From: Andreas Gruenbacher <andreas.gruenbacher@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org,
linux-api@vger.kernel.org, linux-cifs@vger.kernel.org,
linux-security-module@vger.kernel.org,
Andreas Gruenbacher <agruenba@redhat.com>
Subject: [RFC v6 03/40] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags
Date: Tue, 4 Aug 2015 13:53:01 +0200 [thread overview]
Message-ID: <1438689218-6921-4-git-send-email-agruenba@redhat.com> (raw)
In-Reply-To: <1438689218-6921-1-git-send-email-agruenba@redhat.com>
Normally, deleting a file requires write and execute access to the parent
directory. With Richacls, a process with MAY_DELETE_SELF access to a file
may delete the file even without write access to the parent directory.
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 does not override the sticky directory
check. It probably should.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
fs/namei.c | 15 +++++++++++----
include/linux/fs.h | 2 ++
2 files changed, 13 insertions(+), 4 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index 3504d36..2ac759c 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -454,7 +454,7 @@ static int sb_permission(struct super_block *sb, struct inode *inode, int mask)
* changing the "normal" UIDs which are used for other things.
*
* When checking for MAY_APPEND, MAY_CREATE_FILE, MAY_CREATE_DIR,
- * MAY_WRITE must also be set in @mask.
+ * MAY_DELETE_CHILD, MAY_DELETE_SELF, MAY_WRITE must also be set in @mask.
*/
int inode_permission(struct inode *inode, int mask)
{
@@ -2527,7 +2527,7 @@ 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;
@@ -2537,8 +2537,15 @@ 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 && IS_RICHACL(inode)) {
+ /* Deleting is also permitted with MAY_EXEC on the directory
+ * and MAY_DELETE_SELF on the inode. */
+ if (!inode_permission(inode, MAY_DELETE_SELF) &&
+ !inode_permission(dir, mask))
+ error = 0;
+ }
if (error)
return error;
if (IS_APPEND(dir))
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 9c44f27..abf5b0e 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -83,6 +83,8 @@ 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
next prev parent reply other threads:[~2015-08-04 11:54 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-04 11:52 [RFC v6 00/40] Richacls Andreas Gruenbacher
2015-08-04 11:52 ` [RFC v6 01/40] vfs: Add IS_ACL() and IS_RICHACL() tests Andreas Gruenbacher
2015-08-28 20:34 ` J. Bruce Fields
2015-08-04 11:53 ` [RFC v6 02/40] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Gruenbacher
2015-09-02 18:53 ` J. Bruce Fields
2015-09-02 19:06 ` Andreas Gruenbacher
2015-09-02 19:20 ` J. Bruce Fields
2015-09-02 20:23 ` Andreas Gruenbacher
2015-08-04 11:53 ` Andreas Gruenbacher [this message]
2015-08-28 20:44 ` [RFC v6 03/40] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD " J. Bruce Fields
2015-08-28 21:08 ` Andreas Gruenbacher
2015-08-28 21:36 ` Andy Lutomirski
2015-08-28 21:54 ` Andreas Grünbacher
2015-08-29 1:04 ` Andy Lutomirski
2015-08-28 21:57 ` J. Bruce Fields
2015-08-04 11:53 ` [RFC v6 04/40] vfs: Make the inode passed to inode_change_ok non-const Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 05/40] vfs: Add permission flags for setting file attributes Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 06/40] richacl: In-memory representation and helper functions Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 07/40] richacl: Permission mapping functions Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 08/40] richacl: Compute maximum file masks from an acl Andreas Gruenbacher
2015-09-02 19:54 ` J. Bruce Fields
2015-09-02 19:54 ` J. Bruce Fields
2015-09-02 20:38 ` Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 09/40] richacl: Update the file masks in chmod() Andreas Gruenbacher
2015-09-01 21:38 ` J. Bruce Fields
2015-09-02 6:08 ` Andreas Grünbacher
2015-08-04 11:53 ` [RFC v6 10/40] richacl: Permission check algorithm Andreas Gruenbacher
2015-08-28 21:49 ` J. Bruce Fields
2015-08-28 22:06 ` Andreas Grünbacher
2015-08-31 15:23 ` J. Bruce Fields
2015-08-04 11:53 ` [RFC v6 11/40] vfs: Cache base_acl objects in inodes Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 12/40] vfs: Cache richacl in struct inode Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 13/40] richacl: Check if an acl is equivalent to a file mode Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 14/40] richacl: Create-time inheritance Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 15/40] richacl: Automatic Inheritance Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 16/40] richacl: xattr mapping functions Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 17/40] vfs: Add richacl permission checking Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 18/40] ext4: Add richacl support Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 19/40] ext4: Add richacl feature flag Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 20/40] richacl: acl editing helper functions Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 21/40] richacl: Move everyone@ aces down the acl Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 22/40] richacl: Propagate everyone@ permissions to other aces Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 23/40] richacl: Set the owner permissions to the owner mask Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 24/40] richacl: Set the other permissions to the other mask Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 25/40] richacl: Isolate the owner and group classes Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 26/40] richacl: Apply the file masks to a richacl Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 27/40] richacl: Create richacl from mode values Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 28/40] nfsd: Keep list of acls to dispose of in compoundargs Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 29/40] nfsd: Use richacls as internal acl representation Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 30/40] nfsd: Add richacl support Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 31/40] nfsd: Add support for the v4.1 dacl attribute Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 32/40] nfsd: Add support for the MAY_CREATE_{FILE,DIR} permissions Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 33/40] richacl: Add support for unmapped identifiers Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 34/40] ext4: Don't allow unmapped identifiers in richacls Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 35/40] sunrpc: Allow to demand-allocate pages to encode into Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 36/40] sunrpc: Add xdr_init_encode_pages Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 37/40] nfs: Fix GETATTR bitmap verification Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 38/40] nfs: Remove unused xdr page offsets in getacl/setacl arguments Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 39/40] nfs: Add richacl support Andreas Gruenbacher
2015-08-04 11:53 ` [RFC v6 40/40] nfs: Add support for the v4.1 dacl attribute Andreas Gruenbacher
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