From 9452e93e6dae862d7aeff2b11236d79bde6f9b66 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Fri, 13 Jan 2023 12:49:27 +0100 Subject: fs: port privilege checking helpers to mnt_idmap Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner (Microsoft) --- fs/exec.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'fs/exec.c') diff --git a/fs/exec.c b/fs/exec.c index 584d906a6c08..c6278141b467 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1415,7 +1415,6 @@ void would_dump(struct linux_binprm *bprm, struct file *file) { struct inode *inode = file_inode(file); struct mnt_idmap *idmap = file_mnt_idmap(file); - struct user_namespace *mnt_userns = mnt_idmap_owner(idmap); if (inode_permission(idmap, inode, MAY_READ) < 0) { struct user_namespace *old, *user_ns; bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP; @@ -1423,7 +1422,7 @@ void would_dump(struct linux_binprm *bprm, struct file *file) /* Ensure mm->user_ns contains the executable */ user_ns = old = bprm->mm->user_ns; while ((user_ns != &init_user_ns) && - !privileged_wrt_inode_uidgid(user_ns, mnt_userns, inode)) + !privileged_wrt_inode_uidgid(user_ns, idmap, inode)) user_ns = user_ns->parent; if (old != user_ns) { -- cgit