[PATCH v5 29/42] ioctl: handle idmapped mounts
From: Christian Brauner <hidden>
Date: 2021-01-12 22:17:26
Also in:
linux-api, linux-ext4, linux-fsdevel, linux-integrity, linux-xfs, selinux
Subsystem:
filesystems (vfs and infrastructure), fsverity: read-only file-based authenticity protection, the rest · Maintainers:
Alexander Viro, Christian Brauner, Eric Biggers, Theodore Y. Ts'o, Linus Torvalds
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.
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <redacted>
---
/* v2 */
patch introduced
/* v3 */
unchanged
/* v4 */
- Serge Hallyn [off-list ref]:
- Use "mnt_userns" to refer to a vfsmount's userns everywhere to make
terminology consistent.
/* v5 */
base-commit: 7c53f6b671f4aba70ff15e1b05148b10d58c2837
- Christoph Hellwig [off-list ref]:
- Use new file_userns_helper().
---
fs/remap_range.c | 7 +++++--
fs/verity/enable.c | 2 +-
2 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/fs/remap_range.c b/fs/remap_range.c
index 29a4a4dbfe12..dc68394ec9a1 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_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; }
diff --git a/fs/verity/enable.c b/fs/verity/enable.c
index 6809cf8a99b7..9a221e368fa6 100644
--- a/fs/verity/enable.c
+++ b/fs/verity/enable.c@@ -369,7 +369,7 @@ int fsverity_ioctl_enable(struct file *filp, const void __user *uarg) * has verity enabled, and to stabilize the data being hashed. */ - err = inode_permission(&init_user_ns, inode, MAY_WRITE); + err = inode_permission(file_user_ns(filp), inode, MAY_WRITE); if (err) return err;
--
2.30.0