csky/kprobe: reclaim insn_slot on kprobe unregistration

[PATCH] csky/kprobe: reclaim insn_slot on kprobe unregistration

Posted by Liao Chang 3 years, 11 months ago

On kprobe registration kernel allocate one insn_slot for new kprobe,
but it forget to reclaim the insn_slot on unregistration, leading to a
potential leakage.

Reported-by: Chen Guokai <chenguokai17@mails.ucas.ac.cn>
Signed-off-by: Liao Chang <liaochang1@huawei.com>
---
 arch/csky/kernel/probes/kprobes.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/csky/kernel/probes/kprobes.c b/arch/csky/kernel/probes/kprobes.c
index 42920f25e73c..661da54b418f 100644
--- a/arch/csky/kernel/probes/kprobes.c
+++ b/arch/csky/kernel/probes/kprobes.c
@@ -124,6 +124,10 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p)
 
 void __kprobes arch_remove_kprobe(struct kprobe *p)
 {
+	if (p->ainsn.api.insn) {
+		free_insn_slot(p->ainsn.api.insn, 0);
+		p->ainsn.api.insn = NULL;
+	}
 }
 
 static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
-- 
2.17.1

Re: [PATCH] csky/kprobe: reclaim insn_slot on kprobe unregistration

Posted by Masami Hiramatsu (Google) 3 years, 11 months ago

On Wed, 25 May 2022 16:02:41 +0800
Liao Chang <liaochang1@huawei.com> wrote:

> On kprobe registration kernel allocate one insn_slot for new kprobe,
> but it forget to reclaim the insn_slot on unregistration, leading to a
> potential leakage.
> 
> Reported-by: Chen Guokai <chenguokai17@mails.ucas.ac.cn>
> Signed-off-by: Liao Chang <liaochang1@huawei.com>

This looks good to me too. I think this should go through csky tree.

Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Thank you,


> ---
>  arch/csky/kernel/probes/kprobes.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/arch/csky/kernel/probes/kprobes.c b/arch/csky/kernel/probes/kprobes.c
> index 42920f25e73c..661da54b418f 100644
> --- a/arch/csky/kernel/probes/kprobes.c
> +++ b/arch/csky/kernel/probes/kprobes.c
> @@ -124,6 +124,10 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p)
>  
>  void __kprobes arch_remove_kprobe(struct kprobe *p)
>  {
> +	if (p->ainsn.api.insn) {
> +		free_insn_slot(p->ainsn.api.insn, 0);
> +		p->ainsn.api.insn = NULL;
> +	}
>  }
>  
>  static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
> -- 
> 2.17.1
> 


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>

Re: [PATCH] csky/kprobe: reclaim insn_slot on kprobe unregistration

Posted by Guo Ren 3 years, 11 months ago

On Thu, May 26, 2022 at 11:30 PM Masami Hiramatsu <mhiramat@kernel.org> wrote:
>
> On Wed, 25 May 2022 16:02:41 +0800
> Liao Chang <liaochang1@huawei.com> wrote:
>
> > On kprobe registration kernel allocate one insn_slot for new kprobe,
> > but it forget to reclaim the insn_slot on unregistration, leading to a
> > potential leakage.
> >
> > Reported-by: Chen Guokai <chenguokai17@mails.ucas.ac.cn>
> > Signed-off-by: Liao Chang <liaochang1@huawei.com>
>
> This looks good to me too. I think this should go through csky tree.
Okay, I would add the Fix line and put it into Linux-5.19-rc2.

>
> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
>
> Thank you,
>
>
> > ---
> >  arch/csky/kernel/probes/kprobes.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/arch/csky/kernel/probes/kprobes.c b/arch/csky/kernel/probes/kprobes.c
> > index 42920f25e73c..661da54b418f 100644
> > --- a/arch/csky/kernel/probes/kprobes.c
> > +++ b/arch/csky/kernel/probes/kprobes.c
> > @@ -124,6 +124,10 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p)
> >
> >  void __kprobes arch_remove_kprobe(struct kprobe *p)
> >  {
> > +     if (p->ainsn.api.insn) {
> > +             free_insn_slot(p->ainsn.api.insn, 0);
> > +             p->ainsn.api.insn = NULL;
> > +     }
> >  }
> >
> >  static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
> > --
> > 2.17.1
> >
>
>
> --
> Masami Hiramatsu (Google) <mhiramat@kernel.org>



-- 
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/