set correct uid/gid on volumes

When setting up the volumes for a container, make sure that new volumes are created with the correct uid/gid which we're looking up in the container config. Fixes: containers#5698 Signed-off-by: Valentin Rothberg <[email protected]>
vrothberg · Jun 23, 2020 · 407654c · 407654c
1 parent bbaba9f
commit 407654c
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Showing 3 changed files with 48 additions and 3 deletions.
diff --git a/libpod/container.go b/libpod/container.go
@@ -1141,8 +1141,13 @@ func (c *Container) IDMappings() (storage.IDMappingOptions, error) {
 
 // RootUID returns the root user mapping from container
 func (c *Container) RootUID() int {
+	return c.findUID(0)
+}
+
+// findUID returns the UID mapping of the specified uid or 0 if it couldn't be found.
+func (c *Container) findUID(uid int) int {
 	for _, uidmap := range c.config.IDMappings.UIDMap {
-		if uidmap.ContainerID == 0 {
+		if uidmap.ContainerID == uid {
 			return uidmap.HostID
 		}
 	}
@@ -1151,8 +1156,13 @@ func (c *Container) RootUID() int {
 
 // RootGID returns the root user mapping from container
 func (c *Container) RootGID() int {
+	return c.findGID(0)
+}
+
+// findUID returns the GID mapping of the specified gid or 0 if it couldn't be found.
+func (c *Container) findGID(gid int) int {
 	for _, gidmap := range c.config.IDMappings.GIDMap {
-		if gidmap.ContainerID == 0 {
+		if gidmap.ContainerID == gid {
 			return gidmap.HostID
 		}
 	}

diff --git a/libpod/runtime_ctr.go b/libpod/runtime_ctr.go
@@ -8,6 +8,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/containers/buildah/pkg/chrootuser"
 	"github.com/containers/common/pkg/config"
 	"github.com/containers/libpod/libpod/define"
 	"github.com/containers/libpod/libpod/events"
@@ -308,8 +309,15 @@ func (r *Runtime) setupContainer(ctx context.Context, ctr *Container) (_ *Contai
 
 		logrus.Debugf("Creating new volume %s for container", vol.Name)
 
+		// Get the uid/gid of the container user to create the volume
+		// with the correct uid/gid. See github.com/containers/libpod/issues/5698.
+		uid, gid, _, err := chrootuser.GetUser(ctr.state.Mountpoint, ctr.config.User)
+		if err != nil {
+			return nil, errors.Wrapf(err, "error created named volume %q", vol.Name)
+		}
+
 		// The volume does not exist, so we need to create it.
-		volOptions := []VolumeCreateOption{WithVolumeName(vol.Name), WithVolumeUID(ctr.RootUID()), WithVolumeGID(ctr.RootGID())}
+		volOptions := []VolumeCreateOption{WithVolumeName(vol.Name), WithVolumeUID(int(uid)), WithVolumeGID(int(gid))}
 		if isAnonymous {
 			volOptions = append(volOptions, withSetAnon())
 		}

diff --git a/test/e2e/run_userns_test.go b/test/e2e/run_userns_test.go
@@ -238,4 +238,31 @@ var _ = Describe("Podman UserNS support", func() {
 		ok, _ := session.GrepString("4998")
 		Expect(ok).To(BeTrue())
 	})
+
+	It("podman --user with volume", func() {
+		tests := []struct {
+			uid, gid, arg, vol string
+		}{
+			{"0", "0", "0:0", "vol-0"},
+			{"1000", "0", "1000", "vol-1"},
+			{"1000", "1000", "1000:1000", "vol-2"},
+		}
+
+		for _, tt := range tests {
+			session := podmanTest.Podman([]string{"run", "-d", "--user", tt.arg, "--mount", "type=volume,src=" + tt.vol + ",dst=/home/user", "alpine", "top"})
+			session.WaitWithDefaultTimeout()
+			Expect(session.ExitCode()).To(Equal(0))
+
+			inspectUID := podmanTest.Podman([]string{"volume", "inspect", "--format", "{{ .UID }}", tt.vol})
+			inspectUID.WaitWithDefaultTimeout()
+			Expect(inspectUID.ExitCode()).To(Equal(0))
+			Expect(inspectUID.OutputToString()).To(Equal(tt.uid))
+
+			// Make sure we're defaulting to 0.
+			inspectGID := podmanTest.Podman([]string{"volume", "inspect", "--format", "{{ .GID }}", tt.vol})
+			inspectGID.WaitWithDefaultTimeout()
+			Expect(inspectGID.ExitCode()).To(Equal(0))
+			Expect(inspectGID.OutputToString()).To(Equal(tt.gid))
+		}
+	})
 })