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[192.26.29.3]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-69cd2922f9esm3441879a12.17.2026.07.15.11.09.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Jul 2026 11:09:56 -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: Wed, 15 Jul 2026 20:09:56 +0200 Message-Id: Cc: , , , , , Subject: Re: [PATCH bpf-next v1 2/2] bpf: Zero kfunc arg meta before error paths can read it From: "Kumar Kartikeya Dwivedi" To: "Amery Hung" , X-Mailer: aerc 0.21.0 References: <20260715172127.2416388-1-ameryhung@gmail.com> <20260715172127.2416388-3-ameryhung@gmail.com> In-Reply-To: <20260715172127.2416388-3-ameryhung@gmail.com> On Wed Jul 15, 2026 at 7:21 PM CEST, Amery Hung wrote: > check_kfunc_call() reads meta.func_name when bpf_fetch_kfunc_arg_meta() > returns -EACCES, but that error can come from fetch_kfunc_meta() (e.g. > fd_array_get_btf() rejecting BTF binding for a signed program) before > meta is memset(), leaving it uninitialized and risking a garbage deref > in verbose(). > > Move the memset() to the start of bpf_fetch_kfunc_arg_meta() so meta is > zeroed on every error return. The intended "not allowed" -EACCES path > still sets func_name first, so its message is unchanged. > > Signed-off-by: Amery Hung > --- Acked-by: Kumar Kartikeya Dwivedi