linux-sg2042/kernel/audit_watch.c

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/* audit_watch.c -- watching inodes
*
* Copyright 2003-2009 Red Hat, Inc.
* Copyright 2005 Hewlett-Packard Development Company, L.P.
* Copyright 2005 IBM Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/kernel.h>
#include <linux/audit.h>
#include <linux/kthread.h>
#include <linux/mutex.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/netlink.h>
#include <linux/sched.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 16:04:11 +08:00
#include <linux/slab.h>
#include <linux/inotify.h>
#include <linux/security.h>
#include "audit.h"
/*
* Reference counting:
*
* audit_parent: lifetime is from audit_init_parent() to receipt of an IN_IGNORED
* event. Each audit_watch holds a reference to its associated parent.
*
* audit_watch: if added to lists, lifetime is from audit_init_watch() to
* audit_remove_watch(). Additionally, an audit_watch may exist
* temporarily to assist in searching existing filter data. Each
* audit_krule holds a reference to its associated watch.
*/
struct audit_watch {
atomic_t count; /* reference count */
dev_t dev; /* associated superblock device */
char *path; /* insertion path */
unsigned long ino; /* associated inode number */
struct audit_parent *parent; /* associated parent */
struct list_head wlist; /* entry in parent->watches list */
struct list_head rules; /* associated rules */
};
struct audit_parent {
struct list_head ilist; /* entry in inotify registration list */
struct list_head watches; /* associated watches */
struct inotify_watch wdata; /* inotify watch data */
unsigned flags; /* status flags */
};
/* Inotify handle. */
struct inotify_handle *audit_ih;
/*
* audit_parent status flags:
*
* AUDIT_PARENT_INVALID - set anytime rules/watches are auto-removed due to
* a filesystem event to ensure we're adding audit watches to a valid parent.
* Technically not needed for IN_DELETE_SELF or IN_UNMOUNT events, as we cannot
* receive them while we have nameidata, but must be used for IN_MOVE_SELF which
* we can receive while holding nameidata.
*/
#define AUDIT_PARENT_INVALID 0x001
/* Inotify events we care about. */
#define AUDIT_IN_WATCH IN_MOVE|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF
static void audit_free_parent(struct inotify_watch *i_watch)
{
struct audit_parent *parent;
parent = container_of(i_watch, struct audit_parent, wdata);
WARN_ON(!list_empty(&parent->watches));
kfree(parent);
}
void audit_get_watch(struct audit_watch *watch)
{
atomic_inc(&watch->count);
}
void audit_put_watch(struct audit_watch *watch)
{
if (atomic_dec_and_test(&watch->count)) {
WARN_ON(watch->parent);
WARN_ON(!list_empty(&watch->rules));
kfree(watch->path);
kfree(watch);
}
}
void audit_remove_watch(struct audit_watch *watch)
{
list_del(&watch->wlist);
put_inotify_watch(&watch->parent->wdata);
watch->parent = NULL;
audit_put_watch(watch); /* match initial get */
}
char *audit_watch_path(struct audit_watch *watch)
{
return watch->path;
}
struct list_head *audit_watch_rules(struct audit_watch *watch)
{
return &watch->rules;
}
unsigned long audit_watch_inode(struct audit_watch *watch)
{
return watch->ino;
}
dev_t audit_watch_dev(struct audit_watch *watch)
{
return watch->dev;
}
/* Initialize a parent watch entry. */
static struct audit_parent *audit_init_parent(struct nameidata *ndp)
{
struct audit_parent *parent;
s32 wd;
parent = kzalloc(sizeof(*parent), GFP_KERNEL);
if (unlikely(!parent))
return ERR_PTR(-ENOMEM);
INIT_LIST_HEAD(&parent->watches);
parent->flags = 0;
inotify_init_watch(&parent->wdata);
/* grab a ref so inotify watch hangs around until we take audit_filter_mutex */
get_inotify_watch(&parent->wdata);
wd = inotify_add_watch(audit_ih, &parent->wdata,
ndp->path.dentry->d_inode, AUDIT_IN_WATCH);
if (wd < 0) {
audit_free_parent(&parent->wdata);
return ERR_PTR(wd);
}
return parent;
}
/* Initialize a watch entry. */
static struct audit_watch *audit_init_watch(char *path)
{
struct audit_watch *watch;
watch = kzalloc(sizeof(*watch), GFP_KERNEL);
if (unlikely(!watch))
return ERR_PTR(-ENOMEM);
INIT_LIST_HEAD(&watch->rules);
atomic_set(&watch->count, 1);
watch->path = path;
watch->dev = (dev_t)-1;
watch->ino = (unsigned long)-1;
return watch;
}
/* Translate a watch string to kernel respresentation. */
int audit_to_watch(struct audit_krule *krule, char *path, int len, u32 op)
{
struct audit_watch *watch;
if (!audit_ih)
return -EOPNOTSUPP;
if (path[0] != '/' || path[len-1] == '/' ||
krule->listnr != AUDIT_FILTER_EXIT ||
op != Audit_equal ||
krule->inode_f || krule->watch || krule->tree)
return -EINVAL;
watch = audit_init_watch(path);
if (IS_ERR(watch))
return PTR_ERR(watch);
audit_get_watch(watch);
krule->watch = watch;
return 0;
}
/* Duplicate the given audit watch. The new watch's rules list is initialized
* to an empty list and wlist is undefined. */
static struct audit_watch *audit_dupe_watch(struct audit_watch *old)
{
char *path;
struct audit_watch *new;
path = kstrdup(old->path, GFP_KERNEL);
if (unlikely(!path))
return ERR_PTR(-ENOMEM);
new = audit_init_watch(path);
if (IS_ERR(new)) {
kfree(path);
goto out;
}
new->dev = old->dev;
new->ino = old->ino;
get_inotify_watch(&old->parent->wdata);
new->parent = old->parent;
out:
return new;
}
static void audit_watch_log_rule_change(struct audit_krule *r, struct audit_watch *w, char *op)
{
if (audit_enabled) {
struct audit_buffer *ab;
ab = audit_log_start(NULL, GFP_NOFS, AUDIT_CONFIG_CHANGE);
audit_log_format(ab, "auid=%u ses=%u op=",
audit_get_loginuid(current),
audit_get_sessionid(current));
audit_log_string(ab, op);
audit_log_format(ab, " path=");
audit_log_untrustedstring(ab, w->path);
audit_log_key(ab, r->filterkey);
audit_log_format(ab, " list=%d res=1", r->listnr);
audit_log_end(ab);
}
}
/* Update inode info in audit rules based on filesystem event. */
static void audit_update_watch(struct audit_parent *parent,
const char *dname, dev_t dev,
unsigned long ino, unsigned invalidating)
{
struct audit_watch *owatch, *nwatch, *nextw;
struct audit_krule *r, *nextr;
struct audit_entry *oentry, *nentry;
mutex_lock(&audit_filter_mutex);
list_for_each_entry_safe(owatch, nextw, &parent->watches, wlist) {
if (audit_compare_dname_path(dname, owatch->path, NULL))
continue;
/* If the update involves invalidating rules, do the inode-based
* filtering now, so we don't omit records. */
if (invalidating && current->audit_context)
audit_filter_inodes(current, current->audit_context);
nwatch = audit_dupe_watch(owatch);
if (IS_ERR(nwatch)) {
mutex_unlock(&audit_filter_mutex);
audit_panic("error updating watch, skipping");
return;
}
nwatch->dev = dev;
nwatch->ino = ino;
list_for_each_entry_safe(r, nextr, &owatch->rules, rlist) {
oentry = container_of(r, struct audit_entry, rule);
list_del(&oentry->rule.rlist);
list_del_rcu(&oentry->list);
nentry = audit_dupe_rule(&oentry->rule, nwatch);
if (IS_ERR(nentry)) {
list_del(&oentry->rule.list);
audit_panic("error updating watch, removing");
} else {
int h = audit_hash_ino((u32)ino);
list_add(&nentry->rule.rlist, &nwatch->rules);
list_add_rcu(&nentry->list, &audit_inode_hash[h]);
list_replace(&oentry->rule.list,
&nentry->rule.list);
}
audit_watch_log_rule_change(r, owatch, "updated rules");
call_rcu(&oentry->rcu, audit_free_rule_rcu);
}
audit_remove_watch(owatch);
goto add_watch_to_parent; /* event applies to a single watch */
}
mutex_unlock(&audit_filter_mutex);
return;
add_watch_to_parent:
list_add(&nwatch->wlist, &parent->watches);
mutex_unlock(&audit_filter_mutex);
return;
}
/* Remove all watches & rules associated with a parent that is going away. */
static void audit_remove_parent_watches(struct audit_parent *parent)
{
struct audit_watch *w, *nextw;
struct audit_krule *r, *nextr;
struct audit_entry *e;
mutex_lock(&audit_filter_mutex);
parent->flags |= AUDIT_PARENT_INVALID;
list_for_each_entry_safe(w, nextw, &parent->watches, wlist) {
list_for_each_entry_safe(r, nextr, &w->rules, rlist) {
e = container_of(r, struct audit_entry, rule);
audit_watch_log_rule_change(r, w, "remove rule");
list_del(&r->rlist);
list_del(&r->list);
list_del_rcu(&e->list);
call_rcu(&e->rcu, audit_free_rule_rcu);
}
audit_remove_watch(w);
}
mutex_unlock(&audit_filter_mutex);
}
/* Unregister inotify watches for parents on in_list.
* Generates an IN_IGNORED event. */
void audit_inotify_unregister(struct list_head *in_list)
{
struct audit_parent *p, *n;
list_for_each_entry_safe(p, n, in_list, ilist) {
list_del(&p->ilist);
inotify_rm_watch(audit_ih, &p->wdata);
/* the unpin matching the pin in audit_do_del_rule() */
unpin_inotify_watch(&p->wdata);
}
}
/* Get path information necessary for adding watches. */
static int audit_get_nd(char *path, struct nameidata **ndp, struct nameidata **ndw)
{
struct nameidata *ndparent, *ndwatch;
int err;
ndparent = kmalloc(sizeof(*ndparent), GFP_KERNEL);
if (unlikely(!ndparent))
return -ENOMEM;
ndwatch = kmalloc(sizeof(*ndwatch), GFP_KERNEL);
if (unlikely(!ndwatch)) {
kfree(ndparent);
return -ENOMEM;
}
err = path_lookup(path, LOOKUP_PARENT, ndparent);
if (err) {
kfree(ndparent);
kfree(ndwatch);
return err;
}
err = path_lookup(path, 0, ndwatch);
if (err) {
kfree(ndwatch);
ndwatch = NULL;
}
*ndp = ndparent;
*ndw = ndwatch;
return 0;
}
/* Release resources used for watch path information. */
static void audit_put_nd(struct nameidata *ndp, struct nameidata *ndw)
{
if (ndp) {
path_put(&ndp->path);
kfree(ndp);
}
if (ndw) {
path_put(&ndw->path);
kfree(ndw);
}
}
/* Associate the given rule with an existing parent inotify_watch.
* Caller must hold audit_filter_mutex. */
static void audit_add_to_parent(struct audit_krule *krule,
struct audit_parent *parent)
{
struct audit_watch *w, *watch = krule->watch;
int watch_found = 0;
list_for_each_entry(w, &parent->watches, wlist) {
if (strcmp(watch->path, w->path))
continue;
watch_found = 1;
/* put krule's and initial refs to temporary watch */
audit_put_watch(watch);
audit_put_watch(watch);
audit_get_watch(w);
krule->watch = watch = w;
break;
}
if (!watch_found) {
get_inotify_watch(&parent->wdata);
watch->parent = parent;
list_add(&watch->wlist, &parent->watches);
}
list_add(&krule->rlist, &watch->rules);
}
/* Find a matching watch entry, or add this one.
* Caller must hold audit_filter_mutex. */
int audit_add_watch(struct audit_krule *krule)
{
struct audit_watch *watch = krule->watch;
struct inotify_watch *i_watch;
struct audit_parent *parent;
struct nameidata *ndp = NULL, *ndw = NULL;
int ret = 0;
mutex_unlock(&audit_filter_mutex);
/* Avoid calling path_lookup under audit_filter_mutex. */
ret = audit_get_nd(watch->path, &ndp, &ndw);
if (ret) {
/* caller expects mutex locked */
mutex_lock(&audit_filter_mutex);
goto error;
}
/* update watch filter fields */
if (ndw) {
watch->dev = ndw->path.dentry->d_inode->i_sb->s_dev;
watch->ino = ndw->path.dentry->d_inode->i_ino;
}
/* The audit_filter_mutex must not be held during inotify calls because
* we hold it during inotify event callback processing. If an existing
* inotify watch is found, inotify_find_watch() grabs a reference before
* returning.
*/
if (inotify_find_watch(audit_ih, ndp->path.dentry->d_inode,
&i_watch) < 0) {
parent = audit_init_parent(ndp);
if (IS_ERR(parent)) {
/* caller expects mutex locked */
mutex_lock(&audit_filter_mutex);
ret = PTR_ERR(parent);
goto error;
}
} else
parent = container_of(i_watch, struct audit_parent, wdata);
mutex_lock(&audit_filter_mutex);
/* parent was moved before we took audit_filter_mutex */
if (parent->flags & AUDIT_PARENT_INVALID)
ret = -ENOENT;
else
audit_add_to_parent(krule, parent);
/* match get in audit_init_parent or inotify_find_watch */
put_inotify_watch(&parent->wdata);
error:
audit_put_nd(ndp, ndw); /* NULL args OK */
return ret;
}
void audit_remove_watch_rule(struct audit_krule *krule, struct list_head *list)
{
struct audit_watch *watch = krule->watch;
struct audit_parent *parent = watch->parent;
list_del(&krule->rlist);
if (list_empty(&watch->rules)) {
audit_remove_watch(watch);
if (list_empty(&parent->watches)) {
/* Put parent on the inotify un-registration
* list. Grab a reference before releasing
* audit_filter_mutex, to be released in
* audit_inotify_unregister().
* If filesystem is going away, just leave
* the sucker alone, eviction will take
* care of it. */
if (pin_inotify_watch(&parent->wdata))
list_add(&parent->ilist, list);
}
}
}
/* Update watch data in audit rules based on inotify events. */
static void audit_handle_ievent(struct inotify_watch *i_watch, u32 wd, u32 mask,
u32 cookie, const char *dname, struct inode *inode)
{
struct audit_parent *parent;
parent = container_of(i_watch, struct audit_parent, wdata);
if (mask & (IN_CREATE|IN_MOVED_TO) && inode)
audit_update_watch(parent, dname, inode->i_sb->s_dev,
inode->i_ino, 0);
else if (mask & (IN_DELETE|IN_MOVED_FROM))
audit_update_watch(parent, dname, (dev_t)-1, (unsigned long)-1, 1);
/* inotify automatically removes the watch and sends IN_IGNORED */
else if (mask & (IN_DELETE_SELF|IN_UNMOUNT))
audit_remove_parent_watches(parent);
/* inotify does not remove the watch, so remove it manually */
else if(mask & IN_MOVE_SELF) {
audit_remove_parent_watches(parent);
inotify_remove_watch_locked(audit_ih, i_watch);
} else if (mask & IN_IGNORED)
put_inotify_watch(i_watch);
}
static const struct inotify_operations audit_inotify_ops = {
.handle_event = audit_handle_ievent,
.destroy_watch = audit_free_parent,
};
static int __init audit_watch_init(void)
{
audit_ih = inotify_init(&audit_inotify_ops);
if (IS_ERR(audit_ih))
audit_panic("cannot initialize inotify handle");
return 0;
}
subsys_initcall(audit_watch_init);