aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorUlrich Drepper <drepper@redhat.com>2005-11-09 19:26:07 +0000
committerUlrich Drepper <drepper@redhat.com>2005-11-09 19:26:07 +0000
commit1fdf81587d533a8533504366ce47d5c9a7033897 (patch)
tree167637996fb9a3f56f073de19cff227f8f01443b
parent7fe72b72eaa0bec531729660a87ca57ae4d9555e (diff)
downloadglibc-1fdf81587d533a8533504366ce47d5c9a7033897.tar
glibc-1fdf81587d533a8533504366ce47d5c9a7033897.tar.gz
glibc-1fdf81587d533a8533504366ce47d5c9a7033897.tar.bz2
glibc-1fdf81587d533a8533504366ce47d5c9a7033897.zip
(check_one_fd): For writable descriptors, use /dev/full. (__libc_check_standard_fds): Revert modes so that common operations on the descriptors fail.
-rw-r--r--sysdeps/generic/check_fds.c32
1 files changed, 22 insertions, 10 deletions
diff --git a/sysdeps/generic/check_fds.c b/sysdeps/generic/check_fds.c
index 5ae3feee3e..10ba3da395 100644
--- a/sysdeps/generic/check_fds.c
+++ b/sysdeps/generic/check_fds.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2000, 2002, 2003 Free Software Foundation, Inc.
+/* Copyright (C) 2000, 2002, 2003, 2005 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
@@ -44,12 +44,26 @@ check_one_fd (int fd, int mode)
if (__builtin_expect (__libc_fcntl (fd, F_GETFD), 0) == -1
&& errno == EBADF)
{
- struct stat64 st;
+ const char *name;
+ dev_t dev;
+
+ /* For writable descriptors we use /dev/full. */
+ if ((mode & O_ACCMODE) == O_WRONLY)
+ {
+ name = _PATH_DEV "full";
+ dev = makedev (DEV_FULL_MAJOR, DEV_FULL_MINOR);
+ }
+ else
+ {
+ name = _PATH_DEVNULL;
+ dev = makedev (DEV_NULL_MAJOR, DEV_NULL_MINOR);
+ }
/* 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 = open_not_cancel (_PATH_DEVNULL, mode, 0);
+ int nullfd = open_not_cancel (name, mode, 0);
+
/* We are very paranoid here. With all means we try to ensure
that we are actually opening the /dev/null device and nothing
else.
@@ -57,13 +71,11 @@ check_one_fd (int fd, int mode)
Note that the following code assumes that STDIN_FILENO,
STDOUT_FILENO, STDERR_FILENO are the three lowest file
decsriptor numbers, in this order. */
+ struct stat64 st;
if (__builtin_expect (nullfd != fd, 0)
|| __builtin_expect (__fxstat64 (_STAT_VER, fd, &st), 0) != 0
|| __builtin_expect (S_ISCHR (st.st_mode), 1) == 0
-#if defined DEV_NULL_MAJOR && defined DEV_NULL_MINOR
- || st.st_rdev != makedev (DEV_NULL_MAJOR, DEV_NULL_MINOR)
-#endif
- )
+ || st.st_rdev != dev)
/* We cannot even give an error message here since it would
run into the same problems. */
while (1)
@@ -84,7 +96,7 @@ __libc_check_standard_fds (void)
# define O_NOFOLLOW 0
#endif
/* Check all three standard file descriptors. */
- check_one_fd (STDIN_FILENO, O_RDONLY | O_NOFOLLOW);
- check_one_fd (STDOUT_FILENO, O_RDWR | O_NOFOLLOW);
- check_one_fd (STDERR_FILENO, O_RDWR | O_NOFOLLOW);
+ check_one_fd (STDIN_FILENO, O_WRONLY | O_NOFOLLOW);
+ check_one_fd (STDOUT_FILENO, O_RDONLY | O_NOFOLLOW);
+ check_one_fd (STDERR_FILENO, O_RDONLY | O_NOFOLLOW);
}