From: Jiri Olsa <olsajiri@gmail.com>
To: Eugene Syromiatnikov <esyr@redhat.com>
Cc: 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>,
netdev@vger.kernel.org, bpf@vger.kernel.org,
linux-kernel@vger.kernel.org, Shuah Khan <shuah@kernel.org>,
linux-kselftest@vger.kernel.org
Subject: Re: [PATCH bpf-next v3 2/4] bpf_trace: support 32-bit kernels in bpf_kprobe_multi_link_attach
Date: Tue, 17 May 2022 11:12:47 +0200 [thread overview]
Message-ID: <YoNnD1K/v6sF5YiV@krava> (raw)
In-Reply-To: <525b99881dc144b986e381eb23b12617a311f243.1652772731.git.esyr@redhat.com>
On Tue, May 17, 2022 at 09:36:26AM +0200, Eugene Syromiatnikov wrote:
> It seems that there is no reason not to support 32-bit architectures;
> doing so requires a bit of rework with respect to cookies handling,
> however, as the current code implicitly assumes
> that sizeof(long) == sizeof(u64).
>
> Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
> ---
> kernel/trace/bpf_trace.c | 17 ++++++++---------
> 1 file changed, 8 insertions(+), 9 deletions(-)
>
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index 9c041be..a93a54f 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -2435,16 +2435,12 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
> struct bpf_link_primer link_primer;
> void __user *ucookies;
> unsigned long *addrs;
> - u32 flags, cnt, size;
> + u32 flags, cnt, size, cookies_size;
> void __user *uaddrs;
> u64 *cookies = NULL;
> void __user *usyms;
> int err;
>
> - /* no support for 32bit archs yet */
> - if (sizeof(u64) != sizeof(void *))
> - return -EOPNOTSUPP;
> -
> if (prog->expected_attach_type != BPF_TRACE_KPROBE_MULTI)
> return -EINVAL;
>
> @@ -2454,6 +2450,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
>
> uaddrs = u64_to_user_ptr(attr->link_create.kprobe_multi.addrs);
> usyms = u64_to_user_ptr(attr->link_create.kprobe_multi.syms);
> + ucookies = u64_to_user_ptr(attr->link_create.kprobe_multi.cookies);
> if (!!uaddrs == !!usyms)
> return -EINVAL;
>
> @@ -2461,8 +2458,11 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
> if (!cnt)
> return -EINVAL;
>
> - if (check_mul_overflow(cnt, (u32)sizeof(*addrs), &size))
> + if (check_mul_overflow(cnt, (u32)sizeof(*addrs), &size) ||
> + (ucookies &&
> + check_mul_overflow(cnt, (u32)sizeof(*cookies), &cookies_size))) {
> return -EOVERFLOW;
> + }
> addrs = kvmalloc(size, GFP_KERNEL);
> if (!addrs)
> return -ENOMEM;
> @@ -2486,14 +2486,13 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
> goto error;
> }
>
> - ucookies = u64_to_user_ptr(attr->link_create.kprobe_multi.cookies);
> if (ucookies) {
could we check all that in here? so the ucookies checks are on the
one place.. also you would not need cookies_size
jirka
> - cookies = kvmalloc(size, GFP_KERNEL);
> + cookies = kvmalloc(cookies_size, GFP_KERNEL);
> if (!cookies) {
> err = -ENOMEM;
> goto error;
> }
> - if (copy_from_user(cookies, ucookies, size)) {
> + if (copy_from_user(cookies, ucookies, cookies_size)) {
> err = -EFAULT;
> goto error;
> }
> --
> 2.1.4
>
next prev parent reply other threads:[~2022-05-17 9:13 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
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 [this message]
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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