From: Andreas Gruenbacher <agruenba@redhat.com>
To: Alexander Viro <viro@zeniv.linux.org.uk>,
"Theodore Ts'o" <tytso@mit.edu>,
Andreas Dilger <adilger.kernel@dilger.ca>,
"J. Bruce Fields" <bfields@fieldses.org>,
Jeff Layton <jlayton@poochiereds.net>,
Trond Myklebust <trond.myklebust@primarydata.com>,
Anna Schumaker <anna.schumaker@netapp.com>,
Dave Chinner <david@fromorbit.com>,
linux-ext4@vger.kernel.org, xfs@oss.sgi.com,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org,
linux-api@vger.kernel.org
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Subject: [PATCH v16 03/22] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags
Date: Wed, 2 Dec 2015 22:01:09 +0100 [thread overview]
Message-ID: <1449090088-9281-4-git-send-email-agruenba@redhat.com> (raw)
In-Reply-To: <1449090088-9281-1-git-send-email-agruenba@redhat.com>
Normally, deleting a file requires MAY_WRITE access to the parent
directory. With richacls, a file may be deleted with MAY_DELETE_CHILD access
to the parent directory or with MAY_DELETE_SELF access to the file.
To support that, pass the MAY_DELETE_CHILD mask flag to inode_permission()
when checking for delete access inside a directory, and MAY_DELETE_SELF
when checking for delete access to a file itelf.
The MAY_DELETE_SELF permission overrides the sticky directory check.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: J. Bruce Fields <bfields@redhat.com>
---
fs/namei.c | 20 ++++++++++++--------
include/linux/fs.h | 2 ++
2 files changed, 14 insertions(+), 8 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index 3216e73..1284157 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -453,9 +453,9 @@ static int sb_permission(struct super_block *sb, struct inode *inode, int mask)
* this, letting us set arbitrary permissions for filesystem access without
* changing the "normal" UIDs which are used for other things.
*
- * MAY_WRITE must be set in @mask whenever MAY_APPEND, MAY_CREATE_FILE, or
- * MAY_CREATE_DIR are set. That way, file systems that don't support these
- * permissions will check for MAY_WRITE instead.
+ * MAY_WRITE must be set in @mask whenever MAY_APPEND, MAY_CREATE_FILE,
+ * MAY_CREATE_DIR, or MAY_DELETE_CHILD are set. That way, file systems that
+ * don't support these permissions will check for MAY_WRITE instead.
*/
int inode_permission(struct inode *inode, int mask)
{
@@ -2561,14 +2561,18 @@ static int may_delete_or_replace(struct inode *dir, struct dentry *victim,
BUG_ON(victim->d_parent->d_inode != dir);
audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
- error = inode_permission(dir, mask);
+ error = inode_permission(dir, mask | MAY_WRITE | MAY_DELETE_CHILD);
+ if (!error && check_sticky(dir, inode))
+ error = -EPERM;
+ if (error && IS_RICHACL(inode) &&
+ inode_permission(inode, MAY_DELETE_SELF) == 0 &&
+ inode_permission(dir, mask) == 0)
+ error = 0;
if (error)
return error;
if (IS_APPEND(dir))
return -EPERM;
-
- if (check_sticky(dir, inode) || IS_APPEND(inode) ||
- IS_IMMUTABLE(inode) || IS_SWAPFILE(inode))
+ if (IS_APPEND(inode) || IS_IMMUTABLE(inode) || IS_SWAPFILE(inode))
return -EPERM;
if (isdir) {
if (!d_is_dir(victim))
@@ -2586,7 +2590,7 @@ static int may_delete_or_replace(struct inode *dir, struct dentry *victim,
static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
{
- return may_delete_or_replace(dir, victim, isdir, MAY_WRITE | MAY_EXEC);
+ return may_delete_or_replace(dir, victim, isdir, MAY_EXEC);
}
static int may_replace(struct inode *dir, struct dentry *victim, bool isdir)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index c0d5760..7a45120 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -84,6 +84,8 @@ typedef void (dax_iodone_t)(struct buffer_head *bh_map, int uptodate);
#define MAY_NOT_BLOCK 0x00000080
#define MAY_CREATE_FILE 0x00000100
#define MAY_CREATE_DIR 0x00000200
+#define MAY_DELETE_CHILD 0x00000400
+#define MAY_DELETE_SELF 0x00000800
/*
* flags in file.f_mode. Note that FMODE_READ and FMODE_WRITE must correspond
--
2.5.0
next prev parent reply other threads:[~2015-12-02 21:02 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-02 21:01 [PATCH v16 00/22] Richacls (Core and Ext4) Andreas Gruenbacher
2015-12-02 21:01 ` [PATCH v16 01/22] vfs: Add IS_ACL() and IS_RICHACL() tests Andreas Gruenbacher
2015-12-02 21:01 ` [PATCH v16 02/22] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Gruenbacher
2015-12-02 21:01 ` Andreas Gruenbacher [this message]
2015-12-02 21:01 ` [PATCH v16 04/22] vfs: Make the inode passed to inode_change_ok non-const Andreas Gruenbacher
2015-12-02 21:01 ` [PATCH v16 05/22] vfs: Add permission flags for setting file attributes Andreas Gruenbacher
2015-12-02 21:01 ` [PATCH v16 06/22] richacl: In-memory representation and helper functions Andreas Gruenbacher
2015-12-02 21:01 ` [PATCH v16 07/22] richacl: Permission mapping functions Andreas Gruenbacher
2015-12-02 21:01 ` [PATCH v16 08/22] richacl: Compute maximum file masks from an acl Andreas Gruenbacher
2015-12-02 21:01 ` [PATCH v16 09/22] richacl: Permission check algorithm Andreas Gruenbacher
2015-12-02 21:01 ` [PATCH v16 10/22] posix_acl: Unexport acl_by_type and make it static Andreas Gruenbacher
2015-12-02 21:01 ` [PATCH v16 11/22] vfs: Cache base_acl objects in inodes Andreas Gruenbacher
2015-12-02 21:01 ` [PATCH v16 12/22] vfs: Add get_richacl and set_richacl inode operations Andreas Gruenbacher
2015-12-02 21:01 ` [PATCH v16 13/22] vfs: Cache richacl in struct inode Andreas Gruenbacher
2015-12-02 21:01 ` [PATCH v16 14/22] richacl: Update the file masks in chmod() Andreas Gruenbacher
2015-12-02 21:01 ` [PATCH v16 15/22] richacl: Check if an acl is equivalent to a file mode Andreas Gruenbacher
2015-12-02 21:01 ` [PATCH v16 16/22] richacl: Create-time inheritance Andreas Gruenbacher
2015-12-02 21:01 ` [PATCH v16 17/22] richacl: Automatic Inheritance Andreas Gruenbacher
2015-12-02 21:01 ` [PATCH v16 18/22] richacl: xattr mapping functions Andreas Gruenbacher
2015-12-02 21:01 ` [PATCH v16 19/22] richacl: Add richacl xattr handler Andreas Gruenbacher
2015-12-02 21:01 ` [PATCH v16 20/22] vfs: Add richacl permission checking Andreas Gruenbacher
2015-12-02 21:01 ` [PATCH v16 21/22] ext4: Add richacl support Andreas Gruenbacher
2015-12-02 21:01 ` [PATCH v16 22/22] ext4: Add richacl feature flag Andreas Gruenbacher
2015-12-03 22:17 ` [PATCH v16 00/22] Richacls (Core and Ext4) Andreas Gruenbacher
2015-12-15 11:12 ` Andreas Gruenbacher
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