Merge pull request #4372 from evverx/fix-synced-cgroup-hierarchy-perms

3 files changed, 59 insertions, 6 deletions

diff --git a/src/basic/mount-util.c b/src/basic/mount-util.c
index 0ef00676ef..2985cc475a 100644
--- a/src/basic/mount-util.c
+++ b/src/basic/mount-util.c
@@ -162,7 +162,7 @@ int fd_is_mount_point(int fd, const char *filename, int flags) {
 
 fallback_fdinfo:
         r = fd_fdinfo_mnt_id(fd, filename, flags, &mount_id);
-        if (r == -EOPNOTSUPP)
+        if (IN_SET(r, -EOPNOTSUPP, -EACCES))
                 goto fallback_fstat;
         if (r < 0)
                 return r;
diff --git a/src/nspawn/nspawn-mount.c b/src/nspawn/nspawn-mount.c
index 44dc9bfcf4..115de64cf9 100644
--- a/src/nspawn/nspawn-mount.c
+++ b/src/nspawn/nspawn-mount.c
@@ -300,6 +300,59 @@ int mount_sysfs(const char *dest) {
                              MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, NULL);
 }
 
+static int mkdir_userns(const char *path, mode_t mode, bool in_userns, uid_t uid_shift) {
+        int r;
+
+        assert(path);
+
+        r = mkdir(path, mode);
+        if (r < 0 && errno != EEXIST)
+                return -errno;
+
+        if (!in_userns) {
+                r = lchown(path, uid_shift, uid_shift);
+                if (r < 0)
+                        return -errno;
+        }
+
+        return 0;
+}
+
+static int mkdir_userns_p(const char *prefix, const char *path, mode_t mode, bool in_userns, uid_t uid_shift) {
+        const char *p, *e;
+        int r;
+
+        assert(path);
+
+        if (prefix && !path_startswith(path, prefix))
+                return -ENOTDIR;
+
+        /* create every parent directory in the path, except the last component */
+        p = path + strspn(path, "/");
+        for (;;) {
+                char t[strlen(path) + 1];
+
+                e = p + strcspn(p, "/");
+                p = e + strspn(e, "/");
+
+                /* Is this the last component? If so, then we're done */
+                if (*p == 0)
+                        break;
+
+                memcpy(t, path, e - path);
+                t[e-path] = 0;
+
+                if (prefix && path_startswith(prefix, t))
+                        continue;
+
+                r = mkdir_userns(t, mode, in_userns, uid_shift);
+                if (r < 0)
+                        return r;
+        }
+
+        return mkdir_userns(path, mode, in_userns, uid_shift);
+}
+
 int mount_all(const char *dest,
               bool use_userns, bool in_userns,
               bool use_netns,
@@ -361,7 +414,7 @@ int mount_all(const char *dest,
                 if (mount_table[k].what && r > 0)
                         continue;
 
-                r = mkdir_p(where, 0755);
+                r = mkdir_userns_p(dest, where, 0755, in_userns, uid_shift);
                 if (r < 0 && r != -EEXIST) {
                         if (mount_table[k].fatal)
                                 return log_error_errno(r, "Failed to create directory %s: %m", where);
diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c
index 2cbe563953..295293858e 100644
--- a/src/nspawn/nspawn.c
+++ b/src/nspawn/nspawn.c
@@ -2684,6 +2684,10 @@ static int inner_child(
                 }
         }
 
+        r = reset_uid_gid();
+        if (r < 0)
+                return log_error_errno(r, "Couldn't become new root: %m");
+
         r = mount_all(NULL,
                       arg_userns_mode != USER_NAMESPACE_NO,
                       true,
@@ -2726,10 +2730,6 @@ static int inner_child(
                         return r;
         }
 
-        r = reset_uid_gid();
-        if (r < 0)
-                return log_error_errno(r, "Couldn't become new root: %m");
-
         r = setup_boot_id(NULL);
         if (r < 0)
                 return r;