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From: Guo Ren <guoren@kernel.org>
To: Jisheng Zhang <jszhang@kernel.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 1/4] riscv: process: fix kernel info leakage
Date: Wed, 5 Oct 2022 00:04:31 +0800	[thread overview]
Message-ID: <CAJF2gTSdVyAaM12T+7kXAdRPGS4VyuO08X1c7paE-n4Fr8OtRA@mail.gmail.com> (raw)
In-Reply-To: <20221003102921.3973-2-jszhang@kernel.org>

Reviewed-by: Guo Ren <guoren@kernel.org>

On Mon, Oct 3, 2022 at 6:38 PM Jisheng Zhang <jszhang@kernel.org> wrote:
>
> thread_struct's s[12] may contain random kernel memory content, which
> may be finally leaked to userspace. This is a security hole. Fix it
> by clearing the s[12] array in thread_struct when fork.
>
> As for kthread case, it's better to clear the s[12] array as well.
>
> Fixes: 7db91e57a0ac ("RISC-V: Task implementation")
> Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> ---
>  arch/riscv/kernel/process.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
> index ceb9ebab6558..52002d54b163 100644
> --- a/arch/riscv/kernel/process.c
> +++ b/arch/riscv/kernel/process.c
> @@ -164,6 +164,8 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
>         unsigned long tls = args->tls;
>         struct pt_regs *childregs = task_pt_regs(p);
>
> +       memset(&p->thread.s, 0, sizeof(p->thread.s));
> +
>         /* p->thread holds context to be restored by __switch_to() */
>         if (unlikely(args->fn)) {
>                 /* Kernel thread */
> --
> 2.37.2
>


-- 
Best Regards
 Guo Ren

WARNING: multiple messages have this Message-ID
From: Guo Ren <guoren@kernel.org>
To: Jisheng Zhang <jszhang@kernel.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	 Albert Ou <aou@eecs.berkeley.edu>,
	linux-riscv@lists.infradead.org,  linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 1/4] riscv: process: fix kernel info leakage
Date: Wed, 5 Oct 2022 00:04:31 +0800	[thread overview]
Message-ID: <CAJF2gTSdVyAaM12T+7kXAdRPGS4VyuO08X1c7paE-n4Fr8OtRA@mail.gmail.com> (raw)
In-Reply-To: <20221003102921.3973-2-jszhang@kernel.org>

Reviewed-by: Guo Ren <guoren@kernel.org>

On Mon, Oct 3, 2022 at 6:38 PM Jisheng Zhang <jszhang@kernel.org> wrote:
>
> thread_struct's s[12] may contain random kernel memory content, which
> may be finally leaked to userspace. This is a security hole. Fix it
> by clearing the s[12] array in thread_struct when fork.
>
> As for kthread case, it's better to clear the s[12] array as well.
>
> Fixes: 7db91e57a0ac ("RISC-V: Task implementation")
> Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> ---
>  arch/riscv/kernel/process.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
> index ceb9ebab6558..52002d54b163 100644
> --- a/arch/riscv/kernel/process.c
> +++ b/arch/riscv/kernel/process.c
> @@ -164,6 +164,8 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
>         unsigned long tls = args->tls;
>         struct pt_regs *childregs = task_pt_regs(p);
>
> +       memset(&p->thread.s, 0, sizeof(p->thread.s));
> +
>         /* p->thread holds context to be restored by __switch_to() */
>         if (unlikely(args->fn)) {
>                 /* Kernel thread */
> --
> 2.37.2
>


-- 
Best Regards
 Guo Ren

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linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

  reply	other threads:[~2022-10-04 16:04 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-03 10:29 [PATCH v3 0/4] riscv: entry: further clean up and VMAP_STACK fix Jisheng Zhang
2022-10-03 10:29 ` Jisheng Zhang
2022-10-03 10:29 ` [PATCH v3 1/4] riscv: process: fix kernel info leakage Jisheng Zhang
2022-10-03 10:29   ` Jisheng Zhang
2022-10-04 16:04   ` Guo Ren [this message]
2022-10-04 16:04     ` Guo Ren
2022-10-03 10:29 ` [PATCH v3 2/4] riscv: consolidate ret_from_kernel_thread into ret_from_fork Jisheng Zhang
2022-10-03 10:29   ` Jisheng Zhang
2022-10-03 10:29 ` [PATCH v3 3/4] riscv: fix race when vmap stack overflow and remove shadow_stack Jisheng Zhang
2022-10-03 10:29   ` Jisheng Zhang
2022-10-03 10:29 ` [PATCH v3 4/4] riscv: entry: consolidate general regs saving/restoring Jisheng Zhang
2022-10-03 10:29   ` Jisheng Zhang
2022-10-04 16:03   ` Guo Ren
2022-10-04 16:03     ` Guo Ren

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