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Mon, 31 Aug 2026 02:26:09 -0700 (PDT) From: Anastasios Papagiannis To: andrii.nakryiko@gmail.com Cc: akpm@linux-foundation.org, andrii@kernel.org, ast@kernel.org, bpf@vger.kernel.org, brauner@kernel.org, daniel@iogearbox.net, david@kernel.org, eddyz87@gmail.com, kpsingh@kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, matt@bobrowski.net, memxor@gmail.com, song@kernel.org, tasos.papagiannnis@gmail.com, utilityemal77@gmail.com, viro@zeniv.linux.org.uk Subject: Re: [PATCH bpf-next 2/3] bpf: Add user memory access kfuncs for linux_binprm Date: Mon, 31 Aug 2026 12:25:47 +0300 Message-ID: <20260831092548.42348-1-tasos.papagiannnis@gmail.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit > this is probably ok, but also we might want to look into having > verifier still allow to dereference trusted ptr-or-null into untrusted > ptr_to_btf_id to help with smooth transitions like this. > Not sure how complicated that would be in the verifier, but that would > be a nice backwards compat preserving behavior. I have just submitted an updated version of this series that also allows to dereference trusted ptr-or-null into untrusted ptr_to_btf_id in https://lore.kernel.org/bpf/20260831092305.42062-1-tasos.papagiannnis@gmail.com/T/#t. > But to keep things simple today, I'd just mark that bprm->mm pointer > as TRUSTED_OR_NULL. If you think v3 is too complicated, or that the trusted-or-null dereference support should be split into a separate series, please let me know. In that case, I will simply mark the bprm->mm pointer as TRUSTED_OR_NULL. Thanks, Anastasios