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[195.134.167.217]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-49fcab7e333sm19179515e9.7.2026.09.18.02.42.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 18 Sep 2026 02:42:16 -0700 (PDT) Date: Fri, 18 Sep 2026 11:42:13 +0200 From: Mahe Tardy To: Amery Hung Cc: bpf@vger.kernel.org, alexei.starovoitov@gmail.com, andrii@kernel.org, daniel@iogearbox.net, eddyz87@gmail.com, memxor@gmail.com, kernel-team@meta.com Subject: Re: [PATCH bpf-next v2 19/23] bpf: Consolidate function call pkt_access validation Message-ID: References: <20260911220415.1396439-1-ameryhung@gmail.com> <20260911220415.1396439-20-ameryhung@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=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Wed, Sep 16, 2026 at 12:48:01PM -0700, Amery Hung wrote: > Hi, one question I have: Even before my patch, the verifier only > allowed one byte of access based on arg btf (char *data_start here). > What do you do with that single byte of packet data? Hey, we were just using it to compute offsets and sizes within that parsing function. That's why it was not a big change for us to fix this anyway. Thanks for the responses on this btw! > > __attribute__((noinline)) int > parse_something(struct __sk_buff *skb, __u16 off, char *data_start, ...) > > On Tue, Sep 15, 2026 at 3:32 PM Amery Hung wrote: > > > > On Tue, Sep 15, 2026 at 3:44 AM Mahe Tardy wrote: > > > [...]