diff options
Diffstat (limited to 'sysdeps/generic')
| -rw-r--r-- | sysdeps/generic/check_fds.c | 32 |
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); } |