Merge pull request #101 from dan-claude-bot/fix/grant-incus-admin

fix: box grant provisions incus-admin members instead of refusing them

CHANGELOG.md

@@ -32,6 +32,82 @@ which records not just what changed but what each drill run proved.
   verdict, the single `on.push` key, and the same-job tag+publish+re-arm
   in the same daemon-free, fail-closed style.
 
+### Fixed
+
+- **`box grant` provisions an `incus-admin` member instead of refusing them**
+  (#99) — the refusal read "they already have the admin tier; there is
+  nothing tighter to grant", which is true about *permission* and silent
+  about *provisioning*: the `incus` group is indeed a strict subset of what
+  `incus-admin` opens **at the daemon API**, but the `user-<uid>` project, the
+  boxnet narrowing, the snapshot and backup allowances, and the `box-net`
+  profile installed into that project are none of them permissions, and an
+  `incus-admin` member had none of them — `box_tier()` resolves them to
+  `admin`, so they worked in the shared default project next to root and every
+  other admin, with no world of their own and no supported way to get one.
+  `box grant` now runs the full convergence for them.
+
+  The group step is part of that convergence, not an exception to it: an
+  `incus-admin` member is added to `incus` like anyone else. The subset
+  argument holds for the API and **fails at the filesystem**, which is where
+  it matters here — the two sockets are two files with two owning groups
+  (Debian 13 / Incus 6.0.4, measured):
+
+  | socket | group | mode |
+  | --- | --- | --- |
+  | `/var/lib/incus/unix.socket` | `incus-admin` | 0660 |
+  | `/var/lib/incus/unix.socket.user` | `incus` | 0660 |
+
+  `incus-admin` opens the first and not the second, and only the second
+  provisions a `user-<uid>` project. Without the membership the provisioning
+  touch takes `EACCES`, the swallowing `|| true` hides it, no project appears,
+  and the grant dies blaming a perfectly healthy incus-user — the exact
+  incus-admin-only user #99 is about, left no better off. So the membership is
+  granted, and the grant says out loud why: it is the key to a file, not a new
+  privilege (`box_tier()` still reads them as `admin`, both-groups → `admin`).
+
+  The touch itself is **pinned at incus-user's socket**: the incus client picks
+  by writability (`client/connection.go` — the daemon socket when writable,
+  `unix.socket.user` only otherwise), so for an `incus-admin` member an
+  unpinned touch sails past incus-user and provisions nothing. The user-side
+  proof that closes the grant names their project for the same reason, since an
+  unqualified `profile show` would have answered from the shared default
+  project and proved nothing. The socket's existence is probed through `$SUDO`,
+  not a bare `[ -e ]` — `/var/lib/incus` is not traversable by a non-root
+  admin, so an unprivileged stat reports a present socket as absent, and this
+  probe exits on absent (the discipline `box revoke` already documents).
+
+  On success the grant prints the caveat the hard exit was gesturing at, in the
+  two forms it actually takes: the restrictions are a **default placement, not
+  a confinement** (admin membership still wins at the socket — the default
+  project and other users' instances stay one flag away), and until
+  `incus-admin` goes their own `box` commands keep landing in the default
+  project. Dropping `incus-admin` then lands them in their ready project with
+  **no re-grant** — a promise that is only true because they keep `incus`;
+  without it that drop would leave them in neither group, `box_tier()` `none`,
+  and a converged project they could not open. The failure path follows: the
+  membership this run added is rolled back and verified, while the backout
+  refuses to call that a lockout — `incus-admin` is untouched and still opens
+  every project.
+
+  `box revoke` mirrors it. A bare revoke of a granted `incus-admin` member now
+  takes the `incus` membership back and reports **`partial:`** — the socket key
+  `box grant` added is gone, their project is kept, and they are explicitly
+  **not** locked out. An `incus-admin` member who was never granted is still a
+  named **no-op** that makes no privileged call at all. `--purge` unmakes the
+  provisioning while refusing to call them "out". Every path names
+  `gpasswd -d <user> incus-admin` as the only thing that ends their access.
+
+  Unblocks rig's `users apply` (heavy-duty/rig#49), which had to call `box
+  grant` for a user who is both `incus-admin` by hand and role `box` in the
+  fleet file. Driven end to end in `test/cli.sh` under logging incus/sudo shims
+  — every assertion is made against what the run did, not what the source says
+  it would — and, because those shims model neither `INCUS_SOCKET` nor file
+  permissions and so cannot reproduce the `EACCES`, measured on real Incus in
+  CI by a new `drill/multiuser.sh` criterion (o): an `incus-admin`-only member
+  is granted, the membership lands, the project appears, `unix.socket.user`
+  opens as them, and dropping `incus-admin` leaves them in their own project
+  with no re-grant.
+
 ## 0.7.0 — 2026-07-19
 
 ### Added

bin/box

@@ -542,6 +542,17 @@ What it converges, idempotently (safe to re-run, and re-run after upgrades):
     rides snapshots, 'box export' rides backups — #70)
   · installs the box-net profile into their project
 
+An incus-admin member is provisioned too, not refused (#99): they are added
+to 'incus' like anyone else — not a new privilege, since incus-admin already
+opens the daemon, but the key to a FILE, because incus-user's socket is group
+'incus' mode 0660 and nothing below can provision them without it. Everything
+else converges, so they finally have a project of their own. What it is not
+is a confinement:
+incus-admin wins at the socket, so the restrictions are a default placement
+they can step outside at will, and their own client keeps resolving to the
+admin socket (and the default project) until incus-admin is taken away. The
+grant says all of that out loud when it lands.
+
 The user's surface: new/list/info/shell/exec/tmux/snapshot/restore/export/
 import/rm on their own boxes. Not theirs: expose (edits daemon-global
 state), setup-host, grant. Admin boxes and other users' boxes are invisible to them, and the
@@ -561,6 +572,15 @@ recreate the project, unhardened, afterwards — measured, not theoretical),
 then their boxes, images, project, private bridge and trust-store
 certificate are removed — irreversible, so it asks first.
 
+On an incus-admin member a bare revoke takes back the 'incus' membership that
+grant added — reported as 'partial:', because it ends no access: incus-admin
+still opens every project on this host. (One who was never granted is a named
+no-op instead.) Mind what that leaves behind: with 'incus' gone, a later
+'gpasswd -d <user> incus-admin' drops them into NEITHER group and their ready
+project becomes unreachable — grant's "no re-grant needed" holds only while
+they still hold 'incus'. --purge unmakes the provisioning the same way. Only
+'gpasswd -d <user> incus-admin' ends their access, and revoke says so.
+
   box revoke dev1            # take the tier; their boxes keep running
   box revoke dev1 --purge    # ...or end their sessions and delete everything
 EOF

docs/plans/2026-07-18-restricted-tier.md

@@ -127,11 +127,13 @@ It had never worked.
 ## Rehearsal and CI
 
 `drill/multiuser.sh` (root, opt-in via `BOX_MULTIUSER_REHEARSAL=1`) proves
-criteria (a)–(f) from #74 plus the measured extensions (g)–(n): the in-box
+criteria (a)–(f) from #74 plus the measured extensions (g)–(o): the in-box
 isolation contract (egress, DNS, box→host, RFC1918, cross-user sibling drop,
 name enumeration, IPv6-off), the closed escape hatches, re-sync survival, and
-scoped revoke, the raw-attach scoped guarantee (m) and the grant-failure
+scoped revoke, the raw-attach scoped guarantee (m), the grant-failure
-injections (n). Real users, real grants, real mints, probes from inside;
+injections (n) and the `incus-admin`-only grant (o) — the last of these
+because the shim suite models neither `INCUS_SOCKET` nor socket permissions,
+so the group gate on `unix.socket.user` can only be measured live (#99, #101). Real users, real grants, real mints, probes from inside;
 `--container` for CI, VM mode on real hardware; cleanup deletes everything it
 made.
 

drill/multiuser.sh

@@ -30,6 +30,9 @@
 #      host-owned control — the scoped guarantee, measured (#75 review)
 #   n. a grant that fails is fail-closed: fresh user backed out (verified),
 #      pre-existing member warned loudly, re-run converges (#75 review)
+#   o. an incus-admin-ONLY member is provisioned for real: the group step
+#      opens incus-user's socket, the lazy project appears, and dropping
+#      incus-admin lands them in it with no re-grant (#99, #101 review)
 #
 # ok/no/note return 0 by design — the 'A && ok || no' idiom below is the
 # same one drill.sh is built on (and the reason for the SC2015 disable).
@@ -114,7 +117,7 @@ cleanup() {
   [ "$KEEP" = 1 ] && { echo "(--keep: users and boxes left for inspection)"; return; }
   echo
   echo "── cleanup"
-  for u in "$U1" "$U2" boxdrill3 boxdrill4; do
+  for u in "$U1" "$U2" boxdrill3 boxdrill4 boxdrill5; do
     id "$u" >/dev/null 2>&1 || continue
     # A half-failed purge followed by userdel leaves a project owned by
     # nobody — and doctor's leftover check keys on the USER existing. Keep
@@ -469,6 +472,65 @@ else
 fi
 aud "n. fail-closed injections: fresh-user backout verified; pre-existing member warned, not stripped; re-runs converge"
 
+phase "o. an incus-admin-ONLY member — #99's canonical user, on real Incus"
+# The case the shim suite structurally cannot reach: the fake 'incus' in
+# test/cli.sh ignores INCUS_SOCKET and file permissions, so a grant that could
+# never connect() still logged a clean run there. This is the same path over
+# the real daemon, where the socket is a real file with a real owning group.
+#
+# The blocker it exists to catch (#101 review): incus-user's socket is
+# /var/lib/incus/unix.socket.user, group 'incus', mode 0660. incus-admin opens
+# the ADMIN socket and not that one, so an incus-admin-only member without an
+# 'incus' membership takes EACCES on grant's pinned touch — swallowed by its
+# '|| true' — no project is created, and the grant dies blaming a perfectly
+# healthy incus-user. Every assertion below is dead under that implementation.
+U5=boxdrill5
+useradd -m -s /bin/bash "$U5" 2>/dev/null
+usermod -aG incus-admin "$U5"
+gpasswd -d "$U5" incus >/dev/null 2>&1 || true   # stage the ONLY, exactly
+uid5="$(id -u "$U5")"; p5="user-$uid5"
+id -nG "$U5" | tr ' ' '\n' | grep -qx incus \
+  && no "(o) $U5 is already in 'incus' — the admin-ONLY precondition is not staged, so this phase proves nothing" \
+  || ok "(o) $U5 staged in 'incus-admin' only (the precondition the blocker needed)"
+
+out="$(box grant "$U5" 2>&1)"; rc=$?
+if [ "$rc" -eq 0 ]; then
+  ok "(o) box grant converges an incus-admin-only member (rc=0)"
+else
+  no "(o) box grant FAILED for the admin-only member (rc=$rc) — #99 is still closed:"
+  printf '%s\n' "$out" | tail -4 | sed 's/^/        /'
+fi
+id -nG "$U5" | tr ' ' '\n' | grep -qx incus \
+  && ok "(o) the grant put them in 'incus' — the group that owns unix.socket.user" \
+  || no "(o) still not in 'incus': the pinned touch cannot connect() to incus-user's socket"
+incus project show "$p5" >/dev/null 2>&1 \
+  && ok "(o) $p5 exists — the lazy touch really reached incus-user AS them" \
+  || no "(o) $p5 was never created — the touch never reached incus-user (the EACCES this phase is for)"
+
+# The socket, directly: the connect() that used to fail, measured as them.
+# Resolved by incus's own directory rule, not hardcoded.
+sockdir=/var/lib/incus; [ -e /run/incus/unix.socket ] && sockdir=/run/incus
+as_u "$U5" env INCUS_SOCKET="$sockdir/unix.socket.user" incus --project "$p5" profile show box-net >/dev/null 2>&1 \
+  && ok "(o) they can open unix.socket.user and read $p5's box-net profile" \
+  || no "(o) EACCES/unreachable on $sockdir/unix.socket.user — the #101 blocker is back"
+acc5="$(incus project get "$p5" restricted.networks.access 2>/dev/null)"
+[ "$acc5" = boxnet ] \
+  && ok "(o) $p5 is narrowed to boxnet like any other granted project" \
+  || no "(o) $p5 restricted.networks.access = '$acc5' — the admin-only grant converged half a project"
+
+# Grant's own closing promise, measured: "gpasswd -d <user> incus-admin (no
+# re-grant needed; the project is ready)". True only because they were left in
+# 'incus' — under the old no-op this drop left them in NEITHER group, box_tier
+# 'none', and a ready project they could not open. So drop it and look.
+gpasswd -d "$U5" incus-admin >/dev/null 2>&1
+projects5="$(as_u "$U5" incus project list --format csv 2>/dev/null | cut -d, -f1)"
+if [ "$(printf '%s\n' "$projects5" | grep -c .)" = 1 ] && printf '%s' "$projects5" | grep -q "$p5"; then
+  ok "(o) dropping incus-admin lands them in $p5 with NO re-grant — the promise holds"
+else
+  no "(o) after dropping incus-admin they see: '$(printf '%s' "$projects5" | tr '\n' ' ')' — grant's no-re-grant promise is false"
+fi
+aud "o. incus-admin-only grant: in-'incus'=$(id -nG "$U5" 2>/dev/null | tr ' ' '\n' | grep -cx incus), project '$p5' access='$acc5', post-drop projects='$(printf '%s' "$projects5" | tr '\n' ' ')'"
+
 echo
 echo "════════════════════════════════════════════"
 echo "  $pass passed, $fail failed"

host/grant-user.sh

@@ -9,7 +9,10 @@
 # Incus 6.0.4; the full write-up is in docs/plans/2026-07-18-restricted-tier.md.
 #
 # So granting is a per-user CONVERGENCE, and it must be run by an admin:
-#   1. put the user in the 'incus' group (not incus-admin — that is the tier)
+#   1. put the user in the 'incus' group (not incus-admin — that is the tier).
+#      An incus-admin member goes in too, and NOT for privilege: incus-user's
+#      socket is a FILE, group 'incus', mode 0660, so the membership is the
+#      only thing that lets step 2 connect() at all (#99, #101 review)
 #   2. touch incus-user AS the user, so the lazy project exists to converge
 #   3. unpin the private bridge (drop eth0 from the project's default profile)
 #   4. restrict the project's network access to boxnet and ONLY boxnet —
@@ -63,12 +66,34 @@ getent passwd "$user" >/dev/null || { echo "box grant: no such user: $user" >&2;
 uid="$(id -u "$user")"
 [ "$uid" -eq 0 ] && { echo "box grant: root does not need a tier — UID 0 owns the daemon socket outright." >&2; exit 1; }
 
-# An incus-admin member already holds the full socket; "granting" them the
+# An incus-admin member gets the full convergence anyway (#99). This used to
-# restricted tier would not restrict anything (admin membership wins at the
+# be a hard refusal, on the reasoning that admin membership wins at the socket
-# socket), it would only mislead whoever reads the group list later.
+# so nothing here could restrict them. True — and beside the point, because it
+# conflates the two separate things a grant hands over:
+#   · PERMISSION — the 'incus' group. At the DAEMON API they already hold
+#     strictly more through incus-admin, so this group adds no privilege. It
+#     is still required, because the two sockets are two FILES with two
+#     different owning groups (Debian 13 / Incus 6.0.4, measured):
+#         /var/lib/incus/unix.socket       group incus-admin  0660
+#         /var/lib/incus/unix.socket.user  group incus        0660
+#     incus-admin opens the first and not the second, and the second is the
+#     only one that provisions a user-<uid> project. An earlier revision of
+#     this script skipped the usermod for an admin member, reasoning that
+#     'incus' is a subset of incus-admin — true of the API, false of the
+#     filesystem: the pinned touch below took EACCES, the '|| true' swallowed
+#     it, no project appeared, and the grant died blaming a healthy
+#     incus-user. So the group step is a real convergence for everyone.
+#   · PROVISIONING — the user-<uid> project, the boxnet narrowing, the
+#     snapshot and backup allowances, the box-net profile installed INTO that
+#     project. An incus-admin member has none of it: box_tier() resolves them
+#     to 'admin' (bin/box), so they work in the SHARED default project next to
+#     root and every other admin, with no world of their own. This script is
+#     the only thing that provisions one, and refusing left them unable to get
+#     it without first being taken out of incus-admin.
+# So provision, and say plainly at the end what the provisioning does not do.
+admin_member=0
 if id -nG "$user" | tr ' ' '\n' | grep -qx incus-admin; then
-  echo "box grant: $user is in incus-admin — they already have the admin tier; there is nothing tighter to grant." >&2
+  admin_member=1
-  exit 1
 fi
 
 # The stack the tier converges ONTO must exist first. Checked via the daemon,
@@ -93,7 +118,11 @@ fi
 # admin re-runs. Backing out the group closes that window completely for a
 # fresh grant (their existing sessions predate the membership, so no process
 # holds it yet). A user who was already in the group keeps it: not ours to
-# take on a re-run's failure.
+# take on a re-run's failure. An incus-admin member now takes those same two
+# paths (#101): the membership IS added for them and so IS backed out, with
+# one thing extra to say either way — the rollback closes incus-user's socket
+# and never their daemon access, which outlives this failure by a route the
+# script never granted and must not pretend to control.
 added_group=0; was_member=0
 backout() {
   if [ "$added_group" -eq 1 ]; then
@@ -106,6 +135,16 @@ backout() {
       exit 1
     fi
     echo "box grant: FAILED — removed $user from 'incus' again (verified against the group database); fix the cause and re-run" >&2
+    if [ "$admin_member" -eq 1 ]; then
+      # The rollback is real and verified, but for an admin member it is not a
+      # lockout and must not read as one: what came back was incus-user's
+      # socket key, not the daemon. Say what survives, and what would end it.
+      echo "box grant: NOTE — that rollback closed incus-user's socket, NOT $user's access." >&2
+      echo "           They keep full admin socket access throughout via 'incus-admin', which this run" >&2
+      echo "           neither granted nor removed, so every project on this host stays open to them." >&2
+      echo "           Their project may be part-converged; a re-run converges the rest. To close their" >&2
+      echo "           access you must take the admin group itself:  gpasswd -d $user incus-admin" >&2
+    fi
     # The one window the database cannot close: a login STARTED between our
     # usermod and this backout keeps the group in its session credentials.
     # For a fresh grant that is a rare race, but rare is not never — name it
@@ -122,6 +161,14 @@ backout() {
     echo "box grant: FAILED with $user still holding socket access (their membership predates this run)." >&2
     echo "           their project may be part-converged — harmless in itself, and a re-run converges the rest." >&2
     echo "           if their access is not acceptable while you fix the cause:  box revoke $user" >&2
+    if [ "$admin_member" -eq 1 ]; then
+      # Same correction as above, for the member who was in BOTH groups before
+      # this run: 'box revoke' takes the 'incus' key back, and still leaves
+      # them the whole daemon.
+      echo "box grant: NOTE — $user is also in 'incus-admin', which this run neither granted nor removed:" >&2
+      echo "           'box revoke' takes back incus-user's socket key and nothing more. To close their" >&2
+      echo "           access:  gpasswd -d $user incus-admin" >&2
+    fi
   fi
 }
 trap backout EXIT
@@ -132,17 +179,63 @@ if id -nG "$user" | tr ' ' '\n' | grep -qx incus; then
 else
   $SUDO usermod -aG incus "$user"
   added_group=1
+  if [ "$admin_member" -eq 1 ]; then
+    # Say why, because the group list alone would imply a restriction that is
+    # not in force — the concern the old no-op was built around. It was a
+    # cosmetic concern and this is where it gets carried: in output, not in a
+    # skipped mutation that broke the mechanism.
+    echo "group: added $user to 'incus' — NOT a new privilege ('incus-admin' already opens the daemon,"
+    echo "       and box_tier still reads them as 'admin'), but the key to a FILE: incus-user's socket is"
+    echo "       group 'incus' mode 0660, and nothing below can provision $user without it"
+  else
     echo "group: added $user to 'incus' (their next login picks it up; the grant does not wait)"
+  fi
 fi
 
 project="user-$uid"
 
+# The incus CLI picks its socket by WRITABILITY, not by intent: with no
+# INCUS_SOCKET set it takes $INCUS_DIR/unix.socket when that is writable and
+# only falls back to unix.socket.user when it is not (client/connection.go,
+# stable-6.0 — the same branch that then defaults the project to user-<uid>).
+# For a plain 'incus' member the fallback fires and every command below lands
+# where we want it. For an incus-admin member the daemon socket IS writable,
+# so an unpinned client sails straight past incus-user — the touch would not
+# provision anything and the grant would die claiming incus-user was
+# unhealthy. Pin the socket for them, by incus's own directory rule.
+# INCUS_DIR first, then /run/incus if the daemon socket lives there, else
+# /var/lib/incus: incus's resolution order, not an approximation of it — the
+# pinned path has to name the same directory the client would have chosen.
+user_socket=""
+if [ "$admin_member" -eq 1 ]; then
+  incus_dir="${INCUS_DIR:-}"
+  if [ -z "$incus_dir" ]; then
+    incus_dir="/var/lib/incus"; [ -e /run/incus/unix.socket ] && incus_dir="/run/incus"
+  fi
+  user_socket="$incus_dir/unix.socket.user"
+  # $SUDO test, not a bare [ -e ]: revoke-user.sh documents from measurement
+  # that /var/lib/incus is not traversable by a non-root admin, so an
+  # unprivileged stat answers "absent" for a socket that is very much there —
+  # and this check EXITS on absent. Same discipline, same reason (#101 review).
+  $SUDO test -e "$user_socket" \
+    || { echo "box grant: incus-user is active but $user_socket is not there — nothing can provision $project (journalctl -u incus-user)" >&2; exit 1; }
+fi
+
+# Run the incus CLI as the granted user, on the socket that will actually
+# serve them: pinned to incus-user for an admin member, left to the CLI's own
+# resolution for everyone else (whose fallback already gets it right).
+run_as_incus() {
+  if [ -n "$user_socket" ]; then run_as "$user" env INCUS_SOCKET="$user_socket" "$@"
+  else run_as "$user" "$@"
+  fi
+}
+
 # 2. The project is created LAZILY, on the user's first contact with
 # incus-user — an admin cannot pre-create it (incus-user would fight over
 # it), so make that first contact happen now, as the user.
 if ! incus project show "$project" >/dev/null 2>&1 </dev/null; then
   echo "project: touching incus-user as $user to create $project..."
-  run_as "$user" timeout 60 incus project list >/dev/null 2>&1 || true
+  run_as_incus timeout 60 incus project list >/dev/null 2>&1 || true
   incus project show "$project" >/dev/null 2>&1 </dev/null \
     || { echo "box grant: incus-user did not create $project — is incus-user.socket healthy? (journalctl -u incus-user)" >&2; exit 1; }
   echo "project: $project created"
@@ -205,10 +298,53 @@ echo "profile: box-net installed in $project"
 
 # Prove the grant from the USER's side of the socket — the only side that
 # matters. This catches the failure the steps above cannot see one at a time:
-# a converged project the user still cannot reach.
+# a converged project the user still cannot reach. For an admin member the
-run_as "$user" timeout 30 incus profile show box-net >/dev/null 2>&1 \
+# project is named explicitly: an unqualified profile show over the pinned
+# incus-user socket asks about 'default', and over their own admin socket it
+# would answer from the shared default project — a green that proves the
+# convergence nothing at all.
+if [ -n "$user_socket" ]; then
+  run_as_incus timeout 30 incus --project "$project" profile show box-net >/dev/null 2>&1 \
+    || { echo "box grant: converged, but $user cannot reach $project's box-net profile through incus-user — check journalctl -u incus-user" >&2; exit 1; }
+else
+  run_as "$user" timeout 30 incus profile show box-net >/dev/null 2>&1 \
     || { echo "box grant: converged, but $user cannot see the box-net profile through incus-user — check journalctl -u incus-user" >&2; exit 1; }
+fi
 
 trap - EXIT   # converged and verified: the grant stands
-echo "granted: $user has the restricted tier — their 'box new' lands on the hardened boxnet."
+if [ "$admin_member" -eq 1 ]; then
-echo "         (their boxes are theirs alone; 'box revoke $user' takes the tier back)"
+  # The honest version of what the old refusal was gesturing at. The project
+  # is real, converged and theirs — that is what they were missing and what
+  # this run supplied. What it is NOT is confinement, in two distinct ways
+  # that both come from incus-admin winning at the socket, and both belong in
+  # the output rather than in a hard exit:
+  #   · nothing here binds them. Every restriction converged above describes
+  #     project $project; the default project and every other user's instances
+  #     stay one flag away, and no setting inside $project can say otherwise
+  #     while they hold that group.
+  #   · nothing here even routes them, yet. Their unpinned CLI resolves to the
+  #     writable daemon socket and so to the DEFAULT project (the socket rule
+  #     cited at step 2), so their 'box new' still lands beside the other
+  #     admins' until they either drop incus-admin — at which point this
+  #     project becomes their automatic home, no re-run needed — or pin
+  #     INCUS_SOCKET at incus-user by hand.
+  # That "no re-run needed" is a real promise only because the group step
+  # above put them in 'incus' (#101): dropping incus-admin leaves them a
+  # plain 'incus' member, which is exactly the tier whose client falls back
+  # to unix.socket.user and lands in $project. Under the old no-op they would
+  # have been left in NEITHER group — box_tier 'none', no socket at all, and
+  # a converged project they could not open.
+  echo "granted: $user has their own converged project $project (boxnet-only, snapshots, backups, box-net)."
+  echo "         CAVEAT — $user is in 'incus-admin', which wins at the socket: this is a"
+  echo "         DEFAULT PLACEMENT, not a confinement. They can reach the default project and"
+  echo "         every other user's instances whenever they choose to."
+  echo "         And until incus-admin goes, their own 'box' commands keep landing in the DEFAULT"
+  echo "         project — the admin socket is the one their client picks. To make $project theirs"
+  echo "         for real:  gpasswd -d $user incus-admin   (no re-grant needed: they keep 'incus', so"
+  echo "         their client falls straight back to incus-user and $project is already ready)."
+  echo "         'box revoke $user' unwinds this provisioning and takes the 'incus' membership back;"
+  echo "         it cannot touch their admin access."
+else
+  echo "granted: $user has the restricted tier — their 'box new' lands on the hardened boxnet."
+  echo "         (their boxes are theirs alone; 'box revoke $user' takes the tier back)"
+fi

host/revoke-user.sh

@@ -56,14 +56,42 @@ if [ "$purge" -eq 1 ]; then
   fi
 fi
 
+# An incus-admin member is the mirror of grant's #99 case. 'box grant' DOES
+# put them in 'incus' — not for privilege, but because incus-user's socket is
+# a file owned by that group (#101) — so revoke has a real membership to take
+# back here. What it does not have is a lockout: 'incus-admin' opens the
+# daemon and is not this script's to remove, so "revoked" would still be the
+# script claiming something it did not perform. Recorded here, spoken below.
+admin_member=0
+if id -nG "$user" | tr ' ' '\n' | grep -qx incus-admin; then
+  admin_member=1
+fi
+
 # The group, first — access ends even if a purge step below trips.
+dropped_group=0
 if id -nG "$user" | tr ' ' '\n' | grep -qx incus; then
   $SUDO gpasswd -d "$user" incus >/dev/null
+  dropped_group=1
+  if [ "$admin_member" -eq 1 ]; then
+    echo "group: removed $user from 'incus' — that membership was incus-user's socket key, which"
+    echo "       'box grant' added. It is NOT their daemon access: 'incus-admin' is untouched here"
+  else
     echo "group: removed $user from 'incus'"
+  fi
+elif [ "$admin_member" -eq 1 ]; then
+  echo "group: $user is not in 'incus' — nothing here to take; their socket access is 'incus-admin', which this does not touch"
 else
   echo "group: $user was not in 'incus'"
 fi
 
+# Say it once, plainly, before either path's summary: for an admin member the
+# group step above closed nothing, so nothing this script does — including
+# --purge — ends their access to the daemon. Only the admin group itself does.
+if [ "$admin_member" -eq 1 ]; then
+  echo "NOTE: $user is in 'incus-admin' and keeps FULL access to every project on this host"
+  echo "      regardless of what follows. To actually lock them out:  gpasswd -d $user incus-admin"
+fi
+
 # Supplementary groups are fixed AT LOGIN: the database change above does
 # nothing to a session the user already holds — a leftover tmux keeps the
 # socket until it dies. For a bare revoke that is an honest warning. For
@@ -95,8 +123,28 @@ fi
 if [ "$purge" -eq 0 ]; then
   if incus project show "$project" >/dev/null 2>&1 </dev/null; then
     echo "kept: project $project and its boxes (still running — revoking a person does not kill their workloads)"
+    if [ "$admin_member" -eq 1 ]; then
+      # "restores access" would be the wrong promise here: no access was lost.
+      echo "      'box revoke $user --purge' deletes them; 'box grant $user' re-converges the project and the membership"
+    else
       echo "      'box revoke $user --purge' deletes them; 'box grant $user' restores access"
     fi
+  fi
+  if [ "$admin_member" -eq 1 ]; then
+    # Not "revoked", still: what came back is the 'incus' membership grant
+    # added for incus-user's socket, and their access to this host was never
+    # riding on it. The project is kept. So say exactly what was taken and
+    # name the two real options, instead of a summary that reads as a lockout.
+    if [ "$dropped_group" -eq 1 ]; then
+      echo "partial: took $user out of 'incus' — incus-user's socket key, which 'box grant' added."
+      echo "         $user is NOT locked out: 'incus-admin' still opens every project on this host."
+    else
+      echo "no-op: $user was not in 'incus' and holds the admin tier via 'incus-admin' — nothing was taken."
+    fi
+    echo "       to remove their access:      gpasswd -d $user incus-admin"
+    echo "       to remove the project 'box grant' provisioned for them:  box revoke $user --purge"
+    exit 0
+  fi
   echo "revoked: $user no longer has the restricted tier."
   exit 0
 fi
@@ -160,4 +208,13 @@ if [ -n "$leftover" ]; then
   exit 1
 fi
 
-echo "revoked: $user is out, and everything the tier created is gone."
+if [ "$admin_member" -eq 1 ]; then
+  # "is out" would be false: the purge unmade the provisioning, and their
+  # incus-admin membership — untouched by design, it is not this script's to
+  # take — still opens every project on the host, including a fresh one they
+  # can build by hand a second from now.
+  echo "purged: everything 'box grant' created for $user is gone — but $user is NOT out."
+  echo "        'incus-admin' still gives them the whole daemon:  gpasswd -d $user incus-admin"
+else
+  echo "revoked: $user is out, and everything the tier created is gone."
+fi

test/cli.sh

@@ -479,6 +479,22 @@ check "box revoke with no user exits 2 (via the CLI table)" 2 "usage: box revoke
 check "help grant names the hardened network" 0 "boxnet" "$BOX" help grant
 check "help revoke names --purge"             0 "purge"  "$BOX" help revoke
 
+# The help is the PRE-RUN CONTRACT: an operator reads it to decide whether to
+# run the command at all, so it must not promise a mutation that will not
+# happen (or deny one that will). Round 1 of #101 changed what grant/revoke
+# mutate for an incus-admin member and left this prose describing the
+# superseded design — these pins are why that cannot happen silently again.
+# Both directions: the current sentence must be present, and the superseded
+# one must be gone.
+check "help grant: the admin member's group step is a real add, not a no-op" \
+  0 "like anyone else" "$BOX" help grant
+check "help revoke: a bare revoke of a granted admin member is 'partial:'" \
+  0 "partial:" "$BOX" help revoke
+check "help grant no longer calls the admin group step a no-op" 0 "" \
+  bash -c '! "'"$BOX"'" help grant | grep -q "reported no-op"'
+check "help revoke no longer claims there is no membership to drop" 0 "" \
+  bash -c '! "'"$BOX"'" help revoke | grep -q "no membership to drop"'
+
 # Load-bearing lines a daemon-free run cannot exercise — grepped so a deleted
 # guard cannot ship green (the house test discipline).
 # The expose guard must fire before ANY incus call in cmd_expose: line order.
@@ -512,8 +528,8 @@ check "grant: installs the SHIPPED profile into the project" 0 "" \
   grep -qF 'profile edit box-net < "$here/profiles/box-net.yaml"' "$ROOT/host/grant-user.sh"
 check "grant: unpins the private-bridge eth0 from the default profile" 0 "" \
   grep -qF 'profile device remove default eth0' "$ROOT/host/grant-user.sh"
-check "grant: refuses an incus-admin member (nothing tighter to grant)" 0 "" \
+check "grant: an incus-admin member is provisioned, not refused (#99)" 1 "" \
-  grep -qF 'incus-admin' "$ROOT/host/grant-user.sh"
+  grep -qF 'there is nothing tighter to grant' "$ROOT/host/grant-user.sh"
 check "revoke: group removal is the lockout" 0 "" \
   grep -qF 'gpasswd -d' "$ROOT/host/revoke-user.sh"
 # Group membership is read at login: purge must terminate live sessions (a
@@ -549,11 +565,202 @@ check "rehearsal: measures the raw boxnet attach (criterion m)" 0 "" \
 # shellcheck disable=SC2016  # the $-string is a literal in the target file
 check "rehearsal: injects grant failures (criterion n)" 0 "" \
   grep -qF 'grant-user.sh" "$U3"' "$ROOT/drill/multiuser.sh"
+# Criterion o is the real-Incus half of #101: the shim cannot model an EACCES
+# on the user socket, so the admin-only grant is measured where the socket has
+# a real owning group. Pinned so it cannot quietly leave the rehearsal.
+# shellcheck disable=SC2016  # the $-strings are literals in the target file
+check "rehearsal: grants an incus-admin-ONLY member on real Incus (criterion o)" 0 "" \
+  grep -qF 'usermod -aG incus-admin "$U5"' "$ROOT/drill/multiuser.sh"
+# shellcheck disable=SC2016  # ditto
+check "rehearsal: ...and opens the user socket as them, not just the daemon" 0 "" \
+  grep -qF 'INCUS_SOCKET="$sockdir/unix.socket.user"' "$ROOT/drill/multiuser.sh"
 # shellcheck disable=SC2016  # the $-strings are literals in the target file
 check "revoke: purge deletes instances one at a time" 0 "" \
   grep -qF 'delete -f "$inst"' "$ROOT/host/revoke-user.sh"
 check "revoke: purge removes the trust-store certificate" 0 "" \
   grep -qF 'config trust remove' "$ROOT/host/revoke-user.sh"
+
+# ---------------------------------------------------------------------------
+# #99: an incus-admin member is PROVISIONED, not refused. The distinction the
+# old refusal missed is permission (the 'incus' group — theirs already, and
+# stronger) versus provisioning (the user-<uid> project, the boxnet narrowing,
+# snapshots, backups, the box-net profile — theirs not at all). Grepping the
+# new prose would prove only that the prose exists, so both tier scripts are
+# DRIVEN end to end under shims, the same seam setup-host is driven through:
+# every incus and sudo call is logged, and the assertions are made against
+# those logs — what the run did, not what the source says it would do.
+# ---------------------------------------------------------------------------
+GSHIM="$(mktemp -d)"; W99="$(mktemp -d)"
+cat > "$GSHIM/incus" <<'SHIM'
+#!/usr/bin/env bash
+# Fake incus for the driven grant/revoke: logs every call, answers the
+# existence probes from FAKE_*, and models the two state changes the scripts
+# depend on — the project appearing after the incus-user touch, and
+# disappearing after a purge deletes it.
+[ -n "${FAKE_INCUS_LOG:-}" ] && printf 'incus %s\n' "$*" >> "$FAKE_INCUS_LOG"
+case "$*" in *"profile edit"*) cat >/dev/null ;; esac
+case "$*" in
+  "network show boxnet")  [ -n "${FAKE_HAVE_BOXNET:-}" ] || exit 1 ;;
+  "project show "*)
+    [ -e "$FAKE_STATE/deleted" ] && exit 1
+    if [ -n "${FAKE_PROJECT_LAZY:-}" ]; then
+      # Lazy creation: absent on the first look, present afterwards — i.e.
+      # the touch worked. n counts the looks this run has taken.
+      n=0; [ -e "$FAKE_STATE/looks" ] && n="$(cat "$FAKE_STATE/looks")"
+      printf '%s\n' "$((n + 1))" > "$FAKE_STATE/looks"
+      [ "$n" -ge 1 ] || exit 1
+    else
+      [ -n "${FAKE_HAVE_PROJECT:-}" ] || exit 1
+    fi ;;
+  "project delete "*) : > "$FAKE_STATE/deleted" ;;
+  *"restricted.networks.access"*)
+    [ -z "${FAKE_FAIL_NARROW:-}" ] || { echo 'Instance "old" is on incusbr-1000' >&2; exit 1; } ;;
+  *"network show "*) exit 1 ;;   # the private bridge: never there in these runs
+esac
+exit 0
+SHIM
+cat > "$GSHIM/sudo" <<'SHIM'
+#!/usr/bin/env bash
+# Fake sudo: logs and swallows — EXCEPT 'sudo test', which is run for real.
+# Both scripts route filesystem probes through it on purpose (/var/lib/incus
+# is not traversable by a non-root admin, so an unprivileged stat lies), and
+# both directions matter here: revoke's absence assert must see incus-user's
+# state directory as genuinely absent on a clean machine, and grant's socket
+# check must see the shimmed unix.socket.user as genuinely present.
+[ -n "${FAKE_SUDO_LOG:-}" ] && printf 'sudo %s\n' "$*" >> "$FAKE_SUDO_LOG"
+case "${1:-}" in test) shift; test "$@"; exit $? ;; esac
+exit 0
+SHIM
+printf '#!/usr/bin/env bash\nexit 0\n'                > "$GSHIM/getent"
+printf '#!/usr/bin/env bash\nexit 0\n'                > "$GSHIM/systemctl"
+printf '#!/usr/bin/env bash\nexit 1\n'                > "$GSHIM/pgrep"
+chmod +x "$GSHIM/incus" "$GSHIM/sudo" "$GSHIM/getent" "$GSHIM/systemctl" "$GSHIM/pgrep"
+
+# The pinned incus-user socket. box grant resolves it through INCUS_DIR (the
+# client's own first choice), so a directory here is the whole seam.
+mkdir -p "$W99/incusdir"; : > "$W99/incusdir/unix.socket.user"
+
+rungrant() { # rungrant <groups> <state-dir> [VAR=val ...] — the real grant, shimmed
+  local groups="$1" state="$2"; shift 2
+  mkdir -p "$state"
+  env FAKE_UID=1000 FAKE_GROUPS="$groups" FAKE_STATE="$state" \
+      FAKE_HAVE_BOXNET=1 FAKE_PROJECT_LAZY=1 INCUS_DIR="$W99/incusdir" \
+      FAKE_INCUS_LOG="$state/incus.log" FAKE_SUDO_LOG="$state/sudo.log" \
+      PATH="$GSHIM:$SHIMDIR:$PATH" "$@" bash "$ROOT/host/grant-user.sh" dev1
+}
+
+# --- the admin member: full convergence, no group change, honest caveat -----
+A="$W99/admin"
+check "grant: an incus-admin member CONVERGES (exit 0, no refusal)" 0 "granted:" \
+  rungrant "users incus-admin" "$A"
+check "grant: ...and the group step is a real convergence, named as one" 0 "added dev1 to 'incus'" \
+  rungrant "users incus-admin" "$W99/a2"
+check "grant: ...saying WHY (the socket is a file, group 'incus', not a privilege)" 0 "mode 0660" \
+  rungrant "users incus-admin" "$W99/a2b"
+check "grant: ...the caveat calls it a default placement, not a confinement" 0 "DEFAULT PLACEMENT" \
+  rungrant "users incus-admin" "$W99/a3"
+check "grant: ...and names the group that has to go for it to bind" 0 "gpasswd -d dev1 incus-admin" \
+  rungrant "users incus-admin" "$W99/a4"
+# The logs: what the run actually did to the machine.
+# #101's decision, pinned at the seam that broke: an incus-admin member IS
+# usermod'ed into 'incus'. It buys them no API privilege they lack — but
+# incus-user's socket is a FILE, group 'incus' mode 0660, and without the
+# membership the pinned touch below takes EACCES, the '|| true' eats it, and
+# the grant dies blaming a healthy incus-user. The shim cannot model that
+# EACCES (it ignores INCUS_SOCKET and permissions entirely), so the decision
+# is pinned here and MEASURED on real Incus in drill/multiuser.sh criterion o.
+check "grant: the admin member IS added to 'incus' — the user socket's group (#101)" 0 "" \
+  grep -qF 'usermod -aG incus dev1' "$A/sudo.log"
+check "grant: their project is still narrowed to boxnet" 0 "" \
+  grep -qF 'project set user-1000 restricted.networks.access boxnet' "$A/incus.log"
+check "grant: their project still gets snapshots" 0 "" \
+  grep -qF 'project set user-1000 restricted.snapshots allow' "$A/incus.log"
+check "grant: their project still gets backups" 0 "" \
+  grep -qF 'project set user-1000 restricted.backups allow' "$A/incus.log"
+check "grant: box-net is still installed INTO their project" 0 "" \
+  grep -qF -- '--project user-1000 profile edit box-net' "$A/incus.log"
+# The socket pin (#99's teeth): incus's client takes the DAEMON socket when it
+# is writable, and only falls back to unix.socket.user when it is not — so for
+# an incus-admin member an unpinned touch never reaches incus-user at all, and
+# the project it was supposed to create never appears.
+check "grant: the touch is pinned at incus-user's socket (the admin socket would win)" 0 "" \
+  grep -qF "INCUS_SOCKET=$W99/incusdir/unix.socket.user" "$A/sudo.log"
+check "grant: the user-side proof names their project (an unqualified show proves nothing)" 0 "" \
+  grep -qF -- '--project user-1000 profile show box-net' "$A/sudo.log"
+# The socket existence probe rides $SUDO, like revoke's: /var/lib/incus is not
+# traversable by a non-root admin, and a bare [ -e ] there false-fails into an
+# exit that blames incus-user for a socket that is present (#101 review).
+check "grant: the socket probe goes through sudo, not a bare [ -e ]" 0 "" \
+  grep -qF "test -e $W99/incusdir/unix.socket.user" "$A/sudo.log"
+
+# --- the restricted user: unchanged, and unpinned ---------------------------
+R="$W99/restricted"
+check "grant: a plain user is still added to 'incus'" 0 "added dev1 to 'incus'" \
+  rungrant "users" "$R"
+check "grant: ...via usermod (the log, not the prose)" 0 "" \
+  grep -qF 'usermod -aG incus dev1' "$R/sudo.log"
+check "grant: ...and their client is left to its own socket fallback" 1 "" \
+  grep -qF 'INCUS_SOCKET' "$R/sudo.log"
+
+# --- the failure path: what this run added comes back, and says what didn't --
+F="$W99/failed"
+check "grant: a failed grant for an admin member exits 1" 1 "FAILED" \
+  rungrant "users incus-admin" "$F" FAKE_FAIL_NARROW=1
+check "grant: ...says their admin socket was neither granted nor removed here" 1 "neither granted nor removed" \
+  rungrant "users incus-admin" "$W99/f2" FAKE_FAIL_NARROW=1
+# The membership IS this run's now, so the backout IS its business (#101).
+check "grant: ...and DOES roll the 'incus' membership back (this run added it)" 0 "" \
+  grep -qF 'gpasswd -d dev1 incus' "$F/sudo.log"
+check "grant: ...while refusing to call that rollback a lockout" 1 "closed incus-user's socket, NOT" \
+  rungrant "users incus-admin" "$W99/f3" FAKE_FAIL_NARROW=1
+
+# --- revoke, the mirror: it cannot take what it never gave ------------------
+# BOX_YES=1 throughout: --purge is destructive and refuses without a terminal
+# to confirm on, and this suite has none. It changes nothing for a bare revoke.
+runrevoke() { # runrevoke <groups> <state-dir> [script args...]
+  local groups="$1" state="$2"; shift 2
+  mkdir -p "$state"
+  env FAKE_UID=1000 FAKE_GROUPS="$groups" FAKE_STATE="$state" BOX_YES=1 \
+      FAKE_HAVE_PROJECT=1 FAKE_INCUS_LOG="$state/incus.log" FAKE_SUDO_LOG="$state/sudo.log" \
+      PATH="$GSHIM:$SHIMDIR:$PATH" bash "$ROOT/host/revoke-user.sh" dev1 "$@"
+}
+# The granted admin member is in BOTH groups — that is what 'box grant' leaves
+# behind now (#101) — so revoke has a real membership to take back. It takes
+# it, and still refuses to call the result a lockout: 'incus-admin' holds the
+# daemon and is not this script's to remove.
+GRANTED="users incus incus-admin"
+V="$W99/revoke"
+check "revoke: a bare revoke of a granted admin member is 'partial', not 'revoked'" 0 "partial:" \
+  runrevoke "$GRANTED" "$V"
+check "revoke: ...and refuses to call it a lockout" 0 "is NOT locked out" \
+  runrevoke "$GRANTED" "$W99/v2"
+check "revoke: ...naming the group that would actually lock them out" 0 "gpasswd -d dev1 incus-admin" \
+  runrevoke "$GRANTED" "$W99/v3"
+# The mirror of grant's flip: there IS a privileged call now, and it is the
+# membership grant added — asserted against the log, not the prose.
+check "revoke: ...having actually dropped the 'incus' membership (the log)" 0 "" \
+  grep -qF 'gpasswd -d dev1 incus' "$V/sudo.log"
+check "revoke: ...calling that key incus-user's, not their daemon access" 0 "NOT their daemon access" \
+  runrevoke "$GRANTED" "$W99/v4"
+# An admin member who was never granted: nothing to take, and it still says so
+# rather than reporting a revocation it did not perform.
+N="$W99/revoke-ungranted"
+check "revoke: an UNgranted admin member is still a named no-op" 0 "no-op:" \
+  runrevoke "users incus-admin" "$N"
+check "revoke: ...saying their access is incus-admin's, untouched here" 0 "which this does not touch" \
+  runrevoke "users incus-admin" "$W99/n2"
+# Absence of the LOG, not of a line in it: an ungranted admin member's bare
+# revoke makes no privileged call whatsoever, so the file is never created.
+check "revoke: ...having made NO privileged call at all (no membership to drop)" 1 "" \
+  test -e "$N/sudo.log"
+P="$W99/purge"
+check "revoke --purge: still unmakes the provisioning" 0 "purged:" \
+  runrevoke "$GRANTED" "$P" --purge
+check "revoke --purge: ...and refuses to call an admin member 'out'" 0 "is NOT out" \
+  runrevoke "$GRANTED" "$W99/p2" --purge
+check "revoke --purge: ...the project really was deleted (the log, not the summary)" 0 "" \
+  grep -qF 'project delete user-1000' "$P/incus.log"
+rm -rf "$GSHIM" "$W99"
 # shellcheck disable=SC2016  # the $-strings are literals in the target file
 check "setup-host: the restricted gate precedes the sudo resolution" 0 "" bash -c '
   gate="$(grep -n "restricted tier" "'"$ROOT"'/host/setup-host.sh" | head -1 | cut -d: -f1)"