From nobody Thu Apr 9 04:44:12 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 1520CC433FE for ; Fri, 4 Nov 2022 01:28:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230423AbiKDB2R (ORCPT ); Thu, 3 Nov 2022 21:28:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35156 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229863AbiKDB2G (ORCPT ); Thu, 3 Nov 2022 21:28:06 -0400 Received: from out203-205-221-235.mail.qq.com (out203-205-221-235.mail.qq.com [203.205.221.235]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BDBAC23396; Thu, 3 Nov 2022 18:28:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=foxmail.com; s=s201512; t=1667525281; bh=97NTQrGjhU6NxW3LqmcxEye1WtDELGVVc3QpdO5C//o=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=v1FxifU306S8S8Al31LWzWHZMKyyXCwi13rfsB6dl1JLnNX+Pl5SAKzohHX6TET2U lZET6/vS4AzNjJsTclyfA/lc1xWiDof2V8m2ABEMhUIH97xTz67/bJ15bZk4Ijxu/f BUXKuf1iz5L8N6OAhNUImyWL4kR5ML0cIyHi7fRY= Received: from localhost.localdomain ([39.156.73.13]) by newxmesmtplogicsvrszc2-1.qq.com (NewEsmtp) with SMTP id 6F83B809; Fri, 04 Nov 2022 09:27:56 +0800 X-QQ-mid: xmsmtpt1667525276t86v0w579 Message-ID: X-QQ-XMAILINFO: NQR8mRxMnur9CuKnjIQclbzLKdKQoECHB/HARwfNKMRd1slsqwmunFhqL46bBi Kjk1ejNtv+INL6fZOO7emYHBshwONKKXj9zr/u4gUQJtiYrlG6cRFcCH6kZtpzp8oR897CbzxNAf si3v7PwUyKPZR3TTTA/9Cav/0W9DwlzZVX9tgYDSctJy7xRsaEIed0lrMYiQKaqt8bdykduYvre9 D+jeweGGKv1CT7qMQPh6/IeL7lZB+MMD9oJFE9P/PvIqbHS0MuqFiF4oPegTHWgOb0aST+e5lrKd 6V1rZbcGIKSxaNO4Bvp8rCq5ETlhIsBTwzc2Xqtwh6bOvH4YLEvwCIXNXn/dU/UGH1nddplnLS5K 5DexdWjet36EwMRA8XfE5HAXoGO2dY6xTkgZEv8X5aQitUOb9zBbYTjpjJmlqUhoBqwLOcEzUUco whUaRxrAftgscP3PV8zxejCkQ+M2ZMtF+UocUma3++/9arhU6iLhetF4QWLPbBZ3on3bXHvzfG7X WSO3Qy1mdoUy1mSrQhPkbv+zfcPr1D7H4WLpJFlq22UzMnPnBVI1H2gYPsKRsG3Ux3z3cnSv9dwk NQh1ZOLJSd8E1zSD3ziPCpXcnhbgb6jcKwAyv8RhKsxHNCL7aWYNEO11cR549imsaJLpkyhwqtv4 ITFQfsapBz4jjJsvXO2jU72HK2lpNeScqx9OMglSNBwmYB7biCKiJZd3A2lAk4nhv8yGshxngOy7 d4zHMZ0MH6fUQwjcRUsKQBlBAIHfZ25uZQ5fWTSVeoxJtLcBU1vbUNJX+j7Hx+RJmQCVj/5ykP2R 27hrAp0c8yqGnMCK2rLIeXrPewDtD4QHEZPUwaJNpi2b/J5SQ6u4ZYPj4lDY1rx4FENxefbeFnsz Jq3mzaHN3dJWbNhfHOatXT9wt56GbWvuDn4UoDMFivHfY6ie0/wzGZrjgFlZ2KRtoHa34Z0+3ZTm zt/8QDIVimZti6JQWKyC7qd5ljCat+1UZgoniPVRyafEu01Vrnpw== From: Rong Tao To: andrii.nakryiko@gmail.com Cc: andrii@kernel.org, ast@kernel.org, bpf@vger.kernel.org, daniel@iogearbox.net, david.laight@aculab.com, haoluo@google.com, john.fastabend@gmail.com, jolsa@kernel.org, kpsingh@kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, martin.lau@linux.dev, mykolal@fb.com, rongtao@cestc.cn, rtoax@foxmail.com, sdf@google.com, shuah@kernel.org, song@kernel.org, yhs@fb.com Subject: [PATCH bpf-next] selftests/bpf: cgroup_helpers.c: Fix strncpy() fortify warning Date: Fri, 4 Nov 2022 09:27:54 +0800 X-OQ-MSGID: <20221104012754.651653-1-rtoax@foxmail.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Rong Tao Copy libbpf_strlcpy() from libbpf_internal.h to bpf_util.h, and rename it to bpf_strlcpy(), then replace selftests strncpy()/libbpf_strlcpy() with bpf_strlcpy(), fix compile warning. The libbpf_internal.h header cannot be used directly here, because references to cgroup_helpers.c in samples/bpf will generate compilation errors. We also can't add libbpf_strlcpy() directly to bpf_util.h, because the definition of libbpf_strlcpy() in libbpf_internal.h is duplicated. In order not to modify the libbpf code, add a new function bpf_strlcpy() to selftests bpf_util.h. How to reproduce this compilation warning: $ make -C samples/bpf cgroup_helpers.c: In function =E2=80=98__enable_controllers=E2=80=99: cgroup_helpers.c:80:17: warning: =E2=80=98strncpy=E2=80=99 specified bound = 4097 equals destination size [-Wstringop-truncation] 80 | strncpy(enable, controllers, sizeof(enable)); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Signed-off-by: Rong Tao --- tools/testing/selftests/bpf/bpf_util.h | 19 ++++++++++++++ tools/testing/selftests/bpf/cgroup_helpers.c | 3 ++- tools/testing/selftests/bpf/xsk.c | 26 +++----------------- 3 files changed, 25 insertions(+), 23 deletions(-) diff --git a/tools/testing/selftests/bpf/bpf_util.h b/tools/testing/selftes= ts/bpf/bpf_util.h index a3352a64c067..10587a29b967 100644 --- a/tools/testing/selftests/bpf/bpf_util.h +++ b/tools/testing/selftests/bpf/bpf_util.h @@ -20,6 +20,25 @@ static inline unsigned int bpf_num_possible_cpus(void) return possible_cpus; } =20 +/* Copy up to sz - 1 bytes from zero-terminated src string and ensure that= dst + * is zero-terminated string no matter what (unless sz =3D=3D 0, in which = case + * it's a no-op). It's conceptually close to FreeBSD's strlcpy(), but diff= ers + * in what is returned. Given this is internal helper, it's trivial to ext= end + * this, when necessary. Use this instead of strncpy inside libbpf source = code. + */ +static inline void bpf_strlcpy(char *dst, const char *src, size_t sz) +{ + size_t i; + + if (sz =3D=3D 0) + return; + + sz--; + for (i =3D 0; i < sz && src[i]; i++) + dst[i] =3D src[i]; + dst[i] =3D '\0'; +} + #define __bpf_percpu_val_align __attribute__((__aligned__(8))) =20 #define BPF_DECLARE_PERCPU(type, name) \ diff --git a/tools/testing/selftests/bpf/cgroup_helpers.c b/tools/testing/s= elftests/bpf/cgroup_helpers.c index e914cc45b766..dd1aa5afcf5a 100644 --- a/tools/testing/selftests/bpf/cgroup_helpers.c +++ b/tools/testing/selftests/bpf/cgroup_helpers.c @@ -13,6 +13,7 @@ #include =20 #include "cgroup_helpers.h" +#include "bpf_util.h" =20 /* * To avoid relying on the system setup, when setup_cgroup_env is called @@ -77,7 +78,7 @@ static int __enable_controllers(const char *cgroup_path, = const char *controllers enable[len] =3D 0; close(fd); } else { - strncpy(enable, controllers, sizeof(enable)); + bpf_strlcpy(enable, controllers, sizeof(enable)); } =20 snprintf(path, sizeof(path), "%s/cgroup.subtree_control", cgroup_path); diff --git a/tools/testing/selftests/bpf/xsk.c b/tools/testing/selftests/bp= f/xsk.c index 0b3ff49c740d..39d349509ba4 100644 --- a/tools/testing/selftests/bpf/xsk.c +++ b/tools/testing/selftests/bpf/xsk.c @@ -33,6 +33,7 @@ #include #include #include "xsk.h" +#include "bpf_util.h" =20 #ifndef SOL_XDP #define SOL_XDP 283 @@ -521,25 +522,6 @@ static int xsk_create_bpf_link(struct xsk_socket *xsk) return 0; } =20 -/* Copy up to sz - 1 bytes from zero-terminated src string and ensure that= dst - * is zero-terminated string no matter what (unless sz =3D=3D 0, in which = case - * it's a no-op). It's conceptually close to FreeBSD's strlcpy(), but diff= ers - * in what is returned. Given this is internal helper, it's trivial to ext= end - * this, when necessary. Use this instead of strncpy inside libbpf source = code. - */ -static inline void libbpf_strlcpy(char *dst, const char *src, size_t sz) -{ - size_t i; - - if (sz =3D=3D 0) - return; - - sz--; - for (i =3D 0; i < sz && src[i]; i++) - dst[i] =3D src[i]; - dst[i] =3D '\0'; -} - static int xsk_get_max_queues(struct xsk_socket *xsk) { struct ethtool_channels channels =3D { .cmd =3D ETHTOOL_GCHANNELS }; @@ -552,7 +534,7 @@ static int xsk_get_max_queues(struct xsk_socket *xsk) return -errno; =20 ifr.ifr_data =3D (void *)&channels; - libbpf_strlcpy(ifr.ifr_name, ctx->ifname, IFNAMSIZ); + bpf_strlcpy(ifr.ifr_name, ctx->ifname, IFNAMSIZ); err =3D ioctl(fd, SIOCETHTOOL, &ifr); if (err && errno !=3D EOPNOTSUPP) { ret =3D -errno; @@ -771,7 +753,7 @@ static int xsk_create_xsk_struct(int ifindex, struct xs= k_socket *xsk) } =20 ctx->ifindex =3D ifindex; - libbpf_strlcpy(ctx->ifname, ifname, IFNAMSIZ); + bpf_strlcpy(ctx->ifname, ifname, IFNAMSIZ); =20 xsk->ctx =3D ctx; xsk->ctx->has_bpf_link =3D xsk_probe_bpf_link(); @@ -958,7 +940,7 @@ static struct xsk_ctx *xsk_create_ctx(struct xsk_socket= *xsk, ctx->refcount =3D 1; ctx->umem =3D umem; ctx->queue_id =3D queue_id; - libbpf_strlcpy(ctx->ifname, ifname, IFNAMSIZ); + bpf_strlcpy(ctx->ifname, ifname, IFNAMSIZ); =20 ctx->fill =3D fill; ctx->comp =3D comp; --=20 2.31.1