2016-04-29 Florian Weimer <fweimer@redhat.com>
[BZ #19779]
CVE-2016-1234
Avoid copying names of directory entries.
* posix/glob.c (DIRENT_MUST_BE, DIRENT_MIGHT_BE_SYMLINK)
(DIRENT_MIGHT_BE_DIR, CONVERT_D_INO, CONVERT_D_TYPE)
(CONVERT_DIRENT_DIRENT64, REAL_DIR_ENTRY): Remove macros.
(struct readdir_result): New type.
(D_TYPE_TO_RESULT, D_INO_TO_RESULT, READDIR_RESULT_INITIALIZER)
(GL_READDIR): New macros.
(readdir_result_might_be_symlink, readdir_result_might_be_dir)
(convert_dirent, convert_dirent64): New functions.
(glob_in_dir): Use struct readdir_result. Call convert_dirent or
convert_dirent64. Adjust references to the readdir result.
* sysdeps/unix/sysv/linux/i386/glob64.c:
(convert_dirent, GL_READDIR): Redefine for second file inclusion.
* posix/bug-glob2.c (LONG_NAME): Define.
(filesystem): Add LONG_NAME.
(my_DIR): Increase the size of room_for_dirent.
@@ -40,6 +40,17 @@
# define PRINTF(fmt, args...)
#endif
+#define LONG_NAME \
+ "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" \
+ "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" \
+ "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" \
+ "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" \
+ "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" \
+ "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" \
+ "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" \
+ "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" \
+ "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" \
+ "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
static struct
{
@@ -58,6 +69,7 @@ static struct
{ ".", 3, DT_DIR, 0755 },
{ "..", 3, DT_DIR, 0755 },
{ "a", 3, DT_REG, 0644 },
+ { LONG_NAME, 3, DT_REG, 0644 },
{ "unreadable", 2, DT_DIR, 0111 },
{ ".", 3, DT_DIR, 0111 },
{ "..", 3, DT_DIR, 0755 },
@@ -75,7 +87,7 @@ typedef struct
int level;
int idx;
struct dirent d;
- char room_for_dirent[NAME_MAX];
+ char room_for_dirent[sizeof (LONG_NAME)];
} my_DIR;
@@ -24,7 +24,9 @@
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
+#include <stdbool.h>
#include <stddef.h>
+#include <stdint.h>
/* Outcomment the following line for production quality code. */
/* #define NDEBUG 1 */
@@ -73,69 +75,8 @@
# endif /* HAVE_VMSDIR_H */
#endif
-
-/* When used in the GNU libc the symbol _DIRENT_HAVE_D_TYPE is available
- if the `d_type' member for `struct dirent' is available.
- HAVE_STRUCT_DIRENT_D_TYPE plays the same role in GNULIB. */
-#if defined _DIRENT_HAVE_D_TYPE || defined HAVE_STRUCT_DIRENT_D_TYPE
-/* True if the directory entry D must be of type T. */
-# define DIRENT_MUST_BE(d, t) ((d)->d_type == (t))
-
-/* True if the directory entry D might be a symbolic link. */
-# define DIRENT_MIGHT_BE_SYMLINK(d) \
- ((d)->d_type == DT_UNKNOWN || (d)->d_type == DT_LNK)
-
-/* True if the directory entry D might be a directory. */
-# define DIRENT_MIGHT_BE_DIR(d) \
- ((d)->d_type == DT_DIR || DIRENT_MIGHT_BE_SYMLINK (d))
-
-#else /* !HAVE_D_TYPE */
-# define DIRENT_MUST_BE(d, t) false
-# define DIRENT_MIGHT_BE_SYMLINK(d) true
-# define DIRENT_MIGHT_BE_DIR(d) true
-#endif /* HAVE_D_TYPE */
-
-/* If the system has the `struct dirent64' type we use it internally. */
-#if defined _LIBC && !defined COMPILE_GLOB64
-
-# if (defined POSIX || defined WINDOWS32) && !defined __GNU_LIBRARY__
-# define CONVERT_D_INO(d64, d32)
-# else
-# define CONVERT_D_INO(d64, d32) \
- (d64)->d_ino = (d32)->d_ino;
-# endif
-
-# ifdef _DIRENT_HAVE_D_TYPE
-# define CONVERT_D_TYPE(d64, d32) \
- (d64)->d_type = (d32)->d_type;
-# else
-# define CONVERT_D_TYPE(d64, d32)
-# endif
-
-# define CONVERT_DIRENT_DIRENT64(d64, d32) \
- strcpy ((d64)->d_name, (d32)->d_name); \
- CONVERT_D_INO (d64, d32) \
- CONVERT_D_TYPE (d64, d32)
-#endif
-
-
-#if (defined POSIX || defined WINDOWS32) && !defined __GNU_LIBRARY__
-/* Posix does not require that the d_ino field be present, and some
- systems do not provide it. */
-# define REAL_DIR_ENTRY(dp) 1
-#else
-# define REAL_DIR_ENTRY(dp) (dp->d_ino != 0)
-#endif /* POSIX */
-
#include <stdlib.h>
#include <string.h>
-
-/* NAME_MAX is usually defined in <dirent.h> or <limits.h>. */
-#include <limits.h>
-#ifndef NAME_MAX
-# define NAME_MAX (sizeof (((struct dirent *) 0)->d_name))
-#endif
-
#include <alloca.h>
#ifdef _LIBC
@@ -180,8 +121,111 @@
static const char *next_brace_sub (const char *begin, int flags) __THROWNL;
+/* A representation of a directory entry which does not depend on the
+ layout of struct dirent, or the size of ino_t. */
+struct readdir_result
+{
+ const char *name;
+# if defined _DIRENT_HAVE_D_TYPE || defined HAVE_STRUCT_DIRENT_D_TYPE
+ uint8_t type;
+# endif
+ bool skip_entry;
+};
+
+# if defined _DIRENT_HAVE_D_TYPE || defined HAVE_STRUCT_DIRENT_D_TYPE
+/* Initializer based on the d_type member of struct dirent. */
+# define D_TYPE_TO_RESULT(source) (source)->d_type,
+
+/* True if the directory entry D might be a symbolic link. */
+static bool
+readdir_result_might_be_symlink (struct readdir_result d)
+{
+ return d.type == DT_UNKNOWN || d.type == DT_LNK;
+}
+
+/* True if the directory entry D might be a directory. */
+static bool
+readdir_result_might_be_dir (struct readdir_result d)
+{
+ return d.type == DT_DIR || readdir_result_might_be_symlink (d);
+}
+# else /* defined _DIRENT_HAVE_D_TYPE || defined HAVE_STRUCT_DIRENT_D_TYPE */
+# define D_TYPE_TO_RESULT(source)
+
+/* If we do not have type information, symbolic links and directories
+ are always a possibility. */
+
+static bool
+readdir_result_might_be_symlink (struct readdir_result d)
+{
+ return true;
+}
+
+static bool
+readdir_result_might_be_dir (struct readdir_result d)
+{
+ return true;
+}
+
+# endif /* defined _DIRENT_HAVE_D_TYPE || defined HAVE_STRUCT_DIRENT_D_TYPE */
+
+# if (defined POSIX || defined WINDOWS32) && !defined __GNU_LIBRARY__
+/* Initializer for skip_entry. POSIX does not require that the d_ino
+ field be present, and some systems do not provide it. */
+# define D_INO_TO_RESULT(source) false,
+# else
+# define D_INO_TO_RESULT(source) (source)->d_ino == 0,
+# endif
+
+/* Construct an initializer for a struct readdir_result object from a
+ struct dirent *. No copy of the name is made. */
+#define READDIR_RESULT_INITIALIZER(source) \
+ { \
+ source->d_name, \
+ D_TYPE_TO_RESULT (source) \
+ D_INO_TO_RESULT (source) \
+ }
+
#endif /* !defined _LIBC || !defined GLOB_ONLY_P */
+/* Call gl_readdir on STREAM. This macro can be overridden to reduce
+ type safety if an old interface version needs to be supported. */
+#ifndef GL_READDIR
+# define GL_READDIR(pglob, stream) ((pglob)->gl_readdir (stream))
+#endif
+
+/* Extract name and type from directory entry. No copy of the name is
+ made. If SOURCE is NULL, result name is NULL. Keep in sync with
+ convert_dirent64 below. */
+static struct readdir_result
+convert_dirent (const struct dirent *source)
+{
+ if (source == NULL)
+ {
+ struct readdir_result result = { NULL };
+ return result;
+ }
+ struct readdir_result result = READDIR_RESULT_INITIALIZER (source);
+ return result;
+}
+
+#ifndef COMPILE_GLOB64
+/* Like convert_dirent, but works on struct dirent64 instead. Keep in
+ sync with convert_dirent above. */
+static struct readdir_result
+convert_dirent64 (const struct dirent64 *source)
+{
+ if (source == NULL)
+ {
+ struct readdir_result result = { NULL };
+ return result;
+ }
+ struct readdir_result result = READDIR_RESULT_INITIALIZER (source);
+ return result;
+}
+#endif
+
+
#ifndef attribute_hidden
# define attribute_hidden
#endif
@@ -1538,55 +1582,36 @@ glob_in_dir (const char *pattern, const char *directory, int flags,
while (1)
{
- const char *name;
-#if defined _LIBC && !defined COMPILE_GLOB64
- struct dirent64 *d;
- union
- {
- struct dirent64 d64;
- char room [offsetof (struct dirent64, d_name[0])
- + NAME_MAX + 1];
- }
- d64buf;
-
- if (__glibc_unlikely (flags & GLOB_ALTDIRFUNC))
- {
- struct dirent *d32 = (*pglob->gl_readdir) (stream);
- if (d32 != NULL)
- {
- CONVERT_DIRENT_DIRENT64 (&d64buf.d64, d32);
- d = &d64buf.d64;
- }
- else
- d = NULL;
- }
- else
- d = __readdir64 (stream);
+ struct readdir_result d;
+ {
+ if (__builtin_expect (flags & GLOB_ALTDIRFUNC, 0))
+ d = convert_dirent (GL_READDIR (pglob, stream));
+ else
+ {
+#ifdef COMPILE_GLOB64
+ d = convert_dirent (__readdir (stream));
#else
- struct dirent *d = (__builtin_expect (flags & GLOB_ALTDIRFUNC, 0)
- ? ((struct dirent *)
- (*pglob->gl_readdir) (stream))
- : __readdir (stream));
+ d = convert_dirent64 (__readdir64 (stream));
#endif
- if (d == NULL)
+ }
+ }
+ if (d.name == NULL)
break;
- if (! REAL_DIR_ENTRY (d))
+ if (d.skip_entry)
continue;
/* If we shall match only directories use the information
provided by the dirent call if possible. */
- if ((flags & GLOB_ONLYDIR) && !DIRENT_MIGHT_BE_DIR (d))
+ if ((flags & GLOB_ONLYDIR) && !readdir_result_might_be_dir (d))
continue;
- name = d->d_name;
-
- if (fnmatch (pattern, name, fnm_flags) == 0)
+ if (fnmatch (pattern, d.name, fnm_flags) == 0)
{
/* If the file we found is a symlink we have to
make sure the target file exists. */
- if (!DIRENT_MIGHT_BE_SYMLINK (d)
- || link_exists_p (dfd, directory, dirlen, name, pglob,
- flags))
+ if (!readdir_result_might_be_symlink (d)
+ || link_exists_p (dfd, directory, dirlen, d.name,
+ pglob, flags))
{
if (cur == names->count)
{
@@ -1606,7 +1631,7 @@ glob_in_dir (const char *pattern, const char *directory, int flags,
names = newnames;
cur = 0;
}
- names->name[cur] = strdup (d->d_name);
+ names->name[cur] = strdup (d.name);
if (names->name[cur] == NULL)
goto memory_error;
++cur;
@@ -1,3 +1,21 @@
+/* Two glob variants with 64-bit support, for dirent64 and __olddirent64.
+ Copyright (C) 1998-2016 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
+ <http://www.gnu.org/licenses/>. */
+
#include <dirent.h>
#include <glob.h>
#include <sys/stat.h>
@@ -38,11 +56,15 @@ int __old_glob64 (const char *__pattern, int __flags,
#undef dirent
#define dirent __old_dirent64
+#undef GL_READDIR
+# define GL_READDIR(pglob, stream) \
+ ((struct __old_dirent64 *) (pglob)->gl_readdir (stream))
#undef __readdir
#define __readdir(dirp) __old_readdir64 (dirp)
#undef glob
#define glob(pattern, flags, errfunc, pglob) \
__old_glob64 (pattern, flags, errfunc, pglob)
+#define convert_dirent __old_convert_dirent
#define glob_in_dir __old_glob_in_dir
#define GLOB_ATTRIBUTE attribute_compat_text_section