Merge tag 'rtc-4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux

[mirror_ubuntu-bionic-kernel.git] / fs / namei.c

diff --git a/fs/namei.c b/fs/namei.c
index ad74877e1442c0c9ea5fca87b065e59090088b10..da689c9c005ee268f258952bb12bd133bfa51fdf 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1100,7 +1100,6 @@ static int follow_automount(struct path *path, struct nameidata *nd,
                            bool *need_mntput)
 {
        struct vfsmount *mnt;
-       const struct cred *old_cred;
        int err;
 
        if (!path->dentry->d_op || !path->dentry->d_op->d_automount)
@@ -1129,9 +1128,7 @@ static int follow_automount(struct path *path, struct nameidata *nd,
        if (nd->total_link_count >= 40)
                return -ELOOP;
 
-       old_cred = override_creds(&init_cred);
        mnt = path->dentry->d_op->d_automount(path);
-       revert_creds(old_cred);
        if (IS_ERR(mnt)) {
                /*
                 * The filesystem is allowed to return -EISDIR here to indicate
@@ -2941,10 +2938,16 @@ static inline int open_to_namei_flags(int flag)
 
 static int may_o_create(const struct path *dir, struct dentry *dentry, umode_t mode)
 {
+       struct user_namespace *s_user_ns;
        int error = security_path_mknod(dir, dentry, mode, 0);
        if (error)
                return error;
 
+       s_user_ns = dir->dentry->d_sb->s_user_ns;
+       if (!kuid_has_mapping(s_user_ns, current_fsuid()) ||
+           !kgid_has_mapping(s_user_ns, current_fsgid()))
+               return -EOVERFLOW;
+
        error = inode_permission(dir->dentry->d_inode, MAY_WRITE | MAY_EXEC);
        if (error)
                return error;