Ensure that `--userns=keep-id` sets user in config

One of the side-effects of the `--userns=keep-id` command is
switching the default user of the container to the UID of the
user running Podman (though this can still be overridden by the
`--user` flag). However, it did this by setting the UID and GID
in the OCI spec, and not by informing Libpod of its intention to
switch users via the `WithUser()` option. Because of this, a lot
of the code that should have triggered when the container ran
with a non-root user was not triggering. In the case of the issue
that this fixed, the code to remove capabilities from non-root
users was not triggering. Adjust the keep-id code to properly
inform Libpod of our intention to use a non-root user to fix
this.

Also, fix an annoying race around short-running exec sessions
where Podman would always print a warning that the exec session
had already stopped.

Fixes #9919

Signed-off-by: Matthew Heon <matthew.heon@pm.me>

1 files changed, 13 insertions, 1 deletions

diff --git a/test/e2e/exec_test.go b/test/e2e/exec_test.go
index df86eab15..e6f63a391 100644
--- a/test/e2e/exec_test.go
+++ b/test/e2e/exec_test.go
@@ -119,6 +119,19 @@ var _ = Describe("Podman exec", func() {
 		Expect(session.ExitCode()).To(Equal(100))
 	})
 
+	It("podman exec in keep-id container drops privileges", func() {
+		SkipIfNotRootless("This function is not enabled for rootful podman")
+		ctrName := "testctr1"
+		testCtr := podmanTest.Podman([]string{"run", "-d", "--name", ctrName, "--userns=keep-id", ALPINE, "top"})
+		testCtr.WaitWithDefaultTimeout()
+		Expect(testCtr.ExitCode()).To(Equal(0))
+
+		session := podmanTest.Podman([]string{"exec", ctrName, "grep", "CapEff", "/proc/self/status"})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+		Expect(session.OutputToString()).To(ContainSubstring("0000000000000000"))
+	})
+
 	It("podman exec --privileged", func() {
 		session := podmanTest.Podman([]string{"run", "--privileged", "--rm", ALPINE, "sh", "-c", "grep ^CapBnd /proc/self/status | cut -f 2"})
 		session.WaitWithDefaultTimeout()
@@ -143,7 +156,6 @@ var _ = Describe("Podman exec", func() {
 		session.WaitWithDefaultTimeout()
 		Expect(session.ExitCode()).To(Equal(0))
 		Expect(session.OutputToString()).To(ContainSubstring(bndPerms))
-
 	})
 
 	It("podman exec --privileged", func() {