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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 v21 20/22] vfs: Add richacl permission checking
Date: Tue, 10 May 2016 00:02:53 +0200	[thread overview]
Message-ID: <1462831375-23017-21-git-send-email-agruenba@redhat.com> (raw)
In-Reply-To: <1462831375-23017-1-git-send-email-agruenba@redhat.com>

Hook the richacl permission checking function into the vfs.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/namei.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 52 insertions(+), 2 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 2b1bf71..5fbe60a 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -35,6 +35,7 @@
 #include <linux/fs_struct.h>
 #include <linux/posix_acl.h>
 #include <linux/hash.h>
+#include <linux/richacl.h>
 #include <asm/uaccess.h>
 
 #include "internal.h"
@@ -255,7 +256,43 @@ void putname(struct filename *name)
 		__putname(name);
 }
 
-static int check_acl(struct inode *inode, int mask)
+static int check_richacl(struct inode *inode, int mask)
+{
+#ifdef CONFIG_FS_RICHACL
+	if (mask & MAY_NOT_BLOCK) {
+		struct base_acl *base_acl;
+
+		base_acl = rcu_dereference(inode->i_acl);
+		if (!base_acl)
+			goto no_acl;
+		/* no ->get_richacl() calls in RCU mode... */
+		if (is_uncached_acl(base_acl))
+			return -ECHILD;
+		return richacl_permission(inode, richacl(base_acl),
+					  mask & ~MAY_NOT_BLOCK);
+	} else {
+		struct richacl *acl;
+
+		acl = get_richacl(inode);
+		if (IS_ERR(acl))
+			return PTR_ERR(acl);
+		if (acl) {
+			int error = richacl_permission(inode, acl, mask);
+			richacl_put(acl);
+			return error;
+		}
+	}
+no_acl:
+#endif
+	if (mask & (MAY_DELETE_SELF | MAY_TAKE_OWNERSHIP |
+		    MAY_CHMOD | MAY_SET_TIMES)) {
+		/* File permission bits cannot grant this. */
+		return -EACCES;
+	}
+	return -EAGAIN;
+}
+
+static int check_posix_acl(struct inode *inode, int mask)
 {
 #ifdef CONFIG_FS_POSIX_ACL
 	if (mask & MAY_NOT_BLOCK) {
@@ -293,11 +330,24 @@ static int acl_permission_check(struct inode *inode, int mask)
 {
 	unsigned int mode = inode->i_mode;
 
+	/*
+	 * With POSIX ACLs, the (mode & S_IRWXU) bits exactly match the owner
+	 * permissions, and we can skip checking posix acls for the owner.
+	 * With richacls, the owner may be granted fewer permissions than the
+	 * mode bits seem to suggest (for example, append but not write), and
+	 * we always need to check the richacl.
+	 */
+
+	if (IS_RICHACL(inode)) {
+		int error = check_richacl(inode, mask);
+		if (error != -EAGAIN)
+			return error;
+	}
 	if (likely(uid_eq(current_fsuid(), inode->i_uid)))
 		mode >>= 6;
 	else {
 		if (IS_POSIXACL(inode) && (mode & S_IRWXG)) {
-			int error = check_acl(inode, mask);
+			int error = check_posix_acl(inode, mask);
 			if (error != -EAGAIN)
 				return error;
 		}
-- 
2.5.5

  parent reply	other threads:[~2016-05-09 22:05 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-09 22:02 [PATCH v21 00/22] Richacls Andreas Gruenbacher
2016-05-09 22:02 ` [PATCH v21 01/22] vfs: Add IS_ACL() and IS_RICHACL() tests Andreas Gruenbacher
2016-05-09 22:02 ` [PATCH v21 02/22] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Gruenbacher
2016-05-09 22:02 ` [PATCH v21 03/22] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD " Andreas Gruenbacher
2016-05-09 22:02 ` [PATCH v21 04/22] vfs: Make the inode passed to inode_change_ok non-const Andreas Gruenbacher
2016-05-09 22:02 ` [PATCH v21 05/22] vfs: Add permission flags for setting file attributes Andreas Gruenbacher
2016-05-09 22:02 ` [PATCH v21 06/22] richacl: In-memory representation and helper functions Andreas Gruenbacher
2016-05-09 22:02 ` [PATCH v21 07/22] richacl: Permission mapping functions Andreas Gruenbacher
2016-05-09 22:02 ` [PATCH v21 08/22] richacl: Compute maximum file masks from an acl Andreas Gruenbacher
2016-05-09 22:02 ` [PATCH v21 09/22] richacl: Permission check algorithm Andreas Gruenbacher
2016-05-09 22:02 ` [PATCH v21 10/22] posix_acl: Improve xattr fixup code Andreas Gruenbacher
2016-05-09 22:02 ` [PATCH v21 11/22] vfs: Cache base_acl objects in inodes Andreas Gruenbacher
2016-05-09 22:02 ` [PATCH v21 12/22] vfs: Add get_richacl and set_richacl inode operations Andreas Gruenbacher
2016-05-09 22:02 ` [PATCH v21 13/22] vfs: Cache richacl in struct inode Andreas Gruenbacher
2016-05-09 22:02 ` [PATCH v21 14/22] richacl: Update the file masks in chmod() Andreas Gruenbacher
2016-05-09 22:02 ` [PATCH v21 15/22] richacl: Check if an acl is equivalent to a file mode Andreas Gruenbacher
2016-05-09 22:02 ` [PATCH v21 16/22] richacl: Create-time inheritance Andreas Gruenbacher
2016-05-09 22:02 ` [PATCH v21 17/22] richacl: Automatic Inheritance Andreas Gruenbacher
2016-05-09 22:02 ` [PATCH v21 18/22] richacl: xattr mapping functions Andreas Gruenbacher
2016-05-09 22:02 ` [PATCH v21 19/22] richacl: Add richacl xattr handler Andreas Gruenbacher
2016-05-09 22:02 ` Andreas Gruenbacher [this message]
2016-05-09 22:02 ` [PATCH v21 21/22] ext4: Add richacl support Andreas Gruenbacher
2016-05-09 22:02 ` [PATCH v21 22/22] ext4: Add richacl feature flag Andreas Gruenbacher
2016-05-10  4:18 ` [PATCH v21 00/22] Richacls Volker Lendecke
2016-05-10  8:11   ` Jeremy Allison
2016-05-10  8:20     ` Volker Lendecke
2016-05-10 15:55     ` Frank Filz

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