From: Eduard Zingerman <eddyz87@gmail.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>,
Viktor Malik <vmalik@redhat.com>
Cc: bpf@vger.kernel.org, Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>,
Yonghong Song <yonghong.song@linux.dev>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@fomichev.me>, Hao Luo <haoluo@google.com>,
Jiri Olsa <jolsa@kernel.org>
Subject: Re: [PATCH bpf-next 1/2] bpf: Add kfuncs for read-only string operations
Date: Tue, 01 Oct 2024 04:26:49 -0700 [thread overview]
Message-ID: <adaa47618f2b71c2803195749cedd4a5b468cffa.camel@gmail.com> (raw)
In-Reply-To: <CAEf4Bzas4ZxiyJp7h7N5OGmPSMRfZDgPUgEAdTmir3n-4cx-xg@mail.gmail.com>
On Mon, 2024-09-30 at 15:00 -0700, Andrii Nakryiko wrote:
[...]
> Right now, the only way to pass dynamically sized anything is through
> dynptr, AFAIU.
But we do have 'is_kfunc_arg_mem_size()' that checks for __sz suffix,
e.g. used for bpf_copy_from_user_str():
/**
* bpf_copy_from_user_str() - Copy a string from an unsafe user address
* @dst: Destination address, in kernel space. This buffer must be
* at least @dst__sz bytes long.
* @dst__sz: Maximum number of bytes to copy, includes the trailing NUL.
* ...
*/
__bpf_kfunc int bpf_copy_from_user_str(void *dst, u32 dst__sz, const void __user *unsafe_ptr__ign, u64 flags)
However, this suffix won't work for strnstr because of the arguments order.
[...]
next prev parent reply other threads:[~2024-10-01 11:26 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-26 6:18 [PATCH bpf-next 0/2] bpf: Add kfuncs for read-only string operations Viktor Malik
2024-09-26 6:18 ` [PATCH bpf-next 1/2] " Viktor Malik
2024-09-30 22:00 ` Andrii Nakryiko
2024-10-01 11:26 ` Eduard Zingerman [this message]
2024-10-01 14:48 ` Alexei Starovoitov
2024-10-01 17:03 ` Andrii Nakryiko
2024-10-01 17:34 ` Alexei Starovoitov
2024-10-01 17:40 ` Andrii Nakryiko
2024-10-02 6:12 ` Viktor Malik
2024-10-02 16:55 ` Alexei Starovoitov
2024-10-03 4:51 ` Viktor Malik
2024-10-03 17:02 ` Alexei Starovoitov
2024-10-03 19:37 ` Viktor Malik
2024-10-10 2:03 ` Alexei Starovoitov
2025-02-27 16:24 ` Alexei Starovoitov
2025-02-27 16:36 ` Viktor Malik
2025-02-27 17:17 ` Alexei Starovoitov
2024-09-26 6:18 ` [PATCH bpf-next 2/2] selftests/bpf: Add tests for string kfuncs Viktor Malik
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