From 0e844efebdf9c03aed9ae1894f22762a8aee1a3b Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Mon, 23 Aug 2021 17:13:51 +0200 Subject: ksmbd: fix translation in acl entries The ksmbd server performs translation of posix acls to smb acls. Currently the translation is wrong since the idmapping of the mount is used to map the ids into raw userspace ids but what is relevant is the user namespace of ksmbd itself. The user namespace of ksmbd itself which is the initial user namespace. The operation is similar to asking "What *ids would a userspace process see given that k*id in the relevant user namespace?". Before the final translation we need to apply the idmapping of the mount in case any is used. Add two simple helpers for ksmbd. Cc: Steve French Cc: Christoph Hellwig Cc: Namjae Jeon Cc: Hyunchul Lee Cc: Sergey Senozhatsky Cc: linux-cifs@vger.kernel.org Signed-off-by: Christian Brauner Signed-off-by: Namjae Jeon Signed-off-by: Steve French --- fs/ksmbd/smbacl.c | 14 ++++++-------- fs/ksmbd/smbacl.h | 25 +++++++++++++++++++++++++ fs/ksmbd/vfs.c | 4 ++-- 3 files changed, 33 insertions(+), 10 deletions(-) (limited to 'fs/ksmbd') diff --git a/fs/ksmbd/smbacl.c b/fs/ksmbd/smbacl.c index a7025b31d2f2..3307ca776eb1 100644 --- a/fs/ksmbd/smbacl.c +++ b/fs/ksmbd/smbacl.c @@ -587,14 +587,14 @@ static void set_posix_acl_entries_dacl(struct user_namespace *user_ns, uid_t uid; unsigned int sid_type = SIDOWNER; - uid = from_kuid(user_ns, pace->e_uid); + uid = posix_acl_uid_translate(user_ns, pace); if (!uid) sid_type = SIDUNIX_USER; id_to_sid(uid, sid_type, sid); } else if (pace->e_tag == ACL_GROUP) { gid_t gid; - gid = from_kgid(user_ns, pace->e_gid); + gid = posix_acl_gid_translate(user_ns, pace); id_to_sid(gid, SIDUNIX_GROUP, sid); } else if (pace->e_tag == ACL_OTHER && !nt_aces_num) { smb_copy_sid(sid, &sid_everyone); @@ -653,12 +653,12 @@ posix_default_acl: if (pace->e_tag == ACL_USER) { uid_t uid; - uid = from_kuid(user_ns, pace->e_uid); + uid = posix_acl_uid_translate(user_ns, pace); id_to_sid(uid, SIDCREATOR_OWNER, sid); } else if (pace->e_tag == ACL_GROUP) { gid_t gid; - gid = from_kgid(user_ns, pace->e_gid); + gid = posix_acl_gid_translate(user_ns, pace); id_to_sid(gid, SIDCREATOR_GROUP, sid); } else { kfree(sid); @@ -1234,11 +1234,9 @@ int smb_check_perm_dacl(struct ksmbd_conn *conn, struct path *path, pa_entry = posix_acls->a_entries; for (i = 0; i < posix_acls->a_count; i++, pa_entry++) { if (pa_entry->e_tag == ACL_USER) - id = from_kuid(user_ns, - pa_entry->e_uid); + id = posix_acl_uid_translate(user_ns, pa_entry); else if (pa_entry->e_tag == ACL_GROUP) - id = from_kgid(user_ns, - pa_entry->e_gid); + id = posix_acl_gid_translate(user_ns, pa_entry); else continue; diff --git a/fs/ksmbd/smbacl.h b/fs/ksmbd/smbacl.h index 940f686a1d95..73e08cad412b 100644 --- a/fs/ksmbd/smbacl.h +++ b/fs/ksmbd/smbacl.h @@ -209,4 +209,29 @@ int set_info_sec(struct ksmbd_conn *conn, struct ksmbd_tree_connect *tcon, bool type_check); void id_to_sid(unsigned int cid, uint sidtype, struct smb_sid *ssid); void ksmbd_init_domain(u32 *sub_auth); + +static inline uid_t posix_acl_uid_translate(struct user_namespace *mnt_userns, + struct posix_acl_entry *pace) +{ + kuid_t kuid; + + /* If this is an idmapped mount, apply the idmapping. */ + kuid = kuid_into_mnt(mnt_userns, pace->e_uid); + + /* Translate the kuid into a userspace id ksmbd would see. */ + return from_kuid(&init_user_ns, kuid); +} + +static inline gid_t posix_acl_gid_translate(struct user_namespace *mnt_userns, + struct posix_acl_entry *pace) +{ + kgid_t kgid; + + /* If this is an idmapped mount, apply the idmapping. */ + kgid = kgid_into_mnt(mnt_userns, pace->e_gid); + + /* Translate the kgid into a userspace id ksmbd would see. */ + return from_kgid(&init_user_ns, kgid); +} + #endif /* _SMBACL_H */ diff --git a/fs/ksmbd/vfs.c b/fs/ksmbd/vfs.c index 2bb506d1fb32..b047f2980d96 100644 --- a/fs/ksmbd/vfs.c +++ b/fs/ksmbd/vfs.c @@ -1390,14 +1390,14 @@ static struct xattr_smb_acl *ksmbd_vfs_make_xattr_posix_acl(struct user_namespac switch (pa_entry->e_tag) { case ACL_USER: xa_entry->type = SMB_ACL_USER; - xa_entry->uid = from_kuid(user_ns, pa_entry->e_uid); + xa_entry->uid = posix_acl_uid_translate(user_ns, pa_entry); break; case ACL_USER_OBJ: xa_entry->type = SMB_ACL_USER_OBJ; break; case ACL_GROUP: xa_entry->type = SMB_ACL_GROUP; - xa_entry->gid = from_kgid(user_ns, pa_entry->e_gid); + xa_entry->gid = posix_acl_gid_translate(user_ns, pa_entry); break; case ACL_GROUP_OBJ: xa_entry->type = SMB_ACL_GROUP_OBJ; -- cgit v1.2.3-58-ga151