since "normally audit_add_tree_rule() will free it on failure",
need free it completely, when failure occures.
need additional put_tree before return, since get_tree was called.
always need goto error processing area for list_del_init.
Signed-off-by: Chen Gang <[email protected]>
---
kernel/audit_tree.c | 5 ++++-
1 files changed, 4 insertions(+), 1 deletions(-)
diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c
index 642a89c..3729d49 100644
--- a/kernel/audit_tree.c
+++ b/kernel/audit_tree.c
@@ -694,13 +694,15 @@ int audit_add_tree_rule(struct audit_krule *rule)
spin_unlock(&hash_lock);
} else {
trim_marked(tree);
+ put_tree(tree);
goto Err;
}
mutex_lock(&audit_filter_mutex);
if (list_empty(&rule->rlist)) {
put_tree(tree);
- return -ENOENT;
+ err = -ENOENT;
+ got Err1;
}
rule->tree = tree;
put_tree(tree);
@@ -708,6 +710,7 @@ int audit_add_tree_rule(struct audit_krule *rule)
return 0;
Err:
mutex_lock(&audit_filter_mutex);
+Err1:
list_del_init(&tree->list);
list_del_init(&tree->rules);
put_tree(tree);
--
1.7.7.6
better to set krule->watch = NULL.
maybe it is not a real issue, but can make code clearer,
so can help the readers to analyse another issues.
Signed-off-by: Chen Gang <[email protected]>
---
kernel/audit_watch.c | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/kernel/audit_watch.c b/kernel/audit_watch.c
index 22831c4..abd8fdb 100644
--- a/kernel/audit_watch.c
+++ b/kernel/audit_watch.c
@@ -456,6 +456,7 @@ void audit_remove_watch_rule(struct audit_krule *krule)
if (list_empty(&watch->rules)) {
audit_remove_watch(watch);
+ krule->watch = NULL;
if (list_empty(&parent->watches)) {
audit_get_parent(parent);
--
1.7.7.6
oh, sorry, this patch is incorrect, please skip it.
On 2013年04月12日 12:50, Chen Gang wrote:
>
> better to set krule->watch = NULL.
> maybe it is not a real issue, but can make code clearer,
> so can help the readers to analyse another issues.
>
> Signed-off-by: Chen Gang <[email protected]>
> ---
> kernel/audit_watch.c | 1 +
> 1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/kernel/audit_watch.c b/kernel/audit_watch.c
> index 22831c4..abd8fdb 100644
> --- a/kernel/audit_watch.c
> +++ b/kernel/audit_watch.c
> @@ -456,6 +456,7 @@ void audit_remove_watch_rule(struct audit_krule *krule)
>
> if (list_empty(&watch->rules)) {
> audit_remove_watch(watch);
> + krule->watch = NULL;
>
> if (list_empty(&parent->watches)) {
> audit_get_parent(parent);
>
--
Chen Gang
Asianux Corporation
need call audit_put_tree, if tree is valid.
just like another area have done in function audit_add_rule.
Signed-off-by: Chen Gang <[email protected]>
---
kernel/auditfilter.c | 6 ++++++
1 files changed, 6 insertions(+), 0 deletions(-)
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index f9fc54b..81f63f9 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -952,6 +952,12 @@ static inline int audit_add_rule(struct audit_entry *entry)
err = audit_add_watch(&entry->rule, &list);
if (err) {
mutex_unlock(&audit_filter_mutex);
+ /*
+ * normally audit_add_tree_rule() will free it
+ * on failure
+ */
+ if (tree)
+ audit_put_tree(tree);
goto error;
}
}
--
1.7.7.6
oh, sorry, this patch need improving (got --> goto)
and I should compile, install, running in normal condition, and be
sure of no additional issues occur at least.
On 2013年04月12日 12:43, Chen Gang wrote:
>
> since "normally audit_add_tree_rule() will free it on failure",
> need free it completely, when failure occures.
>
> need additional put_tree before return, since get_tree was called.
> always need goto error processing area for list_del_init.
>
> Signed-off-by: Chen Gang <[email protected]>
> ---
> kernel/audit_tree.c | 5 ++++-
> 1 files changed, 4 insertions(+), 1 deletions(-)
>
> diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c
> index 642a89c..3729d49 100644
> --- a/kernel/audit_tree.c
> +++ b/kernel/audit_tree.c
> @@ -694,13 +694,15 @@ int audit_add_tree_rule(struct audit_krule *rule)
> spin_unlock(&hash_lock);
> } else {
> trim_marked(tree);
> + put_tree(tree);
> goto Err;
> }
>
> mutex_lock(&audit_filter_mutex);
> if (list_empty(&rule->rlist)) {
> put_tree(tree);
> - return -ENOENT;
> + err = -ENOENT;
> + got Err1;
> }
> rule->tree = tree;
> put_tree(tree);
> @@ -708,6 +710,7 @@ int audit_add_tree_rule(struct audit_krule *rule)
> return 0;
> Err:
> mutex_lock(&audit_filter_mutex);
> +Err1:
> list_del_init(&tree->list);
> list_del_init(&tree->rules);
> put_tree(tree);
>
--
Chen Gang
Asianux Corporation
since "normally audit_add_tree_rule() will free it on failure",
need free it completely, when failure occures.
need additional put_tree before return, since get_tree was called.
always need goto error processing area for list_del_init.
Signed-off-by: Chen Gang <[email protected]>
---
kernel/audit_tree.c | 5 ++++-
1 files changed, 4 insertions(+), 1 deletions(-)
diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c
index 642a89c..9dfb0da 100644
--- a/kernel/audit_tree.c
+++ b/kernel/audit_tree.c
@@ -694,13 +694,15 @@ int audit_add_tree_rule(struct audit_krule *rule)
spin_unlock(&hash_lock);
} else {
trim_marked(tree);
+ put_tree(tree);
goto Err;
}
mutex_lock(&audit_filter_mutex);
if (list_empty(&rule->rlist)) {
put_tree(tree);
- return -ENOENT;
+ err = -ENOENT;
+ goto Err1;
}
rule->tree = tree;
put_tree(tree);
@@ -708,6 +710,7 @@ int audit_add_tree_rule(struct audit_krule *rule)
return 0;
Err:
mutex_lock(&audit_filter_mutex);
+Err1:
list_del_init(&tree->list);
list_del_init(&tree->rules);
put_tree(tree);
--
1.7.7.6
also please help checking this patch, when you have time.
thanks.
On 2013年04月12日 16:56, Chen Gang wrote:
>
> need call audit_put_tree, if tree is valid.
> just like another area have done in function audit_add_rule.
>
> Signed-off-by: Chen Gang <[email protected]>
> ---
> kernel/auditfilter.c | 6 ++++++
> 1 files changed, 6 insertions(+), 0 deletions(-)
>
> diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
> index f9fc54b..81f63f9 100644
> --- a/kernel/auditfilter.c
> +++ b/kernel/auditfilter.c
> @@ -952,6 +952,12 @@ static inline int audit_add_rule(struct audit_entry *entry)
> err = audit_add_watch(&entry->rule, &list);
> if (err) {
> mutex_unlock(&audit_filter_mutex);
> + /*
> + * normally audit_add_tree_rule() will free it
> + * on failure
> + */
> + if (tree)
> + audit_put_tree(tree);
> goto error;
> }
> }
>
--
Chen Gang
Asianux Corporation
On Wed, 17 Apr 2013 12:04:02 +0800 Chen Gang <[email protected]> wrote:
> since "normally audit_add_tree_rule() will free it on failure",
> need free it completely, when failure occures.
>
> need additional put_tree before return, since get_tree was called.
> always need goto error processing area for list_del_init.
Isn't that get_tree() in audit_add_tree_rule() simply unneeded? In
other words, is this patch correct:
--- a/kernel/audit_tree.c~a
+++ a/kernel/audit_tree.c
@@ -682,7 +682,6 @@ int audit_add_tree_rule(struct audit_kru
goto Err;
}
- get_tree(tree);
err = iterate_mounts(tag_mount, tree, mnt);
drop_collected_mounts(mnt);
@@ -703,7 +702,6 @@ int audit_add_tree_rule(struct audit_kru
return -ENOENT;
}
rule->tree = tree;
- put_tree(tree);
return 0;
Err:
_
On 2013年04月18日 04:07, Andrew Morton wrote:
> On Wed, 17 Apr 2013 12:04:02 +0800 Chen Gang <[email protected]> wrote:
>
>> > since "normally audit_add_tree_rule() will free it on failure",
>> > need free it completely, when failure occures.
>> >
>> > need additional put_tree before return, since get_tree was called.
>> > always need goto error processing area for list_del_init.
> Isn't that get_tree() in audit_add_tree_rule() simply unneeded? In
> other words, is this patch correct:
>
excuse me:
I am not quite familiar with it, and also have to do another things.
so I have to spend additional time resource to make sure about it.
is it ok ?
I should make sure about it within this week (2013-04-21)
I should finish related test (if need), within next week (2013-4-28)
if have additional suggestions or completions, please reply.
(if no reply, I will follow the time point above)
thanks.
gchen.
> --- a/kernel/audit_tree.c~a
> +++ a/kernel/audit_tree.c
> @@ -682,7 +682,6 @@ int audit_add_tree_rule(struct audit_kru
> goto Err;
> }
>
> - get_tree(tree);
> err = iterate_mounts(tag_mount, tree, mnt);
> drop_collected_mounts(mnt);
>
> @@ -703,7 +702,6 @@ int audit_add_tree_rule(struct audit_kru
> return -ENOENT;
> }
> rule->tree = tree;
> - put_tree(tree);
>
> return 0;
> Err:
> _
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>
--
Chen Gang
Flying Transformer
On 2013年04月18日 09:19, Chen Gang F T wrote:
> On 2013年04月18日 04:07, Andrew Morton wrote:
>> > On Wed, 17 Apr 2013 12:04:02 +0800 Chen Gang <[email protected]> wrote:
>> >
>>>> >> > since "normally audit_add_tree_rule() will free it on failure",
>>>> >> > need free it completely, when failure occures.
>>>> >> >
>>>> >> > need additional put_tree before return, since get_tree was called.
>>>> >> > always need goto error processing area for list_del_init.
>> > Isn't that get_tree() in audit_add_tree_rule() simply unneeded? In
>> > other words, is this patch correct:
>> >
after reading code again, I think:
we can remove the pair of get_tree() and put_tree(),
a. the author want to pretect tree not to be freed after unlock audit_filter_mutex
when tree is really freed by others, we have chance to check tree->goner
b. it just like another functions done (audit_tag_tree, audit_trim_trees)
for audit_add_tree_rule, also need let get_tree() protected by audit_filter_mutex.
(move 'get_tree' before unlock audit_filter_mutex)
c. but after read code (at least for audit_add_tree_rule)
during unlock audit_filter_mutex in audit_add_tree_rule:
I find only one posible related work flow which may happen (maybe it can not happen either).
fsnotify_destroy_mark_locked ->
audit_tree_freeing_mark ->
evict_chunk ->
kill_rules ->
call_rcu ->
audit_free_rule_rcu ->
audit_free_rule
it will free rules and entry, but it does not call put_tree().
so I think, at least for audit_add_tree_rule, we can remove the pair of get_tree() and put_tree()
(maybe also need give a check for audit_tag_tree and audit_trim_trees, whether can remove 'get_tree' too)
and the process is incorrect after lock audit_filter_mutex again (line 701..705)
a. if rule->rlist was really empty
the 'rule' itself would already be freed.
the caller and the caller of caller, need notice this (not double free)
instead, we need check tree->gonar (and also need spin_lock protected).
b. we do not need set "rule->tree = tree" again.
i. if 'rule' is not touched by any other thread
it should be rule->tree == tree.
ii. else if rule->tree == NULL (freed by other thread)
'rule' itself might be freed too, we'd better return by failure.
iii. else (!rule->tree && rule->tree != tree) (reused by other thread)
firstly, it should not happen.
if could happen, 'rule->tree = tree' would cause original rule->tree memory leak.
my conclusion is only by reading code (and still I am not quite expert about it, either)
so welcome experts (especially maintainers) to providing suggestions or completions.
thanks.
if no reply within a week (2013-04-28), I should send related patch.
gchen.
653 /* called with audit_filter_mutex */
654 int audit_add_tree_rule(struct audit_krule *rule)
655 {
656 struct audit_tree *seed = rule->tree, *tree;
657 struct path path;
658 struct vfsmount *mnt;
659 int err;
660
661 list_for_each_entry(tree, &tree_list, list) {
662 if (!strcmp(seed->pathname, tree->pathname)) {
663 put_tree(seed);
664 rule->tree = tree;
665 list_add(&rule->rlist, &tree->rules);
666 return 0;
667 }
668 }
669 tree = seed;
670 list_add(&tree->list, &tree_list);
671 list_add(&rule->rlist, &tree->rules);
672 /* do not set rule->tree yet */
673 mutex_unlock(&audit_filter_mutex);
674
675 err = kern_path(tree->pathname, 0, &path);
676 if (err)
677 goto Err;
678 mnt = collect_mounts(&path);
679 path_put(&path);
680 if (IS_ERR(mnt)) {
681 err = PTR_ERR(mnt);
682 goto Err;
683 }
684
685 get_tree(tree);
686 err = iterate_mounts(tag_mount, tree, mnt);
687 drop_collected_mounts(mnt);
688
689 if (!err) {
690 struct node *node;
691 spin_lock(&hash_lock);
692 list_for_each_entry(node, &tree->chunks, list)
693 node->index &= ~(1U<<31);
694 spin_unlock(&hash_lock);
695 } else {
696 trim_marked(tree);
697 goto Err;
698 }
699
700 mutex_lock(&audit_filter_mutex);
701 if (list_empty(&rule->rlist)) {
702 put_tree(tree);
703 return -ENOENT;
704 }
705 rule->tree = tree;
706 put_tree(tree);
707
708 return 0;
709 Err:
710 mutex_lock(&audit_filter_mutex);
711 list_del_init(&tree->list);
712 list_del_init(&tree->rules);
713 put_tree(tree);
714 return err;
715 }
> excuse me:
> I am not quite familiar with it, and also have to do another things.
> so I have to spend additional time resource to make sure about it.
>
> is it ok ?
> I should make sure about it within this week (2013-04-21)
> I should finish related test (if need), within next week (2013-4-28)
>
> if have additional suggestions or completions, please reply.
> (if no reply, I will follow the time point above)
>
> thanks.
>
> gchen.
>
>
--
Chen Gang
Asianux Corporation
On 2013年04月20日 15:31, Chen Gang wrote:
> On 2013年04月18日 09:19, Chen Gang F T wrote:
>> > On 2013年04月18日 04:07, Andrew Morton wrote:
>>>> >> > On Wed, 17 Apr 2013 12:04:02 +0800 Chen Gang <[email protected]> wrote:
>>>> >> >
>>>>>>>> >>>> >> > since "normally audit_add_tree_rule() will free it on failure",
>>>>>>>> >>>> >> > need free it completely, when failure occures.
>>>>>>>> >>>> >> >
>>>>>>>> >>>> >> > need additional put_tree before return, since get_tree was called.
>>>>>>>> >>>> >> > always need goto error processing area for list_del_init.
>>>> >> > Isn't that get_tree() in audit_add_tree_rule() simply unneeded? In
>>>> >> > other words, is this patch correct:
>>>> >> >
>
I hope the maintainers to provide your suggestions or completion. if we
get non-reply from any maintainers, I should continue to analyse.
if we continue analyse independent with original maintainers,
I think, before get a conclusion:
I should understand the API of audit: what it is, how to use it (test
it), know about all of sub-systems which are related with it (such as fs
sub-system);
also should know about the design of audit (read through the code),
and should analyse the lower-level design of audit tree (read the code
completely).
and excuse me, I am not quite familiar with audit, now, and also have to
plan to do another things, so I think I should get a conclusion within
next month (2013-05-31), is it ok ?
BTW:
my plan for 1st half of 2013 is mainly for familiar environments: can
provide contributes to many various sub systems (e.g. arm, powerpc,
drivers, net, kernel ...)
my plan for 2nd half of 2013 is mainly for familiar kernel: should
analyse the deeper issues and kernel API/design step by step (e.g. mm,
fs, kernel API documents...)
the original related mail:
http://linux-kernel.2935.n7.nabble.com/Consult-Plan-personal-contributes-plan-for-2013-td587319.html
> after reading code again, I think:
>
> we can remove the pair of get_tree() and put_tree(),
>
> a. the author want to pretect tree not to be freed after unlock audit_filter_mutex
> when tree is really freed by others, we have chance to check tree->goner
>
> b. it just like another functions done (audit_tag_tree, audit_trim_trees)
> for audit_add_tree_rule, also need let get_tree() protected by audit_filter_mutex.
> (move 'get_tree' before unlock audit_filter_mutex)
>
> c. but after read code (at least for audit_add_tree_rule)
> during unlock audit_filter_mutex in audit_add_tree_rule:
> I find only one posible related work flow which may happen (maybe it can not happen either).
> fsnotify_destroy_mark_locked ->
> audit_tree_freeing_mark ->
> evict_chunk ->
> kill_rules ->
> call_rcu ->
> audit_free_rule_rcu ->
> audit_free_rule
> it will free rules and entry, but it does not call put_tree().
>
> so I think, at least for audit_add_tree_rule, we can remove the pair of get_tree() and put_tree()
> (maybe also need give a check for audit_tag_tree and audit_trim_trees, whether can remove 'get_tree' too)
>
>
> and the process is incorrect after lock audit_filter_mutex again (line 701..705)
>
> a. if rule->rlist was really empty
> the 'rule' itself would already be freed.
> the caller and the caller of caller, need notice this (not double free)
> instead, we need check tree->gonar (and also need spin_lock protected).
>
> b. we do not need set "rule->tree = tree" again.
> i. if 'rule' is not touched by any other thread
> it should be rule->tree == tree.
>
> ii. else if rule->tree == NULL (freed by other thread)
> 'rule' itself might be freed too, we'd better return by failure.
>
> iii. else (!rule->tree && rule->tree != tree) (reused by other thread)
> firstly, it should not happen.
> if could happen, 'rule->tree = tree' would cause original rule->tree memory leak.
>
>
> my conclusion is only by reading code (and still I am not quite expert about it, either)
> so welcome experts (especially maintainers) to providing suggestions or completions.
>
> thanks.
>
>
> if no reply within a week (2013-04-28), I should send related patch.
>
> gchen.
>
> 653 /* called with audit_filter_mutex */
> 654 int audit_add_tree_rule(struct audit_krule *rule)
> 655 {
> 656 struct audit_tree *seed = rule->tree, *tree;
> 657 struct path path;
> 658 struct vfsmount *mnt;
> 659 int err;
> 660
> 661 list_for_each_entry(tree, &tree_list, list) {
> 662 if (!strcmp(seed->pathname, tree->pathname)) {
> 663 put_tree(seed);
> 664 rule->tree = tree;
> 665 list_add(&rule->rlist, &tree->rules);
> 666 return 0;
> 667 }
> 668 }
> 669 tree = seed;
> 670 list_add(&tree->list, &tree_list);
> 671 list_add(&rule->rlist, &tree->rules);
> 672 /* do not set rule->tree yet */
> 673 mutex_unlock(&audit_filter_mutex);
> 674
> 675 err = kern_path(tree->pathname, 0, &path);
> 676 if (err)
> 677 goto Err;
> 678 mnt = collect_mounts(&path);
> 679 path_put(&path);
> 680 if (IS_ERR(mnt)) {
> 681 err = PTR_ERR(mnt);
> 682 goto Err;
> 683 }
> 684
> 685 get_tree(tree);
> 686 err = iterate_mounts(tag_mount, tree, mnt);
> 687 drop_collected_mounts(mnt);
> 688
> 689 if (!err) {
> 690 struct node *node;
> 691 spin_lock(&hash_lock);
> 692 list_for_each_entry(node, &tree->chunks, list)
> 693 node->index &= ~(1U<<31);
> 694 spin_unlock(&hash_lock);
> 695 } else {
> 696 trim_marked(tree);
> 697 goto Err;
> 698 }
> 699
> 700 mutex_lock(&audit_filter_mutex);
> 701 if (list_empty(&rule->rlist)) {
> 702 put_tree(tree);
> 703 return -ENOENT;
> 704 }
> 705 rule->tree = tree;
> 706 put_tree(tree);
> 707
> 708 return 0;
> 709 Err:
> 710 mutex_lock(&audit_filter_mutex);
> 711 list_del_init(&tree->list);
> 712 list_del_init(&tree->rules);
> 713 put_tree(tree);
> 714 return err;
> 715 }
>
>
>
>
>> > excuse me:
>> > I am not quite familiar with it, and also have to do another things.
>> > so I have to spend additional time resource to make sure about it.
>> >
>> > is it ok ?
>> > I should make sure about it within this week (2013-04-21)
>> > I should finish related test (if need), within next week (2013-4-28)
>> >
>> > if have additional suggestions or completions, please reply.
>> > (if no reply, I will follow the time point above)
>> >
>> > thanks.
>> >
>> > gchen.
>> >
>> >
>
> -- Chen Gang Asianux Corporation
>
--
Chen Gang
Asianux Corporation