From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Mon, 8 Aug 2022 18:03:11 +0000 (-0700)
Subject: Merge tag 'ovl-update-6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
X-Git-Tag: v6.6.17~6842
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=65512eb0e9e6308ca08110c88a9619a9e5a19aa9;p=platform%2Fkernel%2Flinux-rpi.git

Merge tag 'ovl-update-6.0' of git://git./linux/kernel/git/mszeredi/vfs

Pull overlayfs update from Miklos Szeredi:
 "Just a small update"

* tag 'ovl-update-6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: fix spelling mistakes
  ovl: drop WARN_ON() dentry is NULL in ovl_encode_fh()
  ovl: improve ovl_get_acl() if POSIX ACL support is off
  ovl: fix some kernel-doc comments
  ovl: warn if trusted xattr creation fails
---

65512eb0e9e6308ca08110c88a9619a9e5a19aa9
diff --cc fs/overlayfs/inode.c
index 7922b619f6c8,beef5e2ff563..b45fea69fff3
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@@ -454,95 -454,26 +454,97 @@@ ssize_t ovl_listxattr(struct dentry *de
  	return res;
  }
  
+ #ifdef CONFIG_FS_POSIX_ACL
 +/*
 + * Apply the idmapping of the layer to POSIX ACLs. The caller must pass a clone
 + * of the POSIX ACLs retrieved from the lower layer to this function to not
 + * alter the POSIX ACLs for the underlying filesystem.
 + */
 +static void ovl_idmap_posix_acl(struct user_namespace *mnt_userns,
 +				struct posix_acl *acl)
 +{
 +	for (unsigned int i = 0; i < acl->a_count; i++) {
 +		vfsuid_t vfsuid;
 +		vfsgid_t vfsgid;
 +
 +		struct posix_acl_entry *e = &acl->a_entries[i];
 +		switch (e->e_tag) {
 +		case ACL_USER:
 +			vfsuid = make_vfsuid(mnt_userns, &init_user_ns, e->e_uid);
 +			e->e_uid = vfsuid_into_kuid(vfsuid);
 +			break;
 +		case ACL_GROUP:
 +			vfsgid = make_vfsgid(mnt_userns, &init_user_ns, e->e_gid);
 +			e->e_gid = vfsgid_into_kgid(vfsgid);
 +			break;
 +		}
 +	}
 +}
 +
 +/*
 + * When the relevant layer is an idmapped mount we need to take the idmapping
 + * of the layer into account and translate any ACL_{GROUP,USER} values
 + * according to the idmapped mount.
 + *
 + * We cannot alter the ACLs returned from the relevant layer as that would
 + * alter the cached values filesystem wide for the lower filesystem. Instead we
 + * can clone the ACLs and then apply the relevant idmapping of the layer.
 + *
 + * This is obviously only relevant when idmapped layers are used.
 + */
  struct posix_acl *ovl_get_acl(struct inode *inode, int type, bool rcu)
  {
  	struct inode *realinode = ovl_inode_real(inode);
 -	const struct cred *old_cred;
 -	struct posix_acl *acl;
 +	struct posix_acl *acl, *clone;
 +	struct path realpath;
  
- 	if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !IS_POSIXACL(realinode))
+ 	if (!IS_POSIXACL(realinode))
  		return NULL;
  
 -	if (rcu)
 -		return get_cached_acl_rcu(realinode, type);
 +	/* Careful in RCU walk mode */
 +	ovl_i_path_real(inode, &realpath);
 +	if (!realpath.dentry) {
 +		WARN_ON(!rcu);
 +		return ERR_PTR(-ECHILD);
 +	}
  
 -	old_cred = ovl_override_creds(inode->i_sb);
 -	acl = get_acl(realinode, type);
 -	revert_creds(old_cred);
 +	if (rcu) {
 +		acl = get_cached_acl_rcu(realinode, type);
 +	} else {
 +		const struct cred *old_cred;
 +
 +		old_cred = ovl_override_creds(inode->i_sb);
 +		acl = get_acl(realinode, type);
 +		revert_creds(old_cred);
 +	}
 +	/*
 +	 * If there are no POSIX ACLs, or we encountered an error,
 +	 * or the layer isn't idmapped we don't need to do anything.
 +	 */
 +	if (!is_idmapped_mnt(realpath.mnt) || IS_ERR_OR_NULL(acl))
 +		return acl;
  
 -	return acl;
 +	/*
 +	 * We only get here if the layer is idmapped. So drop out of RCU path
 +	 * walk so we can clone the ACLs. There's no need to release the ACLs
 +	 * since get_cached_acl_rcu() doesn't take a reference on the ACLs.
 +	 */
 +	if (rcu)
 +		return ERR_PTR(-ECHILD);
 +
 +	clone = posix_acl_clone(acl, GFP_KERNEL);
 +	if (!clone)
 +		clone = ERR_PTR(-ENOMEM);
 +	else
 +		ovl_idmap_posix_acl(mnt_user_ns(realpath.mnt), clone);
 +	/*
 +	 * Since we're not in RCU path walk we always need to release the
 +	 * original ACLs.
 +	 */
 +	posix_acl_release(acl);
 +	return clone;
  }
+ #endif
  
  int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags)
  {