Enable generic ioctls to handle idmapped mounts by passing down the mount's user namespace. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210112220124.837960-30-christian.brauner@xxxxxxxxxx Cc: Christoph Hellwig <hch@xxxxxx> Cc: David Howells <dhowells@xxxxxxxxxx> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: linux-fsdevel@xxxxxxxxxxxxxxx Reviewed-by: Christoph Hellwig <hch@xxxxxx> Signed-off-by: Christian Brauner <christian.brauner@xxxxxxxxxx> --- /* v2 */ patch introduced /* v3 */ unchanged /* v4 */ - Serge Hallyn <serge@xxxxxxxxxx>: - Use "mnt_userns" to refer to a vfsmount's userns everywhere to make terminology consistent. /* v5 */ unchanged base-commit: 7c53f6b671f4aba70ff15e1b05148b10d58c2837 - Christoph Hellwig <hch@xxxxxx>: - Use new file_mnt_user_ns() helper. /* v6 */ base-commit: 19c329f6808995b142b3966301f217c831e7cf31 - Christoph Hellwig <hch@xxxxxx>: - Make use of file_permission() helper. --- fs/remap_range.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/remap_range.c b/fs/remap_range.c index 29a4a4dbfe12..e4a5fdd7ad7b 100644 --- a/fs/remap_range.c +++ b/fs/remap_range.c @@ -432,13 +432,16 @@ EXPORT_SYMBOL(vfs_clone_file_range); /* Check whether we are allowed to dedupe the destination file */ static bool allow_file_dedupe(struct file *file) { + struct user_namespace *mnt_userns = file_mnt_user_ns(file); + struct inode *inode = file_inode(file); + if (capable(CAP_SYS_ADMIN)) return true; if (file->f_mode & FMODE_WRITE) return true; - if (uid_eq(current_fsuid(), file_inode(file)->i_uid)) + if (uid_eq(current_fsuid(), i_uid_into_mnt(mnt_userns, inode))) return true; - if (!inode_permission(&init_user_ns, file_inode(file), MAY_WRITE)) + if (!inode_permission(mnt_userns, inode, MAY_WRITE)) return true; return false; } -- 2.30.0
