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-rw-r--r--sysdeps/generic/check_fds.c62
-rw-r--r--sysdeps/generic/libc-start.c43
2 files changed, 69 insertions, 36 deletions
diff --git a/sysdeps/generic/check_fds.c b/sysdeps/generic/check_fds.c
new file mode 100644
index 0000000..4eea168
--- /dev/null
+++ b/sysdeps/generic/check_fds.c
@@ -0,0 +1,62 @@
+/* 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);
+}
diff --git a/sysdeps/generic/libc-start.c b/sysdeps/generic/libc-start.c
index fe4966c..f5486f9 100644
--- a/sysdeps/generic/libc-start.c
+++ b/sysdeps/generic/libc-start.c
@@ -16,12 +16,8 @@
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);
@@ -32,7 +28,7 @@ extern int __libc_multiple_libcs;
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,
@@ -54,10 +50,14 @@ __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))
@@ -89,32 +89,3 @@ __libc_start_main (int (*main) (int, char **, char **), int argc,
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);
-}