From nobody Wed Feb 11 17:55:46 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B1BD1C77B7D for ; Sat, 6 May 2023 01:32:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232290AbjEFBcA (ORCPT ); Fri, 5 May 2023 21:32:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54486 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232095AbjEFBbx (ORCPT ); Fri, 5 May 2023 21:31:53 -0400 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1E78449D4 for ; Fri, 5 May 2023 18:31:50 -0700 (PDT) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-559d1e8dc42so38036687b3.3 for ; Fri, 05 May 2023 18:31:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1683336709; x=1685928709; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=QbTxYJIrfalCYzXyCjhhSUmz67kNheh66aN+akhEHWk=; b=WWOk88G3muNiSEyLCZtTBwJIQa2OocJuIlljADwsm82KPk2youo8Bi6hAN/nXReTz0 7r1uI7jxcjSqbZ92pFC1GjUhvhjNVjuK8o7y0Z//QAswGFhvfniUWRhLj4P18q9LvU8V XyQOfhD7n7W/99oHPcNTQokqvOCzPLrYlR7puhjDO/d1m6Mk6UKEtSpSmNeHA/O3TCd2 oKUZs5gi7Nzjto/r3S5LSTSvgNBNHBCd2hRT0VWn12Qcjs8M0lHnqbGFxux3WL3ApZCM 1KStVH5+p8h02nzto4SrF74lR+4I0PyarTp6k5Ri8qKg9/8/1guA+bDNz4G0PytGNsQK SlLg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683336709; x=1685928709; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=QbTxYJIrfalCYzXyCjhhSUmz67kNheh66aN+akhEHWk=; b=jQFuLiQrVDxk7F1jgKVnvfrk1LvfNKycST8DgRBSw89VzoriOTpyW9vP5gwlVE82qw BrBCur6j8RBwoqFEMU8vyBXiuksTy5kEp7QhTxVKHBqT+eCgB77eu2ZIlfgKp5hkxLGz HyhbAIMh+uzt8dj0m608UOW5vE7ZhSVt8xrRqt5fohqMvLTEnpmnGUVQtshpdjVcjGmb 9hXdr9MRy3pxp8VLYCUDfnm6jS01XQgbzi5gEKNB2CChBUv+NRadSxIdFQNHSRJETvYj EPMuj0q277o5mHQ6bXEAdIvvCBxRqCYQ1Z4LId8oSCexS4FEFQm1hsMnDTO0POG/gl3g sk6w== X-Gm-Message-State: AC+VfDw78EI3AapmHP+e8gAv/jUE7I9DuX1CNrdkahGYu2bxmnzh/iMH fieqbaf+dpxZQisA5gzNs5AA2y47kTw= X-Google-Smtp-Source: ACHHUZ6+bMT2qUE8qYexYzBwG/ZiwbW6htxo82gL8HL5nwFwc0TUdqnY1SZ54LMlE1W2qQdKF+FLUEIx5KU= X-Received: from drosen.mtv.corp.google.com ([2620:15c:211:201:6826:a1a:a426:bb4a]) (user=drosen job=sendgmr) by 2002:a81:4045:0:b0:55a:613d:429f with SMTP id m5-20020a814045000000b0055a613d429fmr1922195ywn.2.1683336709283; Fri, 05 May 2023 18:31:49 -0700 (PDT) Date: Fri, 5 May 2023 18:31:32 -0700 In-Reply-To: <20230506013134.2492210-1-drosen@google.com> Mime-Version: 1.0 References: <20230506013134.2492210-1-drosen@google.com> X-Mailer: git-send-email 2.40.1.521.gf1e218fcd8-goog Message-ID: <20230506013134.2492210-4-drosen@google.com> Subject: [PATCH bpf-next v3 3/5] selftests/bpf: Check overflow in optional buffer From: Daniel Rosenberg To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Shuah Khan , Jonathan Corbet , Joanne Koong , Mykola Lysenko , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, kernel-team@android.com, Daniel Rosenberg Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" This ensures we still reject invalid memory accesses in buffers that are marked optional. Signed-off-by: Daniel Rosenberg --- .../testing/selftests/bpf/progs/dynptr_fail.c | 20 +++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/dynptr_fail.c b/tools/testin= g/selftests/bpf/progs/dynptr_fail.c index efe4ce72d00e..c2f0e18af951 100644 --- a/tools/testing/selftests/bpf/progs/dynptr_fail.c +++ b/tools/testing/selftests/bpf/progs/dynptr_fail.c @@ -1665,3 +1665,23 @@ int clone_xdp_packet_data(struct xdp_md *xdp) =20 return 0; } + +/* Buffers that are provided must be sufficiently long */ +SEC("?cgroup_skb/egress") +__failure __msg("memory, len pair leads to invalid memory access") +int test_dynptr_skb_small_buff(struct __sk_buff *skb) +{ + struct bpf_dynptr ptr; + char buffer[8] =3D {}; + __u64 *data; + + if (bpf_dynptr_from_skb(skb, 0, &ptr)) { + err =3D 1; + return 1; + } + + /* This may return NULL. SKB may require a buffer */ + data =3D bpf_dynptr_slice(&ptr, 0, buffer, 9); + + return !!data; +} --=20 2.40.1.521.gf1e218fcd8-goog