]> git.ipfire.org Git - thirdparty/systemd.git/blobdiff - src/machine/machine-dbus.c
Add SPDX license identifiers to source files under the LGPL
[thirdparty/systemd.git] / src / machine / machine-dbus.c
index af745b65677b67d74d5d26d6ff00feefae8db15a..ea1568ea372f1043a95f57756eb18205b224155c 100644 (file)
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 /***
   This file is part of systemd.
 
@@ -411,7 +412,7 @@ int bus_machine_method_get_os_release(sd_bus_message *message, void *userdata, s
                         if (fd < 0)
                                 _exit(EXIT_FAILURE);
 
-                        r = copy_bytes(fd, pair[1], (uint64_t) -1, false);
+                        r = copy_bytes(fd, pair[1], (uint64_t) -1, 0);
                         if (r < 0)
                                 _exit(EXIT_FAILURE);
 
@@ -836,11 +837,14 @@ int bus_machine_method_bind_mount(sd_bus_message *message, void *userdata, sd_bu
         bool mount_slave_created = false, mount_slave_mounted = false,
                 mount_tmp_created = false, mount_tmp_mounted = false,
                 mount_outside_created = false, mount_outside_mounted = false;
+        _cleanup_free_ char *chased_src = NULL;
+        int read_only, make_file_or_directory;
         const char *dest, *src;
         Machine *m = userdata;
-        int read_only, make_directory;
-        pid_t child;
+        struct stat st;
         siginfo_t si;
+        pid_t child;
+        uid_t uid;
         int r;
 
         assert(message);
@@ -849,7 +853,7 @@ int bus_machine_method_bind_mount(sd_bus_message *message, void *userdata, sd_bu
         if (m->class != MACHINE_CONTAINER)
                 return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED, "Bind mounting is only supported on container machines.");
 
-        r = sd_bus_message_read(message, "ssbb", &src, &dest, &read_only, &make_directory);
+        r = sd_bus_message_read(message, "ssbb", &src, &dest, &read_only, &make_file_or_directory);
         if (r < 0)
                 return r;
 
@@ -875,6 +879,12 @@ int bus_machine_method_bind_mount(sd_bus_message *message, void *userdata, sd_bu
         if (r == 0)
                 return 1; /* Will call us back */
 
+        r = machine_get_uid_shift(m, &uid);
+        if (r < 0)
+                return r;
+        if (uid != 0)
+                return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED, "Can't bind mount on container with user namespacing applied.");
+
         /* One day, when bind mounting /proc/self/fd/n works across
          * namespace boundaries we should rework this logic to make
          * use of it... */
@@ -883,6 +893,15 @@ int bus_machine_method_bind_mount(sd_bus_message *message, void *userdata, sd_bu
         if (laccess(p, F_OK) < 0)
                 return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED, "Container does not allow propagation of mount points.");
 
+        r = chase_symlinks(src, NULL, 0, &chased_src);
+        if (r < 0)
+                return sd_bus_error_set_errnof(error, r, "Failed to resolve source path: %m");
+
+        if (lstat(chased_src, &st) < 0)
+                return sd_bus_error_set_errnof(error, errno, "Failed to stat() source path: %m");
+        if (S_ISLNK(st.st_mode)) /* This shouldn't really happen, given that we just chased the symlinks above, but let's better be safeā€¦ */
+                return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED, "Source directory can't be a symbolic link");
+
         /* Our goal is to install a new bind mount into the container,
            possibly read-only. This is irritatingly complex
            unfortunately, currently.
@@ -909,18 +928,21 @@ int bus_machine_method_bind_mount(sd_bus_message *message, void *userdata, sd_bu
                 goto finish;
         }
 
-        /* Second, we mount the source directory to a directory inside
-           of our MS_SLAVE playground. */
+        /* Second, we mount the source file or directory to a directory inside of our MS_SLAVE playground. */
         mount_tmp = strjoina(mount_slave, "/mount");
-        if (mkdir(mount_tmp, 0700) < 0) {
-                r = sd_bus_error_set_errnof(error, errno, "Failed to create temporary mount point %s: %m", mount_tmp);
+        if (S_ISDIR(st.st_mode))
+                r = mkdir(mount_tmp, 0700) < 0 ? -errno : 0;
+        else
+                r = touch(mount_tmp);
+        if (r < 0) {
+                sd_bus_error_set_errnof(error, errno, "Failed to create temporary mount point %s: %m", mount_tmp);
                 goto finish;
         }
 
         mount_tmp_created = true;
 
-        if (mount(src, mount_tmp, NULL, MS_BIND, NULL) < 0) {
-                r = sd_bus_error_set_errnof(error, errno, "Failed to overmount %s: %m", mount_tmp);
+        if (mount(chased_src, mount_tmp, NULL, MS_BIND, NULL) < 0) {
+                r = sd_bus_error_set_errnof(error, errno, "Failed to mount %s: %m", chased_src);
                 goto finish;
         }
 
@@ -933,13 +955,18 @@ int bus_machine_method_bind_mount(sd_bus_message *message, void *userdata, sd_bu
                         goto finish;
                 }
 
-        /* Fourth, we move the new bind mount into the propagation
-         * directory. This way it will appear there read-only
+        /* Fourth, we move the new bind mount into the propagation directory. This way it will appear there read-only
          * right-away. */
 
         mount_outside = strjoina("/run/systemd/nspawn/propagate/", m->name, "/XXXXXX");
-        if (!mkdtemp(mount_outside)) {
-                r = sd_bus_error_set_errnof(error, errno, "Cannot create propagation directory %s: %m", mount_outside);
+        if (S_ISDIR(st.st_mode))
+                r = mkdtemp(mount_outside) ? 0 : -errno;
+        else {
+                r = mkostemp_safe(mount_outside);
+                safe_close(r);
+        }
+        if (r < 0) {
+                sd_bus_error_set_errnof(error, errno, "Cannot create propagation file or directory %s: %m", mount_outside);
                 goto finish;
         }
 
@@ -953,7 +980,10 @@ int bus_machine_method_bind_mount(sd_bus_message *message, void *userdata, sd_bu
         mount_outside_mounted = true;
         mount_tmp_mounted = false;
 
-        (void) rmdir(mount_tmp);
+        if (S_ISDIR(st.st_mode))
+                (void) rmdir(mount_tmp);
+        else
+                (void) unlink(mount_tmp);
         mount_tmp_created = false;
 
         (void) umount(mount_slave);
@@ -992,8 +1022,14 @@ int bus_machine_method_bind_mount(sd_bus_message *message, void *userdata, sd_bu
                         goto child_fail;
                 }
 
-                if (make_directory)
-                        (void) mkdir_p(dest, 0755);
+                if (make_file_or_directory) {
+                        if (S_ISDIR(st.st_mode))
+                                (void) mkdir_p(dest, 0755);
+                        else {
+                                (void) mkdir_parents(dest, 0755);
+                                safe_close(open(dest, O_CREAT|O_EXCL|O_WRONLY|O_CLOEXEC|O_NOCTTY, 0600));
+                        }
+                }
 
                 /* Fifth, move the mount to the right place inside */
                 mount_inside = strjoina("/run/systemd/nspawn/incoming/", basename(mount_outside));
@@ -1035,19 +1071,27 @@ int bus_machine_method_bind_mount(sd_bus_message *message, void *userdata, sd_bu
 
 finish:
         if (mount_outside_mounted)
-                umount(mount_outside);
-        if (mount_outside_created)
-                rmdir(mount_outside);
+                (void) umount(mount_outside);
+        if (mount_outside_created) {
+                if (S_ISDIR(st.st_mode))
+                        (void) rmdir(mount_outside);
+                else
+                        (void) unlink(mount_outside);
+        }
 
         if (mount_tmp_mounted)
-                umount(mount_tmp);
-        if (mount_tmp_created)
-                rmdir(mount_tmp);
+                (void) umount(mount_tmp);
+        if (mount_tmp_created) {
+                if (S_ISDIR(st.st_mode))
+                        (void) rmdir(mount_tmp);
+                else
+                        (void) unlink(mount_tmp);
+        }
 
         if (mount_slave_mounted)
-                umount(mount_slave);
+                (void) umount(mount_slave);
         if (mount_slave_created)
-                rmdir(mount_slave);
+                (void) rmdir(mount_slave);
 
         return r;
 }
@@ -1055,10 +1099,12 @@ finish:
 int bus_machine_method_copy(sd_bus_message *message, void *userdata, sd_bus_error *error) {
         const char *src, *dest, *host_path, *container_path, *host_basename, *host_dirname, *container_basename, *container_dirname;
         _cleanup_close_pair_ int errno_pipe_fd[2] = { -1, -1 };
+        CopyFlags copy_flags = COPY_REFLINK|COPY_MERGE;
         _cleanup_close_ int hostfd = -1;
         Machine *m = userdata;
         bool copy_from;
         pid_t child;
+        uid_t uid_shift;
         char *t;
         int r;
 
@@ -1097,6 +1143,10 @@ int bus_machine_method_copy(sd_bus_message *message, void *userdata, sd_bus_erro
         if (r == 0)
                 return 1; /* Will call us back */
 
+        r = machine_get_uid_shift(m, &uid_shift);
+        if (r < 0)
+                return r;
+
         copy_from = strstr(sd_bus_message_get_member(message), "CopyFrom");
 
         if (copy_from) {
@@ -1151,10 +1201,13 @@ int bus_machine_method_copy(sd_bus_message *message, void *userdata, sd_bus_erro
                         goto child_fail;
                 }
 
+                /* Run the actual copy operation. Note that when an UID shift is set we'll either clamp the UID/GID to
+                 * 0 or to the actual UID shift depending on the direction we copy. If no UID shift is set we'll copy
+                 * the UID/GIDs as they are. */
                 if (copy_from)
-                        r = copy_tree_at(containerfd, container_basename, hostfd, host_basename, true);
+                        r = copy_tree_at(containerfd, container_basename, hostfd, host_basename, uid_shift == 0 ? UID_INVALID : 0, uid_shift == 0 ? GID_INVALID : 0, copy_flags);
                 else
-                        r = copy_tree_at(hostfd, host_basename, containerfd, container_basename, true);
+                        r = copy_tree_at(hostfd, host_basename, containerfd, container_basename, uid_shift == 0 ? UID_INVALID : uid_shift, uid_shift == 0 ? GID_INVALID : uid_shift, copy_flags);
 
                 hostfd = safe_close(hostfd);
                 containerfd = safe_close(containerfd);
@@ -1276,6 +1329,32 @@ int bus_machine_method_open_root_directory(sd_bus_message *message, void *userda
         return sd_bus_reply_method_return(message, "h", fd);
 }
 
+int bus_machine_method_get_uid_shift(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        Machine *m = userdata;
+        uid_t shift = 0;
+        int r;
+
+        assert(message);
+        assert(m);
+
+        /* You wonder why this is a method and not a property? Well, properties are not supposed to return errors, but
+         * we kinda have to for this. */
+
+        if (m->class == MACHINE_HOST)
+                return sd_bus_reply_method_return(message, "u", UINT32_C(0));
+
+        if (m->class != MACHINE_CONTAINER)
+                return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED, "UID/GID shift may only be determined for container machines.");
+
+        r = machine_get_uid_shift(m, &shift);
+        if (r == -ENXIO)
+                return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED, "Machine %s uses a complex UID/GID mapping, cannot determine shift", m->name);
+        if (r < 0)
+                return r;
+
+        return sd_bus_reply_method_return(message, "u", (uint32_t) shift);
+}
+
 const sd_bus_vtable machine_vtable[] = {
         SD_BUS_VTABLE_START(0),
         SD_BUS_PROPERTY("Name", "s", NULL, offsetof(Machine, name), SD_BUS_VTABLE_PROPERTY_CONST),
@@ -1293,6 +1372,7 @@ const sd_bus_vtable machine_vtable[] = {
         SD_BUS_METHOD("Kill", "si", NULL, bus_machine_method_kill, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("GetAddresses", NULL, "a(iay)", bus_machine_method_get_addresses, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("GetOSRelease", NULL, "a{ss}", bus_machine_method_get_os_release, SD_BUS_VTABLE_UNPRIVILEGED),
+        SD_BUS_METHOD("GetUIDShift", NULL, "u", bus_machine_method_get_uid_shift, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("OpenPTY", NULL, "hs", bus_machine_method_open_pty, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("OpenLogin", NULL, "hs", bus_machine_method_open_login, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("OpenShell", "ssasas", "hs", bus_machine_method_open_shell, SD_BUS_VTABLE_UNPRIVILEGED),