From patchwork Mon Sep 5 17:25:31 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Aneesh Kumar K.V" X-Patchwork-Id: 1125292 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter2.kernel.org (8.14.4/8.14.4) with ESMTP id p85HXCP9003721 for ; Mon, 5 Sep 2011 17:33:12 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752836Ab1IERcO (ORCPT ); Mon, 5 Sep 2011 13:32:14 -0400 Received: from e28smtp04.in.ibm.com ([122.248.162.4]:58784 "EHLO e28smtp04.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752046Ab1IER1V (ORCPT ); Mon, 5 Sep 2011 13:27:21 -0400 Received: from d28relay01.in.ibm.com (d28relay01.in.ibm.com [9.184.220.58]) by e28smtp04.in.ibm.com (8.14.4/8.13.1) with ESMTP id p85HRJrT021742; Mon, 5 Sep 2011 22:57:19 +0530 Received: from d28av03.in.ibm.com (d28av03.in.ibm.com [9.184.220.65]) by d28relay01.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p85HRJfD2826406; Mon, 5 Sep 2011 22:57:19 +0530 Received: from d28av03.in.ibm.com (loopback [127.0.0.1]) by d28av03.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p85HRI49021566; Tue, 6 Sep 2011 03:27:18 +1000 Received: from skywalker.ibm.com ([9.126.239.225]) by d28av03.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id p85HR6rQ021311; Tue, 6 Sep 2011 03:27:17 +1000 From: "Aneesh Kumar K.V" To: agruen@kernel.org, bfields@fieldses.org, akpm@linux-foundation.org, dhowells@redhat.com Cc: aneesh.kumar@linux.vnet.ibm.com, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH -V6 09/26] vfs: Add delete child and delete self permission flags Date: Mon, 5 Sep 2011 22:55:31 +0530 Message-Id: <1315243548-18664-10-git-send-email-aneesh.kumar@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1315243548-18664-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> References: <1315243548-18664-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter2.kernel.org [140.211.167.43]); Mon, 05 Sep 2011 17:33:12 +0000 (UTC) From: Andreas Gruenbacher Normally, deleting a file requires write access to the parent directory. Some permission models use a different permission on the parent directory to indicate delete access. In addition, a process can have per-file delete access even without delete access on the parent directory. Introduce two new inode_permission() mask flags and use them in may_delete() Signed-off-by: Andreas Gruenbacher Signed-off-by: Aneesh Kumar K.V --- fs/namei.c | 41 +++++++++++++++++++++++++++-------------- include/linux/fs.h | 2 ++ 2 files changed, 29 insertions(+), 14 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index d52a4cd..eacb530 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -337,7 +337,7 @@ static inline int do_inode_permission(struct inode *inode, int mask) * 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) { @@ -1862,7 +1862,7 @@ static inline int check_sticky(struct inode *dir, struct inode *inode) return 0; other_userns: - return !ns_capable(inode_userns(inode), CAP_FOWNER); + return 1; } /* @@ -1884,30 +1884,43 @@ other_userns: * 10. We don't allow removal of NFS sillyrenamed files; it's handled by * nfs_async_unlink(). */ -static int may_delete(struct inode *dir,struct dentry *victim,int isdir) +static int may_delete(struct inode *dir, struct dentry *victim, + int isdir, int replace) { - int error; + int mask, error, is_sticky; + struct inode *inode = victim->d_inode; - if (!victim->d_inode) + if (!inode) return -ENOENT; BUG_ON(victim->d_parent->d_inode != dir); audit_inode_child(victim, dir); - error = inode_permission(dir, MAY_WRITE | MAY_EXEC); + mask = MAY_WRITE | MAY_EXEC | MAY_DELETE_CHILD; + if (replace) + mask |= S_ISDIR(inode->i_mode) ? + MAY_CREATE_DIR : MAY_CREATE_FILE; + is_sticky = check_sticky(dir, inode); + error = inode_permission(dir, mask); + if ((error || is_sticky) && IS_RICHACL(inode) && + !inode_permission(dir, mask & ~(MAY_WRITE | MAY_DELETE_CHILD)) && + !inode_permission(inode, MAY_DELETE_SELF)) + error = 0; + else if (!error && is_sticky && + !ns_capable(inode_userns(inode), CAP_FOWNER)) + error = -EPERM; if (error) return error; if (IS_APPEND(dir)) return -EPERM; - if (check_sticky(dir, victim->d_inode)||IS_APPEND(victim->d_inode)|| - IS_IMMUTABLE(victim->d_inode) || IS_SWAPFILE(victim->d_inode)) + if (IS_APPEND(inode) || IS_IMMUTABLE(inode) || IS_SWAPFILE(inode)) return -EPERM; if (isdir) { - if (!S_ISDIR(victim->d_inode->i_mode)) + if (!S_ISDIR(inode->i_mode)) return -ENOTDIR; if (IS_ROOT(victim)) return -EBUSY; - } else if (S_ISDIR(victim->d_inode->i_mode)) + } else if (S_ISDIR(inode->i_mode)) return -EISDIR; if (IS_DEADDIR(dir)) return -ENOENT; @@ -2614,7 +2627,7 @@ void dentry_unhash(struct dentry *dentry) int vfs_rmdir(struct inode *dir, struct dentry *dentry) { - int error = may_delete(dir, dentry, 1); + int error = may_delete(dir, dentry, 1, 0); if (error) return error; @@ -2707,7 +2720,7 @@ SYSCALL_DEFINE1(rmdir, const char __user *, pathname) int vfs_unlink(struct inode *dir, struct dentry *dentry) { - int error = may_delete(dir, dentry, 0); + int error = may_delete(dir, dentry, 0, 0); if (error) return error; @@ -3101,14 +3114,14 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, if (old_dentry->d_inode == new_dentry->d_inode) return 0; - error = may_delete(old_dir, old_dentry, is_dir); + error = may_delete(old_dir, old_dentry, is_dir, 0); if (error) return error; if (!new_dentry->d_inode) error = may_create(new_dir, new_dentry, is_dir); else - error = may_delete(new_dir, new_dentry, is_dir); + error = may_delete(new_dir, new_dentry, is_dir, 1); if (error) return error; diff --git a/include/linux/fs.h b/include/linux/fs.h index 8707f43..c5c98c5 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -69,6 +69,8 @@ struct inodes_stat_t { #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