Subject: [bug#61462] [PATCH 10/10] system: Add privileged-programs to <operating-system>.

From: Tobias Geerinckx-Rice <[email-masked]>
Date: Sun, 5 Feb 2023 01:00:19 +0100

* gnu/system.scm (<operating-system>): Add new privileged-programs
field, that defaults to…
(%default-privileged-programs): …this new variable, renamed from…
(%setuid-programs): …this, which is now defined as the empty list.
* doc/guix.texi (Setuid Programs): Rename this…
(Privileged Programs): …to this.  Adjust all refs.  Update all mentions
of ‘setuid’ (whether in prose, variable names, or code samples) to use
the new ‘privilege[d]’ terminology instead.
(operating-system Reference, X Window, Desktop Services,
Invoking guix system, Service Reference): Adjust likewise.
---
 doc/guix.texi           | 89 ++++++++++++++++++++++-------------------
 gnu/packages/crypto.scm |  2 +-
 gnu/services.scm        |  1 -
 gnu/system.scm          | 21 ++++++++--
 4 files changed, 65 insertions(+), 48 deletions(-)

diff --git a/doc/guix.texi b/doc/guix.texi
index 009bcf5d40..7e54abcffb 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -358,7 +358,7 @@ System Configuration
 * Keyboard Layout::             How the system interprets key strokes.
 * Locales::                     Language and cultural convention settings.
 * Services::                    Specifying system services.
-* Setuid Programs::             Programs running with elevated privileges.
+* Privileged Programs::         Programs running with elevated privileges.
 * X.509 Certificates::          Authenticating HTTPS servers.
 * Name Service Switch::         Configuring libc's name service switch.
 * Initial RAM Disk::            Linux-Libre bootstrapping.
@@ -16146,7 +16146,7 @@ instance to support new system services.
 * Keyboard Layout::             How the system interprets key strokes.
 * Locales::                     Language and cultural convention settings.
 * Services::                    Specifying system services.
-* Setuid Programs::             Programs running with elevated privileges.
+* Privileged Programs::         Programs running with elevated privileges.
 * X.509 Certificates::          Authenticating HTTPS servers.
 * Name Service Switch::         Configuring libc's name service switch.
 * Initial RAM Disk::            Linux-Libre bootstrapping.
@@ -16591,9 +16591,9 @@ As a user you should @emph{never} need to touch this field.
 Linux @dfn{pluggable authentication module} (PAM) services.
 @c FIXME: Add xref to PAM services section.
 
-@item @code{setuid-programs} (default: @code{%setuid-programs})
-List of @code{<setuid-program>}.  @xref{Setuid Programs}, for more
-information.
+@item @code{privileged-programs} (default: @code{%default-privileged-programs})
+List of @code{<privileged-program>}.  @xref{Privileged Programs}, for
+more information.
 
 @item @code{sudoers-file} (default: @code{%sudoers-specification})
 @cindex sudoers file
@@ -22047,8 +22047,8 @@ Usually the X server is started by a login manager.
 
 @deffn {Scheme Procedure} screen-locker-service @var{package} [@var{program}]
 Add @var{package}, a package for a screen locker or screen saver whose
-command is @var{program}, to the set of setuid programs and add a PAM entry
-for it.  For example:
+command is @var{program}, to the set of privileged programs and add a PAM
+entry for it.  For example:
 
 @lisp
 (screen-locker-service xlockmore "xlock")
@@ -22965,9 +22965,9 @@ to operate with elevated privileges on a limited number of special-purpose
 system interfaces.  Additionally, adding a service of type
 @code{mate-desktop-service-type} adds the MATE metapackage to the system
 profile.  ``Adding Enlightenment'' means that @code{dbus} is extended
-appropriately, and several of Enlightenment's binaries are set as setuid,
-allowing Enlightenment's screen locker and other functionality to work as
-expected.
+appropriately, and several of Enlightenment's binaries are set as privileged
+programs, allowing Enlightenment's screen locker and other functionality to
+work as expected.
 
 The desktop environments in Guix use the Xorg display server by
 default.  If you'd like to use the newer display server protocol
@@ -25905,7 +25905,7 @@ remote servers.  Run @command{man smtpd.conf} for more information.
 Make the following commands setgid to @code{smtpq} so they can be
 executed: @command{smtpctl}, @command{sendmail}, @command{send-mail},
 @command{makemap}, @command{mailq}, and @command{newaliases}.
-@xref{Setuid Programs}, for more information on setgid programs.
+@xref{Privileged Programs}, for more information on setgid programs.
 @end table
 @end deftp
 
@@ -37704,8 +37704,8 @@ create and run application bundles (aka. ``containers'').  The value for this
 service is the Singularity package to use.
 
 The service does not install a daemon; instead, it installs helper programs as
-setuid-root (@pxref{Setuid Programs}) such that unprivileged users can invoke
-@command{singularity run} and similar commands.
+setuid-root (@pxref{Privileged Programs}) such that unprivileged users can
+invoke @command{singularity run} and similar commands.
 @end defvar
 
 @cindex Audit
@@ -38136,11 +38136,14 @@ Mode for filter.
 
 @c End of auto-generated fail2ban documentation.
 
-@node Setuid Programs
-@section Setuid Programs
+@node Privileged Programs
+@section Privileged Programs
 
+@cindex privileged programs
 @cindex setuid programs
 @cindex setgid programs
+@cindex capabilities, POSIX
+@cindex setcap
 Some programs need to run with elevated privileges, even when they are
 launched by unprivileged users.  A notorious example is the
 @command{passwd} program, which users can run to change their
@@ -38151,46 +38154,48 @@ obvious security reasons.  To address that, @command{passwd} should be
 (@pxref{How Change Persona,,, libc, The GNU C Library Reference Manual},
 for more info about the setuid mechanism).
 
-The store itself @emph{cannot} contain setuid programs: that would be a
-security issue since any user on the system can write derivations that
+The store itself @emph{cannot} contain privileged programs: that would be
+a security issue since any user on the system can write derivations that
 populate the store (@pxref{The Store}).  Thus, a different mechanism is
-used: instead of changing the setuid or setgid bits directly on files that
-are in the store, we let the system administrator @emph{declare} which
+used: instead of directly granting permissions to files that are in
+the store, we let the system administrator @emph{declare} which
 programs should be entrusted with these additional privileges.
 
-The @code{setuid-programs} field of an @code{operating-system}
-declaration contains a list of @code{<setuid-program>} denoting the
+The @code{privileged-programs} field of an @code{operating-system}
+declaration contains a list of @code{<privileged-program>} denoting the
 names of programs to have a setuid or setgid bit set (@pxref{Using the
 Configuration System}).  For instance, the @command{mount.nfs} program,
 which is part of the nfs-utils package, with a setuid root can be
 designated like this:
 
 @lisp
-(setuid-program
-  (program (file-append nfs-utils "/sbin/mount.nfs")))
+(privileged-program
+  (program (file-append nfs-utils "/sbin/mount.nfs"))
+  (setuid? #t))
 @end lisp
 
 And then, to make @command{mount.nfs} setuid on your system, add the
 previous example to your operating system declaration by appending it to
-@code{%setuid-programs} like this:
+@code{%default-privileged-programs} like this:
 
 @lisp
 (operating-system
   ;; Some fields omitted...
-  (setuid-programs
-    (append (list (setuid-program
-                    (program (file-append nfs-utils "/sbin/mount.nfs"))))
-            %setuid-programs)))
+  (privileged-programs
+    (append (list (privileged-program
+                    (program (file-append nfs-utils "/sbin/mount.nfs"))
+                    (setuid? #t))
+            %default-privileged-programs)))
 @end lisp
 
-@deftp {Data Type} setuid-program
-This data type represents a program with a setuid or setgid bit set.
+@deftp {Data Type} privileged-program
+This data type represents a program with special privileges, such as setuid
 
 @table @asis
 @item @code{program}
-A file-like object having its setuid and/or setgid bit set.
+A file-like object to which all given privileges should apply.
 
-@item @code{setuid?} (default: @code{#t})
+@item @code{setuid?} (default: @code{#f})
 Whether to set user setuid bit.
 
 @item @code{setgid?} (default: @code{#f})
@@ -38207,18 +38212,18 @@ defaults to root.
 @end table
 @end deftp
 
-A default set of setuid programs is defined by the
-@code{%setuid-programs} variable of the @code{(gnu system)} module.
+A default set of privileged programs is defined by the
+@code{%default-privileged-programs} variable of the @code{(gnu system)} module.
 
-@defvar %setuid-programs
-A list of @code{<setuid-program>} denoting common programs that are
-setuid-root.
+@defvar {Scheme Variable} %default-privileged-programs
+A list of @code{<privileged-program>} denoting common programs with
+elevated privileges.
 
 The list includes commands such as @command{passwd}, @command{ping},
 @command{su}, and @command{sudo}.
 @end defvar
 
-Under the hood, the actual setuid programs are created in the
+Under the hood, the actual privileged programs are created in the
 @file{/run/privileged/bin} directory at system activation time.  The
 files in this directory refer to the ``real'' binaries, which are in the
 store.
@@ -39089,7 +39094,7 @@ once @command{reconfigure} has completed.
 @end quotation
 
 This effects all the configuration specified in @var{file}: user
-accounts, system services, global package list, setuid programs, etc.
+accounts, system services, global package list, privileged programs, etc.
 The command starts system services specified in @var{file} that are not
 currently running; if a service is currently running this command will
 arrange for it to be upgraded the next time it is stopped (e.g.@: by
@@ -40535,10 +40540,10 @@ tiresome to create multiple records with it so in practice the procedure
 @end quotation
 @end defvar
 
-@defvar setuid-program-service-type
-Type for the ``setuid-program service''.  This service collects lists of
+@defvar privileged-program-service-type
+Type for the ``privileged-program service''.  This service collects lists of
 executable file names, passed as gexps, and adds them to the set of
-setuid and setgid programs on the system (@pxref{Setuid Programs}).
+privileged programs on the system (@pxref{Privileged Programs}).
 @end defvar
 
 @defvar profile-service-type
diff --git a/gnu/packages/crypto.scm b/gnu/packages/crypto.scm
index 57a42a6a84..87c26f10ad 100644
--- a/gnu/packages/crypto.scm
+++ b/gnu/packages/crypto.scm
@@ -499,7 +499,7 @@ (define-public tomb
      `(#:make-flags (list (string-append "PREFIX=" (assoc-ref %outputs "out")))
        ;; The "sudo" input is needed only to satisfy dependency checks in the
        ;; 'check' phase.  The "sudo" used at runtime should come from the
-       ;; system's setuid-programs, so ensure no reference is kept.
+       ;; system's privileged-programs, so ensure no reference is kept.
        #:disallowed-references (,sudo)
        ;; TODO: Build and install gtk and qt trays
        #:phases
diff --git a/gnu/services.scm b/gnu/services.scm
index 09ff58dcd1..9825f4a4a5 100644
--- a/gnu/services.scm
+++ b/gnu/services.scm
@@ -44,7 +44,6 @@ (define-module (gnu services)
   #:use-module (gnu packages bash)
   #:use-module (gnu packages hurd)
   #:use-module (gnu system privilege)
-  #:use-module (gnu system setuid)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-9)
   #:use-module (srfi srfi-9 gnu)
diff --git a/gnu/system.scm b/gnu/system.scm
index 3b66847b4f..1a22dc65f5 100644
--- a/gnu/system.scm
+++ b/gnu/system.scm
@@ -75,6 +75,7 @@ (define-module (gnu system)
   #:use-module (gnu system locale)
   #:use-module (gnu system pam)
   #:use-module (gnu system linux-initrd)
+  #:use-module (gnu system privilege)
   #:use-module (gnu system setuid)
   #:use-module (gnu system uuid)
   #:use-module (gnu system file-systems)
@@ -128,6 +129,7 @@ (define-module (gnu system)
             operating-system-keyboard-layout
             operating-system-name-service-switch
             operating-system-pam-services
+            operating-system-privileged-programs
             operating-system-setuid-programs
             operating-system-skeletons
             operating-system-sudoers-file
@@ -173,6 +175,7 @@ (define-module (gnu system)
             local-host-aliases                    ;deprecated
             local-host-entries
             %root-account
+            %default-privileged-programs
             %setuid-programs
             %sudoers-specification
             %base-packages
@@ -296,7 +299,10 @@ (define-record-type* <operating-system> operating-system
 
   (pam-services operating-system-pam-services     ; list of PAM services
                 (default (base-pam-services)))
+  (privileged-programs operating-system-privileged-programs ; list of <privileged-program>
+                       (default %default-privileged-programs))
   (setuid-programs operating-system-setuid-programs
+                   ;; For backwards compatibility; will be removed.
                    (default %setuid-programs))    ; list of <setuid-program>
 
   (sudoers-file operating-system-sudoers-file     ; file-like
@@ -785,7 +791,8 @@ (define known-fs
            (host-name-service host-name)
            procs root-fs
            (service privileged-program-service-type
-                    (operating-system-setuid-programs os))
+                    (append (operating-system-privileged-programs os)
+                            (operating-system-setuid-programs os)))
            (service profile-service-type
                     (operating-system-packages os))
            boot-fs non-boot-fs
@@ -826,7 +833,8 @@ (define (hurd-default-essential-services os)
               (service hosts-service-type
                        (local-host-entries host-name)))
           (service privileged-program-service-type
-                   (operating-system-setuid-programs os))
+                   (append (operating-system-privileged-programs os)
+                           (operating-system-setuid-programs os)))
           (service profile-service-type (operating-system-packages os)))))
 
 (define* (operating-system-services os)
@@ -1213,8 +1221,7 @@ (define (operating-system-environment-variables os)
     ;; TODO: Remove when [email-masked] is long gone.
     ("GUIX_LOCPATH" . "/run/current-system/locale")))
 
-(define %setuid-programs
-  ;; Default set of setuid-root programs.
+(define %default-privileged-programs
   (let ((shadow (@ (gnu packages admin) shadow)))
     (map file-like->setuid-program
          (list (file-append shadow "/bin/passwd")
@@ -1236,6 +1243,12 @@ (define %setuid-programs
                (file-append util-linux "/bin/mount")
                (file-append util-linux "/bin/umount")))))
 
+(define %setuid-programs
+  ;; Do not add to this list or use it in new code!  It's defined only to ease
+  ;; transition to %default-privileged-programs and will be removed.  Some rare
+  ;; use cases already break, such as the obvious (remove … %setuid-programs).
+  '())
+
 (define %sudoers-specification
   ;; Default /etc/sudoers contents: 'root' and all members of the 'wheel'
   ;; group can do anything.  See
-- 
2.39.1