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[192.26.29.3]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-485883acd33sm52207742f8f.18.2026.09.10.08.14.25 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 10 Sep 2026 08:14:26 -0700 (PDT) Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Thu, 10 Sep 2026 17:14:23 +0200 Message-Id: Cc: , , Subject: Re: [PATCH bpf 1/4] bpf: Add KF_PERFMON kfunc flag From: "Kumar Kartikeya Dwivedi" To: "Mykyta Yatsenko" , "Daniel Borkmann" , X-Mailer: aerc 0.21.0 References: <20260910142107.40582-1-daniel@iogearbox.net> In-Reply-To: On Thu Sep 10, 2026 at 5:03 PM CEST, Mykyta Yatsenko wrote: > On 9/10/26 3:21 PM, Daniel Borkmann wrote: >> Tracing related BPF helpers e.g. under bpf_base_func_proto() are gated >> behind CAP_PERFMON. However, the same is currently not true for kfuncs >> and they are accessible via plain CAP_BPF. Add a new KF_PERFMON flag >> which can be used such that check_kfunc_call() ensures env->allow_ptr_le= aks >> is permitted. This follows similar pattern to existing KF_DESTRUCTIVE fl= ag. >> > > This problem has been reported and patch sent some time ago: > https://lore.kernel.org/all/20260615-f01-07-dynptr-probe-read-cap-v1-0-e6= 26cd61a381@mails.tsinghua.edu.cn/ > We ended up discussing this and decided to go ahead, since it's a bit weird= to continue to have the discrepancy against helpers that have similar restrict= ions. In practice it won't matter much to actual users, but easier to just fix it= and put the thing to rest. This one is also a more comprehensive fix compared = to Nuoqi's. > [...]