From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Eugene Syromiatnikov <esyr@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@kernel.org>,
Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>,
Shuah Khan <shuah@kernel.org>,
"open list:KERNEL SELFTEST FRAMEWORK"
<linux-kselftest@vger.kernel.org>
Subject: Re: [PATCH bpf-next v3 1/4] bpf_trace: check size for overflow in bpf_kprobe_multi_link_attach
Date: Wed, 18 May 2022 16:30:14 -0700 [thread overview]
Message-ID: <CAEf4BzYpNZSY+D6_QP4NE2dN25g4wD43UmJyzmqXCL=HOE9HFA@mail.gmail.com> (raw)
In-Reply-To: <9e4171972a3d75e656073e0c25cd4071a6f652e4.1652772731.git.esyr@redhat.com>
On Tue, May 17, 2022 at 12:36 AM Eugene Syromiatnikov <esyr@redhat.com> wrote:
>
> Check that size would not overflow before calculation (and return
> -EOVERFLOW if it will), to prevent potential out-of-bounds write
> with the following copy_from_user. Use kvmalloc_array
> in copy_user_syms to prevent out-of-bounds write into syms
> (and especially buf) as well.
>
> Fixes: 0dcac272540613d4 ("bpf: Add multi kprobe link")
> Cc: <stable@vger.kernel.org> # 5.18
> Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
> ---
> kernel/trace/bpf_trace.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index 7141ca8..9c041be 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -2261,11 +2261,11 @@ static int copy_user_syms(struct user_syms *us, unsigned long __user *usyms, u32
> int err = -ENOMEM;
> unsigned int i;
>
> - syms = kvmalloc(cnt * sizeof(*syms), GFP_KERNEL);
> + syms = kvmalloc_array(cnt, sizeof(*syms), GFP_KERNEL);
> if (!syms)
> goto error;
>
> - buf = kvmalloc(cnt * KSYM_NAME_LEN, GFP_KERNEL);
> + buf = kvmalloc_array(cnt, KSYM_NAME_LEN, GFP_KERNEL);
> if (!buf)
> goto error;
>
> @@ -2461,7 +2461,8 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
> if (!cnt)
> return -EINVAL;
>
> - size = cnt * sizeof(*addrs);
> + if (check_mul_overflow(cnt, (u32)sizeof(*addrs), &size))
> + return -EOVERFLOW;
> addrs = kvmalloc(size, GFP_KERNEL);
any good reason not to use kvmalloc_array() here as well and delegate
overflow to it. And then use long size (as expected by copy_from_user
anyway) everywhere?
> if (!addrs)
> return -ENOMEM;
> --
> 2.1.4
>
next prev parent reply other threads:[~2022-05-18 23:30 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-17 7:36 [PATCH bpf-next v3 0/4] Fix 32-bit arch and compat support for the kprobe_multi attach type Eugene Syromiatnikov
2022-05-17 7:36 ` [PATCH bpf-next v3 1/4] bpf_trace: check size for overflow in bpf_kprobe_multi_link_attach Eugene Syromiatnikov
2022-05-17 9:12 ` Jiri Olsa
2022-05-18 23:30 ` Andrii Nakryiko [this message]
2022-05-19 14:37 ` Eugene Syromiatnikov
2022-05-20 0:48 ` Andrii Nakryiko
2022-05-17 7:36 ` [PATCH bpf-next v3 2/4] bpf_trace: support 32-bit kernels " Eugene Syromiatnikov
2022-05-17 9:12 ` Jiri Olsa
2022-05-18 23:31 ` Andrii Nakryiko
2022-05-17 7:36 ` [PATCH bpf-next v3 3/4] bpf_trace: handle compat in copy_user_syms Eugene Syromiatnikov
2022-05-18 23:39 ` Andrii Nakryiko
2022-05-17 7:36 ` [PATCH bpf-next v3 4/4] bpf_trace: pass array of u64 values in kprobe_multi.addrs Eugene Syromiatnikov
2022-05-17 9:12 ` Jiri Olsa
2022-05-17 12:30 ` Eugene Syromiatnikov
2022-05-17 20:03 ` Jiri Olsa
2022-05-17 21:34 ` Yonghong Song
2022-05-18 11:24 ` Jiri Olsa
2022-05-18 12:30 ` Eugene Syromiatnikov
2022-05-18 23:47 ` Andrii Nakryiko
2022-05-18 23:48 ` Andrii Nakryiko
2022-05-19 17:33 ` Eugene Syromiatnikov
2022-05-20 23:16 ` Andrii Nakryiko
2022-05-18 23:50 ` Andrii Nakryiko
2022-05-19 14:43 ` Eugene Syromiatnikov
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