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From: Christian Brauner <brauner@kernel.org>
To: Steve French <stfrench@microsoft.com>,
	Christoph Hellwig <hch@infradead.org>,
	Namjae Jeon <namjae.jeon@samsung.com>,
	linux-cifs@vger.kernel.org
Cc: Hyunchul Lee <hyc.lee@gmail.com>,
	Sergey Senozhatsky <senozhatsky@chromium.org>,
	Christian Brauner <christian.brauner@ubuntu.com>
Subject: [PATCH 11/11] ksmbd: defer notify_change() call
Date: Mon, 23 Aug 2021 17:13:57 +0200	[thread overview]
Message-ID: <20210823151357.471691-12-brauner@kernel.org> (raw)
In-Reply-To: <20210823151357.471691-1-brauner@kernel.org>

From: Christian Brauner <christian.brauner@ubuntu.com>

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@microsoft.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Namjae Jeon <namjae.jeon@samsung.com>
Cc: Hyunchul Lee <hyc.lee@gmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: linux-cifs@vger.kernel.org
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---
 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)
 			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


  parent reply	other threads:[~2021-08-23 15:15 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20210823030840epcas1p24b226d445a683012925efd81a72ecb6d@epcas1p2.samsung.com>
2021-08-23  2:58 ` [PATCH v8 00/13] ksmbd: introduce new SMB3 kernel server Namjae Jeon
     [not found]   ` <CGME20210823030841epcas1p1a811d4a6aec75c09581a9b0fb575d23e@epcas1p1.samsung.com>
2021-08-23  2:58     ` [PATCH v8 01/13] ksmbd: add document Namjae Jeon
     [not found]   ` <CGME20210823030842epcas1p27cdeb782776f6659826110cd9a3524d4@epcas1p2.samsung.com>
2021-08-23  2:58     ` [PATCH v8 02/13] ksmbd: add server handler Namjae Jeon
     [not found]   ` <CGME20210823030843epcas1p4502dad130066a74f08745c849b981112@epcas1p4.samsung.com>
2021-08-23  2:58     ` [PATCH v8 03/13] ksmbd: add tcp transport layer Namjae Jeon
     [not found]   ` <CGME20210823030844epcas1p2a9dc2c02d32df86e9eb3c2af975c7d81@epcas1p2.samsung.com>
2021-08-23  2:58     ` [PATCH v8 04/13] ksmbd: add ipc " Namjae Jeon
     [not found]   ` <CGME20210823030845epcas1p3ff50078868ed215c43898356c9248d24@epcas1p3.samsung.com>
2021-08-23  2:58     ` [PATCH v8 05/13] ksmbd: add rdma " Namjae Jeon
     [not found]   ` <CGME20210823030845epcas1p2c72588cd470ca46463fd46b42b7b9603@epcas1p2.samsung.com>
2021-08-23  2:58     ` [PATCH v8 06/13] ksmbd: add a utility code that tracks (and caches) sessions data Namjae Jeon
     [not found]   ` <CGME20210823030846epcas1p35bd3c665d8afd6205c617840e709afc7@epcas1p3.samsung.com>
2021-08-23  2:58     ` [PATCH v8 07/13] ksmbd: add authentication Namjae Jeon
     [not found]   ` <CGME20210823030849epcas1p39035b8f9ec5cdc87dc7beca86590932c@epcas1p3.samsung.com>
2021-08-23  2:58     ` [PATCH v8 10/13] ksmbd: add oplock/lease cache mechanism Namjae Jeon
     [not found]   ` <CGME20210823030850epcas1p1eea7803d1ca2e854a0199f4c83cd8190@epcas1p1.samsung.com>
2021-08-23  2:58     ` [PATCH v8 11/13] ksmbd: add file operations Namjae Jeon
     [not found]   ` <CGME20210823030851epcas1p2d141386b64cd9039121a9f6a5074a362@epcas1p2.samsung.com>
2021-08-23  2:58     ` [PATCH v8 12/13] ksmbd: add Kconfig and Makefile Namjae Jeon
     [not found]   ` <CGME20210823030851epcas1p3df6319948e331e2e0225adba4e81e660@epcas1p3.samsung.com>
2021-08-23  2:58     ` [PATCH v8 13/13] MAINTAINERS: add ksmbd kernel server Namjae Jeon
2021-08-23 15:13   ` [PATCH 00/11] ksmbd: various fixes Christian Brauner
2021-08-23 15:13     ` [PATCH 01/11] ksmbd: fix lookup on idmapped mounts Christian Brauner
2021-08-23 15:13     ` [PATCH 02/11] ksmbd: fix translation in smb2_populate_readdir_entry() Christian Brauner
2021-08-23 15:13     ` [PATCH 03/11] ksmbd: fix translation in create_posix_rsp_buf() Christian Brauner
2021-08-23 15:13     ` [PATCH 04/11] smb2pdu: fix translation in ksmbd_acls_fattr() Christian Brauner
2021-08-23 15:13     ` [PATCH 05/11] ksmbd: fix translation in acl entries Christian Brauner
2021-08-23 15:13     ` [PATCH 06/11] ksmbd: fix subauth 0 handling in sid_to_id() Christian Brauner
2021-08-24  8:13       ` Namjae Jeon
2021-08-24 11:37         ` Christian Brauner
2021-08-23 15:13     ` [PATCH 07/11] ksmbd: fix translation " Christian Brauner
2021-08-23 15:13     ` [PATCH 08/11] ndr: fix translation in ndr_encode_posix_acl() Christian Brauner
2021-08-23 15:13     ` [PATCH 09/11] ksmbd: ensure error is surfaced in set_file_basic_info() Christian Brauner
2021-08-23 15:13     ` [PATCH 10/11] ksmbd: remove setattr preparations " Christian Brauner
2021-09-01 12:47       ` Namjae Jeon
2021-09-02 13:43         ` Christian Brauner
2021-10-01 18:51       ` Marios Makassikis
2021-10-02  0:41         ` Namjae Jeon
2021-10-02 19:29           ` Marios Makassikis
2021-10-03  0:12             ` Namjae Jeon
2021-08-23 15:13     ` Christian Brauner [this message]
2021-08-24  8:20       ` [PATCH 11/11] ksmbd: defer notify_change() call Namjae Jeon
2021-08-24 11:36         ` Christian Brauner
2021-09-01 12:53       ` Namjae Jeon
2021-09-02 13:42         ` Christian Brauner

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