test "run --user and verify gid in supplemental groups" {
+  skip_if_no_runtime
+
+  # Create the container.
+  _prefetch alpine
+  run_buildah from $WITH_POLICY_JSON alpine
+  ctr="$output"
+
+  # Run with uid:gid 1000:1000 and verify if gid is present in additional groups
+  run_buildah run --user 1000:1000 "$ctr" cat /proc/self/status
+  # gid 1000 must be in additional/supplemental groups
+  expect_output --substring "Groups:	1000 "
+}
+
 @test "run --workingdir" {
 	skip_if_no_runtime