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From: Song Liu <[email protected]>
To: Wan Jiabing <[email protected]>
Cc: Steven Rostedt <[email protected]>,
	Ingo Molnar <[email protected]>,
	Alexei Starovoitov <[email protected]>,
	Daniel Borkmann <[email protected]>,
	Andrii Nakryiko <[email protected]>, Martin Lau <[email protected]>,
	Yonghong Song <[email protected]>,
	John Fastabend <[email protected]>,
	KP Singh <[email protected]>,
	Networking <[email protected]>, bpf <[email protected]>,
	Linux Kernel Mailing List <[email protected]>
Subject: Re: [PATCH 3/3] bpf: use vmemdup_user instead of kvmalloc and copy_from_user
Date: Thu, 12 May 2022 16:45:24 +0000	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>



> On May 12, 2022, at 7:17 AM, Wan Jiabing <[email protected]> wrote:
> 
> Fix following coccicheck warning:
> ./kernel/trace/bpf_trace.c:2488:12-20: WARNING opportunity for vmemdup_user
> 
> Use vmemdup_user instead of kvmalloc and copy_from_user.
> 
> Signed-off-by: Wan Jiabing <[email protected]>
> ---
> kernel/trace/bpf_trace.c | 10 +++-------
> 1 file changed, 3 insertions(+), 7 deletions(-)
> 
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index 1b0db8f78dc8..48fc97a6db50 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -2483,15 +2483,11 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
> 
> 	ucookies = u64_to_user_ptr(attr->link_create.kprobe_multi.cookies);
> 	if (ucookies) {
> -		cookies = kvmalloc(size, GFP_KERNEL);
> -		if (!cookies) {
> -			err = -ENOMEM;
> +		cookies = vmemdup_user(ucookies, size);

vmemdup_user() uses GFP_USER, so this is a behavior change. 

Song

> +		if (IS_ERR(cookies)) {
> +			err = PTR_ERR(cookies);
> 			goto error_addrs;
> 		}
> -		if (copy_from_user(cookies, ucookies, size)) {
> -			err = -EFAULT;
> -			goto error_cookies;
> -		}
> 	}
> 
> 	link = kzalloc(sizeof(*link), GFP_KERNEL);
> -- 
> 2.35.1
> 



      reply	other threads:[~2022-05-12 16:45 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-12 14:17 [PATCH 0/3] bpf: optimize the bpf_kprobe_multi_link_attach function Wan Jiabing
2022-05-12 14:17 ` [PATCH 1/3] bpf: use 'error_xxx' tags in bpf_kprobe_multi_link_attach Wan Jiabing
2022-05-12 16:40   ` Song Liu
2022-05-12 17:05   ` David Vernet
2022-05-12 14:17 ` [PATCH 2/3] bpf: simplify if-if to if " Wan Jiabing
2022-05-12 16:44   ` Song Liu
2022-05-12 14:17 ` [PATCH 3/3] bpf: use vmemdup_user instead of kvmalloc and copy_from_user Wan Jiabing
2022-05-12 16:45   ` Song Liu [this message]

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