From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-x52c.google.com (mail-pg1-x52c.google.com [IPv6:2607:f8b0:4864:20::52c]) by sourceware.org (Postfix) with ESMTPS id 8F9823857C73 for ; Tue, 22 Jun 2021 21:24:58 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 8F9823857C73 Received: by mail-pg1-x52c.google.com with SMTP id h4so6618298pgp.5 for ; Tue, 22 Jun 2021 14:24:58 -0700 (PDT) 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=N/sKPAFe9YEdcEVbPv3yuKH/r/m6oDl9eg+glwTTflY=; b=C+kXDPQpwCayMpX16YSoyjNo8qn1OZiWYg7dfPEdWNqkl0lRVPZZ/NAYhToLaYqsWc y62UoaerbJriW2INouIWiLzEWDNgEGtJVSIbvsTe7pd19Pwx7d0Vg1Ai3CJhXHa2X90K gxIRKWqhEx4yWc7QCIcir6hxAUUn2rspuwipH63t9u+91iktJvCLL7JYYVZCVeI6ScBX ODJlkpQ5HR3spAgmhZjVHDKhzC4CVfccy8U2Hrj4pIbENPnfR6D50SeGfzshi9uRCit5 oqz6mkOJqlmCSz7dko4eKzOrQsYwrRGD8m/Ht13UIe2bp12yE8NwKaOU/JyEptEwsAye dl2A== X-Gm-Message-State: AOAM532+4MgFLUgD2XGtBzA6aI1B68r4QC/CU3hd5tBBkPl2X7SiS5CW yqiUzX07alvBOYJusTduR07rzLixjY3w9MJBfRU= X-Google-Smtp-Source: ABdhPJx46lTZyKPs1Ww2nR0GxwdLxDLWn0aiH4irqDROx1DxWqFv0YwDJB6u8Tvm/65Z5uoEl1y+hHyqrqetGtxcahE= X-Received: by 2002:a63:180c:: with SMTP id y12mr626669pgl.180.1624397097682; Tue, 22 Jun 2021 14:24:57 -0700 (PDT) MIME-Version: 1.0 References: <20210609205257.123944-1-goldstein.w.n@gmail.com> <20210622181111.185897-1-goldstein.w.n@gmail.com> In-Reply-To: <20210622181111.185897-1-goldstein.w.n@gmail.com> From: "H.J. Lu" Date: Tue, 22 Jun 2021 14:24:21 -0700 Message-ID: Subject: Re: [PATCH v2 1/3] String: Add overflow tests for strnlen, memchr, and strncat [BZ #27974] To: Noah Goldstein Cc: GNU C Library , "Carlos O'Donell" Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-3031.8 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 22 Jun 2021 21:25:00 -0000 On Tue, Jun 22, 2021 at 11:20 AM Noah Goldstein wrote: > > This commit adds tests for a bug in the wide char variant of the > functions where the implementation may assume that maxlen for wcsnlen > or n for wmemchr/strncat will not overflow when multiplied by > sizeof(wchar_t). > > These tests show the following implementations failing on x86_64: > > wcsnlen-sse4_1 > wcsnlen-avx2 > > wmemchr-sse2 > wmemchr-avx2 > > strncat would fail as well if it where on a system that prefered > either of the wcsnlen implementations that failed as it relies on > wcsnlen. > > Signed-off-by: Noah Goldstein > --- > Some notes: > > I only tested this patch (and the subsequent fixes) on a machine that > prefers EVEX. > > The fix for wcsnlen-sse2 is possibly invalid. What it does is checks > if the computation is maxlen * sizeof(wchar_t) + s overflows, and if > so just calls wcslen. The rational is that either the end of the > string will be found in readable memory or the user invoked UB by > calling wcsnlen on a string that is not contained in valid memory > and without a maxlen to that will bound it in valid memory. > > string/test-memchr.c | 39 ++++++++++++++++++++++++--- > string/test-strncat.c | 61 +++++++++++++++++++++++++++++++++++++++++++ > string/test-strnlen.c | 33 +++++++++++++++++++++++ > 3 files changed, 130 insertions(+), 3 deletions(-) > > diff --git a/string/test-memchr.c b/string/test-memchr.c > index 665edc32af..ce964284aa 100644 > --- a/string/test-memchr.c > +++ b/string/test-memchr.c > @@ -65,8 +65,8 @@ do_one_test (impl_t *impl, const CHAR *s, int c, size_t n, CHAR *exp_res) > CHAR *res = CALL (impl, s, c, n); > if (res != exp_res) > { > - error (0, 0, "Wrong result in function %s %p %p", impl->name, > - res, exp_res); > + error (0, 0, "Wrong result in function %s (%p, %d, %zu) -> %p != %p", > + impl->name, s, c, n, res, exp_res); > ret = 1; > return; > } > @@ -91,7 +91,7 @@ do_test (size_t align, size_t pos, size_t len, size_t n, int seek_char) > } > buf[align + len] = 0; > > - if (pos < len) > + if (pos < MIN(n, len)) > { > buf[align + pos] = seek_char; > buf[align + len] = -seek_char; > @@ -107,6 +107,38 @@ do_test (size_t align, size_t pos, size_t len, size_t n, int seek_char) > do_one_test (impl, (CHAR *) (buf + align), seek_char, n, result); > } > > +static void > +do_overflow_tests (void) > +{ > + size_t i, j, len; > + const size_t one = 1; > + uintptr_t buf_addr = (uintptr_t) buf1; > + > + for (i = 0; i < 750; ++i) > + { > + do_test (0, i, 751, SIZE_MAX - i, BIG_CHAR); > + do_test (0, i, 751, i - buf_addr, BIG_CHAR); > + do_test (0, i, 751, -buf_addr - i, BIG_CHAR); > + do_test (0, i, 751, SIZE_MAX - buf_addr - i, BIG_CHAR); > + do_test (0, i, 751, SIZE_MAX - buf_addr + i, BIG_CHAR); > + > + len = 0; > + for (j = 8 * sizeof(size_t) - 1; j ; --j) > + { > + len |= one << j; > + do_test (0, i, 751, len - i, BIG_CHAR); > + do_test (0, i, 751, len + i, BIG_CHAR); > + do_test (0, i, 751, len - buf_addr - i, BIG_CHAR); > + do_test (0, i, 751, len - buf_addr + i, BIG_CHAR); > + > + do_test (0, i, 751, ~len - i, BIG_CHAR); > + do_test (0, i, 751, ~len + i, BIG_CHAR); > + do_test (0, i, 751, ~len - buf_addr - i, BIG_CHAR); > + do_test (0, i, 751, ~len - buf_addr + i, BIG_CHAR); > + } > + } > +} > + > static void > do_random_tests (void) > { > @@ -221,6 +253,7 @@ test_main (void) > do_test (page_size / 2 - i, i, i, 1, 0x9B); > > do_random_tests (); > + do_overflow_tests (); > return ret; > } > > diff --git a/string/test-strncat.c b/string/test-strncat.c > index 2ef917b820..37ea26ea05 100644 > --- a/string/test-strncat.c > +++ b/string/test-strncat.c > @@ -134,6 +134,66 @@ do_test (size_t align1, size_t align2, size_t len1, size_t len2, > } > } > > +static void > +do_overflow_tests (void) > +{ > + size_t i, j, len; > + const size_t one = 1; > + CHAR *s1, *s2; > + uintptr_t s1_addr; > + s1 = (CHAR *) buf1; > + s2 = (CHAR *) buf2; > + s1_addr = (uintptr_t)s1; > + for (j = 0; j < 200; ++j) > + s2[j] = 32 + 23 * j % (BIG_CHAR - 32); > + s2[200] = 0; > + for (i = 0; i < 750; ++i) { > + for (j = 0; j < i; ++j) > + s1[j] = 32 + 23 * j % (BIG_CHAR - 32); > + s1[i] = '\0'; > + > + FOR_EACH_IMPL (impl, 0) > + { > + s2[200] = '\0'; > + do_one_test (impl, s2, s1, SIZE_MAX - i); > + s2[200] = '\0'; > + do_one_test (impl, s2, s1, i - s1_addr); > + s2[200] = '\0'; > + do_one_test (impl, s2, s1, -s1_addr - i); > + s2[200] = '\0'; > + do_one_test (impl, s2, s1, SIZE_MAX - s1_addr - i); > + s2[200] = '\0'; > + do_one_test (impl, s2, s1, SIZE_MAX - s1_addr + i); > + } > + > + len = 0; > + for (j = 8 * sizeof(size_t) - 1; j ; --j) > + { > + len |= one << j; > + FOR_EACH_IMPL (impl, 0) > + { > + s2[200] = '\0'; > + do_one_test (impl, s2, s1, len - i); > + s2[200] = '\0'; > + do_one_test (impl, s2, s1, len + i); > + s2[200] = '\0'; > + do_one_test (impl, s2, s1, len - s1_addr - i); > + s2[200] = '\0'; > + do_one_test (impl, s2, s1, len - s1_addr + i); > + > + s2[200] = '\0'; > + do_one_test (impl, s2, s1, ~len - i); > + s2[200] = '\0'; > + do_one_test (impl, s2, s1, ~len + i); > + s2[200] = '\0'; > + do_one_test (impl, s2, s1, ~len - s1_addr - i); > + s2[200] = '\0'; > + do_one_test (impl, s2, s1, ~len - s1_addr + i); > + } > + } > + } > +} > + > static void > do_random_tests (void) > { > @@ -316,6 +376,7 @@ test_main (void) > } > > do_random_tests (); > + do_overflow_tests (); > return ret; > } > > diff --git a/string/test-strnlen.c b/string/test-strnlen.c > index 920f58e97b..f53e09263f 100644 > --- a/string/test-strnlen.c > +++ b/string/test-strnlen.c > @@ -89,6 +89,38 @@ do_test (size_t align, size_t len, size_t maxlen, int max_char) > do_one_test (impl, (CHAR *) (buf + align), maxlen, MIN (len, maxlen)); > } > > +static void > +do_overflow_tests (void) > +{ > + size_t i, j, len; > + const size_t one = 1; > + uintptr_t buf_addr = (uintptr_t) buf1; > + > + for (i = 0; i < 750; ++i) > + { > + do_test (0, i, SIZE_MAX - i, BIG_CHAR); > + do_test (0, i, i - buf_addr, BIG_CHAR); > + do_test (0, i, -buf_addr - i, BIG_CHAR); > + do_test (0, i, SIZE_MAX - buf_addr - i, BIG_CHAR); > + do_test (0, i, SIZE_MAX - buf_addr + i, BIG_CHAR); > + > + len = 0; > + for (j = 8 * sizeof(size_t) - 1; j ; --j) > + { > + len |= one << j; > + do_test (0, i, len - i, BIG_CHAR); > + do_test (0, i, len + i, BIG_CHAR); > + do_test (0, i, len - buf_addr - i, BIG_CHAR); > + do_test (0, i, len - buf_addr + i, BIG_CHAR); > + > + do_test (0, i, ~len - i, BIG_CHAR); > + do_test (0, i, ~len + i, BIG_CHAR); > + do_test (0, i, ~len - buf_addr - i, BIG_CHAR); > + do_test (0, i, ~len - buf_addr + i, BIG_CHAR); > + } > + } > +} > + > static void > do_random_tests (void) > { > @@ -283,6 +315,7 @@ test_main (void) > do_random_tests (); > do_page_tests (); > do_page_2_tests (); > + do_overflow_tests (); > return ret; > } > > -- > 2.25.1 > LGTM. Reviewed-by: H.J. Lu Thanks. -- H.J.