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Wed, 22 Jul 2026 04:38:26 -0700 (PDT) Date: Wed, 22 Jul 2026 21:08:09 +0930 From: Daniel Wade To: Yiyang Chen Cc: Andrii Nakryiko , Alexei Starovoitov , bpf@vger.kernel.org, Daniel Borkmann , Eduard Zingerman , Emil Tsalapatis , Ihor Solodrai , John Fastabend , Jiri Olsa , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Martin KaFai Lau , Kumar Kartikeya Dwivedi , Shuah Khan , Song Liu , Yonghong Song Subject: Re: [PATCH bpf-next v3 0/3] bpf: Preserve pointer state for commuted arithmetic Message-ID: <20260722210809.382642@kali> In-Reply-To: References: 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-Transfer-Encoding: 8bit Hi Eduard, Yiyang, Thanks for the pointer. I independently tested Yiyang's v3 series on the source-matched f105f3631d51 base with the same kernel config used for my original report. Before the series, my impact witness reached chosen-address kernel read/write and changed UID/GID 65534 with CAP_BPF and CAP_PERFMON to UID/GID 0 in 3/3 runs. With all three v3 patches applied, the intended untrusted-pointer positive control still passed, while the impact program was rejected at "R0 pointer += pointer prohibited" before any address leak or privilege transition in 3/3 runs. I also ran the three focused cases added by the v3 series. All passed: mem_rdonly_untrusted/ldx_is_ok_commuted_addr dynptr/dynptr_slice_commuted_invalidate verifier_basic_stack/stack pointer arithmetic preserves frame number Given that the affected code has shipped and the issue reaches kernel read/write from a CAP_BPF and CAP_PERFMON context, should this be routed through bpf and marked for stable rather than bpf-next? For the v3 series: Tested-by: Daniel Wade Regards, Daniel