| /* Test for access to file, relative to open directory. Hurd version. |
| Copyright (C) 2006-2018 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 <errno.h> |
| #include <fcntl.h> |
| #include <stddef.h> |
| #include <unistd.h> |
| #include <sys/types.h> |
| #include <hurd.h> |
| #include <hurd/fd.h> |
| #include <hurd/port.h> |
| #include <hurd/id.h> |
| #include <hurd/lookup.h> |
| |
| static int |
| hurd_fail_seterrno (error_t err) |
| { |
| return __hurd_fail (err); |
| } |
| |
| static int |
| hurd_fail_noerrno (error_t err) |
| { |
| return -1; |
| } |
| |
| static int |
| __faccessat_common (int fd, const char *file, int type, int at_flags, |
| int (*errfunc) (error_t)) |
| { |
| error_t err; |
| file_t rcrdir, rcwdir, io; |
| int flags, allowed; |
| |
| if ((at_flags & AT_EACCESS) == AT_EACCESS) |
| { |
| /* Use effective permissions. */ |
| io = __file_name_lookup_at (fd, at_flags &~ AT_EACCESS, file, 0, 0); |
| if (io == MACH_PORT_NULL) |
| return -1; |
| } |
| else |
| { |
| /* We have to use real permissions instead of the |
| usual effective permissions. */ |
| |
| int hurd_flags = 0; |
| __hurd_at_flags (&at_flags, &hurd_flags); |
| |
| error_t reauthenticate_cwdir_at (file_t *result) |
| { |
| /* Get a port to the FD directory, authenticated with the real IDs. */ |
| error_t err; |
| mach_port_t ref; |
| ref = __mach_reply_port (); |
| err = HURD_DPORT_USE |
| (fd, |
| ({ |
| err = __io_reauthenticate (port, ref, MACH_MSG_TYPE_MAKE_SEND); |
| if (!err) |
| err = __auth_user_authenticate (_hurd_id.rid_auth, |
| ref, MACH_MSG_TYPE_MAKE_SEND, |
| result); |
| err; |
| })); |
| __mach_port_destroy (__mach_task_self (), ref); |
| return err; |
| } |
| |
| error_t reauthenticate (int which, file_t *result) |
| { |
| /* Get a port to our root directory, authenticated with the real IDs. */ |
| error_t err; |
| mach_port_t ref; |
| ref = __mach_reply_port (); |
| err = HURD_PORT_USE |
| (&_hurd_ports[which], |
| ({ |
| err = __io_reauthenticate (port, ref, MACH_MSG_TYPE_MAKE_SEND); |
| if (!err) |
| err = __auth_user_authenticate (_hurd_id.rid_auth, |
| ref, MACH_MSG_TYPE_MAKE_SEND, |
| result); |
| err; |
| })); |
| __mach_port_destroy (__mach_task_self (), ref); |
| return err; |
| } |
| |
| error_t init_port (int which, error_t (*operate) (mach_port_t)) |
| { |
| switch (which) |
| { |
| case INIT_PORT_AUTH: |
| return (*operate) (_hurd_id.rid_auth); |
| case INIT_PORT_CRDIR: |
| return (reauthenticate (INIT_PORT_CRDIR, &rcrdir) ?: |
| (*operate) (rcrdir)); |
| case INIT_PORT_CWDIR: |
| if (fd == AT_FDCWD || file[0] == '/') |
| return (reauthenticate (INIT_PORT_CWDIR, &rcwdir) ?: |
| (*operate) (rcwdir)); |
| else |
| return (reauthenticate_cwdir_at (&rcwdir) ?: |
| (*operate) (rcwdir)); |
| default: |
| return _hurd_ports_use (which, operate); |
| } |
| } |
| |
| rcrdir = rcwdir = MACH_PORT_NULL; |
| |
| HURD_CRITICAL_BEGIN; |
| |
| __mutex_lock (&_hurd_id.lock); |
| /* Get _hurd_id up to date. */ |
| if (err = _hurd_check_ids ()) |
| goto lose; |
| |
| if (_hurd_id.rid_auth == MACH_PORT_NULL) |
| { |
| /* Set up _hurd_id.rid_auth. This is a special auth server port |
| which uses the real uid and gid (the first aux uid and gid) as |
| the only effective uid and gid. */ |
| |
| if (_hurd_id.aux.nuids < 1 || _hurd_id.aux.ngids < 1) |
| { |
| /* We do not have a real UID and GID. Lose, lose, lose! */ |
| err = EGRATUITOUS; |
| goto lose; |
| } |
| |
| /* Create a new auth port using our real UID and GID (the first |
| auxiliary UID and GID) as the only effective IDs. */ |
| if (err = __USEPORT (AUTH, |
| __auth_makeauth (port, |
| NULL, MACH_MSG_TYPE_COPY_SEND, 0, |
| _hurd_id.aux.uids, 1, |
| _hurd_id.aux.uids, |
| _hurd_id.aux.nuids, |
| _hurd_id.aux.gids, 1, |
| _hurd_id.aux.gids, |
| _hurd_id.aux.ngids, |
| &_hurd_id.rid_auth))) |
| goto lose; |
| } |
| |
| if (!err) |
| /* Look up the file name using the modified init ports. */ |
| err = __hurd_file_name_lookup (&init_port, &__getdport, 0, |
| file, hurd_flags, 0, &io); |
| |
| /* We are done with _hurd_id.rid_auth now. */ |
| lose: |
| __mutex_unlock (&_hurd_id.lock); |
| |
| HURD_CRITICAL_END; |
| |
| if (rcrdir != MACH_PORT_NULL) |
| __mach_port_deallocate (__mach_task_self (), rcrdir); |
| if (rcwdir != MACH_PORT_NULL) |
| __mach_port_deallocate (__mach_task_self (), rcwdir); |
| if (err) |
| return errfunc (err); |
| } |
| |
| /* Find out what types of access we are allowed to this file. */ |
| err = __file_check_access (io, &allowed); |
| __mach_port_deallocate (__mach_task_self (), io); |
| if (err) |
| return errfunc (err); |
| |
| flags = 0; |
| if (type & R_OK) |
| flags |= O_READ; |
| if (type & W_OK) |
| flags |= O_WRITE; |
| if (type & X_OK) |
| flags |= O_EXEC; |
| |
| if (flags & ~allowed) |
| /* We are not allowed all the requested types of access. */ |
| return errfunc (EACCES); |
| |
| return 0; |
| } |
| |
| int |
| __faccessat_noerrno (int fd, const char *file, int type, int at_flags) |
| { |
| return __faccessat_common (fd, file, type, at_flags, hurd_fail_noerrno); |
| } |
| |
| int |
| __faccessat (int fd, const char *file, int type, int at_flags) |
| { |
| return __faccessat_common (fd, file, type, at_flags, hurd_fail_seterrno); |
| } |
| weak_alias (__faccessat, faccessat) |