From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754085AbXITT4T (ORCPT ); Thu, 20 Sep 2007 15:56:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752138AbXITTxO (ORCPT ); Thu, 20 Sep 2007 15:53:14 -0400 Received: from e35.co.us.ibm.com ([32.97.110.153]:41910 "EHLO e35.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752086AbXITTxI (ORCPT ); Thu, 20 Sep 2007 15:53:08 -0400 Subject: [PATCH 08/25] elevate writer count for chown and friends To: akpm@osdl.org Cc: linux-kernel@vger.kernel.org, hch@infradead.org, Dave Hansen From: Dave Hansen Date: Thu, 20 Sep 2007 12:52:58 -0700 References: <20070920195249.852667D5@kernel> In-Reply-To: <20070920195249.852667D5@kernel> Message-Id: <20070920195258.EAC06921@kernel> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org chown/chmod,etc... don't call permission in the same way that the normal "open for write" calls do. They still write to the filesystem, so bump the write count during these operations. This conflicts with the current (~2.6.23-rc7) audit git tree in -mm. wiggle'ing the patch merges it. Signed-off-by: Dave Hansen Acked-by: Christoph Hellwig --- lxc-dave/fs/open.c | 39 ++++++++++++++++++++++++++++++--------- 1 file changed, 30 insertions(+), 9 deletions(-) diff -puN fs/open.c~elevate-writer-count-for-chown-and-friends fs/open.c --- lxc/fs/open.c~elevate-writer-count-for-chown-and-friends 2007-09-20 12:16:13.000000000 -0700 +++ lxc-dave/fs/open.c 2007-09-20 12:16:13.000000000 -0700 @@ -571,12 +571,12 @@ asmlinkage long sys_fchmod(unsigned int audit_inode(NULL, inode); - err = -EROFS; - if (IS_RDONLY(inode)) + err = mnt_want_write(file->f_vfsmnt); + if (err) goto out_putf; err = -EPERM; if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) - goto out_putf; + goto out_drop_write; mutex_lock(&inode->i_mutex); if (mode == (mode_t) -1) mode = inode->i_mode; @@ -585,6 +585,8 @@ asmlinkage long sys_fchmod(unsigned int err = notify_change(dentry, &newattrs); mutex_unlock(&inode->i_mutex); +out_drop_write: + mnt_drop_write(file->f_vfsmnt); out_putf: fput(file); out: @@ -604,13 +606,13 @@ asmlinkage long sys_fchmodat(int dfd, co goto out; inode = nd.dentry->d_inode; - error = -EROFS; - if (IS_RDONLY(inode)) + error = mnt_want_write(nd.mnt); + if (error) goto dput_and_out; error = -EPERM; if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) - goto dput_and_out; + goto out_drop_write; mutex_lock(&inode->i_mutex); if (mode == (mode_t) -1) @@ -620,6 +622,8 @@ asmlinkage long sys_fchmodat(int dfd, co error = notify_change(nd.dentry, &newattrs); mutex_unlock(&inode->i_mutex); +out_drop_write: + mnt_drop_write(nd.mnt); dput_and_out: path_release(&nd); out: @@ -642,9 +646,6 @@ static int chown_common(struct dentry * printk(KERN_ERR "chown_common: NULL inode\n"); goto out; } - error = -EROFS; - if (IS_RDONLY(inode)) - goto out; error = -EPERM; if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) goto out; @@ -674,7 +675,12 @@ asmlinkage long sys_chown(const char __u error = user_path_walk(filename, &nd); if (error) goto out; + error = mnt_want_write(nd.mnt); + if (error) + goto out_release; error = chown_common(nd.dentry, user, group); + mnt_drop_write(nd.mnt); +out_release: path_release(&nd); out: return error; @@ -694,7 +700,12 @@ asmlinkage long sys_fchownat(int dfd, co error = __user_walk_fd(dfd, filename, follow, &nd); if (error) goto out; + error = mnt_want_write(nd.mnt); + if (error) + goto out_release; error = chown_common(nd.dentry, user, group); + mnt_drop_write(nd.mnt); +out_release: path_release(&nd); out: return error; @@ -708,7 +719,12 @@ asmlinkage long sys_lchown(const char __ error = user_path_walk_link(filename, &nd); if (error) goto out; + error = mnt_want_write(nd.mnt); + if (error) + goto out_release; error = chown_common(nd.dentry, user, group); + mnt_drop_write(nd.mnt); +out_release: path_release(&nd); out: return error; @@ -725,9 +741,14 @@ asmlinkage long sys_fchown(unsigned int if (!file) goto out; + error = mnt_want_write(file->f_vfsmnt); + if (error) + goto out_fput; dentry = file->f_path.dentry; audit_inode(NULL, dentry->d_inode); error = chown_common(dentry, user, group); + mnt_drop_write(file->f_vfsmnt); +out_fput: fput(file); out: return error; _