Messages in this thread Patch in this message | | | Subject | [patch 1/1] selinux: do not clear f_op when removing entries | From | Stephen Smalley <> | Date | Wed, 21 Nov 2007 09:01:36 -0500 |
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On Tue, 2007-11-20 at 15:17 +0000, Christoph Hellwig wrote: > On Tue, Nov 20, 2007 at 10:05:05AM -0500, Stephen Smalley wrote: > > > Nice, getting rid of this is a very good step formwards. Unfortunately > > > we have another copy of this junk in > > > security/selinux/selinuxfs.c:sel_remove_entries() which would need the > > > same treatment. > > > > Can't just be dropped completely for selinux - we need a way to drop > > obsolete entries from the prior policy when we load a new policy. > > > > Is the only real problem here the clearing of f_op? If so, we can > > likely remove that from sel_remove_entries() without harm, and fix the > > checks for it to use something more reliable. > > f_op removal is the biggest issue. It can't really work and this is the > last instance. But in general having some half-backed attempts at revoke > is never a good idea.
Do not clear f_op when removing entries since it isn't safe to do.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
---
security/selinux/selinuxfs.c | 28 +--------------------------- 1 file changed, 1 insertion(+), 27 deletions(-)
diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c index f5f3e6d..ac6fe99 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -838,10 +838,6 @@ static ssize_t sel_read_bool(struct file *filep, char __user *buf, ret = -EFAULT; - /* check to see if this file has been deleted */ - if (!filep->f_op) - goto out; - if (count > PAGE_SIZE) { ret = -EINVAL; goto out; @@ -882,10 +878,6 @@ static ssize_t sel_write_bool(struct file *filep, const char __user *buf, if (length) goto out; - /* check to see if this file has been deleted */ - if (!filep->f_op) - goto out; - if (count >= PAGE_SIZE) { length = -ENOMEM; goto out; @@ -940,10 +932,6 @@ static ssize_t sel_commit_bools_write(struct file *filep, if (length) goto out; - /* check to see if this file has been deleted */ - if (!filep->f_op) - goto out; - if (count >= PAGE_SIZE) { length = -ENOMEM; goto out; @@ -982,11 +970,9 @@ static const struct file_operations sel_commit_bools_ops = { .write = sel_commit_bools_write, }; -/* partial revoke() from fs/proc/generic.c proc_kill_inodes */ static void sel_remove_entries(struct dentry *de) { - struct list_head *p, *node; - struct super_block *sb = de->d_sb; + struct list_head *node; spin_lock(&dcache_lock); node = de->d_subdirs.next; @@ -1006,18 +992,6 @@ static void sel_remove_entries(struct dentry *de) } spin_unlock(&dcache_lock); - - file_list_lock(); - list_for_each(p, &sb->s_files) { - struct file * filp = list_entry(p, struct file, f_u.fu_list); - struct dentry * dentry = filp->f_path.dentry; - - if (dentry->d_parent != de) { - continue; - } - filp->f_op = NULL; - } - file_list_unlock(); } #define BOOL_DIR_NAME "booleans"
-- Stephen Smalley National Security Agency
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