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From 1836bb2ebf62bd9a3588f2ed2d851c8ae810097a Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Wed, 25 Aug 2021 11:17:06 -0300
Subject: [PATCH] io: Fix ftw internal realloc buffer (BZ #28126)
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.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
---
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 9871ecb..ecf65ab 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 f0db173..fe95345 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 0000000..94044ab
--- /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
+ <https://www.gnu.org/licenses/>. */
+
+#include <errno.h>
+#include <ftw.h>
+#include <limits.h>
+#include <string.h>
+#include <stdlib.h>
+#include <support/check.h>
+#include <support/support.h>
+#include <support/temp_file.h>
+#include <support/xunistd.h>
+#include <stdio.h>
+
+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 <support/test-driver.c>
--
1.8.3.1
|
