linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
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, linux-xfs@vger.kernel.org,
	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 v28 14/21] richacl: Create-time inheritance
Date: Mon, 13 Feb 2017 16:32:30 +0100	[thread overview]
Message-ID: <1486999957-2381-15-git-send-email-agruenba@redhat.com> (raw)
In-Reply-To: <1486999957-2381-1-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>
Reviewed-by: Jeff Layton <jlayton@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 1022983..8051181 100644
--- a/fs/richacl.c
+++ b/fs/richacl.c
@@ -716,3 +716,154 @@ 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 a865f37..6354ef0 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -191,5 +191,7 @@ extern int richacl_permission(struct inode *, const struct richacl *, int);
 extern void richacl_compute_max_masks(struct richacl *);
 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 */
-- 
2.7.4

  parent reply	other threads:[~2017-02-13 15:39 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-13 15:32 [PATCH v28 00/21] Richacls (Core and Ext4) Andreas Gruenbacher
2017-02-13 15:32 ` [PATCH v28 01/21] vfs: Add IS_ACL() and IS_RICHACL() tests Andreas Gruenbacher
2017-02-13 15:32 ` [PATCH v28 02/21] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Gruenbacher
2017-02-13 15:32 ` [PATCH v28 03/21] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD " Andreas Gruenbacher
2017-02-13 15:32 ` [PATCH v28 04/21] vfs: Add permission flags for setting file attributes Andreas Gruenbacher
2017-02-13 15:32 ` [PATCH v28 05/21] richacl: In-memory representation and helper functions Andreas Gruenbacher
2017-02-13 15:32 ` [PATCH v28 06/21] richacl: Permission mapping functions Andreas Gruenbacher
2017-02-13 15:32 ` [PATCH v28 07/21] richacl: Permission check algorithm Andreas Gruenbacher
2017-02-13 15:32 ` [PATCH v28 08/21] richacl: Compute maximum file masks from an acl Andreas Gruenbacher
2017-02-13 15:32 ` [PATCH v28 09/21] vfs: Cache base_acl objects in inodes Andreas Gruenbacher
2017-02-13 15:32 ` [PATCH v28 10/21] vfs: Add get_richacl and set_richacl inode operations Andreas Gruenbacher
2017-02-13 15:32 ` [PATCH v28 11/21] vfs: Cache richacl in struct inode Andreas Gruenbacher
2017-02-13 15:32 ` [PATCH v28 12/21] richacl: Update the file masks in chmod() Andreas Gruenbacher
2017-02-13 15:32 ` [PATCH v28 13/21] richacl: Check if an acl is equivalent to a file mode Andreas Gruenbacher
2017-02-13 15:32 ` Andreas Gruenbacher [this message]
2017-02-13 15:32 ` [PATCH v28 15/21] richacl: Automatic Inheritance Andreas Gruenbacher
2017-02-13 15:32 ` [PATCH v28 16/21] richacl: xattr mapping functions Andreas Gruenbacher
2017-02-13 15:32 ` [PATCH v28 17/21] richacl: Add richacl xattr handler Andreas Gruenbacher
2017-02-13 15:32 ` [PATCH v28 18/21] vfs: Add richacl permission checking Andreas Gruenbacher
2017-02-13 15:32 ` [PATCH v28 19/21] vfs: Move check_posix_acl and check_richacl out of fs/namei.c Andreas Gruenbacher
2017-02-13 15:32 ` [PATCH v28 20/21] ext4: Add richacl support Andreas Gruenbacher
2017-02-13 15:32 ` [PATCH v28 21/21] ext4: Add richacl feature flag Andreas Gruenbacher

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1486999957-2381-15-git-send-email-agruenba@redhat.com \
    --to=agruenba@redhat.com \
    --cc=adilger.kernel@dilger.ca \
    --cc=anna.schumaker@netapp.com \
    --cc=bfields@fieldses.org \
    --cc=david@fromorbit.com \
    --cc=hch@infradead.org \
    --cc=jlayton@poochiereds.net \
    --cc=linux-api@vger.kernel.org \
    --cc=linux-cifs@vger.kernel.org \
    --cc=linux-ext4@vger.kernel.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-nfs@vger.kernel.org \
    --cc=linux-xfs@vger.kernel.org \
    --cc=trond.myklebust@primarydata.com \
    --cc=tytso@mit.edu \
    --cc=viro@zeniv.linux.org.uk \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).