From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 33D55C4320A for ; Fri, 13 Aug 2021 23:28:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 05D9A610F7 for ; Fri, 13 Aug 2021 23:28:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235709AbhHMX2s (ORCPT ); Fri, 13 Aug 2021 19:28:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47806 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235330AbhHMX2q (ORCPT ); Fri, 13 Aug 2021 19:28:46 -0400 Received: from mail-yb1-xb35.google.com (mail-yb1-xb35.google.com [IPv6:2607:f8b0:4864:20::b35]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 69469C061756; Fri, 13 Aug 2021 16:28:19 -0700 (PDT) Received: by mail-yb1-xb35.google.com with SMTP id w17so21747581ybl.11; Fri, 13 Aug 2021 16:28:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=P+SltoyU/N2j1xguB2Et8FTVeM8VFa3dNugcyncKwts=; b=AqoOfTR9+NMWIvtEsraBvCF6VCLvvgG0mDIwq+0xnPWnumDH4CqaDpW/K83qR5EB4f XgRJfs3G2edvXO32bnplnodVeTjWKd9i0IRwXTZjqk5B3TdR+2lfkReelJ7NL3CJynbw 966WioGcporq1+9n5NoYmw73L9pYC66rRcWPmdVXVnSL/z00sPlfDgKMuPWeEpLLZuIZ GgXw6M9YjDivQ5Ts71qAdjAyV+U/9dLL5W0vBJpqtqMqaCcCS1p3CLfPaADfF60VA/Wv MY88leTm8gM8whKGtd3l7NfKgV5epccTn7DQJCC26rrNcR7PtUlbc54nPgFyvlcZgktX DrdQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=P+SltoyU/N2j1xguB2Et8FTVeM8VFa3dNugcyncKwts=; b=oxfrv8ess7tgxP65cCGqsbDqyU+lzidOLQ0urSyApkhn8LpCrxe5u9mFT5+srHxoEs 7MALMU987ZJyWd3lZR5w8vx15mIi9Sc7pxkUTJnqmkqBICr8HFO5Ac9SZlfoBVQxdnqh 51xMNnVRAcNWeZ56sfmjVnvVu++rnCzqyEpENYu3cnmoihMaiD8yDLK/O7kATS4FEFHo IsX47oswU/z6VwHXlP+/bni0EGDsqJKQ6R2a9hPXjlwPL9v0GJkMuSyYF/Y2eoa/GHuI Aq5LTNgwzs1KetzSTvw5IPvyBZTluRrtnR/Jv7Nw7BlyVmwsZ84GNzOAU6fbxWlwkjZq ZIWA== X-Gm-Message-State: AOAM532YGpZSt7yK3rNNBslcmu/Pco4j9VfOA9pnV390yr42UuD1vbUV c4OgltclDXkEHz1mNpTm3kOiIkU8AqQpdutMP/0= X-Google-Smtp-Source: ABdhPJxLeaBwdc2P5ltaOYpztf7v5DCTlXlVHUbepH5U8Uq0/MjKGoLush4LrMPazomyhCwq9oLBFi48AMG97tgL9Qs= X-Received: by 2002:a25:d691:: with SMTP id n139mr6096531ybg.27.1628897298709; Fri, 13 Aug 2021 16:28:18 -0700 (PDT) MIME-Version: 1.0 References: <20210812164557.79046-1-kuniyu@amazon.co.jp> <20210812164557.79046-5-kuniyu@amazon.co.jp> In-Reply-To: <20210812164557.79046-5-kuniyu@amazon.co.jp> From: Andrii Nakryiko Date: Fri, 13 Aug 2021 16:28:07 -0700 Message-ID: Subject: Re: [PATCH v5 bpf-next 4/4] selftest/bpf: Extend the bpf_snprintf() test for "%c". To: Kuniyuki Iwashima Cc: "David S. Miller" , Jakub Kicinski , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Benjamin Herrenschmidt , Kuniyuki Iwashima , bpf , Networking Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, Aug 12, 2021 at 9:47 AM Kuniyuki Iwashima wrote: > > This patch adds a "positive" pattern for "%c", which intentionally uses a > __u32 value (0x64636261, "dbca") to print a single character "a". If the > implementation went wrong, other 3 bytes might show up as the part of the > latter "%+05s". > > Also, this patch adds two "negative" patterns for wide character. > > Signed-off-by: Kuniyuki Iwashima > --- > tools/testing/selftests/bpf/prog_tests/snprintf.c | 4 +++- > tools/testing/selftests/bpf/progs/test_snprintf.c | 7 ++++--- > 2 files changed, 7 insertions(+), 4 deletions(-) > > diff --git a/tools/testing/selftests/bpf/prog_tests/snprintf.c b/tools/testing/selftests/bpf/prog_tests/snprintf.c > index dffbcaa1ec98..f77d7def7fed 100644 > --- a/tools/testing/selftests/bpf/prog_tests/snprintf.c > +++ b/tools/testing/selftests/bpf/prog_tests/snprintf.c > @@ -19,7 +19,7 @@ > #define EXP_ADDR_OUT "0000000000000000 ffff00000add4e55 " > #define EXP_ADDR_RET sizeof(EXP_ADDR_OUT "unknownhashedptr") > > -#define EXP_STR_OUT "str1 longstr" > +#define EXP_STR_OUT "str1 a longstr" > #define EXP_STR_RET sizeof(EXP_STR_OUT) > > #define EXP_OVER_OUT "%over" > @@ -114,6 +114,8 @@ void test_snprintf_negative(void) > ASSERT_ERR(load_single_snprintf("%"), "invalid specifier 3"); > ASSERT_ERR(load_single_snprintf("%12345678"), "invalid specifier 4"); > ASSERT_ERR(load_single_snprintf("%--------"), "invalid specifier 5"); > + ASSERT_ERR(load_single_snprintf("%lc"), "invalid specifier 6"); > + ASSERT_ERR(load_single_snprintf("%llc"), "invalid specifier 7"); > ASSERT_ERR(load_single_snprintf("\x80"), "non ascii character"); > ASSERT_ERR(load_single_snprintf("\x1"), "non printable character"); > } > diff --git a/tools/testing/selftests/bpf/progs/test_snprintf.c b/tools/testing/selftests/bpf/progs/test_snprintf.c > index e2ad26150f9b..afc2c583125b 100644 > --- a/tools/testing/selftests/bpf/progs/test_snprintf.c > +++ b/tools/testing/selftests/bpf/progs/test_snprintf.c > @@ -40,6 +40,7 @@ int handler(const void *ctx) > /* Convenient values to pretty-print */ > const __u8 ex_ipv4[] = {127, 0, 0, 1}; > const __u8 ex_ipv6[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}; > + const __u32 chr1 = 0x64636261; /* dcba */ > static const char str1[] = "str1"; > static const char longstr[] = "longstr"; > > @@ -59,9 +60,9 @@ int handler(const void *ctx) > /* Kernel pointers */ > addr_ret = BPF_SNPRINTF(addr_out, sizeof(addr_out), "%pK %px %p", > 0, 0xFFFF00000ADD4E55, 0xFFFF00000ADD4E55); > - /* Strings embedding */ > - str_ret = BPF_SNPRINTF(str_out, sizeof(str_out), "%s %+05s", > - str1, longstr); > + /* Strings and single-byte character embedding */ > + str_ret = BPF_SNPRINTF(str_out, sizeof(str_out), "%s % 9c %+05s", > + str1, chr1, longstr); Why this hackery with __u32? You are making an endianness assumption (it will break on big-endian), and you'd never write real code like that. Just pass 'a', what's wrong with that? > /* Overflow */ > over_ret = BPF_SNPRINTF(over_out, sizeof(over_out), "%%overflow"); > /* Padding of fixed width numbers */ > -- > 2.30.2 >