* csu/Makefile (routines): Add check_fds.
* elf/rtld.c (dl_main): Call __libc_check_standard_fds for SUID
binaries. Add various __builtin_expect.
* sysdeps/generic/libc-start.c: Move check_fds and helper functions...
* sysdeps/generic/check_fds.c: ...here. New file.
* malloc/malloc.c (ptmalloc_init): Only enable debugging for SUID
binaries if file /etc/suid-debug is available.
2000-05-24 Ulrich Drepper <drepper@redhat.com>
+ * csu/Makefile (routines): Add check_fds.
+ * elf/rtld.c (dl_main): Call __libc_check_standard_fds for SUID
+ binaries. Add various __builtin_expect.
+ * sysdeps/generic/libc-start.c: Move check_fds and helper functions...
+ * sysdeps/generic/check_fds.c: ...here. New file.
+
+ * malloc/malloc.c (ptmalloc_init): Only enable debugging for SUID
+ binaries if file /etc/suid-debug is available.
+
* locale/programs/ld-collate.c (struct element_t): Add mbseqorder
and wcseqorder members.
(struct locale_collate_t): Likewise.
subdir := csu
-routines = init-first libc-start $(libc-init) sysdep version
+routines = init-first libc-start $(libc-init) sysdep version check_fds
csu-dummies = $(filter-out $(start-installed-name),crt1.o Mcrt1.o)
extra-objs = start.o gmon-start.o \
$(start-installed-name) g$(start-installed-name) \
size_t *filesize_ptr,
int mmap_prot);
+/* Protec SUID program against misuse of file descriptors. */
+extern void __libc_check_standard_fds (void);
+
/* Helper function to handle errors while resolving symbols. */
static void print_unresolved (int errcode, const char *objname,
const char *errsting);
hp_timing_t diff;
#endif
+ /* First thing, if this is a SUID program we make sure that FDs 0,
+ 1, and 2 are allocated. If necessary we are doing it ourself.
+ If it is not possible we stop the program. */
+ if (__builtin_expect (__libc_enable_secure, 0))
+ __libc_check_standard_fds ();
+
/* Process the environment variable which control the behaviour. */
process_envvars (&mode, &_dl_lazy);
preloads = NULL;
npreloads = 0;
- if (preloadlist)
+ if (__builtin_expect (preloadlist != NULL, 0))
{
/* The LD_PRELOAD environment variable gives list of libraries
separated by white space or colons that are loaded before the
while ((p = strsep (&list, " :")) != NULL)
if (p[0] != '\0'
- && (! __libc_enable_secure || strchr (p, '/') == NULL))
+ && (__builtin_expect (! __libc_enable_secure, 1)
+ || strchr (p, '/') == NULL))
{
struct link_map *new_map = _dl_map_object (_dl_loaded, p, 1,
lt_library, 0);
/* Read the contents of the file. */
file = _dl_sysdep_read_whole_file ("/etc/ld.so.preload", &file_size,
PROT_READ | PROT_WRITE);
- if (file)
+ if (__builtin_expect (file != NULL, 0))
{
/* Parse the file. It contains names of libraries to be loaded,
separated by white spaces or `:'. It may also contain
__munmap (file, file_size);
}
- if (npreloads != 0)
+ if (__builtin_expect (npreloads, 0) != 0)
{
/* Set up PRELOADS with a vector of the preloaded libraries. */
struct link_map *l;
this has to go here because the calls it makes should use the
rtld versions of the functions (particularly calloc()), but it
needs to have _dl_profile_map set up by the relocator. */
- if (_dl_profile_map != NULL)
+ if (__builtin_expect (_dl_profile_map != NULL, 0))
/* We must prepare the profiling. */
_dl_start_profile (_dl_profile_map, _dl_profile_output);
__malloc_hook = save_malloc_hook;
__free_hook = save_free_hook;
#endif
- if(s) {
+ if(s && (! __libc_enable_secure || access ("/etc/suid-debug", F_OK) == 0)) {
if(s[0]) mALLOPt(M_CHECK_ACTION, (int)(s[0] - '0'));
__malloc_check_init();
}
--- /dev/null
+/* Copyright (C) 2000 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 Library General Public License as
+ published by the Free Software Foundation; either version 2 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
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <paths.h>
+#include <unistd.h>
+
+/* Try to get a machine dependent instruction which will make the
+ program crash. This is used in case everything else fails. */
+#include <abort-instr.h>
+#ifndef ABORT_INSTRUCTION
+/* No such instruction is available. */
+# define ABORT_INSTRUCTION
+#endif
+
+
+/* Should other OSes (e.g., Hurd) have different versions which can
+ be written in a better way? */
+static void
+check_one_fd (int fd, int mode)
+{
+ if (__builtin_expect (__libc_fcntl (fd, F_GETFD), 0) == -1
+ && errno == EBADF)
+ {
+ /* Something is wrong with this descriptor, it's probably not
+ opened. Open /dev/null so that the SUID program we are
+ about to start does not accidently use this descriptor. */
+ int nullfd = __libc_open (_PATH_DEVNULL, mode);
+ if (__builtin_expect (nullfd, 0) == -1)
+ /* We cannot even give an error message here since it would
+ run into the same problems. */
+ while (1)
+ /* Try for ever and ever. */
+ ABORT_INSTRUCTION;
+ }
+}
+
+
+void
+__libc_check_standard_fds (void)
+{
+/* Check all three standard file descriptors. */
+ check_one_fd (STDIN_FILENO, O_RDONLY);
+ check_one_fd (STDOUT_FILENO, O_RDWR);
+ check_one_fd (STDERR_FILENO, O_RDWR);
+}
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
-#include <errno.h>
-#include <fcntl.h>
-#include <paths.h>
#include <stdlib.h>
#include <unistd.h>
-#include <sys/ioctl.h>
#include <ldsodefs.h>
extern void __libc_init_first (int argc, char **argv, char **envp);
extern void *__libc_stack_end;
/* Prototype for local function. */
-static void check_standard_fds (void);
+extern void __libc_check_standard_fds (void);
int
__libc_start_main (int (*main) (int, char **, char **), int argc,
/* Set the global _environ variable correctly. */
__environ = &argv[argc + 1];
+#ifndef SHARED
/* Some security at this point. Prevent starting a SUID binary where
- the standard file descriptors are not opened. */
+ the standard file descriptors are not opened. We have to do this
+ only for statically linked applications since otherwise the dynamic
+ loader did the work already. */
if (__builtin_expect (__libc_enable_secure, 0))
- check_standard_fds ();
+ __libc_check_standard_fds ();
+#endif
/* Register the destructor of the dynamic linker if there is any. */
if (__builtin_expect (rtld_fini != NULL, 1))
exit ((*main) (argc, argv, __environ));
}
-
-
-/* Should other OSes (e.g., Hurd) have different versions which can
- be written in a better way? */
-static void
-check_one_fd (int fd, int mode)
-{
- if (__libc_fcntl (fd, F_GETFD) == -1 && errno == EBADF)
- {
- /* Something is wrong with this descriptor, it's probably not
- opened. Open /dev/null so that the SUID program we are
- about to start does not accidently use this descriptor. */
- int nullfd = __libc_open (_PATH_DEVNULL, mode);
- if (nullfd == -1)
- /* We cannot even give an error message here since it would
- run into the same problems. */
- abort ();
- }
-}
-
-
-static void
-check_standard_fds (void)
-{
-/* Check all three standard file descriptors. */
- check_one_fd (STDIN_FILENO, O_RDONLY);
- check_one_fd (STDOUT_FILENO, O_RDWR);
- check_one_fd (STDERR_FILENO, O_RDWR);
-}
projects / thirdparty / glibc.git / commitdiff
