From: Siddhesh Poyarekar <siddhesh@sourceware.org>
To: libc-alpha@sourceware.org
Cc: adhemerval.zanella@linaro.org, fweimer@redhat.com
Subject: [PATCH 1/3] support: Add helpers to create paths longer than PATH_MAX
Date: Tue, 18 Jan 2022 14:37:26 +0530 [thread overview]
Message-ID: <20220118090728.1825487-2-siddhesh@sourceware.org> (raw)
In-Reply-To: <20220118090728.1825487-1-siddhesh@sourceware.org>
Add new helpers support_create_and_chdir_toolong_temp_directory and
support_chdir_toolong_temp_directory to create and descend into
directory trees longer than PATH_MAX.
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
---
support/temp_file.c | 157 +++++++++++++++++++++++++++++++++++++++++---
support/temp_file.h | 11 ++++
2 files changed, 160 insertions(+), 8 deletions(-)
diff --git a/support/temp_file.c b/support/temp_file.c
index e7bb8aadb9..c3e83912ac 100644
--- a/support/temp_file.c
+++ b/support/temp_file.c
@@ -36,14 +36,31 @@ static struct temp_name_list
struct temp_name_list *next;
char *name;
pid_t owner;
+ bool toolong;
} *temp_name_list;
/* Location of the temporary files. Set by the test skeleton via
support_set_test_dir. The string is not be freed. */
static const char *test_dir = _PATH_TMP;
-void
-add_temp_file (const char *name)
+/* Name of subdirectories in a too long temporary directory tree. */
+static char toolong_subdir[NAME_MAX + 1];
+
+/* Return the maximum size of path on the target. */
+static inline size_t
+get_path_max (void)
+{
+#ifdef PATH_MAX
+ return PATH_MAX;
+#else
+ size_t path_max = pathconf ("/", _PC_PATH_MAX);
+ return (path_max < 0 ? 1024
+ : path_max <= PTRDIFF_MAX ? path_max : PTRDIFF_MAX);
+#endif
+}
+
+static void
+add_temp_file_internal (const char *name, bool toolong)
{
struct temp_name_list *newp
= (struct temp_name_list *) xcalloc (sizeof (*newp), 1);
@@ -53,12 +70,19 @@ add_temp_file (const char *name)
newp->name = newname;
newp->next = temp_name_list;
newp->owner = getpid ();
+ newp->toolong = toolong;
temp_name_list = newp;
}
else
free (newp);
}
+void
+add_temp_file (const char *name)
+{
+ add_temp_file_internal (name, false);
+}
+
int
create_temp_file_in_dir (const char *base, const char *dir, char **filename)
{
@@ -90,8 +114,8 @@ create_temp_file (const char *base, char **filename)
return create_temp_file_in_dir (base, test_dir, filename);
}
-char *
-support_create_temp_directory (const char *base)
+static char *
+create_temp_directory_internal (const char *base, bool toolong)
{
char *path = xasprintf ("%s/%sXXXXXX", test_dir, base);
if (mkdtemp (path) == NULL)
@@ -99,16 +123,124 @@ support_create_temp_directory (const char *base)
printf ("error: mkdtemp (\"%s\"): %m", path);
exit (1);
}
- add_temp_file (path);
+ add_temp_file_internal (path, toolong);
return path;
}
-/* Helper functions called by the test skeleton follow. */
+char *
+support_create_temp_directory (const char *base)
+{
+ return create_temp_directory_internal (base, false);
+}
+
+static void
+ensure_toolong_subdir_initialized (void)
+{
+ for (size_t i = 0; i < NAME_MAX; i++)
+ if (toolong_subdir[i] != 'X')
+ {
+ printf ("uninitialized toolong directory tree\n");
+ exit (1);
+ }
+}
+
+char *
+support_create_and_chdir_toolong_temp_directory (const char *basename)
+{
+ size_t path_max = get_path_max ();
+
+ char *base = create_temp_directory_internal (basename, true);
+
+ if (chdir (base) != 0)
+ {
+ printf ("error creating toolong base: chdir (\"%s\"): %m", base);
+ exit (1);
+ }
+
+ memset (toolong_subdir, 'X', sizeof (toolong_subdir) - 1);
+ toolong_subdir[NAME_MAX] = '\0';
+
+ /* Create directories and descend into them so that the final path is larger
+ than PATH_MAX. */
+ for (size_t i = 0; i <= path_max / sizeof (toolong_subdir); i++)
+ {
+ if (mkdir (toolong_subdir, S_IRWXU) != 0)
+ {
+ printf ("error creating toolong subdir: mkdir (\"%s\"): %m",
+ toolong_subdir);
+ exit (1);
+ }
+ if (chdir (toolong_subdir) != 0)
+ {
+ printf ("error creating toolong subdir: chdir (\"%s\"): %m",
+ toolong_subdir);
+ exit (1);
+ }
+ }
+ return base;
+}
void
-support_set_test_dir (const char *path)
+support_chdir_toolong_temp_directory (const char *base)
{
- test_dir = path;
+ size_t path_max = get_path_max ();
+ ensure_toolong_subdir_initialized ();
+
+ if (chdir (base) != 0)
+ {
+ printf ("error: chdir (\"%s\"): %m", base);
+ exit (1);
+ }
+
+ for (size_t i = 0; i <= path_max / sizeof (toolong_subdir); i++)
+ if (chdir (toolong_subdir) != 0)
+ {
+ printf ("error subdir: chdir (\"%s\"): %m", toolong_subdir);
+ exit (1);
+ }
+}
+
+/* Helper functions called by the test skeleton follow. */
+
+static void
+remove_toolong_subdirs (const char *base)
+{
+ size_t path_max = get_path_max ();
+
+ ensure_toolong_subdir_initialized ();
+
+ if (chdir (base) != 0)
+ {
+ printf ("warning: toolong cleanup base failed: chdir (\"%s\"): %m\n",
+ base);
+ return;
+ }
+
+ /* Descend. */
+ int levels = 0;
+ for (levels = 0; levels <= path_max / sizeof (toolong_subdir); levels++)
+ if (chdir (toolong_subdir) != 0)
+ {
+ printf ("warning: toolong cleanup failed: chdir (\"%s\"): %m\n",
+ toolong_subdir);
+ return;
+ }
+
+ /* Ascend and remove. */
+ while (--levels >= 0)
+ {
+ if (chdir ("..") != 0)
+ {
+ printf ("warning: toolong cleanup failed: chdir (\"..\"): %m\n");
+ return;
+ }
+ if (remove (toolong_subdir) != 0)
+ {
+ printf ("warning: could not remove subdirectory: %s: %m\n",
+ toolong_subdir);
+ return;
+ }
+ }
}
void
@@ -123,6 +255,9 @@ support_delete_temp_files (void)
around, to prevent PID reuse.) */
if (temp_name_list->owner == pid)
{
+ if (temp_name_list->toolong)
+ remove_toolong_subdirs (temp_name_list->name);
+
if (remove (temp_name_list->name) != 0)
printf ("warning: could not remove temporary file: %s: %m\n",
temp_name_list->name);
@@ -147,3 +282,9 @@ support_print_temp_files (FILE *f)
fprintf (f, ")\n");
}
}
+
+void
+support_set_test_dir (const char *path)
+{
+ test_dir = path;
+}
diff --git a/support/temp_file.h b/support/temp_file.h
index 50a443abe4..de01fbbceb 100644
--- a/support/temp_file.h
+++ b/support/temp_file.h
@@ -19,6 +19,8 @@
#ifndef SUPPORT_TEMP_FILE_H
#define SUPPORT_TEMP_FILE_H
+#include <limits.h>
+#include <unistd.h>
#include <sys/cdefs.h>
__BEGIN_DECLS
@@ -44,6 +46,15 @@ int create_temp_file_in_dir (const char *base, const char *dir,
returns. The caller should free this string. */
char *support_create_temp_directory (const char *base);
+/* Create a temporary directory tree that is longer than PATH_MAX and schedule
+ it for deletion. BASENAME is used as a prefix for the unique directory
+ name, which the function returns. The caller should free this string. */
+char *support_create_and_chdir_toolong_temp_directory (const char *basename);
+
+/* Change into the innermost directory of the directory tree BASE, which was
+ created using support_create_and_chdir_toolong_temp_directory. */
+void support_chdir_toolong_temp_directory (const char *base);
+
__END_DECLS
#endif /* SUPPORT_TEMP_FILE_H */
--
2.34.1
next prev parent reply other threads:[~2022-01-18 9:07 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-18 9:07 [PATCH 0/3] Fixes for CVE-2021-3998 and CVE-2021-3999 Siddhesh Poyarekar
2022-01-18 9:07 ` Siddhesh Poyarekar [this message]
2022-01-18 19:42 ` [PATCH 1/3] support: Add helpers to create paths longer than PATH_MAX Adhemerval Zanella
2022-01-19 1:33 ` Siddhesh Poyarekar
2022-01-18 9:07 ` [PATCH 2/3] realpath: Set errno to ENAMETOOLONG for result larger than PATH_MAX [BZ #28770] Siddhesh Poyarekar
2022-01-18 19:43 ` Adhemerval Zanella
2022-01-18 9:07 ` [PATCH 3/3] getcwd: Set errno to ERANGE for size == 1 (CVE-2021-3999) Siddhesh Poyarekar
2022-01-18 11:52 ` Andreas Schwab
2022-01-18 13:10 ` Siddhesh Poyarekar
2022-01-18 13:13 ` Andreas Schwab
2022-01-18 13:16 ` Siddhesh Poyarekar
2022-01-18 13:30 ` Andreas Schwab
2022-01-18 13:33 ` Siddhesh Poyarekar
2022-01-18 13:41 ` Andreas Schwab
2022-01-18 13:45 ` Siddhesh Poyarekar
2022-01-18 13:56 ` Siddhesh Poyarekar
2022-01-18 13:57 ` Andreas Schwab
2022-01-18 14:40 ` Siddhesh Poyarekar
2022-01-18 13:59 ` Adhemerval Zanella
2022-01-18 14:44 ` Siddhesh Poyarekar
2022-01-18 16:30 ` Adhemerval Zanella
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