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2002-05-12 Roland McGrath <roland@frob.com> 

* hurd/hurdexec.c (_hurd_exec): Reauthenticate ports/dtable used in
	file_exec to effect svuid=euid, svgid=egid if that is not a no-op.
This commit is contained in:
Roland McGrath 2002-05-13 01:27:28 +00:00
parent 8f7500ba69
commit 98e1c93a21
1 changed files with 189 additions and 38 deletions
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227
hurd/hurdexec.c
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@ -1,4 +1,5 @@
/* Copyright (C) 1991,92,93,94,95,96,97,99,2001 Free Software Foundation, Inc.
/* Copyright (C) 1991,92,93,94,95,96,97,99,2001,02
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
@ -25,6 +26,7 @@
#include <hurd.h>
#include <hurd/fd.h>
#include <hurd/signal.h>
#include <hurd/id.h>
#include <assert.h>
#include <argz.h>
@ -41,12 +43,17 @@ _hurd_exec (task_t task, file_t file,
int ints[INIT_INT_MAX];
mach_port_t ports[_hurd_nports];
struct hurd_userlink ulink_ports[_hurd_nports];
inline void free_port (unsigned int i)
{
_hurd_port_free (&_hurd_ports[i], &ulink_ports[i], ports[i]);
}
file_t *dtable;
unsigned int dtablesize, i;
struct hurd_port **dtable_cells;
struct hurd_userlink *ulink_dtable;
struct hurd_sigstate *ss;
mach_port_t *please_dealloc, *pdp;
int reauth = 0;
/* XXX needs to be hurdmalloc XXX */
if (argv == NULL)
@ -67,7 +74,7 @@ _hurd_exec (task_t task, file_t file,
if (err = __USEPORT (PROC, __proc_task2proc (port, task, &ports[i])))
{
while (--i > 0)
_hurd_port_free (&_hurd_ports[i], &ulink_ports[i], ports[i]);
free_port (i);
goto outenv;
}
}
@ -132,7 +139,7 @@ _hurd_exec (task_t task, file_t file,
them, the new program would have duplicate user references for them.
But we cannot deallocate them ourselves, because we must still have
them after a failed exec call. */
please_dealloc = __alloca ((_hurd_nports + (2 * dtablesize))
please_dealloc = __alloca ((_hurd_nports + 3 + (3 * dtablesize))
* sizeof (mach_port_t));
else
please_dealloc = NULL;
@ -190,55 +197,199 @@ _hurd_exec (task_t task, file_t file,
while (dtablesize > 0 && dtable[dtablesize - 1] == MACH_PORT_NULL)
--dtablesize;
/* See if we need to diddle the auth port of the new program.
The purpose of this is to get the effect setting the saved-set UID and
GID to the respective effective IDs after the exec, as POSIX.1 requires.
Note that we don't reauthenticate with the proc server; that would be a
no-op since it only keeps track of the effective UIDs, and if it did
keep track of the available IDs we would have the problem that we'd be
changing the IDs before the exec and have to change them back after a
failure. Arguably we could skip all the reauthentications because the
available IDs have no bearing on any filesystem. But the conservative
approach is to reauthenticate all the io ports so that no state anywhere
reflects that our whole ID set differs from what we've set it to. */
__mutex_lock (&_hurd_id.lock);
err = _hurd_check_ids ();
if (err == 0 && ((_hurd_id.aux.nuids >= 2 && _hurd_id.gen.nuids >= 1
&& _hurd_id.aux.uids[1] != _hurd_id.gen.uids[0])
|| (_hurd_id.aux.ngids >= 2 && _hurd_id.gen.ngids >= 1
&& _hurd_id.aux.gids[1] != _hurd_id.gen.gids[0])))
{
/* We have euid != svuid or egid != svgid. POSIX.1 says that exec
sets svuid = euid and svgid = egid. So we must get a new auth
port and reauthenticate everything with it. We'll pass the new
ports in file_exec instead of our own ports. */
auth_t newauth;
_hurd_id.aux.uids[1] = _hurd_id.gen.uids[0];
_hurd_id.aux.gids[1] = _hurd_id.gen.gids[0];
_hurd_id.valid = 0;
if (_hurd_id.rid_auth != MACH_PORT_NULL)
{
__mach_port_deallocate (__mach_task_self (), _hurd_id.rid_auth);
_hurd_id.rid_auth = MACH_PORT_NULL;
}
err = __auth_makeauth (ports[INIT_PORT_AUTH],
NULL, MACH_MSG_TYPE_COPY_SEND, 0,
_hurd_id.gen.uids, _hurd_id.gen.nuids,
_hurd_id.aux.uids, _hurd_id.aux.nuids,
_hurd_id.gen.gids, _hurd_id.gen.ngids,
_hurd_id.aux.gids, _hurd_id.aux.ngids,
&newauth);
if (err == 0)
{
/* Now we have to reauthenticate the ports with this new ID.
*/
inline error_t reauth_io (io_t port, io_t *newport)
{
mach_port_t ref = __mach_reply_port ();
*newport = MACH_PORT_NULL;
error_t err = __io_reauthenticate (port,
ref, MACH_MSG_TYPE_MAKE_SEND);
if (!err)
err = __auth_user_authenticate (newauth,
ref, MACH_MSG_TYPE_MAKE_SEND,
newport);
__mach_port_destroy (__mach_task_self (), ref);
return err;
}
inline void reauth_port (unsigned int idx)
{
io_t newport;
err = reauth_io (ports[idx], &newport) ?: err;
if (pdp)
*pdp++ = ports[idx]; /* XXX presumed still in _hurd_ports */
free_port (idx);
ports[idx] = newport;
}
if (pdp)
*pdp++ = ports[INIT_PORT_AUTH];
free_port (INIT_PORT_AUTH);
ports[INIT_PORT_AUTH] = newauth;
reauth_port (INIT_PORT_CRDIR);
reauth_port (INIT_PORT_CWDIR);
if (!err)
{
/* Now we'll reauthenticate each file descriptor. */
if (ulink_dtable == NULL)
{
assert (dtable == _hurd_init_dtable);
dtable = __alloca (dtablesize * sizeof (dtable[0]));
for (i = 0; i < dtablesize; ++i)
if (_hurd_init_dtable[i] != MACH_PORT_NULL)
{
if (pdp)
*pdp++ = _hurd_init_dtable[i];
err = reauth_io (_hurd_init_dtable[i], &dtable[i]);
if (err)
{
while (++i < dtablesize)
dtable[i] = MACH_PORT_NULL;
break;
}
}
else
dtable[i] = MACH_PORT_NULL;
}
else
{
if (pdp)
{
/* Ask to deallocate all the old fd ports,
since we will have new ones in DTABLE. */
memcpy (pdp, dtable, dtablesize * sizeof pdp[0]);
pdp += dtablesize;
}
for (i = 0; i < dtablesize; ++i)
if (dtable[i] != MACH_PORT_NULL)
{
io_t newport;
err = reauth_io (dtable[i], &newport);
_hurd_port_free (dtable_cells[i], &ulink_dtable[i],
dtable[i]);
dtable[i] = newport;
if (err)
{
while (++i < dtablesize)
_hurd_port_free (dtable_cells[i],
&ulink_dtable[i], dtable[i]);
break;
}
}
ulink_dtable = NULL;
dtable_cells = NULL;
}
}
}
reauth = 1;
}
__mutex_unlock (&_hurd_id.lock);
/* The information is all set up now. Try to exec the file. */
if (!err)
{
int flags;
{
int flags;
if (pdp)
{
/* Request the exec server to deallocate some ports from us if
the exec succeeds. The init ports and descriptor ports will
arrive in the new program's exec_startup message. If we
failed to deallocate them, the new program would have
duplicate user references for them. But we cannot deallocate
them ourselves, because we must still have them after a failed
exec call. */
if (pdp)
{
/* Request the exec server to deallocate some ports from us if the exec
succeeds. The init ports and descriptor ports will arrive in the
new program's exec_startup message. If we failed to deallocate
them, the new program would have duplicate user references for them.
But we cannot deallocate them ourselves, because we must still have
them after a failed exec call. */
for (i = 0; i < _hurd_nports; ++i)
*pdp++ = ports[i];
for (i = 0; i < dtablesize; ++i)
*pdp++ = dtable[i];
}
for (i = 0; i < _hurd_nports; ++i)
*pdp++ = ports[i];
for (i = 0; i < dtablesize; ++i)
*pdp++ = dtable[i];
}
flags = 0;
flags = 0;
#ifdef EXEC_SIGTRAP
/* PTRACE_TRACEME sets all bits in _hurdsig_traced, which is propagated
through exec by INIT_TRACEMASK, so this checks if PTRACE_TRACEME has
been called in this process in any of its current or prior lives. */
if (__sigismember (&_hurdsig_traced, SIGKILL))
flags |= EXEC_SIGTRAP;
/* PTRACE_TRACEME sets all bits in _hurdsig_traced, which is
propagated through exec by INIT_TRACEMASK, so this checks if
PTRACE_TRACEME has been called in this process in any of its
current or prior lives. */
if (__sigismember (&_hurdsig_traced, SIGKILL))
flags |= EXEC_SIGTRAP;
#endif
err = __file_exec (file, task, flags,
args, argslen, env, envlen,
dtable, MACH_MSG_TYPE_COPY_SEND, dtablesize,
ports, MACH_MSG_TYPE_COPY_SEND, _hurd_nports,
ints, INIT_INT_MAX,
please_dealloc, pdp - please_dealloc,
&_hurd_msgport, task == __mach_task_self () ? 1 : 0);
}
err = __file_exec (file, task, flags,
args, argslen, env, envlen,
dtable, MACH_MSG_TYPE_COPY_SEND, dtablesize,
ports, MACH_MSG_TYPE_COPY_SEND, _hurd_nports,
ints, INIT_INT_MAX,
please_dealloc, pdp - please_dealloc,
&_hurd_msgport, task == __mach_task_self () ? 1 : 0);
}
/* Release references to the standard ports. */
for (i = 0; i < _hurd_nports; ++i)
if (i == INIT_PORT_PROC && task != __mach_task_self ())
if ((i == INIT_PORT_PROC && task != __mach_task_self ())
|| (reauth && (i == INIT_PORT_AUTH
|| i == INIT_PORT_CRDIR || i == INIT_PORT_CWDIR)))
__mach_port_deallocate (__mach_task_self (), ports[i]);
else
_hurd_port_free (&_hurd_ports[i], &ulink_ports[i], ports[i]);
free_port (i);
/* Release references to the file descriptor ports. */
if (ulink_dtable != NULL)
/* Release references to the file descriptor ports. */
{
for (i = 0; i < dtablesize; ++i)
if (dtable[i] != MACH_PORT_NULL)
_hurd_port_free (dtable_cells[i], &ulink_dtable[i], dtable[i]);
}
else if (dtable && dtable != _hurd_init_dtable)
for (i = 0; i < dtablesize; ++i)
if (dtable[i] != MACH_PORT_NULL)
_hurd_port_free (dtable_cells[i], &ulink_dtable[i], dtable[i]);
__mach_port_deallocate (__mach_task_self (), dtable[i]);
/* Release lock on the file descriptor table. */
__mutex_unlock (&_hurd_dtable_lock);