From 1dd7f13dfbc1dd377eabace0239b1c05cd60b144 Mon Sep 17 00:00:00 2001
From: baude <bbaude@redhat.com>
Date: Thu, 25 Oct 2018 13:39:25 -0500
Subject: get user and group information using securejoin and runc's user
 library

for the purposes of performance and security, we use securejoin to contstruct
the root fs's path so that symlinks are what they appear to be and no pointing
to something naughty.

then instead of chrooting to parse /etc/passwd|/etc/group, we now use the runc user/group
methods which saves us quite a bit of performance.

Signed-off-by: baude <bbaude@redhat.com>
---
 libpod/container_internal_linux.go | 44 ++++++++------------------------------
 1 file changed, 9 insertions(+), 35 deletions(-)

(limited to 'libpod/container_internal_linux.go')

diff --git a/libpod/container_internal_linux.go b/libpod/container_internal_linux.go
index 0a1784ba7..7bf2c71ca 100644
--- a/libpod/container_internal_linux.go
+++ b/libpod/container_internal_linux.go
@@ -19,12 +19,10 @@ import (
 	cnitypes "github.com/containernetworking/cni/pkg/types/current"
 	"github.com/containernetworking/plugins/pkg/ns"
 	crioAnnotations "github.com/containers/libpod/pkg/annotations"
-	"github.com/containers/libpod/pkg/chrootuser"
 	"github.com/containers/libpod/pkg/criu"
+	"github.com/containers/libpod/pkg/lookup"
 	"github.com/containers/libpod/pkg/rootless"
 	"github.com/containers/storage/pkg/idtools"
-	"github.com/cyphar/filepath-securejoin"
-	"github.com/opencontainers/runc/libcontainer/user"
 	spec "github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/opencontainers/runtime-tools/generate"
 	"github.com/opencontainers/selinux/go-selinux/label"
@@ -135,6 +133,10 @@ func (c *Container) cleanupNetwork() error {
 // Generate spec for a container
 // Accepts a map of the container's dependencies
 func (c *Container) generateSpec(ctx context.Context) (*spec.Spec, error) {
+	execUser, err := lookup.GetUserGroupInfo(c.state.Mountpoint, c.config.User, nil)
+	if err != nil {
+		return nil, err
+	}
 	g := generate.NewFromSpec(c.config.Spec)
 
 	// If network namespace was requested, add it now
@@ -188,7 +190,6 @@ func (c *Container) generateSpec(ctx context.Context) (*spec.Spec, error) {
 		}
 	}
 
-	var err error
 	if !rootless.IsRootless() {
 		if c.state.ExtensionStageHooks, err = c.setupOCIHooks(ctx, g.Config); err != nil {
 			return nil, errors.Wrapf(err, "error setting up OCI Hooks")
@@ -206,13 +207,9 @@ func (c *Container) generateSpec(ctx context.Context) (*spec.Spec, error) {
 		if !c.state.Mounted {
 			return nil, errors.Wrapf(ErrCtrStateInvalid, "container %s must be mounted in order to translate User field", c.ID())
 		}
-		uid, gid, err := chrootuser.GetUser(c.state.Mountpoint, c.config.User)
-		if err != nil {
-			return nil, err
-		}
 		// User and Group must go together
-		g.SetProcessUID(uid)
-		g.SetProcessGID(gid)
+		g.SetProcessUID(uint32(execUser.Uid))
+		g.SetProcessGID(uint32(execUser.Gid))
 	}
 
 	// Add addition groups if c.config.GroupAdd is not empty
@@ -220,11 +217,8 @@ func (c *Container) generateSpec(ctx context.Context) (*spec.Spec, error) {
 		if !c.state.Mounted {
 			return nil, errors.Wrapf(ErrCtrStateInvalid, "container %s must be mounted in order to add additional groups", c.ID())
 		}
-		for _, group := range c.config.Groups {
-			gid, err := chrootuser.GetGroup(c.state.Mountpoint, group)
-			if err != nil {
-				return nil, err
-			}
+		gids, _ := lookup.GetContainerGroups(c.config.Groups, c.state.Mountpoint, nil)
+		for _, gid := range gids {
 			g.AddProcessAdditionalGid(gid)
 		}
 	}
@@ -237,26 +231,6 @@ func (c *Container) generateSpec(ctx context.Context) (*spec.Spec, error) {
 
 	// Look up and add groups the user belongs to, if a group wasn't directly specified
 	if !rootless.IsRootless() && !strings.Contains(c.config.User, ":") {
-		var groupDest, passwdDest string
-		defaultExecUser := user.ExecUser{
-			Uid:  0,
-			Gid:  0,
-			Home: "/",
-		}
-
-		// Make sure the /etc/group  and /etc/passwd destinations are not a symlink to something naughty
-		if groupDest, err = securejoin.SecureJoin(c.state.Mountpoint, "/etc/group"); err != nil {
-			logrus.Debug(err)
-			return nil, err
-		}
-		if passwdDest, err = securejoin.SecureJoin(c.state.Mountpoint, "/etc/passwd"); err != nil {
-			logrus.Debug(err)
-			return nil, err
-		}
-		execUser, err := user.GetExecUserPath(c.config.User, &defaultExecUser, passwdDest, groupDest)
-		if err != nil {
-			return nil, err
-		}
 		for _, gid := range execUser.Sgids {
 			g.AddProcessAdditionalGid(uint32(gid))
 		}
-- 
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