From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl1-x630.google.com (mail-pl1-x630.google.com [IPv6:2607:f8b0:4864:20::630]) by sourceware.org (Postfix) with ESMTPS id 548963858C60 for ; Thu, 7 Oct 2021 12:50:43 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 548963858C60 Received: by mail-pl1-x630.google.com with SMTP id x8so3835177plv.8 for ; Thu, 07 Oct 2021 05:50:43 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=fgIk5AYmQ9etfNaVKz8tMBSIjsnVjGih19aWfhpimdI=; b=eG3Sx66QyglNHQhfQxQnESma/IHKB95diSKpHRHAJZLufNGILQ7mjPlmNPi3yGokM7 xJKs62qeqwcn70CnWGz/5LwI55pdaii7OK4/sKsyCF/A3R06e8Pl5p6JvD5Has7m1U10 seepH89ECGqtvSUuvIBM6fOMjqrhravRTBn7b1OEebaBucQNtBB2CTyqP8N1XA0cwh6D UBF9l4dEp3+U0tG2/rHU/DM24qddvKgr3gCp5kntVa2zcHRvnA7m1XnlJvO3fSSnzcnc +BzIWid8BzRzecQGGHLhJGLcLrzsqSt5456SJSAQREyDpuR5KhtEBBJHGLhZ6jACEuVB iFqA== X-Gm-Message-State: AOAM532K2BGCU2nL7S0pb/xP69mQctfTC9SsFMGk9VYg58bo9zXm57Tp dBNvasK5VTditFPgaDD3G8qxKZeyuGW/IZ2HiYE= X-Google-Smtp-Source: ABdhPJxg1IDXQTZkR/Y4pd+sL4hxsbcYopxLJWalK13k+oAMPZwxLvmOWrRter8mDNqUZSlzt2qkGMbf9f8YnreqbEs= X-Received: by 2002:a17:903:1103:b0:13e:ec6d:524a with SMTP id n3-20020a170903110300b0013eec6d524amr3492083plh.85.1633611042307; Thu, 07 Oct 2021 05:50:42 -0700 (PDT) MIME-Version: 1.0 References: <20211007111816.2702850-1-adhemerval.zanella@linaro.org> In-Reply-To: <20211007111816.2702850-1-adhemerval.zanella@linaro.org> From: "H.J. Lu" Date: Thu, 7 Oct 2021 05:50:06 -0700 Message-ID: Subject: Re: [PATCH v7] io: Fix ftw internal realloc buffer (BZ #28126) To: Adhemerval Zanella Cc: GNU C Library , Siddhesh Poyarekar Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-3030.6 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) 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: Thu, 07 Oct 2021 12:50:45 -0000 On Thu, Oct 7, 2021 at 4:18 AM Adhemerval Zanella wrote: > > The 106ff08526d3ca did not take in consideration the buffer might be > reallocated if the total path is larger than PATH_MAX. The realloc > uses 'dirbuf', where 'dirstreams' is the allocated buffer. > > Checked on x86_64-linux-gnu. > > --- > v7: Move common ftw_data allocate logic to ftw_allocate(). > > --- > io/Makefile | 1 + > io/ftw.c | 39 +++++++++--------- > io/tst-ftw-bz28126.c | 97 ++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 117 insertions(+), 20 deletions(-) > create mode 100644 io/tst-ftw-bz28126.c > > diff --git a/io/Makefile b/io/Makefile > index 9871ecbc74..ecf65aba60 100644 > --- a/io/Makefile > +++ b/io/Makefile > @@ -79,6 +79,7 @@ tests := test-utime test-stat test-stat2 test-lfs tst-getcwd \ > tst-futimens \ > tst-utimensat \ > tst-closefrom \ > + tst-ftw-bz28126 > > tests-time64 := \ > tst-futimens-time64 \ > diff --git a/io/ftw.c b/io/ftw.c > index f0db173727..fe953454f2 100644 > --- a/io/ftw.c > +++ b/io/ftw.c > @@ -203,6 +203,20 @@ struct ftw_data > void *known_objects; > }; > > +static bool > +ftw_allocate (struct ftw_data *data, size_t newsize) > +{ > + void *newp = realloc (data->dirstreams, data->maxdir > + * sizeof (struct dir_data *) > + + newsize); > + if (newp == NULL) > + return false; > + data->dirstreams = newp; > + data->dirbufsize = newsize; > + data->dirbuf = (char *) data->dirstreams > + + data->maxdir * sizeof (struct dir_data *); > + return true; > +} > > /* Internally we use the FTW_* constants used for `nftw'. When invoked > as `ftw', map each flag to the subset of values used by `ftw'. */ > @@ -388,17 +402,9 @@ process_entry (struct ftw_data *data, struct dir_data *dir, const char *name, > return 0; > > new_buflen = data->ftw.base + namlen + 2; > - if (data->dirbufsize < new_buflen) > - { > - /* Enlarge the buffer. */ > - char *newp; > - > - data->dirbufsize = 2 * new_buflen; > - newp = (char *) realloc (data->dirbuf, data->dirbufsize); > - if (newp == NULL) > - return -1; > - data->dirbuf = newp; > - } > + if (data->dirbufsize < new_buflen > + && !ftw_allocate (data, 2 * new_buflen)) > + return -1; > > *((char *) __mempcpy (data->dirbuf + data->ftw.base, name, namlen)) = '\0'; > > @@ -628,7 +634,7 @@ __attribute ((noinline)) > ftw_startup (const char *dir, int is_nftw, void *func, int descriptors, > int flags) > { > - struct ftw_data data; > + struct ftw_data data = { .dirstreams = NULL }; > struct STRUCT_STAT st; > int result = 0; > int save_err; > @@ -646,16 +652,9 @@ ftw_startup (const char *dir, int is_nftw, void *func, int descriptors, > data.maxdir = descriptors < 1 ? 1 : descriptors; > data.actdir = 0; > /* PATH_MAX is always defined when we get here. */ > - data.dirbufsize = MAX (2 * strlen (dir), PATH_MAX); > - data.dirstreams = malloc (data.maxdir * sizeof (struct dir_data *) > - + data.dirbufsize); > - if (data.dirstreams == NULL) > + if (!ftw_allocate (&data, MAX (2 * strlen (dir), PATH_MAX))) > return -1; > - > memset (data.dirstreams, '\0', data.maxdir * sizeof (struct dir_data *)); > - > - data.dirbuf = (char *) data.dirstreams > - + data.maxdir * sizeof (struct dir_data *); > cp = __stpcpy (data.dirbuf, dir); > /* Strip trailing slashes. */ > while (cp > data.dirbuf + 1 && cp[-1] == '/') > diff --git a/io/tst-ftw-bz28126.c b/io/tst-ftw-bz28126.c > new file mode 100644 > index 0000000000..94044ab9d1 > --- /dev/null > +++ b/io/tst-ftw-bz28126.c > @@ -0,0 +1,97 @@ > +/* Check if internal buffer reallocation work for large paths (BZ #28126) > + Copyright (C) 2021 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library is distributed in the hope that it will be useful, > + but WITHOUT ANY WARRANTY; without even the implied warranty of > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + . */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +static int > +my_func (const char *file, const struct stat *sb, int flag) > +{ > + return 0; > +} > + > +static const char folder[NAME_MAX] = { [0 ... 253] = 'a', [254] = '\0' }; > + > +#define NSUBFOLDERS 16 > +static int nsubfolders; > + > +static void > +do_cleanup (void) > +{ > + xchdir (".."); > + for (int i = 0; i < nsubfolders; i++) > + { > + remove (folder); > + xchdir (".."); > + } > + remove (folder); > +} > +#define CLEANUP_HANDLER do_cleanup > + > +static void > +check_mkdir (const char *path) > +{ > + int r = mkdir (path, 0777); > + /* Some filesystem such as overlayfs does not support larger path required > + to trigger the internal buffer reallocation. */ > + if (r != 0) > + { > + if (errno == ENAMETOOLONG) > + FAIL_UNSUPPORTED ("the filesystem does not support the required" > + "large path"); > + else > + FAIL_EXIT1 ("mkdir (\"%s\", 0%o): %m", folder, 0777); > + } > +} > + > +static int > +do_test (void) > +{ > + char *tempdir = support_create_temp_directory ("tst-bz28126"); > + > + /* Create path with various subfolders to force an internal buffer > + reallocation within ntfw. */ > + char *path = xasprintf ("%s/%s", tempdir, folder); > + check_mkdir (path); > + xchdir (path); > + free (path); > + for (int i = 0; i < NSUBFOLDERS - 1; i++) > + { > + check_mkdir (folder); > + xchdir (folder); > + nsubfolders++; > + } > + > + TEST_COMPARE (ftw (tempdir, my_func, 20), 0); > + > + free (tempdir); > + > + do_cleanup (); > + > + return 0; > +} > + > +#include > -- > 2.30.2 > LGTM. Reviewed-by: H.J. Lu Thanks. -- H.J.