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[PATCH v13 03/51] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags

From Andreas Gruenbacher <agruenba@redhat.com>
Newsgroups linux.kernel
Subject [PATCH v13 03/51] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags
Date 2015-11-03 17:20 +0100
Message-ID <qqMts-57V-11@gated-at.bofh.it> (permalink)
References <qqLxo-4or-5@gated-at.bofh.it>
Organization linux.* mail to news gateway

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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         | 21 ++++++++++++---------
 include/linux/fs.h |  2 ++
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 0259392..2eab19e 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)
 {
@@ -2555,7 +2555,7 @@ static int may_delete(struct inode *dir, struct dentry *victim,
 		      bool isdir, bool replace)
 {
 	struct inode *inode = d_backing_inode(victim);
-	int error, mask = MAY_WRITE | MAY_EXEC;
+	int error, mask = MAY_EXEC;
 
 	if (d_is_negative(victim))
 		return -ENOENT;
@@ -2565,15 +2565,18 @@ static int may_delete(struct inode *dir, struct dentry *victim,
 	audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
 
 	if (replace)
-		mask |= isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE;
-	error = inode_permission(dir, mask);
+		mask |= MAY_WRITE | (isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE);
+	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)
+		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))
diff --git a/include/linux/fs.h b/include/linux/fs.h
index d6e2330..402acd7 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

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Thread

[PATCH v13 00/51] Richacls Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:20 +0100
  [PATCH v13 08/51] richacl: Compute maximum file masks from an acl Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:20 +0100
  [PATCH v13 10/51] vfs: Cache base_acl objects in inodes Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:20 +0100
    Re: [PATCH v13 10/51] vfs: Cache base_acl objects in inodes Andreas Dilger <adilger@dilger.ca> - 2015-11-03 23:40 +0100
      Re: [PATCH v13 10/51] vfs: Cache base_acl objects in inodes Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-04 23:00 +0100
  [PATCH v13 07/51] richacl: Permission mapping functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:20 +0100
  [PATCH v13 02/51] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:20 +0100
    Re: [PATCH v13 02/51] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Dilger <adilger@dilger.ca> - 2015-11-04 03:40 +0100
      Re: [PATCH v13 02/51] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR  permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-04 04:10 +0100
  [PATCH v13 11/51] vfs: Add get_richacl and set_richacl inode operations Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:20 +0100
  [PATCH v13 04/51] vfs: Make the inode passed to inode_change_ok non-const Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:20 +0100
  [PATCH v13 12/51] vfs: Cache richacl in struct inode Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:20 +0100
    Re: [PATCH v13 12/51] vfs: Cache richacl in struct inode Andreas Dilger <adilger@dilger.ca> - 2015-11-04 03:10 +0100
      Re: [PATCH v13 12/51] vfs: Cache richacl in struct inode Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-04 23:20 +0100
  [PATCH v13 05/51] vfs: Add permission flags for setting file attributes Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:20 +0100
  [PATCH v13 06/51] richacl: In-memory representation and helper functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:20 +0100
  [PATCH v13 29/51] richacl: Move everyone@ aces down the acl Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
  [PATCH v13 50/51] nfs: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
  [PATCH v13 30/51] richacl: Propagate everyone@ permissions to other aces Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
  [PATCH v13 40/51] nfsd: Add support for the MAY_CREATE_{FILE,DIR} permissions Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
  [PATCH v13 43/51] ext4: Don't allow unmapped identifiers in richacls Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
    Re: [PATCH v13 43/51] ext4: Don't allow unmapped identifiers in richacls Andreas Dilger <adilger@dilger.ca> - 2015-11-04 03:30 +0100
  [PATCH v13 26/51] xfs: Plug memory leak in xfs_attrmulti_attr_set Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
  [PATCH v13 45/51] sunrpc: Allow to demand-allocate pages to encode into Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
    Re: [PATCH v13 45/51] sunrpc: Allow to demand-allocate pages to  encode into Trond Myklebust <trond.myklebust@primarydata.com> - 2015-11-03 17:30 +0100
      Re: [PATCH v13 45/51] sunrpc: Allow to demand-allocate pages to  encode into Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 12:10 +0100
        Re: [PATCH v13 45/51] sunrpc: Allow to demand-allocate pages to  encode into Trond Myklebust <trond.myklebust@primarydata.com> - 2015-11-05 17:00 +0100
          Re: [PATCH v13 45/51] sunrpc: Allow to demand-allocate pages to  encode into Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-08 23:20 +0100
  [PATCH v13 48/51] nfs: Remove unused xdr page offsets in getacl/setacl arguments Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
  [PATCH v13 51/51] nfs: Add support for the v4.1 dacl attribute Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
  [PATCH v13 39/51] nfsd: Add support for the v4.1 dacl attribute Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
  [PATCH v13 32/51] richacl: Set the other permissions to the other mask Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
  [PATCH v13 33/51] richacl: Isolate the owner and group classes Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
  [PATCH v13 28/51] richacl: acl editing helper functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
  [PATCH v13 47/51] nfs: Fix GETATTR bitmap verification Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
    Re: [PATCH v13 47/51] nfs: Fix GETATTR bitmap verification Trond Myklebust <trond.myklebust@primarydata.com> - 2015-11-03 17:40 +0100
  [PATCH v13 42/51] nfsd: Add support for unmapped richace identifiers Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
  [PATCH v13 19/51] vfs: Add richacl permission checking Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
  [PATCH v13 25/51] xfs: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
  [PATCH v13 44/51] xfs: Don't allow unmapped identifiers in richacls Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
  [PATCH v13 46/51] sunrpc: Add xdr_init_encode_pages Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
  [PATCH v13 49/51] nfs: Distinguish missing users and groups from nobody Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
  [PATCH v13 41/51] richacl: Add support for unmapped identifiers Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
  [PATCH v13 38/51] nfsd: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
  [PATCH v13 36/51] nfsd: Keep list of acls to dispose of in compoundargs Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
  [PATCH v13 37/51] nfsd: Use richacls as internal acl representation Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:40 +0100
  [PATCH v13 35/51] richacl: Create richacl from mode values Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:40 +0100
  [PATCH v13 31/51] richacl: Set the owner permissions to the owner mask Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:50 +0100
  [PATCH v13 34/51] richacl: Apply the file masks to a richacl Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:50 +0100
  [PATCH v13 27/51] xfs: Fix richacl access by ioctl Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:50 +0100
  [PATCH v13 16/51] richacl: Automatic Inheritance Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:00 +0100
  [PATCH v13 15/51] richacl: Create-time inheritance Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:00 +0100
  [PATCH v13 24/51] xfs: Change how listxattr generates synthetic attributes Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:00 +0100
  [PATCH v13 21/51] ext4: Add richacl feature flag Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:00 +0100
    Re: [PATCH v13 21/51] ext4: Add richacl feature flag Andreas Dilger <adilger@dilger.ca> - 2015-11-04 03:20 +0100
      Re: [PATCH v13 21/51] ext4: Add richacl feature flag Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-04 03:30 +0100
        Re: [PATCH v13 21/51] ext4: Add richacl feature flag Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-04 03:50 +0100
  [PATCH v13 14/51] richacl: Check if an acl is equivalent to a file mode Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:00 +0100
  [PATCH v13 20/51] ext4: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:00 +0100
    Re: [PATCH v13 20/51] ext4: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-04 03:20 +0100
    Re: [PATCH v13 20/51] ext4: Add richacl support Andreas Dilger <adilger@dilger.ca> - 2015-11-04 03:20 +0100
  [PATCH v13 18/51] richacl: Add richacl xattr handler Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:00 +0100
  [PATCH v13 22/51] xfs: Fix error path in xfs_get_acl Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:00 +0100
  [PATCH v13 23/51] xfs: Make xfs_set_mode non-static Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:00 +0100
  [PATCH v13 13/51] richacl: Update the file masks in chmod() Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:00 +0100
  [PATCH v13 09/51] richacl: Permission check algorithm Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:10 +0100
  [PATCH v13 17/51] richacl: xattr mapping functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:10 +0100
  [PATCH v13 03/51] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:20 +0100

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