Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754218AbZKVCtw (ORCPT ); Sat, 21 Nov 2009 21:49:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752903AbZKVCtv (ORCPT ); Sat, 21 Nov 2009 21:49:51 -0500 Received: from wine.ocn.ne.jp ([122.1.235.145]:57409 "EHLO smtp.wine.ocn.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750804AbZKVCtu (ORCPT ); Sat, 21 Nov 2009 21:49:50 -0500 To: linux-security-module@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] LSM: Move security_path_chmod()/security_path_chown() to after mutex_lock(). From: Tetsuo Handa References: <20091004124946.788396453@I-love.SAKURA.ne.jp> <20091004125327.105675949@I-love.SAKURA.ne.jp> <20091029051211.GB11558@us.ibm.com> <200910300056.IFD65194.MSOLHFOVJQtOFF@I-love.SAKURA.ne.jp> In-Reply-To: <200910300056.IFD65194.MSOLHFOVJQtOFF@I-love.SAKURA.ne.jp> Message-Id: <200911221149.HCF73996.FSLtOOHVJFQOFM@I-love.SAKURA.ne.jp> X-Mailer: Winbiff [Version 2.51 PL2] X-Accept-Language: ja,en,zh Date: Sun, 22 Nov 2009 11:49:55 +0900 Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4180 Lines: 127 [PATCH] LSM: Move security_path_chmod()/security_path_chown() to after mutex_lock(). We should call security_path_chmod()/security_path_chown() after mutex_lock() in order to avoid races. Signed-off-by: Tetsuo Handa --- fs/open.c | 36 +++++++++++++++--------------------- 1 file changed, 15 insertions(+), 21 deletions(-) --- security-testing-2.6.orig/fs/open.c +++ security-testing-2.6/fs/open.c @@ -619,17 +619,17 @@ SYSCALL_DEFINE2(fchmod, unsigned int, fd err = mnt_want_write_file(file); if (err) goto out_putf; + mutex_lock(&inode->i_mutex); err = security_path_chmod(dentry, file->f_vfsmnt, mode); if (err) - goto out_drop_write; - mutex_lock(&inode->i_mutex); + goto out_unlock; if (mode == (mode_t) -1) mode = inode->i_mode; newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; err = notify_change(dentry, &newattrs); +out_unlock: mutex_unlock(&inode->i_mutex); -out_drop_write: mnt_drop_write(file->f_path.mnt); out_putf: fput(file); @@ -652,17 +652,17 @@ SYSCALL_DEFINE3(fchmodat, int, dfd, cons error = mnt_want_write(path.mnt); if (error) goto dput_and_out; + mutex_lock(&inode->i_mutex); error = security_path_chmod(path.dentry, path.mnt, mode); if (error) - goto out_drop_write; - mutex_lock(&inode->i_mutex); + goto out_unlock; if (mode == (mode_t) -1) mode = inode->i_mode; newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; error = notify_change(path.dentry, &newattrs); +out_unlock: mutex_unlock(&inode->i_mutex); -out_drop_write: mnt_drop_write(path.mnt); dput_and_out: path_put(&path); @@ -675,9 +675,9 @@ SYSCALL_DEFINE2(chmod, const char __user return sys_fchmodat(AT_FDCWD, filename, mode); } -static int chown_common(struct dentry * dentry, uid_t user, gid_t group) +static int chown_common(struct path *path, uid_t user, gid_t group) { - struct inode *inode = dentry->d_inode; + struct inode *inode = path->dentry->d_inode; int error; struct iattr newattrs; @@ -694,7 +694,9 @@ static int chown_common(struct dentry * newattrs.ia_valid |= ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV; mutex_lock(&inode->i_mutex); - error = notify_change(dentry, &newattrs); + error = security_path_chown(path, user, group); + if (!error) + error = notify_change(path->dentry, &newattrs); mutex_unlock(&inode->i_mutex); return error; @@ -711,9 +713,7 @@ SYSCALL_DEFINE3(chown, const char __user error = mnt_want_write(path.mnt); if (error) goto out_release; - error = security_path_chown(&path, user, group); - if (!error) - error = chown_common(path.dentry, user, group); + error = chown_common(&path, user, group); mnt_drop_write(path.mnt); out_release: path_put(&path); @@ -738,9 +738,7 @@ SYSCALL_DEFINE5(fchownat, int, dfd, cons error = mnt_want_write(path.mnt); if (error) goto out_release; - error = security_path_chown(&path, user, group); - if (!error) - error = chown_common(path.dentry, user, group); + error = chown_common(&path, user, group); mnt_drop_write(path.mnt); out_release: path_put(&path); @@ -759,9 +757,7 @@ SYSCALL_DEFINE3(lchown, const char __use error = mnt_want_write(path.mnt); if (error) goto out_release; - error = security_path_chown(&path, user, group); - if (!error) - error = chown_common(path.dentry, user, group); + error = chown_common(&path, user, group); mnt_drop_write(path.mnt); out_release: path_put(&path); @@ -784,9 +780,7 @@ SYSCALL_DEFINE3(fchown, unsigned int, fd goto out_fput; dentry = file->f_path.dentry; audit_inode(NULL, dentry); - error = security_path_chown(&file->f_path, user, group); - if (!error) - error = chown_common(dentry, user, group); + error = chown_common(&file->f_path, user, group); mnt_drop_write(file->f_path.mnt); out_fput: fput(file); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/