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From: Andreas Gruenbacher <agruenba@redhat.com>
To: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Gruenbacher <agruenba@redhat.com>,
	Christoph Hellwig <hch@infradead.org>,
	"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
Subject: [PATCH v23 16/22] richacl: Create-time inheritance
Date: Thu, 30 Jun 2016 15:47:07 +0200	[thread overview]
Message-ID: <1467294433-3222-17-git-send-email-agruenba@redhat.com> (raw)
In-Reply-To: <1467294433-3222-1-git-send-email-agruenba@redhat.com>

When a new file is created, it can inherit an acl from its parent
directory; this is similar to how default acls work in POSIX ACLs.

As with POSIX ACLs, if a file inherits an acl from its parent directory,
the intersection between the create mode and the permissions granted by
the inherited acl determines the file masks and file permission bits,
and the umask is ignored.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/richacl.c            | 151 ++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/richacl.h |   2 +
 2 files changed, 153 insertions(+)

diff --git a/fs/richacl.c b/fs/richacl.c
index e8a383b..29eaf89 100644
--- a/fs/richacl.c
+++ b/fs/richacl.c
@@ -722,3 +722,154 @@ richacl_equiv_mode(const struct richacl *acl, umode_t *mode_p)
 	return 0;
 }
 EXPORT_SYMBOL_GPL(richacl_equiv_mode);
+
+static inline bool
+ace_inherits_to_directory(const struct richace *ace)
+{
+	if (ace->e_flags & RICHACE_DIRECTORY_INHERIT_ACE)
+		return true;
+	if ((ace->e_flags & RICHACE_FILE_INHERIT_ACE) &&
+	    !(ace->e_flags & RICHACE_NO_PROPAGATE_INHERIT_ACE))
+		return true;
+	return false;
+}
+
+/**
+ * richacl_inherit  -  compute the inherited acl of a new file
+ * @dir_acl:	acl of the containing directory
+ * @isdir:	inherit by a directory or non-directory?
+ *
+ * A directory can have acl entries which files and/or directories created
+ * inside the directory will inherit.  This function computes the acl for such
+ * a new file.  If there is no inheritable acl, it will return %NULL.
+ */
+struct richacl *
+richacl_inherit(const struct richacl *dir_acl, int isdir)
+{
+	const struct richace *dir_ace;
+	struct richacl *acl = NULL;
+	struct richace *ace;
+	int count = 0;
+
+	if (isdir) {
+		richacl_for_each_entry(dir_ace, dir_acl) {
+			if (!ace_inherits_to_directory(dir_ace))
+				continue;
+			count++;
+		}
+		if (!count)
+			return NULL;
+		acl = richacl_alloc(count, GFP_KERNEL);
+		if (!acl)
+			return ERR_PTR(-ENOMEM);
+		ace = acl->a_entries;
+		richacl_for_each_entry(dir_ace, dir_acl) {
+			if (!ace_inherits_to_directory(dir_ace))
+				continue;
+			richace_copy(ace, dir_ace);
+			if (dir_ace->e_flags & RICHACE_NO_PROPAGATE_INHERIT_ACE)
+				ace->e_flags &= ~RICHACE_INHERITANCE_FLAGS;
+			else if (dir_ace->e_flags & RICHACE_DIRECTORY_INHERIT_ACE)
+				ace->e_flags &= ~RICHACE_INHERIT_ONLY_ACE;
+			else
+				ace->e_flags |= RICHACE_INHERIT_ONLY_ACE;
+			ace++;
+		}
+	} else {
+		richacl_for_each_entry(dir_ace, dir_acl) {
+			if (!(dir_ace->e_flags & RICHACE_FILE_INHERIT_ACE))
+				continue;
+			count++;
+		}
+		if (!count)
+			return NULL;
+		acl = richacl_alloc(count, GFP_KERNEL);
+		if (!acl)
+			return ERR_PTR(-ENOMEM);
+		ace = acl->a_entries;
+		richacl_for_each_entry(dir_ace, dir_acl) {
+			if (!(dir_ace->e_flags & RICHACE_FILE_INHERIT_ACE))
+				continue;
+			richace_copy(ace, dir_ace);
+			ace->e_flags &= ~RICHACE_INHERITANCE_FLAGS;
+			/*
+			 * RICHACE_DELETE_CHILD is meaningless for
+			 * non-directories, so clear it.
+			 */
+			ace->e_mask &= ~RICHACE_DELETE_CHILD;
+			ace++;
+		}
+	}
+
+	return acl;
+}
+
+/*
+ * richacl_inherit_inode  -  compute inherited acl and file mode
+ * @dir_acl:	acl of the containing directory
+ * @mode_p:	mode of the new inode
+ *
+ * The file permission bits in @mode_p must be set to the create mode by the
+ * caller.
+ *
+ * If there is an inheritable acl, the maximum permissions that the acl grants
+ * are computed and the file masks of the new acl are set accordingly.
+ */
+static struct richacl *
+richacl_inherit_inode(const struct richacl *dir_acl, umode_t *mode_p)
+{
+	struct richacl *acl;
+	umode_t mode = *mode_p;
+
+	acl = richacl_inherit(dir_acl, S_ISDIR(mode));
+	if (acl) {
+		if (richacl_equiv_mode(acl, &mode) == 0) {
+			*mode_p &= mode;
+			richacl_put(acl);
+			acl = NULL;
+		} else {
+			richacl_compute_max_masks(acl);
+			/*
+			 * Ensure that the acl will not grant any permissions
+			 * beyond the create mode.
+			 */
+			acl->a_flags |= RICHACL_MASKED;
+			acl->a_owner_mask &=
+				richacl_mode_to_mask(mode >> 6);
+			acl->a_group_mask &=
+				richacl_mode_to_mask(mode >> 3);
+			acl->a_other_mask &=
+				richacl_mode_to_mask(mode);
+		}
+	} else
+		*mode_p &= ~current_umask();
+
+	return acl;
+}
+
+/**
+ * richacl_create  -  filesystem create helper
+ * @mode_p:	mode of the new inode
+ * @dir:	containing directory
+ *
+ * Compute the inherited acl for a new inode.  If there is no acl to inherit,
+ * apply the umask.  Use when creating a new inode on a richacl enabled file
+ * system.
+ */
+struct richacl *richacl_create(umode_t *mode_p, struct inode *dir)
+{
+	struct richacl *dir_acl, *acl = NULL;
+
+	if (S_ISLNK(*mode_p))
+		return NULL;
+	dir_acl = get_richacl(dir);
+	if (dir_acl) {
+		if (IS_ERR(dir_acl))
+			return dir_acl;
+		acl = richacl_inherit_inode(dir_acl, mode_p);
+		richacl_put(dir_acl);
+	} else
+		*mode_p &= ~current_umask();
+	return acl;
+}
+EXPORT_SYMBOL_GPL(richacl_create);
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
index 9212edb..7aca1a3 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -192,5 +192,7 @@ extern void richacl_compute_max_masks(struct richacl *);
 extern int richacl_permission(struct inode *, const struct richacl *, int);
 extern int richacl_chmod(struct inode *, umode_t);
 extern int richacl_equiv_mode(const struct richacl *, umode_t *);
+extern struct richacl *richacl_inherit(const struct richacl *, int);
+extern struct richacl *richacl_create(umode_t *, struct inode *);
 
 #endif /* __RICHACL_H */
-- 
2.5.5

  parent reply	other threads:[~2016-06-30 13:54 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-30 13:46 [PATCH v23 00/22] Richacls (Core and Ext4) Andreas Gruenbacher
2016-06-30 13:46 ` [PATCH v23 01/22] vfs: Add IS_ACL() and IS_RICHACL() tests Andreas Gruenbacher
2016-07-05 11:00   ` Jeff Layton
2016-06-30 13:46 ` [PATCH v23 02/22] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Gruenbacher
2016-07-05 11:02   ` Jeff Layton
2016-06-30 13:46 ` [PATCH v23 03/22] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD " Andreas Gruenbacher
2016-07-05 11:07   ` Jeff Layton
2016-06-30 13:46 ` [PATCH v23 04/22] vfs: Make the inode passed to inode_change_ok non-const Andreas Gruenbacher
2016-07-05 11:12   ` Jeff Layton
2016-06-30 13:46 ` [PATCH v23 05/22] vfs: Add permission flags for setting file attributes Andreas Gruenbacher
2016-07-05 11:18   ` Jeff Layton
2016-06-30 13:46 ` [PATCH v23 06/22] richacl: In-memory representation and helper functions Andreas Gruenbacher
2016-07-05 11:34   ` Jeff Layton
2016-07-11 10:11     ` Andreas Gruenbacher
2016-06-30 13:46 ` [PATCH v23 07/22] richacl: Permission mapping functions Andreas Gruenbacher
2016-07-05 13:39   ` Jeff Layton
2016-07-11 13:26     ` Andreas Gruenbacher
2016-06-30 13:46 ` [PATCH v23 08/22] richacl: Compute maximum file masks from an acl Andreas Gruenbacher
2016-07-05 14:22   ` Jeff Layton
2016-07-05 17:08     ` Frank Filz
2016-07-13 12:34       ` Andreas Gruenbacher
2016-07-13 19:38         ` Frank Filz
2016-06-30 13:47 ` [PATCH v23 09/22] richacl: Permission check algorithm Andreas Gruenbacher
2016-07-05 14:59   ` Jeff Layton
2016-07-11 13:28     ` Andreas Gruenbacher
2016-06-30 13:47 ` [PATCH v23 10/22] posix_acl: Improve xattr fixup code Andreas Gruenbacher
2016-07-05 15:38   ` Jeff Layton
2016-06-30 13:47 ` [PATCH v23 11/22] vfs: Cache base_acl objects in inodes Andreas Gruenbacher
2016-07-05 15:56   ` Jeff Layton
2016-06-30 13:47 ` [PATCH v23 12/22] vfs: Add get_richacl and set_richacl inode operations Andreas Gruenbacher
2016-07-06 18:31   ` Jeff Layton
2016-06-30 13:47 ` [PATCH v23 13/22] vfs: Cache richacl in struct inode Andreas Gruenbacher
2016-07-06 18:57   ` Jeff Layton
2016-07-14 20:02     ` Andreas Gruenbacher
2016-07-07 14:14   ` David Howells
2016-06-30 13:47 ` [PATCH v23 14/22] richacl: Update the file masks in chmod() Andreas Gruenbacher
2016-07-12 11:36   ` Jeff Layton
2016-06-30 13:47 ` [PATCH v23 15/22] richacl: Check if an acl is equivalent to a file mode Andreas Gruenbacher
2016-07-12 11:39   ` Jeff Layton
2016-06-30 13:47 ` Andreas Gruenbacher [this message]
2016-07-12 11:41   ` [PATCH v23 16/22] richacl: Create-time inheritance Jeff Layton
2016-06-30 13:47 ` [PATCH v23 17/22] richacl: Automatic Inheritance Andreas Gruenbacher
2016-07-12 11:56   ` Jeff Layton
2016-07-12 19:11     ` J. Bruce Fields
2016-07-12 20:28       ` Andreas Gruenbacher
2016-06-30 13:47 ` [PATCH v23 18/22] richacl: xattr mapping functions Andreas Gruenbacher
2016-07-12 12:02   ` Jeff Layton
2016-07-14 20:33     ` Andreas Gruenbacher
2016-06-30 13:47 ` [PATCH v23 19/22] richacl: Add richacl xattr handler Andreas Gruenbacher
2016-07-12 12:13   ` Jeff Layton
2016-06-30 13:47 ` [PATCH v23 20/22] vfs: Add richacl permission checking Andreas Gruenbacher
2016-07-12 12:13   ` Jeff Layton
2016-07-14 20:59     ` Andreas Gruenbacher
2016-06-30 13:47 ` [PATCH v23 21/22] ext4: Add richacl support Andreas Gruenbacher
2016-06-30 13:47 ` [PATCH v23 22/22] ext4: Add richacl feature flag Andreas Gruenbacher
2016-06-30 14:11 ` [PATCH v23 00/22] Richacls (Core and Ext4) Volker Lendecke

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