jschoubben
2a2be687f3
ADR 0328 supersedes ADR 0325: shared data is a library with one home, kept usable by its group rather than by ACL entries. The engine now makes each library's group and each module's user in its libraries' groups; keeps a library's root and requested sub-paths in its group with group write and setgid on its home, making missing sub-paths as the root is; waits for the operator's word before touching a root that holds data, and on the take act walks it by descriptor (no link, same filesystem, bounded and resumed, files with other names left); holds the containers of a library whose disk or mount is not there; and puts the tool runner's account in the group. The ACL keeping, mask repair and watch are gone; an access is again as before ADR 0325.
113 lines
4.5 KiB
Go
113 lines
4.5 KiB
Go
package system
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import (
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"context"
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"fmt"
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"strconv"
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"strings"
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)
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// A module's identity as a system account (novox/hq ADR 0328 §3, §4): an account and a group with exactly the numbers
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// the controller allocated, no login shell, no home and no password. Optional beside System: a system that has
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// none (android) makes no module identity, and the engine says so.
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// CreateSystemGroup makes a system group with gid.
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func (arch) CreateSystemGroup(ctx context.Context, run Runner, name string, gid int) error {
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if _, err := run(ctx, "groupadd", "--system", "--gid", strconv.Itoa(gid), name); err != nil {
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return fmt.Errorf("cannot create the group %q: %w", name, err)
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}
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return nil
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}
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// CreateSystemAccount makes a system account with uid and the group gid as its own: no home made, `/` as the
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// home field, nologin as its shell, and the password useradd leaves locked.
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func (arch) CreateSystemAccount(ctx context.Context, run Runner, name string, uid, gid int, groups []string) error {
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args := []string{"--system", "--uid", strconv.Itoa(uid), "--gid", strconv.Itoa(gid)}
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if len(groups) > 0 {
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args = append(args, "--groups", strings.Join(groups, ","))
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}
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args = append(args, "--no-create-home", "--home-dir", "/", "--shell", "/usr/bin/nologin", name)
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if _, err := run(ctx, "useradd", args...); err != nil {
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return fmt.Errorf("cannot create the account %q: %w", name, err)
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}
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return nil
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}
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// ModifyAccount gives an account the mesh made its primary group gid and exactly groups as its added groups.
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func (arch) ModifyAccount(ctx context.Context, run Runner, name string, gid int, groups []string) error {
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if _, err := run(ctx, "usermod", "--gid", strconv.Itoa(gid), "--groups", strings.Join(groups, ","),
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name); err != nil {
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return fmt.Errorf("cannot give the account %q its groups: %w", name, err)
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}
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return nil
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}
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// RemoveAccount removes an account, leaving every file it owns where it is.
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func (arch) RemoveAccount(ctx context.Context, run Runner, name string) error {
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if _, err := run(ctx, "userdel", name); err != nil {
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return fmt.Errorf("cannot remove the account %q: %w", name, err)
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}
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return nil
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}
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// RemoveGroup removes a group.
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func (arch) RemoveGroup(ctx context.Context, run Runner, name string) error {
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if _, err := run(ctx, "groupdel", name); err != nil {
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return fmt.Errorf("cannot remove the group %q: %w", name, err)
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}
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return nil
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}
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// CreateSystemGroup makes a system group with gid, with busybox's addgroup.
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func (alpine) CreateSystemGroup(ctx context.Context, run Runner, name string, gid int) error {
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if _, err := run(ctx, "addgroup", "-S", "-g", strconv.Itoa(gid), name); err != nil {
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return fmt.Errorf("cannot create the group %q: %w", name, err)
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}
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return nil
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}
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// CreateSystemAccount makes a system account with busybox's adduser: -S system, -D no password, -H no home made.
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func (alpine) CreateSystemAccount(ctx context.Context, run Runner, name string, uid, gid int, groups []string) error {
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group, err := run(ctx, "getent", "group", strconv.Itoa(gid))
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if err != nil {
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return fmt.Errorf("cannot create the account %q: its group gid %d is not here: %w", name, gid, err)
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}
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groupName := name
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if n, _, ok := strings.Cut(group, ":"); ok {
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groupName = n
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}
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if _, err := run(ctx, "adduser", "-S", "-D", "-H", "-h", "/", "-s", "/sbin/nologin", "-u", strconv.Itoa(uid),
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"-G", groupName, name); err != nil {
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return fmt.Errorf("cannot create the account %q: %w", name, err)
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}
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for _, g := range groups {
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if _, err := run(ctx, "addgroup", name, g); err != nil {
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return fmt.Errorf("cannot put the account %q in %q: %w", name, g, err)
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}
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}
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return nil
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}
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// ModifyAccount is not one busybox can do: it has no usermod to change an account's primary group, and removing
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// an added group is a hand edit of /etc/group. Refused, saying so: the account is left as it is.
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func (alpine) ModifyAccount(context.Context, Runner, string, int, []string) error {
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return fmt.Errorf("this system cannot change an account's groups once it is made (busybox has no usermod): %w",
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ErrUnsupported)
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}
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// RemoveAccount removes an account with busybox's deluser.
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func (alpine) RemoveAccount(ctx context.Context, run Runner, name string) error {
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if _, err := run(ctx, "deluser", name); err != nil {
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return fmt.Errorf("cannot remove the account %q: %w", name, err)
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}
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return nil
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}
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// RemoveGroup removes a group with busybox's delgroup.
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func (alpine) RemoveGroup(ctx context.Context, run Runner, name string) error {
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if _, err := run(ctx, "delgroup", name); err != nil {
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return fmt.Errorf("cannot remove the group %q: %w", name, err)
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}
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return nil
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}
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