2021-08-24 0:13 GMT+09:00, Christian Brauner <brauner@xxxxxxxxxx>:
> From: Christian Brauner <christian.brauner@xxxxxxxxxx>
>
> When ownership is changed we might in certain scenarios loose the
> ability to alter the inode after we changed ownership. This can e.g.
> happen when we are on an idmapped mount where uid 0 is mapped to uid
> 1000 and uid 1000 is mapped to uid 0.
> A caller with fs*id 1000 will be able to create files as *id 1000 on
> disk. They will also be able to change ownership of files owned by *id 0
> to *id 1000 but they won't be able to change ownership in the other
> direction. This means acl operations following notify_change() would
> fail. Move the notify_change() call after the acls have been updated.
> This guarantees that we don't end up with spurious "hash value diff"
> warnings later on because we managed to change ownership but didn't
> manage to alter acls.
>
> Cc: Steve French <stfrench@xxxxxxxxxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
> Cc: Namjae Jeon <namjae.jeon@xxxxxxxxxxx>
> Cc: Hyunchul Lee <hyc.lee@xxxxxxxxx>
> Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
> Cc: linux-cifs@xxxxxxxxxxxxxxx
> Signed-off-by: Christian Brauner <christian.brauner@xxxxxxxxxx>
> ---
> fs/ksmbd/smbacl.c | 21 ++++++++++++++-------
> 1 file changed, 14 insertions(+), 7 deletions(-)
>
> diff --git a/fs/ksmbd/smbacl.c b/fs/ksmbd/smbacl.c
> index ef5896297607..8457a3c27c12 100644
> --- a/fs/ksmbd/smbacl.c
> +++ b/fs/ksmbd/smbacl.c
> @@ -1334,25 +1334,27 @@ int set_info_sec(struct ksmbd_conn *conn, struct
> ksmbd_tree_connect *tcon,
> newattrs.ia_valid |= ATTR_MODE;
> newattrs.ia_mode = (inode->i_mode & ~0777) | (fattr.cf_mode & 0777);
>
> - inode_lock(inode);
> - rc = notify_change(user_ns, path->dentry, &newattrs, NULL);
> - inode_unlock(inode);
> - if (rc)
> - goto out;
> -
> ksmbd_vfs_remove_acl_xattrs(user_ns, path->dentry);
> /* Update posix acls */
> if (IS_ENABLED(CONFIG_FS_POSIX_ACL) && fattr.cf_dacls) {
> rc = set_posix_acl(user_ns, inode,
> ACL_TYPE_ACCESS, fattr.cf_acls);
> + if (rc < 0)
> + ksmbd_debug(SMB,
> + "Set posix acl(ACL_TYPE_ACCESS) failed, rc : %d\n",
> + rc);
> if (S_ISDIR(inode->i_mode) && fattr.cf_dacls)
You seem to have missed adding braces after adding a debug print.
I will directly update it if you don't mind.
Thanks!
> rc = set_posix_acl(user_ns, inode,
> ACL_TYPE_DEFAULT, fattr.cf_dacls);
> + if (rc)
> + ksmbd_debug(SMB,
> + "Set posix acl(ACL_TYPE_DEFAULT) failed, rc : %d\n",
> + rc);
> }
>
> /* Check it only calling from SD BUFFER context */
> if (type_check && !(le16_to_cpu(pntsd->type) & DACL_PRESENT))
> - goto out;
> + goto out_change;
>
> if (test_share_config_flag(tcon->share_conf, KSMBD_SHARE_FLAG_ACL_XATTR))
> {
> /* Update WinACL in xattr */
> @@ -1361,6 +1363,11 @@ int set_info_sec(struct ksmbd_conn *conn, struct
> ksmbd_tree_connect *tcon,
> path->dentry, pntsd, ntsd_len);
> }
>
> +out_change:
> + inode_lock(inode);
> + rc = notify_change(user_ns, path->dentry, &newattrs, NULL);
> + inode_unlock(inode);
> +
> out:
> posix_acl_release(fattr.cf_acls);
> posix_acl_release(fattr.cf_dacls);
> --
> 2.30.2
>
>
