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[PATCH v12 19/49] vfs: Add richacl permission checking

From Andreas Gruenbacher <agruenba@redhat.com>
Newsgroups linux.kernel
Subject [PATCH v12 19/49] vfs: Add richacl permission checking
Date 2015-10-23 20:50 +0200
Message-ID <qmPzD-1ob-81@gated-at.bofh.it> (permalink)
References <qmPzA-1ob-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Hook the richacl permission checking function into the vfs.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/namei.c     | 51 +++++++++++++++++++++++++++++++++++++++++++++++++--
 fs/posix_acl.c |  6 +++---
 2 files changed, 52 insertions(+), 5 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 2eab19e..3822b5e 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 +256,40 @@ 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
+	struct richacl *acl;
+
+	if (mask & MAY_NOT_BLOCK) {
+		acl = get_cached_richacl_rcu(inode);
+		if (!acl)
+			goto no_acl;
+		/* no ->get_richacl() calls in RCU mode... */
+		if (acl == ACL_NOT_CACHED)
+			return -ECHILD;
+		return richacl_permission(inode, acl, mask & ~MAY_NOT_BLOCK);
+	}
+
+	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
 	struct posix_acl *acl;
@@ -290,11 +324,24 @@ 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;
 		}
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 1d766a5..3459bd5 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -100,13 +100,13 @@ struct posix_acl *get_acl(struct inode *inode, int type)
 {
 	struct posix_acl *acl;
 
+	if (!IS_POSIXACL(inode))
+		return NULL;
+
 	acl = get_cached_acl(inode, type);
 	if (acl != ACL_NOT_CACHED)
 		return acl;
 
-	if (!IS_POSIXACL(inode))
-		return NULL;
-
 	/*
 	 * A filesystem can force a ACL callback by just never filling the
 	 * ACL cache. But normally you'd fill the cache either at inode
-- 
2.5.0

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Thread

[PATCH v12 00/49] Richacls Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 04/49] vfs: Make the inode passed to inode_change_ok non-const Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 01/49] vfs: Add IS_ACL() and IS_RICHACL() tests Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 08/49] richacl: Compute maximum file masks from an acl Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 38/49] nfsd: Add support for the MAY_CREATE_{FILE,DIR} permissions Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 25/49] xfs: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 09/49] richacl: Permission check algorithm Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 34/49] nfsd: Keep list of acls to dispose of in compoundargs Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 42/49] xfs: Don't allow unmapped identifiers in richacls Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 13/49] richacl: Update the file masks in chmod() Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 32/49] richacl: Apply the file masks to a richacl Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 28/49] richacl: Propagate everyone@ permissions to other aces Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 49/49] nfs: Add support for the v4.1 dacl attribute Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 41/49] ext4: Don't allow unmapped identifiers in richacls Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 33/49] richacl: Create richacl from mode values Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 03/49] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 12/49] vfs: Cache richacl in struct inode Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 44/49] sunrpc: Add xdr_init_encode_pages Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 16/49] richacl: Automatic Inheritance Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 29/49] richacl: Set the owner permissions to the owner mask Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 17/49] richacl: xattr mapping functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 20/49] ext4: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 06/49] richacl: In-memory representation and helper functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 45/49] nfs: Fix GETATTR bitmap verification Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 15/49] richacl: Create-time inheritance Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 48/49] nfs: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 35/49] nfsd: Use richacls as internal acl representation Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 21/49] ext4: Add richacl feature flag Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
    Re: [PATCH v12 21/49] ext4: Add richacl feature flag Austin S Hemmelgarn <ahferroin7@gmail.com> - 2015-10-23 21:40 +0200
  [PATCH v12 47/49] nfs: Distinguish missing users and groups from nobody Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 24/49] xfs: Change how listxattr generates synthetic attributes Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 31/49] richacl: Isolate the owner and group classes Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 26/49] richacl: acl editing helper functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 02/49] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 05/49] vfs: Add permission flags for setting file attributes Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 19/49] vfs: Add richacl permission checking Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 14/49] richacl: Check if an acl is equivalent to a file mode Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 07/49] richacl: Permission mapping functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 40/49] nfsd: Add support for unmapped richace identifiers Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 11/49] vfs: Add get_richacl and set_richacl inode operations Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 39/49] richacl: Add support for unmapped identifiers Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 43/49] sunrpc: Allow to demand-allocate pages to encode into Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 37/49] nfsd: Add support for the v4.1 dacl attribute Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 36/49] nfsd: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 21:00 +0200
  [PATCH v12 27/49] richacl: Move everyone@ aces down the acl Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 21:10 +0200
  [PATCH v12 30/49] richacl: Set the other permissions to the other mask Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 21:10 +0200
  [PATCH v12 23/49] xfs: Make xfs_set_mode non-static Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 21:20 +0200
  [PATCH v12 18/49] richacl: Add richacl xattr handler Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 21:20 +0200
  [PATCH v12 22/49] xfs: Fix error path in xfs_get_acl Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 21:20 +0200
  RE: [PATCH v12 00/49] Richacls "Frank Filz" <ffilzlnx@mindspring.com> - 2015-10-23 22:20 +0200

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