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[163.53.146.23]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-3339b314cfcsm35093697eec.19.2026.09.08.03.12.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 08 Sep 2026 03:12:48 -0700 (PDT) Date: Tue, 8 Sep 2026 20:12:33 +1000 From: Matt Bobrowski To: Anastasios Papagiannis Cc: bpf@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, david@kernel.org, akpm@linux-foundation.org, andrii@kernel.org, ast@kernel.org, brauner@kernel.org, daniel@iogearbox.net, eddyz87@gmail.com, kpsingh@kernel.org, ljs@kernel.org, memxor@gmail.com, song@kernel.org, sun.jian.kdev@gmail.com, utilityemal77@gmail.com, viro@zeniv.linux.org.uk Subject: Re: [PATCH bpf-next v5 6/7] bpf: Mark linux_binprm->mm as trusted-or-null Message-ID: References: <20260907165220.52431-1-tasos.papagiannnis@gmail.com> <20260907165220.52431-7-tasos.papagiannnis@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260907165220.52431-7-tasos.papagiannnis@gmail.com> On Mon, Sep 07, 2026 at 07:52:19PM +0300, Anastasios Papagiannis wrote: > Mark linux_binprm->mm as a trusted-or-null nested pointer so BPF programs > can pass it to kfuncs after a NULL check. > > The field is either NULL or points to a live mm_struct whenever BPF can > access a linux_binprm. On successful exec, exec_mmap() installs the new > address space before begin_new_exec() clears bprm->mm. The bprm_mm_init() > error path clears the field before mmdrop(), and free_bprm() clears it > before mmput(), as ensured by an earlier patch in this series. > > Signed-off-by: Anastasios Papagiannis > Reviewed-by: Sun Jian Feel free to add RVB tags: Reviewed-By: Matt Bobrowski > --- > kernel/bpf/verifier.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c > index b5186e664aea..6799d9e080fc 100644 > --- a/kernel/bpf/verifier.c > +++ b/kernel/bpf/verifier.c > @@ -6004,6 +6004,10 @@ BTF_TYPE_SAFE_TRUSTED_OR_NULL(struct dentry) { > struct inode *d_inode; > }; > > +BTF_TYPE_SAFE_TRUSTED_OR_NULL(struct linux_binprm) { > + struct mm_struct *mm; > +}; > + > BTF_TYPE_SAFE_TRUSTED_OR_NULL(struct socket) { > struct sock *sk; > }; > @@ -6058,6 +6062,7 @@ static bool type_is_trusted_or_null(struct bpf_verifier_env *env, > { > BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED_OR_NULL(struct socket)); > BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED_OR_NULL(struct dentry)); > + BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED_OR_NULL(struct linux_binprm)); > BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED_OR_NULL(struct vm_area_struct)); > > return btf_nested_type_is_trusted(&env->log, reg, field_name, btf_id, > -- > 2.55.0 >