diff options
Diffstat (limited to 'gnu')
| -rw-r--r-- | gnu/build/linux-container.scm | 111 | ||||
| -rw-r--r-- | gnu/system/linux-container.scm | 4 |
2 files changed, 37 insertions, 78 deletions
diff --git a/gnu/build/linux-container.scm b/gnu/build/linux-container.scm index b6f8563f7d0..0df51c390b5 100644 --- a/gnu/build/linux-container.scm +++ b/gnu/build/linux-container.scm @@ -190,10 +190,7 @@ for the process." (remount-read-only "/")))) (define* (initialize-user-namespace pid host-uids - #:key - (host-uid (getuid)) - (host-gid (getgid)) - (guest-uid 0) (guest-gid 0)) + #:key (guest-uid 0) (guest-gid 0)) "Configure the user namespace for PID. HOST-UIDS specifies the number of host user identifiers to map into the user namespace. GUEST-UID and GUEST-GID specify the first UID (respectively GID) that host UIDs (respectively GIDs) @@ -204,21 +201,24 @@ map to in the namespace." (define (scope file) (string-append proc-dir file)) - ;; Only root can write to the gid map without first disabling the - ;; setgroups syscall. - (unless (and (zero? host-uid) (zero? host-gid)) - (call-with-output-file (scope "/setgroups") - (lambda (port) - (display "deny" port)))) + (let ((uid (getuid)) + (gid (getgid))) + + ;; Only root can write to the gid map without first disabling the + ;; setgroups syscall. + (unless (and (zero? uid) (zero? gid)) + (call-with-output-file (scope "/setgroups") + (lambda (port) + (display "deny" port)))) - ;; Map the user/group that created the container to the root user - ;; within the container. - (call-with-output-file (scope "/uid_map") - (lambda (port) - (format port "~d ~d ~d" guest-uid host-uid host-uids))) - (call-with-output-file (scope "/gid_map") - (lambda (port) - (format port "~d ~d ~d" guest-gid host-gid host-uids)))) + ;; Map the user/group that created the container to the root user + ;; within the container. + (call-with-output-file (scope "/uid_map") + (lambda (port) + (format port "~d ~d ~d" guest-uid uid host-uids))) + (call-with-output-file (scope "/gid_map") + (lambda (port) + (format port "~d ~d ~d" guest-gid gid host-uids))))) (define (namespaces->bit-mask namespaces) "Return the number suitable for the 'flags' argument of 'clone' that @@ -239,14 +239,12 @@ corresponds to the symbols in NAMESPACES." #:key (guest-uid 0) (guest-gid 0) (populate-file-system (const #t)) (loopback-network? #t) - (lock-mounts? #t) writable-root?) "Run THUNK in a new container process and return its PID. ROOT specifies the root directory for the container. MOUNTS is a list of <file-system> objects that specify file systems to mount inside the container. NAMESPACES is a list of symbols that correspond to the possible Linux namespaces: mnt, -ipc, uts, user, and net. When LOCK-MOUNTS? is true, arrange so that none of -MOUNTS can be unmounted or remounted individually from within THUNK. +ipc, uts, user, and net. When LOOPBACK-NETWORK? is true and 'net is amount NAMESPACES, set up the loopback device (\"lo\") and a minimal /etc/hosts. @@ -306,28 +304,6 @@ that host UIDs (respectively GIDs) map to in the namespace." ;; cannot be 'read' so they shouldn't be written as is. (write args child) (primitive-exit 3)))) - - (when (and lock-mounts? - (memq 'mnt namespaces) - (memq 'user namespaces)) - ;; Create a new mount namespace owned by a new user - ;; namespace to "lock" together previous mounts, such that - ;; they cannot be unmounted or remounted separately--see - ;; mount_namespaces(7). - ;; - ;; Note: at this point, the process is single-threaded (no - ;; GC mark threads, no finalization thread, etc.) which is - ;; why unshare(CLONE_NEWUSER) can be used. - (let ((uid (getuid)) (gid (getgid))) - (unshare (logior CLONE_NEWUSER CLONE_NEWNS)) - (when (file-exists? "/proc/self") - (initialize-user-namespace (getpid) - host-uids - #:host-uid uid - #:host-gid gid - #:guest-uid guest-uid - #:guest-gid guest-gid)))) - ;; TODO: Manage capabilities. (write 'ready child) (close-port child) @@ -400,7 +376,6 @@ if there are no child processes left." (define* (call-with-container mounts thunk #:key (namespaces %namespaces) (host-uids 1) (guest-uid 0) (guest-gid 0) - (lock-mounts? #t) (relayed-signals (list SIGINT SIGTERM)) (child-is-pid1? #t) (populate-file-system (const #t)) @@ -485,7 +460,6 @@ load path must be adjusted as needed." (call-with-temporary-directory (lambda (root) (let ((pid (run-container root mounts namespaces host-uids thunk* - #:lock-mounts? lock-mounts? #:guest-uid guest-uid #:guest-gid guest-gid #:populate-file-system populate-file-system @@ -506,35 +480,24 @@ return the exit status, an integer as returned by 'waitpid'." (0 (call-with-clean-exit (lambda () - ;; First, determine the user namespace that owns the pid namespace and - ;; join that user namespace (the assumption is that it also owns all - ;; the other namespaces). It's important that the user namespace is - ;; joined first, so that the user will have the privileges to join the - ;; other namespaces. - (let* ((pid-ns (open-fdes (namespace-file pid "pid") - (logior O_CLOEXEC O_RDONLY))) - (user-ns (get-user-ns pid-ns))) - (close-fdes pid-ns) - (unless (equal? (stat user-ns) - (stat (namespace-file (getpid) "user"))) - (setns user-ns 0)) - (close-fdes user-ns) - - ;; Then join all the remaining namespaces. - (for-each (lambda (ns) - (let ((source (namespace-file (getpid) ns)) - (target (namespace-file pid ns))) - ;; Joining the namespace that the process already - ;; belongs to would throw an error so avoid that. - ;; XXX: This /proc interface leads to TOCTTOU. - (unless (string=? (readlink source) (readlink target)) - (call-with-input-file target - (lambda (new-ns-port) - (setns (fileno new-ns-port) 0)))))) - ;; It's important that the mount namespace is joined last, - ;; otherwise the /proc mount point would no longer be - ;; accessible. - '("ipc" "uts" "net" "pid" "mnt"))) + (for-each (lambda (ns) + (let ((source (namespace-file (getpid) ns)) + (target (namespace-file pid ns))) + ;; Joining the namespace that the process already + ;; belongs to would throw an error so avoid that. + ;; XXX: This /proc interface leads to TOCTTOU. + (unless (string=? (readlink source) (readlink target)) + (call-with-input-file source + (lambda (current-ns-port) + (call-with-input-file target + (lambda (new-ns-port) + (setns (fileno new-ns-port) 0)))))))) + ;; It's important that the user namespace is joined first, + ;; so that the user will have the privileges to join the + ;; other namespaces. Furthermore, it's important that the + ;; mount namespace is joined last, otherwise the /proc mount + ;; point would no longer be accessible. + '("user" "ipc" "uts" "net" "pid" "mnt")) (purify-environment) (chdir "/") diff --git a/gnu/system/linux-container.scm b/gnu/system/linux-container.scm index d16d1e78b56..9bcdf24a7e0 100644 --- a/gnu/system/linux-container.scm +++ b/gnu/system/linux-container.scm @@ -317,10 +317,6 @@ Run the container with the given options.")) #:namespaces (if #$shared-network? (delq 'net %namespaces) %namespaces) - - ;; XXX: Work around <https://issues.guix.gnu.org/78356>. - #:lock-mounts? #f - #:writable-root? #t #:process-spawned-hook explain))))) |